Energy-Water Nexus
Many Uncertainties Remain about National and Regional Effects of Increased Biofuel Production on Water Resources Gao ID: GAO-10-116 November 30, 2009In response to concerns about the nation's energy dependence on imported oil, climate change, and other issues, the federal government has encouraged the use of biofuels. Water plays a crucial role in all stages of biofuel production--from cultivation of feedstock through its conversion into biofuel. As demand for water from various sectors increases and places additional stress on already constrained supplies, the effects of expanded biofuel production may need to be considered. To understand these potential effects, GAO was asked to examine (1) the known water resource effects of biofuel production in the United States; (2) agricultural conservation practices and technological innovations that could address these effects and any barriers to their adoption; and (3) key research needs regarding the effects of water resources on biofuel production. To address these issues, GAO reviewed scientific studies, interviewed experts and federal and state officials, and selected five states to study their programs and plans related to biofuel production. GAO is not making any recommendations in this report. A draft of this report was provided to the Departments of Agriculture (USDA), Energy (DOE), and the Interior (DOI); and the Environmental Protection Agency (EPA). USDA, DOE, and DOI concurred with the report and, in addition to EPA, provided technical comments, which were incorporated as appropriate.
The extent to which increased biofuels production will affect the nation's water resources depends on the type of feedstock selected and how and where it is grown. For example, to the extent that this increase is met from the cultivation of conventional feedstocks, such as corn, it could have greater water resource impacts than if the increase is met by next generation feedstocks, such as perennial grasses and woody biomass, according to experts and officials. This is because corn is a relatively resource-intensive crop, and in certain parts of the country requires considerable irrigated water as well as fertilizer and pesticide application. However, experts and officials noted that next generation feedstocks have not yet been grown on a commercial scale and therefore their actual effects on water resources are not fully known at this time. Water is also used in the process of converting feedstocks to biofuels, and while the efficiency of biorefineries producing corn ethanol has increased over time, the amount of water required for converting next generation feedstocks into biofuels is still not well known. Finally, experts generally agree that it will be important to take into account the regional variability of water resources when choosing which feedstocks to grow and how and where to expand their production in the United States. The use of certain agricultural practices, alternative water sources, and technological innovations can mitigate the effects of biofuels production on water resources, but there are some barriers to their widespread adoption. According to experts and officials, agricultural conservation practices can reduce water use and nutrient runoff, but they are often costly to implement. Similarly, alternative water sources, such as brackish water, may be viable for some aspects of the biofuel conversion process and can help reduce biorefineries' reliance on freshwater. However, the high cost of retrofitting plants to use these water sources may be a barrier, according to experts and officials. Finally, innovations--such as dry cooling systems and thermochemical processes--have the potential to reduce the amount of water used by biorefineries, but many of these innovations are currently not economically feasible or remain untested at the commercial scale. Many of the experts GAO spoke with identified several areas where additional research is needed. These needs fall into two broad areas: (1) feedstock cultivation and biofuel conversion and (2) data on water resources. For example, some experts noted the need for further research into improved crop varieties, which could help reduce water and fertilizer needs. In addition, several experts identified research that would aid in developing next generation feedstocks. For example, several experts said research is needed on how to increase cultivation of algae for biofuel to a commercial scale and how to control for potential water quality problems. In addition, several experts said research is needed on how to optimize conversion technologies to help ensure water efficiency. Finally, some experts said that better data on water resources in local aquifers and surface water bodies would aid in decisions about where to cultivate feedstocks and locate biorefineries.
GAO-10-116, Energy-Water Nexus: Many Uncertainties Remain about National and Regional Effects of Increased Biofuel Production on Water Resources
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Report to the Chairman, Committee on Science and Technology, House of
Representatives:
United States Government Accountability Office:
GAO:
November 2009:
Energy-Water Nexus:
Many Uncertainties Remain about National and Regional Effects of
Increased Biofuel Production on Water Resources:
GAO-10-116:
GAO Highlights:
Highlights of GAO-10-116, a report to Chairman, Committee on Science
and Technology, House of Representatives.
Why GAO Did This Study:
In response to concerns about the nation‘s energy dependence on
imported oil, climate change, and other issues, the federal government
has encouraged the use of biofuels. Water plays a crucial role in all
stages of biofuel production”from cultivation of feedstock through its
conversion into biofuel. As demand for water from various sectors
increases and places additional stress on already constrained supplies,
the effects of expanded biofuel production may need to be considered.
To understand these potential effects, GAO was asked to examine (1) the
known water resource effects of biofuel production in the United
States; (2) agricultural conservation practices and technological
innovations that could address these effects and any barriers to their
adoption; and (3) key research needs regarding the effects of water
resources on biofuel production. To address these issues, GAO reviewed
scientific studies, interviewed experts and federal and state
officials, and selected five states to study their programs and plans
related to biofuel production.
GAO is not making any recommendations in this report. A draft of this
report was provided to the Departments of Agriculture (USDA), Energy
(DOE), and the Interior (DOI); and the Environmental Protection Agency
(EPA). USDA, DOE, and DOI concurred with the report and, in addition to
EPA, provided technical comments, which were incorporated as
appropriate.
What GAO Found:
The extent to which increased biofuels production will affect the
nation‘s water resources depends on the type of feedstock selected and
how and where it is grown. For example, to the extent that this
increase is met from the cultivation of conventional feedstocks, such
as corn, it could have greater water resource impacts than if the
increase is met by next generation feedstocks, such as perennial
grasses and woody biomass, according to experts and officials. This is
because corn is a relatively resource-intensive crop, and in certain
parts of the country requires considerable irrigated water as well as
fertilizer and pesticide application. However, experts and officials
noted that next generation feedstocks have not yet been grown on a
commercial scale and therefore their actual effects on water resources
are not fully known at this time. Water is also used in the process of
converting feedstocks to biofuels, and while the efficiency of
biorefineries producing corn ethanol has increased over time, the
amount of water required for converting next generation feedstocks into
biofuels is still not well known. Finally, experts generally agree that
it will be important to take into account the regional variability of
water resources when choosing which feedstocks to grow and how and
where to expand their production in the United States.
The use of certain agricultural practices, alternative water sources,
and technological innovations can mitigate the effects of biofuels
production on water resources, but there are some barriers to their
widespread adoption. According to experts and officials, agricultural
conservation practices can reduce water use and nutrient runoff, but
they are often costly to implement. Similarly, alternative water
sources, such as brackish water, may be viable for some aspects of the
biofuel conversion process and can help reduce biorefineries‘ reliance
on freshwater. However, the high cost of retrofitting plants to use
these water sources may be a barrier, according to experts and
officials. Finally, innovations”such as dry cooling systems and
thermochemical processes”have the potential to reduce the amount of
water used by biorefineries, but many of these innovations are
currently not economically feasible or remain untested at the
commercial scale.
Many of the experts GAO spoke with identified several areas where
additional research is needed. These needs fall into two broad areas:
(1) feedstock cultivation and biofuel conversion and (2) data on water
resources. For example, some experts noted the need for further
research into improved crop varieties, which could help reduce water
and fertilizer needs. In addition, several experts identified research
that would aid in developing next generation feedstocks. For example,
several experts said research is needed on how to increase cultivation
of algae for biofuel to a commercial scale and how to control for
potential water quality problems. In addition, several experts said
research is needed on how to optimize conversion technologies to help
ensure water efficiency. Finally, some experts said that better data on
water resources in local aquifers and surface water bodies would aid in
decisions about where to cultivate feedstocks and locate biorefineries.
View GAO-10-116 or key components. For more information, contact Anu
Mittal or Mark Gaffigan at (202) 512-3841 or mittala@gao.gov or
gaffiganm@gao.gov.
[End of section]
Contents:
Letter:
Background:
Each Stage of Biofuel Production Affects Water Resources, but the
Extent Depends on the Feedstock and Region:
Agricultural Practices, Technological Innovations, and Alternative
Water Sources Can Mitigate Some Water Resource Effects of Biofuels
Production, but There Are Barriers to Adoption:
Experts Identified a Variety of Key Research and Data Needs Related to
Increased Biofuels Production and Local and Regional Water Resources:
Agency Comments and Our Evaluation:
Appendix I: Objectives, Scope, and Methodology:
Appendix II: Examples of Agricultural Practices Available to Reduce the
Water Quality and Water Supply Effects of Feedstock Cultivation for
Biofuels:
Appendix III: Comments from the U.S. Department of Agriculture:
Appendix IV: Comments from the Department of Energy:
Appendix V: Comments from the Department of the Interior:
Appendix VI: GAO Contacts and Staff Acknowledgments:
Table:
Table 1: Average Water Consumed in Corn Ethanol Production in Primary
Producing Regions in the United States, in Gallons of Water/Gallon of
Ethanol Produced:
Figures:
Figure 1: Biofuels Life Cycle:
Figure 2: Agricultural Water Cycle:
Figure 3: Diagram of Conversion Process for a Typical Corn-Based
Ethanol Biorefinery:
Figure 4: Existing and Planned Ethanol Facilities (as of 2007) and
Their Estimated Total Water Use Mapped with the Principal Bedrock
Aquifers, including the Ogallala, or High Plains, Aquifer, of the
United States and Total Water Use in 2000:
Figure 5: Example of a Riparian Buffer Adjacent to Cropland:
Figure 6: Example of Conservation Tillage:
Figure 7: Example of Low-Energy Precision-Application Irrigation:
Abbreviations:
CRP: Conservation Reserve Program:
NPDES: National Pollutant Discharge Elimination System:
DOE: Department of Energy:
EIA: Energy Information Administration:
EISA: Energy Independence and Security Act of 2007:
EPA: Environmental Protection Agency:
RFS: Renewable Fuel Standard:
USDA: U.S. Department of Agriculture:
USGS: U.S. Geological Survey:
UST: underground storage tank:
[End of section]
United States Government Accountability Office:
Washington, DC 20548:
November 30, 2009:
The Honorable Bart Gordon:
Chairman:
Committee on Science and Technology:
House of Representatives:
Dear Mr. Chairman:
In recent years, the federal government has increasingly encouraged the
use of biofuels and other alternatives to petroleum in response to
concerns over U.S. dependence on imported oil, climate change, and
other issues. The United States is the largest user of petroleum in the
world, consuming 19.4 million barrels per day in 2008, over half of
which is imported. Biofuels, such as ethanol and biodiesel, can be
produced domestically and are derived from renewable sources, such as
corn, sugar cane, and soybeans. The Energy Independence and Security
Act of 2007 (EISA) expanded the Renewable Fuel Standard (RFS) by
requiring that U.S. transportation fuel contain 9 billion gallons of
renewable fuels in 2008 and increasing this amount annually to 36
billion gallons in 2022.[Footnote 1] Currently, the vast majority of
domestic biofuel production is ethanol derived from corn starch, which
EISA defines as a "conventional" feedstock. However, in 2022, the RFS's
36-billion-gallon total requires that at least 16 billion gallons be
derived from "cellulosic" materials, such as stalks, stems, branches,
and leaves. These cellulosic materials, along with newer feedstocks,
such as algae, are often referred to as "next generation" feedstocks,
and the fuels produced from them are often referred to as "advanced"
biofuels.[Footnote 2]
Although freshwater flows abundantly in many of the nation's lakes,
rivers, and streams, water is a dwindling resource in many parts of the
country and is not always available when and where it is needed or in
the amount desired because of competing demands on water supplies,
climatic changes contributing to drought conditions in parts of the
country, and population growth. Foremost among these competing demands
is irrigation, which accounts for 40 percent of the nation's freshwater
withdrawals.[Footnote 3] Water is crucial to many stages of the biofuel
life cycle and is needed for the growth of the feedstock as well as for
fermentation, distillation, and cooling during the process of
converting the feedstock into biofuel. As biofuel production increases,
questions have emerged about the effects that increased production
could have on the nation's water resources.
To understand the potential effects of increased biofuel production on
water resources, you asked us to describe (1) the known water resource
effects of increased biofuel production in the United States; (2) the
agricultural conservation practices and technological innovations that
exist or are being developed to address these effects, and any barriers
that may prevent the adoption of these practices and technologies; and
(3) key research needs regarding the effects of biofuel production on
water resources.
To address all of these objectives, we conducted a systematic analysis
of relevant articles from scientific journals and key federal and state
government publications. In addition, in consultation with the National
Academy of Sciences, we identified and interviewed recognized experts
who have published peer-reviewed research analyzing the water supply
requirements of one or more biofuel feedstocks and the implications of
increased biofuel production on water resources. These experts included
research scientists in such fields as environmental science, agronomy,
soil science, hydrogeology, ecology, and engineering. Furthermore, we
studied five states in greater depth--Georgia, Iowa, Minnesota,
Nebraska, and Texas--to gain an understanding of the programs and plans
they have or are developing to address increased biofuel production. We
selected these states based on several criteria, including ethanol and
biodiesel production, feedstock cultivation type, reliance on
irrigation, geographic diversity, and varying approaches to water
resource management and law. For each of the states, we analyzed
documentation from and conducted interviews with a wide range of
stakeholders to gain the views of diverse organizations covering all
stages of biofuel production. These groups included relevant state
agencies, including those responsible for oversight of agriculture,
environmental quality, and water and soil resources; federal agency
officials with responsibility for a particular state or region, such as
officials from the U.S. Geological Survey (USGS), the U.S. Department
of Agriculture's (USDA) Natural Resources Conservation Service, and the
Environmental Protection Agency (EPA); university researchers; industry
representatives; and relevant nongovernmental organizations, such as
environmental groups, state-level corn growers' associations, and
ethanol producer associations.
We also interviewed senior officials, scientists, economists,
researchers, and other federal officials from USDA, the Departments of
Defense and Energy (DOE), EPA, the National Aeronautics and Space
Administration, the Department of Commerce's National Oceanic and
Atmospheric Administration, the National Science Foundation, and USGS
about effects on water supply and water quality during biofuel
production. We also interviewed representatives of nongovernmental
organizations, such as the Renewable Fuels Association, the
Biotechnology Industry Organization, the Pacific Institute, and the
Fertilizer Institute. A more detailed description of our scope and
methodology is presented in appendix I. We conducted our work from
January 2009 to November 2009 in accordance with all sections of GAO's
Quality Assurance Framework that are relevant to our objectives. The
framework requires that we plan and perform the engagement to obtain
sufficient and appropriate evidence to meet our stated objectives and
to discuss any limitations in our work. We believe that the information
and data obtained, and the analysis conducted, provide a reasonable
basis for any findings and conclusions in this product.
Background:
Biofuels, such as ethanol and biodiesel, are an alternative to
petroleum-based transportation fuels and are produced in the United
States from a variety of renewable sources such as corn, sugar cane,
and soybeans. Ethanol, the most common U.S. biofuel, is mainly used as
a gasoline additive in blends of about 10 percent ethanol and 90
percent gasoline, known as E10, which is available in most states. A
relatively small volume is also blended at a higher level called E85--
a blend of 85 percent ethanol and 15 percent gasoline--which can only
be used in specially designed vehicles, known as flexible fuel
vehicles. Biodiesel is a renewable alternative fuel produced from a
range of plant oils, animal fats, and recycled cooking oils. Pure
biodiesel or biodiesel blended with petroleum diesel--generally in a
blend of 20 percent biodiesel and 80 percent diesel--can be used to
fuel diesel vehicles.
The federal government has promoted biofuels as an alternative to
petroleum-based fuels since the 1970s, and production of ethanol from
corn starch reached 9 billion gallons in 2008. The Energy Policy Act of
2005 originally created an RFS that generally required U.S.
transportation fuel to contain 4 billion gallons of renewable fuels in
2006 and 7.5 billion gallons in 2012.[Footnote 4] EISA expanded the RFS
by requiring that U.S. transportation fuel contain 9 billion gallons of
renewable fuels in 2008 and increasing this amount annually to 36
billion gallons in 2022.[Footnote 5] Moreover, the 36-billion-gallon
total must include at least 21 billion gallons of advanced biofuels,
defined as renewable fuels other than ethanol derived from corn starch
that meet certain criteria; only 15 billion of the 36 billion gallons
of renewable fuels can come from conventional biofuels. In addition, at
least 16 billion gallons of the 21-billion-gallon advanced biofuels
requirement must be made from cellulosic feedstocks, such as perennial
grasses, crop residue, and woody biomass. Unlike corn starch, most of
the energy in plant and tree biomass is locked away in complex
cellulose and hemicellulose molecules, and technologies to produce
biofuels economically from this type of feedstock are still being
developed. Some cellulosic biorefineries are piloting the use of
biochemical processes, in which microbes and enzymes break down these
complex plant molecules to produce ethanol, while others are piloting
the use of thermochemical processes, which use heat and chemical
catalysts to convert plant material into a liquid that more closely
resembles petroleum.
There are a number of steps in the biofuels life cycle, from
cultivation of the feedstock through distribution to the end user at
the fuel pump (see figure 1).
Figure 1: Biofuels Life Cycle:
[Refer to PDF for image: illustration]
Biofuels Life Cycle:
Feedstock:
Transportation;
Biorefinery;
Processing and Conversion;
Distribution;
End User.
Source: DOE.
[End of figure]
Water plays a critical role in many aspects of this life cycle. On the
cultivation side, water is needed to grow the feedstock. Crops can be
either rainfed, with all water requirements provided by natural
precipitation and soil moisture, or irrigated, with at least some
portion of water requirements met through applied water from surface or
groundwater sources. Figure 2 shows the various water inputs (sources
of water) and outputs (water losses) that are part of the agricultural
water cycle.
Figure 2: Agricultural Water Cycle:
[Refer to PDF for image: illustration]
Precipitation:
Runoff;
Infiltration;
Uptake by crops;
Groundwater flow to stream from surficial aquifer, clay aquitard and
confined aquifer;
Evapotranspiration.
Source: © 2008 International Mapping.
[End of figure]
Water is also important for conversion of feedstocks into biofuels. In
particular, water is used for heating and cooling as well as for
processing. For example, during the processing of corn-based ethanol,
corn is converted to ethanol through fermentation using one of two
standard processes, dry milling or wet milling. The main difference is
the initial treatment of the corn kernel. In the dry-mill process, the
kernel is first ground into flour meal and processed without separating
the components of the corn kernel. The meal is then slurried with water
to form a mash, and enzymes are added to convert the starch in the mash
to a fermentable sugar. The sugar is then fermented and distilled to
produce ethanol. In the wet-mill process, the corn kernel is steeped in
a mixture of water and sulfurous acid that helps separate the kernel
into starch, germ, and fiber components. The starch that remains after
this separation can then be fermented and distilled into fuel ethanol.
Traditional dry-mill ethanol plants cost less to construct and operate
than wet-mill plants, but yield fewer marketable co-products. Dry-mill
plants produce distiller's grains (that can be used as cattle feed) and
carbon dioxide (that can be used to carbonate soft drinks) as co-
products, while wet-mill plants produce many more co-products,
including corn oil, carbon dioxide, corn gluten meal, and corn gluten
feed. The majority of ethanol biorefineries in the United States are
dry-mill facilities. Figure 3 depicts the conversion process for a
typical dry-mill biorefinery.
Figure 3: Diagram of Conversion Process for a Typical Corn-Based
Ethanol Biorefinery:
[Refer to PDF for image: illustration]
1) Grain receiving:
2) Grain storage;
3) Hammer Mill;
4) Cook/Slurry Tanks;
5) Jet Cooker;
6) Liquefaction Tanks;
7) Ethanol Fermentation;
* To atmosphere or recovery facility: Carbon Dioxide;
8) Distillation;
9) Molecular Sieve;
10) Denaturant added;
11) Ethanol storage: Fuel Ethanol.
12) from Distillation: Centrifuge Grain Recovery;
13) Liquids; (sent to Cook/Slurry Tanks to repeat process); or:
14) Evaporation System;
15) Syrup Tank (includes solids fro Centrifuge Grain Recovery);
16) Wet Distillers Grains; or:
17) Grain Drying;
18) Dried Distillers Grain.
Source: © 2007 ICM, Inc.
[End of figure]
Each Stage of Biofuel Production Affects Water Resources, but the
Extent Depends on the Feedstock and Region:
The extent to which increased biofuel production will affect the
nation's water resources will depend on which feedstocks are selected
for production and which areas of the country they are produced in.
Specifically, increases in corn cultivation in areas that are highly
dependent on irrigated water could have greater impacts on water
availability than if the corn is cultivated in areas that primarily
produce rainfed crops. In addition, most experts believe that greater
corn production, regardless of where it is produced, may cause greater
impairments to water quality than other feedstocks, because corn
production generally relies on greater chemical inputs and the related
chemical runoff will impact water bodies. In contrast, many experts
expect next generation feedstocks to require less water and provide
some water quality benefits, but even with these feedstocks the effects
on water resources will largely depend on which feedstock is selected,
and where and how these feedstocks are grown. Similarly, the conversion
of feedstocks into biofuels may also affect water supply and water
quality, but these effects also vary by feedstock chosen and type of
biofuel produced. Many experts agree that as the agriculture and
biofuel production industries make decisions about which feedstocks to
grow and where to locate or expand conversion facilities, it will be
important for them to consider regional differences and potential
impacts on water resources.
Water Supply and Water Quality Effects of Increased Corn Cultivation:
Many experts and officials told us that corn cultivation requires
substantial quantities of water, although the amount used depends on
where the crop is grown and how much irrigation water is used. The
primary corn production regions are in the upper and lower Midwest and
include 12 states classified as USDA farm production Regions 5, 6, and
7. Together, these regions accounted for 89 percent of corn production
in 2007 and 2008, and 95 percent of ethanol production in the United
States in 2007. Corn cultivation in these three regions averages
anywhere from 7 to 321 gallons of irrigation water for every gallon of
ethanol produced, as shown in table 1.[Footnote 6] However, the impact
of corn cultivation on water supplies in these regions varies
considerably. For example, in USDA Region 7, which comprises North
Dakota, South Dakota, Kansas, and Nebraska, the production of one
bushel of corn consumes an average of 865 gallons of freshwater from
irrigation. In contrast, in USDA Regions 5 and 6, which comprise Iowa,
Illinois, Indiana, Ohio, Missouri, Minnesota, Wisconsin, and Michigan,
corn is mostly rainfed and only requires on average 19 to 38 gallons of
supplemental irrigation water per bushel.[Footnote 7]
Table 1: Average Water Consumed in Corn Ethanol Production in Primary
Producing Regions in the United States, in Gallons of Water/Gallon of
Ethanol Produced:
Type of water consumed: Cultivation: Corn irrigation, groundwater;
USDA Region 5 (Iowa, Indiana, Illinois, Ohio, Missouri): 6.7;
USDA Region 6 (Minnesota, Wisconsin, Michigan): 10.7;
USDA Region 7 (North Dakota, South Dakota, Nebraska, Kansas): 281.2.
Type of water consumed: Cultivation: Corn irrigation, surface water;
USDA Region 5 (Iowa, Indiana, Illinois, Ohio, Missouri): 0.4;
USDA Region 6 (Minnesota, Wisconsin, Michigan): 3.2;
USDA Region 7 (North Dakota, South Dakota, Nebraska, Kansas): 39.4.
Type of water consumed: Total irrigated water;
USDA Region 5 (Iowa, Indiana, Illinois, Ohio, Missouri): 7.1;
USDA Region 6 (Minnesota, Wisconsin, Michigan): 13.9;
USDA Region 7 (North Dakota, South Dakota, Nebraska, Kansas): 320.6.
Type of water consumed: Conversion - Corn ethanol;
USDA Region 5 (Iowa, Indiana, Illinois, Ohio, Missouri): 3.0;
USDA Region 6 (Minnesota, Wisconsin, Michigan): 3.0;
USDA Region 7 (North Dakota, South Dakota, Nebraska, Kansas): 3.0.
Type of water consumed: Total water consumption;
USDA Region 5 (Iowa, Indiana, Illinois, Ohio, Missouri): 10.0;
USDA Region 6 (Minnesota, Wisconsin, Michigan): 16.8;
USDA Region 7 (North Dakota, South Dakota, Nebraska, Kansas): 323.6.
Source: Center for Transportation Research, Energy Systems Division,
Argonne National Laboratory, "Consumptive Water Use in the Production
of Ethanol and Petroleum Gasoline," Center for Transportation Research,
Energy Systems Division, Argonne Laboratory, January 2009:
Note: The numbers may not add up due to rounding. The Argonne National
Laboratory study estimated the water consumed in corn ethanol
production in each of the major ethanol producing regions considering
water consumed in both corn cultivation and conversion processing
steps. Estimates were based on average consumption of 3.0 gallons of
water per gallon of corn ethanol produced in a corn dry mill, average
consumptive use of irrigation water for corn in major corn producing
regions, and dry-mill yield of 2.7 gallons of ethanol per bushel. In
evaluating corn cultivation, the water consumed is based on total
amount of irrigation water used for corn production and total corn
production for each region, and does not include precipitation. In
addition, the calculation assumes that 30 percent of water recharges
local surface and groundwater, and the remaining 70 percent of the
water is consumed by evapotranspiration (water lost through evaporation
from the soil and plants) and other factors.
[End of table]
The effects of increased corn production for ethanol on water supplies
are likely to be greatest in water-constrained regions of the United
States where corn is grown using irrigation. For example, some of the
largest increases in corn acres (1.1 million acres) are projected to
occur in the Northern Plains region, which is already a water
constrained region. Parts of this region draw heavily from the Ogallala
Aquifer, where water withdrawals are already greater than the natural
recharge rate from precipitation. A 2009 USGS report found water levels
in the aquifer had dropped more than 150 feet in parts of southwest
Kansas and the Texas Panhandle, where crop irrigation is intense and
recharge to the aquifer is minimal.[Footnote 8] In 2000, about 97
percent of the water withdrawn from the aquifer was used for
irrigation, according to USGS.[Footnote 9]
Many officials told us that an increase in corn cultivation using
current agricultural practices will also impair water quality as a
result of the runoff of fertilizer into lakes and streams. This will
happen because corn requires high applications of fertilizers relative
to soybeans and other potential biofuel feedstocks, such as perennial
grasses.[Footnote 10] For example, in Iowa, the expansion of biofuel
production has already led to an increasing amount of land dedicated to
corn and other row crops, resulting in surface water impacts, including
nutrient runoff and increased bacteria counts as well as leaching of
nitrogen and phosphorus into groundwater, according to a state
official. Fertilizer runoff containing nitrogen and phosphorus can lead
to overenrichment and excessive growth of algae in surface waters. In
some waters, such enrichment has resulted in harmful algal blooms,
decreased water clarity, and reduced oxygen in the water, which impair
aquatic life.[Footnote 11] In marine waters, this excessive algal
growth has created "dead zones," which cannot support fish or any other
organism that needs oxygen to survive.[Footnote 12] The number of
reported dead zones around the world has increased since the 1960s to
more than 400.[Footnote 13] Many of them are along the Gulf of Mexico
and the Atlantic Coast, areas that receive drainage from agricultural
and urban landscapes, including a large portion of the Corn Belt, where
many of the existing and planned ethanol production facilities are
located. A 2007 USGS model estimated that 52 percent of the nitrogen
and 25 percent of the phosphorus entering the Gulf system are from corn
and soybean cultivation in the Mississippi River basin.[Footnote 14]
Increased corn production will also increase the use of pesticides--
including insecticides and herbicides--which also have the potential to
affect surface water and groundwater quality. For example, a 10-year
nationwide study by USGS detected pesticides in 97 percent of streams
in agricultural and urban watersheds.[Footnote 15] As would be
expected, the highest concentrations of pesticides have been found in
those areas that have the highest use. For instance, application rates
of atrazine, a commonly used pesticide for corn production, are highest
in the Corn Belt, and atrazine was also the most widely detected
pesticide in watersheds in this area, according to the USGS nationwide
study. USGS determined that the concentrations of atrazine and other
pesticides detected had the potential to adversely affect aquatic
plants and invertebrates in some of the streams, since organisms are
vulnerable to short-term exposure to relatively small amounts of
certain pesticides. Similarly, increased pesticide use for the
cultivation of corn could impair groundwater supplies. USGS found
pesticides in 61 percent of shallow wells sampled in agricultural
areas. Once groundwater is contaminated, it is difficult to clean up,
according to the experts we contacted.
According to some of the experts and officials we spoke with, increased
demand for biofuel feedstocks may also create incentives for farmers to
place marginal lands back into production. Marginal lands generally
have lower productivity soils, so cultivating them may require more
nutrient and pesticide inputs than more productive lands, potentially
leading to further water quality impairments. Furthermore, delivery of
sediments, nutrients, and pesticides to surrounding water bodies may
increase if these lands are placed back into production because these
lands are often highly susceptible to erosion due to wind and water. Of
particular concern to many of the experts with whom we spoke are the
millions of acres of land currently enrolled in the Conservation
Reserve Program (CRP). This federal program provides annual rental
payments and cost share assistance to landowners who contractually
agree to retire highly erodible or other environmentally-sensitive
cropland from agricultural purposes. As part of the contract, farmers
are generally required to plant or maintain vegetative covers (such as
native grasses) on the land, which provide a range of environmental
benefits, including improved water quality, reduced erosion, enhanced
wildlife habitat, and preserved soil productivity. However, many
experts and officials we spoke with from the five selected states are
concerned that higher corn prices and increased demand for biofuel
feedstocks may encourage farmers to return CRP land to crop production.
If such conversion does occur, these officials noted that water quality
may further decline in the future.
Little Is Yet Known about the Water Resource Implications of Next
Generation Feedstocks:
Next generation feedstocks for biofuels have the potential for fewer
negative effects on water resources, although several of the experts
and officials that we spoke with said that the magnitude of these
effects remains largely unknown because these feedstocks have not yet
been grown on a commercial scale. These experts suggested that certain
water resource impacts were likely for the following potential
feedstocks:
* Agricultural residues, such as corn stover, collected from fields
that have already been harvested, can provide feedstock for cellulosic
ethanol production. The primary advantage of using agricultural
residues is that they are a byproduct of crop cultivation and thus do
not require additional water or nutrient inputs. However, removal of
these residues has consequences for both soil and water quality, so
there may be limits on how much agricultural residues can be removed
for cellulosic ethanol production. According to the experts we spoke
with, leaving crop residues unharvested on the field benefits soil
quality by providing nutrients that help maintain long-term soil
productivity, enhancing soil moisture retention, increasing net soil
carbon, and reducing the need for nutrient inputs for future crops.
[Footnote 16] In addition, leaving crop residues on the field helps
prevent soil erosion due to wind and water and nutrient runoff into
the water supply. Farmers could reduce the negative effects of residue
removal by harvesting only corn cobs or part of the stover, but the
optimal removal rate is not yet fully known, and is currently being
studied by several federal agencies and academic institutions.
* Perennial grasses may require less water and provide some water
quality benefits. Perennial grasses such as mixed prairie and
switchgrass can grow with less water than corn. But some experts
cautioned that any water supply benefits from these grasses will only
occur if they are rainfed. For instance, officials in Minnesota told us
that because the state's crops are primarily rainfed, shifting to the
cultivation of cellulosic feedstocks, like perennial grasses, without
irrigation would have a minimal impact on the state's water supply.
However, other experts and local officials pointed out that if farmers
choose to irrigate perennial grasses in order to achieve maximum yields
and profits as they do for other crops, then producing these feedstocks
could have the same detrimental effects on water supplies as do other
crops. This concern was reiterated by the National Research Council,
which stated that while irrigation of native grasses is unusual now, it
could easily become more common as cellulosic biofuel production gets
under way.[Footnote 17]
Perennial grasses can also help preserve water quality by reducing
soil, nutrient, and pesticide runoff. Research indicates that perennial
grasses cycle nitrogen more efficiently than some row crops and protect
soil from erosion due to wind and water. As a result, they can reduce
the need for most fertilizers after crops are established, and the land
on which these crops are grown do not need to be tilled every year,
which reduces soil erosion and sedimentation. According to experts,
farmers could also plant a mix of perennial grasses, which could
minimize the need for pesticides by promoting greater diversity and an
abundance of natural enemies for agricultural pests. In addition,
perennial grasses cultivated across an agricultural landscape may help
reduce nutrient and chemical runoff from farm lands. Grasses can also
be planted next to water bodies to help filter out nutrients and secure
soil and can serve as a windbreak to help minimize erosion. However,
the type of land and cultivation methods used to grow perennial grasses
will influence the extent to which they improve water quality. For
instance, if perennial grasses were harvested down to the soil, they
would not reduce soil erosion as compared to conventional feedstocks in
the long run, according to some experts. In addition, according to some
experts, if farmers choose to use fertilizers to maximize yields from
these crops as they do for other crops or if these crops are grown on
lands with decreased soil quality that require increased nutrient
application, then cultivation of perennial grasses could also lead to
water quality impairments.
* Woody biomass, such as biomass from the thinning of forests and
cultivation of certain fast-growing tree varieties, could serve as
feedstock for cellulosic ethanol production, according to some experts.
Use of thinnings is not expected to impact water supply, as they are
residuals from forest management. Thinning of forests can have the
added benefit of reducing the intensity of wildfires, the aftermath of
which facilitates runoff of nutrients and sediment into surface waters.
Waste from urban areas or lumber mills may also provide another source
of biomass that would not require additional water resources. This
waste would include the woody portions of commercial, industrial, and
municipal solid waste, as well as byproducts generated from processing
lumber, engineered wood products, or wood particles; however, almost
all of the commercial wood waste is currently used as fuels or raw
material for existing products. In addition, some experts said that
fast-growing tree species, such as poplar, willow, and cottonwood, are
potential cellulosic feedstocks. However, these experts also cautioned
that some of these varieties may require irrigation to cultivate and
may have relatively high consumptive water requirements.
* Algae are also being explored as a possible feedstock for advanced
biofuels. According to several experts, one advantage of algae is that
they can be cultivated in brackish or degraded water and do not need
freshwater supplies. However, currently algae cultivation is expected
to consume a great deal of water, although consumption estimates vary
widely--from 40 to 1,600 gallons of water per gallon of biofuel
produced, according to experts--depending on what cultivation method is
used. With open-air, outdoor pond cultivation, water loss is expected
to be greater due to evaporation, and additional freshwater will be
needed to replenish the water lost and maintain the water quality
necessary for new algal growth. In contrast, when algae are cultivated
in a closed environment, as much as 90 percent less water is lost to
evaporation, according to one expert.[Footnote 18]
The Extent to Which Biofuel Conversion May Affect Water Resources also
Depends on the Feedstock Used and Biofuel Produced:
During the process of converting feedstocks into biofuels,
biorefineries not only need a supply of high-quality water, but also
discharge certain contaminants that could impact water quality. The
amount of water needed and the contaminant discharge vary by type of
biofuel produced and type of feedstock used in the conversion process.
For example, ethanol production requires greater amounts of high-
quality water than does biodiesel. Conversion of corn to ethanol
requires approximately 3 gallons of water per gallon of ethanol
produced, which represents a decrease from an estimated 5.8 gallons of
water per gallon of ethanol in 1998.[Footnote 19] According to some
experts, these gains in efficiency are, for the most part, the result
of ethanol plants improving their water recycling efforts and cooling
systems.
According to some experts we spoke with, the biofuel conversion process
generally requires high-quality water because the primary use for
ethanol production is for cooling towers and boilers, and cleaner water
transfers heat more efficiently and does less damage to this equipment.
As a result, ethanol biorefineries prefer to use groundwater because it
is generally cleaner, of more consistent quality, and its supply is
less variable than surface water. Furthermore, the use of lesser-
quality water leaves deposits on biorefinery equipment that require
additional water to remove. However, despite water efficiency gains,
some communities have become concerned about the potential impacts of
withdrawals for biofuel production on their drinking water and
municipal supplies and are pressuring states to limit ethanol
facilities' use of the water. For example, at least one Minnesota local
water district denied a permit for a proposed biorefinery due to
concerns about limited water supply in the area.
Current estimates of the water needed to convert cellulosic feedstocks
to ethanol range from 1.9 to 6.0 gallons of water per gallon of
ethanol, depending on the technology used. Conversion of these next
generation feedstocks is expected to use less water when compared to
conventional feedstocks in the long run, according to some experts.
[Footnote 20] For example, officials from a company in the process of
establishing a biorefinery expect the conversion of pine and other
cellulosic feedstocks to consume less water than the conversion of corn
to ethanol once the plant is operating at a commercial scale. However,
some researchers cautioned that the processes for converting cellulosic
feedstocks currently require greater quantities of water than needed
for corn ethanol. They said the technology has not been optimized and
commercial-scale production has not yet been demonstrated, therefore
any estimates on water use by cellulosic biorefineries are simply
projections at this time.
In contrast, biodiesel conversion requires less water than ethanol
conversion--approximately 1 gallon of freshwater per gallon of
biodiesel. Similar to ethanol conversion, much of this water is lost
during the cooling and feedstock drying processes. Biodiesel facilities
can use a variety of plant and animal-based feedstocks, providing more
options when choosing a location. This flexibility in type of feedstock
that can be converted allows such facilities to be built in locations
with plentiful water supplies, lessening their potential impact.
In addition to the water supply effects, biorefineries can have water
quality effects because of the contaminants they discharge. However,
the type of contaminant discharged varies by the type of biofuel
produced. For example, ethanol biorefineries generally discharge
chemicals or salts that build up in cooling towers and boilers or are
produced as waste by reverse osmosis, a process used to remove salts
and other contaminants from water prior to discharge from the
biorefinery.[Footnote 21] EPA officials told us that the concentrated
salts discharged from reverse osmosis are a concern due to their
effects on water quality and potential toxicity to aquatic organisms.
In contrast, biodiesel refineries discharge other pollutants such as
glycerin that may be harmful to water quality. EPA officials told us
that glycerin from small biodiesel refineries can be a problem if it is
released into local municipal wastewater facilities because it may
disrupt the microbial processes used in wastewater treatment.[Footnote
22] Glycerin is less of a concern with larger biodiesel refineries
because, according to EPA officials, it is often extracted from the
waste stream prior to discharge and refined for use in other products.
Several state officials we spoke with told us these discharges are
generally well-regulated under the Clean Water Act. Under the act,
refineries that discharge pollutants into federally regulated waters
are required to obtain a federal National Pollutant Discharge
Elimination System (NPDES) permit, either from EPA or from a state
agency authorized by EPA to implement the NPDES program. These permits
generally allow a point source, such as a biorefinery, to discharge
specified pollutants into federally regulated waters under specific
limits and conditions. State officials we spoke with reported they
closely monitor the quality of water being discharged from biofuel
conversion facilities, and that the facilities are required to treat
their water discharges to a high level of quality, sometimes superior
to the quality of the water in the receiving water body.
Storage and Distribution of Biofuels Can Have Some Water Quality
Consequences:
The storage and distribution of ethanol-blended fuels could result in
water quality impacts in the event that these fuels leak from storage
tanks or the pipes used to transport these fuels. Ethanol is highly
corrosive and there is potential for releases into the environment that
could contaminate groundwater and surface water, among other issues.
[Footnote 23] When ethanol-blended fuels leak from underground storage
tanks (UST) and aboveground tank systems, the contamination may pose
greater risks than petroleum. This is because the ethanol in these
blended fuels causes benzene, a soluble and carcinogenic chemical in
gasoline, to travel longer distances and persist longer in soil and
groundwater than it would in the absence of ethanol,[Footnote 24]
increasing the likelihood that it could reach some drinking water
supplies.[Footnote 25] Federal officials told us that, because it is
illegal to store ethanol-blended fuels in tanks not designed for the
purpose, they had not encountered any concerns specific to ethanol
storage. However, officials from two states did express concern about
the possibility of leaks and told us that ethanol-blended fuels are
still sometimes stored in tanks not designed for the fuel. For
instance, one of these states reported a 700-gallon spill of ethanol-
blended fuels due to the scouring of rust plugs in a UST.[Footnote 26]
According to EPA officials, a large number of the 617,000 federally
regulated UST systems currently in use at approximately 233,000 sites
across the country are not certified to handle fuel blends that contain
more than 10 percent ethanol.[Footnote 27] Moreover, according to EPA
officials, most tank owners do not have records of all the UST systems'
components, such as the seals and gaskets. Glues and adhesives used in
UST piping systems were not required to be tested for compatibility
with ethanol-blended fuel until recently. Thus there may be many
compatible tanks used for storing ethanol-blended fuels that have
incompatible system components, increasing the potential for equipment
failure and fuel leakage, according to EPA officials. EPA told us that
it is continuing to work with government and industry partners to study
the compatibility of these components with various ethanol blends. EPA
officials also stressed the importance of understanding the fate and
transport of biofuels into surface water because biofuels are
transported mainly by barge, rail, and truck. The officials noted that
spills of biofuels or their byproducts have already occurred into
surface waters.
The Effect of Increased Biofuel Production Will Vary by Region, Due to
Differences in Water Resources and State Laws:
According to many experts and officials that we contacted, as biofuel
production increases, farmers and the biofuel production industry will
need to consider regional differences in water supply and quality when
choosing which feedstocks to grow and how and where to expand their
biofuel production capacity. Specifically, they noted that in the case
of cultivation, certain states may be better suited to cultivate
particular feedstocks because of the amount and type of water
available. Some examples they provided include the following:
* Certain cellulosic feedstocks, such as switchgrass, would be well-
suited for areas with limited rainfall, such as Texas, because these
feedstocks generally require less water and are drought tolerant.
* In the Midwest, switchgrass and other native perennial grasses could
be grown as stream buffer strips or as cover crops, which are crops
planted to keep the soil in place between primary plantings.
* In Georgia, some experts said pine was likely to be cultivated as a
next generation biofuel feedstock because the state has relatively
limited land available for cultivation and increased cultivation of
pine or other woody biomass without irrigation would not cause a strain
on water supplies.
* In the Southeast and Pacific Northwest, waste from logging operations
and paper production was identified as a potential feedstock for
cellulosic ethanol production.
* Areas with limited freshwater supplies and a ready supply of lower-
quality water, such as brackish water or water from wastewater
treatment plants, would be better suited to the cultivation of algae.
For example, Texas was identified as a state suitable for algae
cultivation because of the large amounts of brackish water in many of
its aquifers, as well as its abundant sunlight and supplies of carbon
dioxide from industrial facilities.
Research indicates that in making decisions about feedstock production
for biofuels it will be important to consider the effects that
additional cultivation will have on the quality of individual water
bodies and regional watersheds. Farmers need to consider local water
quality effects when making decisions regarding the suitability of a
particular feedstock or where to employ agricultural management
practices that minimize nutrient application. In addition, state
officials should consider these effects when deciding where programs
such as the CRP may be the most effective. For example, experts and
officials told us it will be important to identify watersheds in the
Midwest that are delivering the largest nutrient loads into the
Mississippi River basin and, consequently, contributing to the Gulf of
Mexico dead zone, in order to minimize additional degradation that
could result from increased crop cultivation in these watersheds. In
addition, research has shown it is important that management practices
be tailored to local landscape conditions, such as topography and soil
quality, and landowner objectives, so that efforts to reduce nutrient
and sediment runoff can be maximized.
In the case of biofuel conversion, some experts and officials said that
state regulators and industry will need to consider the availability of
freshwater supplies and the quality of those supplies when identifying
and approving sites for biorefineries. Currently, many biorefineries
are located in areas with limited water resources. For instance, as
figure 4 shows, many existing and planned ethanol facilities are
located on stressed aquifers, such as the Ogallala, or High Plains,
Aquifer. These facilities require 100,000 to 1 million gallons of water
per day, and as mentioned earlier, the rate of water withdrawal from
the aquifer is already much greater than its recharge rate, allowing
water withdrawals in Nebraska or South Dakota to affect water supplies
in other states that draw from that aquifer. Experts noted that states
with enough rainfall to replenish underlying aquifers may be more
appropriate locations for biorefineries.
Figure 4: Existing and Planned Ethanol Facilities (as of 2007) and
Their Estimated Total Water Use Mapped with the Principal Bedrock
Aquifers, including the Ogallala, or High Plains, Aquifer, of the
United States and Total Water Use in 2000:
[Refer to PDF for image: illustrated U.S. map]
Identified on the map are:
High Plains Aquifers;
Glacial Aquifers.
Principal Bedrock Aquifers 2000 Water Use: Irrigation/Public
Supply/Industrial, in millions of gallons per day:
Map indicates:
0-250;
250-500;
500-750;
750-1000;
1000-1250;
1250-1500;
greater than 1500.
2007 Existing and Planned Ethanol Facilities; Estimated Total Water Use
in millions of gallons per day:
Map indicates the location of facilities and water use of:
0-0.05;
0.05-0.10;
0.10-0.50;
0.50-1.00;
greater than 1.00.
Source: Created by USGS for use in the National Research Council 2008
report, Water Implications of Biofuels Production in the U.S.
[End of figure]
Finally, relevant water laws in certain states may influence the
location of future biorefineries. Specifically, several states have
enacted laws that require permits for groundwater or surface water
withdrawals and this requirement could impact where biorefineries will
be sited. These laws specify what types of withdrawals must be
permitted by the responsible regulatory authority and the requirements
for receiving a permit. For instance, Georgia's Environmental
Protection Division grants permits for certain withdrawals of
groundwater and surface water, including for use by a biorefinery, when
the use will not have unreasonable adverse effects on other water uses.
According to state officials, there has not yet been a case where a
permit for a biorefinery was denied because the amount of projected
withdrawal was seen as unreasonable. In contrast, groundwater decisions
are made at the local level in Texas, where more than half of the
counties have groundwater conservation districts, and Nebraska. In
deciding whether to issue a permit, the Texas groundwater conservation
districts consider whether the proposed water use unreasonably affects
either existing groundwater and surface water resources or existing
permit holders, among other factors. In Nebraska, permits are only
required for withdrawals and transfers of groundwater for industrial
purposes. In addition, in Nebraska, where water supplies are already
fully allocated in many parts of the state, natural resource districts
can require biofuel conversion facilities to offset the water they will
consume by reducing water use in other areas of the region. The volume
of withdrawals can also factor into the need for a permit. While Texas
conservation district permits are required for almost all types of
groundwater wells, Georgia state withdrawal permits are only required
for water users who withdraw more than an average of 100,000 gallons
per day[Footnote 28].
Agricultural Practices, Technological Innovations, and Alternative
Water Sources Can Mitigate Some Water Resource Effects of Biofuels
Production, but There Are Barriers to Adoption:
Agricultural conservation practices can reduce the effects of increased
biofuel feedstock cultivation on water supply and water quality, but
there are several barriers to widespread adoption of these practices.
Similarly, the process of converting feedstocks to biofuels,
technological innovations, and the use of alternative water sources can
help reduce water supply and water quality impacts, but these options
can be cost prohibitive and certain noneconomic barriers to their
widespread use remain.
Certain Agricultural Practices Can Benefit Water Supply and Water
Quality, but Barriers May Limit Widespread Adoption:
Many experts and officials we spoke with highlighted the importance of
using agricultural conservation practices to reduce the potential
effects of increased biofuel feedstock cultivation on water resources.
These practices can reduce nutrient and pesticide runoff as well as
soil erosion by retaining additional moisture and nutrients in the soil
and disturbing the land less. For example, several experts and
officials we spoke with said that installing and maintaining permanent
vegetation areas adjacent to lakes and streams, known as riparian
zones, could significantly reduce the impacts of agricultural runoff.
More specifically, several experts and officials said that planting
buffer strips of permanent vegetation, such as perennial grasses, or
constructing or restoring wetlands in riparian areas would reduce the
effects that crop cultivation can have on water quality, as shown in
figure 5.
Figure 5: Example of a Riparian Buffer Adjacent to Cropland:
[Refer to PDF for image: photograph]
Source: USDA.
[End of figure]
Experts also identified conservation tillage practices--such as "no-
till" systems or reduced tillage systems, where the previous year's
crop residues are left on the fields and new crops are planted directly
into these residues--as an important way to reduce soil erosion (see
figure 6). Research conducted by USDA has shown a substantial reduction
in cropland erosion since 1985, when incentives were put in place to
encourage the adoption of conservation tillage practices.[Footnote 29]
Another practice, crop rotation, also reduces erosion and helps
replenish nutrients in the soil. This contrasts with practices such as
continuous corn cultivation--in which farmers plant corn on the same
land year after year instead of rotating to other crops--which often
leads to decreased soil quality. Furthermore, experts identified cover
crops, a practice related to crop rotation, as a way to mitigate some
of the impacts of agricultural runoff. Cover crops are planted prior to
or following a harvested crop, primarily for seasonal soil protection
and nutrient recovery before planting the next year's crops. These
crops, which include grains or perennial grasses, absorb nutrients and
protect the soil surface from erosion caused by wind and rain,
especially when combined with conservation tillage practices.
Figure 6: Example of Conservation Tillage:
[Refer to PDF for image: photograph]
Source: USDA.
Note: The picture depicts conservation tillage, a process in which last
year's crop residues are left on the field and planting occurs directly
into this minimally tilled soil.
[End of figure]
Experts also identified "precision agriculture" as an important tool
that can reduce fertilizer runoff and water demand by closely matching
nitrogen fertilizer application and irrigation to a crop's nutrient and
water needs. Precision agriculture uses technologies such as geographic
information systems and global positioning systems to track crop yield,
soil moisture content, and soil quality to optimize water and nutrient
application rates. Farmers can use this information to tailor water,
fertilizer, and pesticide application to specific plots within a field,
thus potentially reducing fertilizer and pesticide costs, increasing
yields, and reducing environmental impacts. Other precision agriculture
tools, like low-energy precision-application irrigation and subsurface
drip irrigation systems, operate at lower pressures and have higher
irrigation water application and distribution efficiencies than
conventional irrigation systems, as shown in figure 7.[Footnote 30]
Several experts and officials said that in order to promote such
practices, it is important to continue funding and enrollment in
federal programs, such as USDA's Environmental Quality Incentives
Program, which pay farmers or provide education and technical support.
See appendix II for an expanded discussion of agricultural conservation
practices.
Figure 7: Example of Low-Energy Precision-Application Irrigation:
[Refer to PDF for image: photograph]
Source: USDA.
[End of figure]
Several experts and officials we spoke with also said that genetic
engineering has the potential to decrease the water, nutrient, and
pesticide requirements of biofuel feedstocks.[Footnote 31] According to
an industry trade group, biotechnology firms are currently developing
varieties of drought-resistant corn that may be available to farmers
within the next several years. These varieties could significantly
increase yields in arid regions of the country that traditionally
require irrigation for corn production. Companies are also working to
develop crops that absorb additional nutrients or use nutrients more
efficiently, giving them the potential to reduce nutrient inputs and
the resulting runoff. However, industry officials believe it may be up
to a decade before these varieties become available commercially.
Furthermore, according to EPA, planting drought-resistant crops, such
as corn, may lead to increased cultivation in areas where it has not
previously occurred and may result in problems including increased
nutrient runoff.
Experts and officials told us there are both economic and noneconomic
barriers to the adoption of agricultural conservation practices.
* Economic barriers. According to several experts, as with any
business, farming decisions are made in an attempt to maximize profits.
As a result, experts told us that some farmers may be reluctant to
adopt certain conservation practices that may reduce yields and
profits, especially in the short term. Furthermore, experts and
officials also said that some of these agricultural conservation
practices can be costly, especially precision agriculture. For example,
the installation of low-energy precision irrigation and subsurface drip
irrigation systems is significantly more expensive than conventional
irrigation systems because of the equipment needed, among other
reasons.[Footnote 32] Farmers may also hesitate to switch from
traditional row crops to next generation cellulosic crops because of
potential problems with cash flow and lack of established markets.
Specifically, it can take up to 3 years to establish a mature,
economically productive crop of perennial grasses, and farmers would be
hard-pressed to forgo income during this period. Moreover, farmers may
not be willing to cultivate perennial grasses unless they are assured
that a market exists for the crop and that they could earn a profit
from its cultivation. Furthermore, efficient cultivation and harvest
could require farmers to buy new equipment, which would be costly and
would add to the price they would have to receive for perennial grasses
in order to make a profit.
* Noneconomic barriers. Experts and officials we contacted said that
many farmers do not have the expertise or training to implement certain
practices, and some agricultural practices may be less suited for some
places. For example, state officials told us that farmers usually need
a year or more of experience with reduced tillage before they can
achieve the same crop yields they had with conventional tillage. In
addition, precision agriculture relies on technologies and equipment
that require training and support. Officials told us that to help
address this training need, USDA and states have programs in place that
help educate farmers on how to incorporate these practices and, in some
cases, provide funding to help do so. In addition, some experts and
officials cited regional challenges associated with some agricultural
practices and the cultivation of biofuel feedstocks. For example, these
experts and officials said that the amount of agricultural residue that
can be removed would vary by region and even by farm. Similarly,
cultivation of certain cover crops as biofuel feedstocks may not be
suitable in the relatively short growing seasons of northern regions.
Use of Innovative Technologies and Alternative Water Sources Could
Reduce the Water Resource Effects of Biorefineries, but Costs and
Logistics Impede Adoption:
Technological improvements have already increased water use efficiency
in the ethanol conversion process. Newly built biorefineries with
improved processes have reduced water use dramatically over the past 10
years, and some plants have reduced their wastewater discharge to zero.
Of the remaining water use, water loss from cooling towers for
biorefineries is responsible for approximately 50 to 70 percent of
water consumption in modern dry-milling ethanol plants.[Footnote 33]
Some industry experts we spoke with said that further improvements in
water efficiency at corn ethanol plants are likely to come from
minimizing water loss from cooling towers or from using alternative
water sources, such as effluent from sewage treatment plants. One
alternative technology that can substantially reduce water lost through
cooling towers is a dry cooling system,[Footnote 34] which relies
primarily on air rather than water to transfer heat from industrial
processes.[Footnote 35] In addition, some ethanol plants are beginning
to replace freshwater with alternative sources of water, such as
effluent from sewage treatment plants, water from retention ponds at
power plants, or excess water from adjacent rock quarries. For example,
a corn ethanol conversion plant in Iowa gets a third of its water from
a local wastewater treatment plant. By using these alternative water
sources, the biorefineries can lower their use of freshwater during the
conversion process. While these strategies of improved water efficiency
at biorefineries show considerable promise, there are barriers to their
adoption. For example, technologies such as dry cooling systems are
often prohibitively expensive and can increase energy consumption.
Furthermore, according to industry experts, alternative water sources
can create a need for expensive wastewater treatment equipment. Some
industry experts also told us that the physical layout of a conversion
facility may need to be changed to make room for these improvements.
Because of the considerable costs of such improvements, several experts
told us, it is difficult for biorefineries to integrate these water-
conserving technologies while remaining competitive in the economically
strained ethanol industry.
Many experts and officials stated that technological innovations for
next generation biofuel conversion also have the potential to reduce
the water supply and water quality impacts of increased biofuel
production. For example, thermochemical production of cellulosic
ethanol could require less than 2 gallons of water per gallon of
ethanol produced.[Footnote 36] In addition, some next generation
biofuels, known as "drop-in" fuels, are being developed that are
compatible with the existing fuel infrastructure, which could reduce
the risk that leaks and spills could contaminate local water bodies.
For example, biobutanol is produced using fermentation processes
similar to those used to make conventional ethanol, but it does not
have the same corrosive properties as ethanol and could be distributed
through the existing gasoline infrastructure.[Footnote 37] In addition,
liquid hydrocarbons derived from algae have the potential to be
converted to gasoline, diesel, and jet fuel, which also can be readily
used in the existing fuel infrastructure.[Footnote 38] However, while
these proposed technological innovations can reduce the water resource
impacts of increased biofuel production, the efficacy of most of these
innovations has not yet been demonstrated on a commercial scale, and
some innovations' efficacy has not yet been demonstrated on a pilot
scale.
Experts Identified a Variety of Key Research and Data Needs Related to
Increased Biofuels Production and Local and Regional Water Resources:
Many of the experts and officials we spoke with identified areas where
additional research is needed to evaluate and understand the effects of
increased biofuel production on water resources. These needs fall into
two broad areas: (1) research on the water effects of feedstock
cultivation and conversion and (2) better data on local and regional
water resources.
Experts and officials identified the following research needs on the
water resource effects of feedstock cultivation and conversion
processes:
Genetically engineered biofuel feedstocks. Many experts and officials
cited the need for more research into the development of drought-
tolerant and water-and nutrient-efficient crop varieties to decrease
the amount of water needed for irrigation and the amount of fertilizer
that needs to be applied to biofuel feedstocks. According to the
National Research Council, this research should also address the
current lack of knowledge on the general water requirements and
evapotranspiration rates of genetically engineered crops, including
next generation crops.[Footnote 39] Regarding nutrient efficiency, some
experts and officials noted that research into the development of
feedstocks that more efficiently take up and store nitrogen from the
soil would help reduce nitrogen runoff. In addition, USDA officials
added that research to determine the water requirements for
conventional biofuel feedstocks and new feedstock varieties developed
specifically for biofuel production is also needed.
Effects of cellulosic crops on hydrology. Many experts and officials
also told us there is a need to better understand the water
requirements of cellulosic crops and the impact of commercial-scale
cellulosic feedstock cultivation on hydrology, which is the movement of
water through land and the atmosphere into receiving water bodies.
According to one expert, these feedstocks differ from corn in their
life cycles, root systems, harvest times, and evapotranspiration
levels, all of which may influence hydrology. In addition, some
research suggests that farmers may cultivate cellulosic feedstocks on
marginal or degraded lands because these lands are not currently being
farmed and may be suitable for these feedstocks. However, according to
the National Research Council, the current evapotranspiration rates of
crops grown on such lands is not well known.[Footnote 40]
Effects of cellulosic crops on water quality. Many experts and
officials we spoke with said research is needed to better understand
the nutrient needs of cellulosic crops grown on a commercial scale.
Specifically, field research is needed on the movement of fertilizer in
the soil, air, and water after it is applied to these crops. One expert
explained there are water quality models that can describe what happens
to fertilizer when applied to corn, soy, and other traditional row
crops. However, such models are less precise for perennial grasses due
to the lack of data from field trials. Similarly, several experts and
officials told us that additional research is also needed on the
potential water quality impacts from the harvesting of corn stover. In
particular, research is needed on the erosion and sediment delivery
rates of different cropping systems in order to determine the
acceptable rates of residue removal for different crops, soils, and
locations and to develop the technology to harvest residue at these
rates.
Cultivation of algae. Although algae can be cultivated using lower-
quality water, the impact on water supply and water quality will
ultimately depend on which cultivation methods are determined to be the
most viable once this nascent technology reaches commercial scale. Many
experts we spoke with noted the need for research on how to more
efficiently cultivate algae to minimize the freshwater consumption and
water quality impacts. For example, research on how to maximize the
quantity of water that can be recycled during harvest will be essential
to making algae a more viable feedstock option. Further research is
also needed to determine whether the pathogens and predators in the
lower-quality water are harmful to the algae.[Footnote 41] In addition,
research is also needed on how to manage water discharges during
cultivation and harvest of algae. Although it is expected that most
water will be recycled, a certain amount must be removed to prevent the
buildup of salt. This water may contain pollutants--such as nutrients,
heavy metals, and accumulated toxics--that need to be removed to meet
federal and state water quality standards.
Data on land use. Better data are needed on what lands are currently
being used to cultivate feedstocks, what lands may be most suitable for
future cultivation, and how land is actually being managed, according
to experts and officials. For example, some experts and officials told
us there is a need for improved data on the status and trends in the
CRP. According to a CRP official, USDA does not track what happens to
land after it is withdrawn from the CRP. Such data would be useful
because it would help officials gain a better understanding of the
extent to which marginal lands are being put back into production. In
addition, improved data on land use would help better target and remove
the least productive lands from agricultural production, resulting in
water supply and water quality benefits because these lands generally
require greater amounts of inputs, according to these experts and
officials. Research is also needed to determine optimal placement of
feedstocks and use of agricultural conservation practices to get the
best yields and minimize adverse environmental impacts.
Farmer decision making. Several experts and officials told us that a
better understanding of how farmers make cultivation decisions, such as
which crops to plant or how to manage their lands, is needed in the
context of the water resource effects of biofuel feedstocks.
Specifically, several experts and officials said that research is
needed to better understand how farmers decide whether to adopt
agricultural conservation practices. In particular, some experts and
officials said research should explore how absentee ownership of land
affects the choice of farming practices. These experts and officials
told us it is common for landowners to live elsewhere and rent their
farmland to someone else. For example, in Iowa, 50 percent of
agricultural land is rented, according to one expert, and renters may
be making cultivation decisions that maximize short-term gains rather
than focusing on the long-term health of the land. In addition, several
experts and officials said that research is needed to understand the
cultural pressures that may make farmers slow to adopt agricultural
conservation practices. For example, some experts and officials we
spoke with said that some farmers may be hesitant to move away from
traditional farming approaches.
Conversion. Existing and emerging technology innovations, such as those
discussed earlier in the report, may be able to address some effects of
conversion on water resources, but more research into optimizing
current technologies is also needed, according to experts. For example,
research into new technologies that further reduce water needs for
biorefinery cooling systems would have a significant impact on the
overall water use at a biorefinery, according to several experts.
Congress is considering legislation--the Energy and Water Research
Integration Act--that would require DOE's research, development, and
demonstration programs to seek to advance energy and energy efficiency
technologies that minimize freshwater use, increase water use
efficiency, and utilize nontraditional water sources with efforts to
improve the quality of that water.[Footnote 42] It would also require
the Secretary of Energy to create a council to promote and enable, in
part, improved energy and water resource data collection. Similarly,
with regard to conversion facilities for the next generation
feedstocks, further research is needed to ensure that the next
generation of biorefineries is as water efficient as possible. For
example, for the conversion of algae into biofuels, research is needed
on how to extract oil from algal cells so as to preserve the water
contained in the cell, which would allow some of that water to be
recycled.
Storage and distribution. EPA officials noted that additional research
related to storage and distribution of biofuels is also needed to help
reduce the effects of leaks that can result from the storage of biofuel
blends in incompatible tank systems. Although EPA has some research
under way, more is needed into the compatibility of fuel blends
containing more than 10 percent ethanol with the existing fueling
infrastructure. In addition, research should evaluate advanced
conversion technologies that can be used to produce a variety of
renewable fuels that can be used in the existing infrastructure.
Similarly, research is needed into biodiesel distribution and storage,
such as assessing the compatibility of blends greater than 5 percent
with the existing storage and distribution infrastructure.
In addition, experts and officials identified the following needs for
better data on local and regional water resources:
Water availability data. Because some local aquifers and surface water
bodies are already stressed, many experts called for more and better
data on water resources.[Footnote 43] Although USGS reports data on
water use every 5 years, the agency acknowledges that it does not have
good estimates of water use for biofuel production for irrigation or
fuel production, so it is unclear how much water has been or will be
actually consumed with increases in cultivation and conversion of
biofuel feedstocks. Furthermore, some experts and officials told us
that even when local water data are available, the data sources are
often inconsistent or out of date. For example, the data may capture
different information or lack the information necessary for making
decisions regarding biofuel production.
According to several experts and officials, better data on water
supplies would also help ensure that new biorefineries are built in
areas with enough water for current and future conversion processes.
Although biorefineries account for only a small percentage of water
used during the biofuel production process, the additional withdrawals
from aquifers can affect other users that share these water sources.
Improving water supply data would help determine whether the existing
water supplies can support the addition of a biorefinery in a
particular area. Some experts also noted the need for research on the
availability of lower-quality water sources such as brackish
groundwater, which could be used for cultivation of some next
generation feedstocks, especially algae. Better information is
necessary to better define the spatial distribution, depth, quantity,
physical and chemical characteristics, and sustainable withdrawal rates
for these lower-quality water sources, and to predict the long-term
effects of water extraction.
Linkages between datasets. Some experts also cited a need for better
linkages between existing datasets. For example, datasets on current
land use could be combined with aquifer data to help determine what
land is available for biofuel feedstock cultivation that would have
minimal effects on water resources. In addition, some experts said that
while there are data that state agencies and private engineering
companies have collected on small local aquifers, a significant effort
would be required to identify, coordinate, and analyze this information
because linkages do not currently exist.
Geological process data. Several experts and officials also said that
research into geological processes is needed to understand the rate at
which aquifers are replenished and the impact of increased biofuel
production on those aquifers. Although research suggests there should
be sufficient water resources to meet future biofuel feedstock
production demands at a national level, increased production may lead
to significant water shortages in certain regions. For example,
additional withdrawals in states relying heavily on irrigation for
agriculture may place new demands on already stressed aquifers in the
Midwest. Even in water-rich states, such as Iowa, concerns have arisen
over the effects of increased biofuel production, and research is
needed to assess the hydrology and quality of a state's aquifers to
help ensure it is on a path to sustainable production, according to one
state official.
Agency Comments and Our Evaluation:
We provided a draft of this report to USDA, DOE, DOI, and EPA for
review and comment. USDA generally agreed with the findings of our
report and provided several comments for our consideration.
Specifically, USDA suggested that we consider condensing our discussion
of agricultural practices, equipment, and grower decisions, as these
items may or may not be relevant depending on the feedstock or
regulatory control. However, we made no revisions to the report because
we believe that cultivation is a significant part of the biofuels life
cycle, and these items are relevant and necessary to consider when
discussing the potential effect of biofuel production on water
resources. USDA also noted that the report is more focused on corn
ethanol production than next generation biofuels and that we had not
adequately recognized industry efforts to be more sustainable through a
movement toward advanced biofuels. Given the maturity of the corn
ethanol industry, the extent of knowledge about the effects on water
supply and quality from cultivation of corn and its conversion into
ethanol, and the uncertainty related to the effects of next generation
biofuel production, we believe the balance in the report is
appropriate. Moreover, although the shift toward next generation
biofuels is a positive step in terms of sustainability, this industry
is still developing and the full extent of the environmental benefits
from this shift is still unknown. USDA also provided technical
comments, which we incorporated as appropriate. See appendix III for
USDA's letter.
DOE generally agreed with our findings and approved of the overall
content of the report and provided several comments for our
consideration. Specifically, DOE noted that it may be too early to make
projections on the amount of CRP land that will be converted and the
amount of additional inputs that will be needed for cultivation of
biofuel feedstocks. In addition, DOE suggested we expand our discussion
of efforts to address risks of ethanol transport and note the water use
associated with the production of biomass-to-liquid fuels. We adjusted
the text as appropriate to reflect these suggestions. DOE also
suggested that the report should discuss water pricing; however, this
was outside the scope of our review. See appendix IV for DOE's letter.
In its general comments, DOI stated that the report is useful and
agreed with the finding on the need for better data on water resources
to aid the decision about where to cultivate feedstocks and locate
biorefineries. DOI also suggested that the report should include a
discussion of the other environmental impacts of biofuel production,
such as effects on wildlife habitat or effects on soil. In response, we
note that this report was specifically focused on the impacts of
biofuel production on water resources; however, for a broader
discussion of biofuel production, including other environmental
effects, see our August 2009 report.[Footnote 44] DOI also provided
additional technical comments that we incorporated into the report as
appropriate. See appendix V for DOI's letter.
EPA did not submit formal comments, but did provide technical comments
that we incorporated into the final report as appropriate.
We are sending copies of this report to interested congressional
committees; the Secretaries of Agriculture, Energy, and the Interior;
the Administrator of the Environmental Protection Agency; and other
interested parties. In addition, the report will be available at no
charge on the GAO Web site at [hyperlink, http://www.gao.gov].
If you or your staff have questions about this report, please contact
us at (202) 512-3841 or mittala@gao.gov or gaffiganm@gao.gov. Contact
points for our Offices of Congressional Relations and Public Affairs
may be found on the last page of this report. GAO staff who made key
contributions to this report are listed in appendix VI.
Sincerely yours,
Signed by:
Ms. Anu K. Mittal:
Director, Natural Resources and Environment:
Signed by:
Mark E. Gaffigan:
Director, Natural Resources and Environment:
[End of section]
Appendix I: Objectives, Scope, and Methodology:
Our objectives for this review were to describe (1) the known water
resource effects of biofuel production in the United States; (2) the
agricultural conservation practices and technological innovations that
exist or are being developed to address these effects and any barriers
that may prevent the adoption of these practices and technologies; and
(3) key research needs regarding the effects of biofuel production on
water resources.
To address each of these objectives, we conducted a systematic analysis
of relevant articles of relevant scientific articles, U.S.
multidisciplinary studies, and key federal and state government reports
addressing the production of biofuels and its impact on water supply
and quality, including impacts from the cultivation of biofuel
feedstock and water use and effluent release from biofuel conversion
processes. In conducting this review, we searched databases such as
SciSearch, Biosis Previews, and ProQuest and used a snowball technique
to identify additional studies, asking experts to identify relevant
studies and reviewing studies from article bibliographies. We reviewed
studies that fit the following criteria for selection: (1) the research
was of sufficient breadth and depth to provide observations or
conclusions directly related to our objectives; (2) the research was
targeted specifically toward projecting or demonstrating effects of
increased biofuel feedstock cultivation, conversion, and use on U.S.
water supply and water quality; and (3) typically published from 2004
to 2009. We examined key assumptions, methods, and relevant findings of
major scientific articles, primarily on water supply and water quality.
We believe we have included the key scientific studies and have
qualified our findings where appropriate. However, it is important to
note that, given our methodology, we may not have identified all of the
studies with findings relevant to these three objectives. Where
applicable, we assessed the reliability of the data we obtained and
found them to be sufficiently reliable for our purposes.
In collaboration with the National Academy of Sciences, we identified
and interviewed recognized experts affiliated with U.S.-based
institutions, including academic institutions, the federal government,
and research-oriented entities. These experts have (1) published
research analyzing the water resource requirements of one or more
biofuel feedstocks and the implications of increased biofuels
production on lands with limited water resources, (2) analyzed the
possible effects of increased biofuel production on water, or (3)
analyzed the water impacts of biofuels production and use. Together
with the National Academy of Sciences' lists of experts, we identified
authors of key agricultural and environmental studies as a basis for
conducting semistructured interviews to assess what is known about the
effects of the increasing production of biofuels and important areas
that need additional research. The experts we interviewed included
research scientists in such fields as environmental science, agronomy,
soil science, hydrogeology, ecology, and engineering.
Furthermore, to gain an understanding of the programs and plans states
have or are developing to address increased biofuel production, we
conducted in-depth reviews of the following five states: Georgia, Iowa,
Minnesota, Nebraska, and Texas. We selected these states based on a
number of criteria: ethanol and biodiesel production levels, feedstock
cultivation type, reliance on irrigation, geographic diversity among
states currently producing biofuels, and approaches to water resource
management and law. For each of the states, we analyzed documentation
from and conducted interviews with a wide range of stakeholders to gain
the views of diverse organizations covering all stages of biofuel
production. These stakeholders included relevant state agencies,
including those responsible for oversight of agriculture, environmental
quality, and water and soil resources; federal agency officials with
responsibility for a particular state or region, such as officials from
the Department of the Interior's U.S. Geological Survey (USGS), the
U.S. Department of Agriculture's (USDA) Natural Resources Conservation
Service, and the Environmental Protection Agency (EPA); university
researchers; industry representatives; feedstock producers; and
relevant nongovernmental organizations, such as state-level corn
associations, ethanol producer associations, and environmental
organizations. We also conducted site visits to Iowa and Texas to
observe agricultural practices and the operation of selected biofuels
production plants.
We also interviewed senior officials, scientists, economists,
researchers, and other federal officials from USDA, the Departments of
Defense and Energy, EPA, the National Aeronautics and Space
Administration, the Department of Commerce's National Oceanic and
Atmospheric Administration, the National Science Foundation, and USGS
about effects on the water supply and water quality during the
cultivation of biofuel feedstocks and the conversion and storage of the
finished biofuels. In addition, we interviewed state officials from
Georgia, Iowa, Minnesota, Nebraska, and Texas as well as agricultural
producers and representatives of biofuel conversion facilities to
determine the impact of biofuels production in each state. We also
interviewed representatives of nongovernmental organizations, such as
the Renewable Fuels Association, the Biotechnology Industry
Organization, the Pacific Institute, and the Fertilizer Institute.
To conduct the interview content analysis, we reviewed interviews,
selected relevant statements from the interviews, and identified and
labeled trends using a coding system. Codes were based on trends
identified by previous GAO biofuel-related work, background information
collected for the review, and the interviews for this review. The
methodology for each objective varied slightly, because the first
objective focused on regional differences and therefore relied on case
study interviews, while analysis performed for the remaining two
objectives used expert interviews in addition to case study interviews.
Once relevant data were extracted and coded, we used the coded data to
identify and analyze trends. For the purposes of reporting our results,
we used the following categories to quantify responses of experts and
officials: "some" refers to responses from 2 to 3 individuals,
"several" refers to responses from 4 to 6 individuals, and "many"
refers to responses from 7 or more individuals.
We conducted our work from January 2009 to November 2009 in accordance
with all sections of GAO's Quality Assurance Framework that are
relevant to our objectives. The framework requires that we plan and
perform the engagement to obtain sufficient and appropriate evidence to
meet our stated objectives and to discuss any limitations in our work.
We believe that the information and data obtained, and the analysis
conducted, provide a reasonable basis for any findings and conclusions
in this product.
[End of section]
Appendix II: Examples of Agricultural Practices Available to Reduce the
Water Quality and Water Supply Effects of Feedstock Cultivation for
Biofuels:
Soil erosion prevention:
Agricultural conservation practice: Crop residue management;
Description: Any tillage method that leaves a portion of the previous
crop residues (unharvested portions of the crop) on the soil surface;
Potential environmental benefits:
* Reduces soil erosion caused by tillage and exposure of bare soil to
wind and water;
* Reduces water lost to evaporation;
* Improves soil quality;
* Reduces sediment and fertilizer runoff.
Agricultural conservation practice: No-till;
Description: Method that leaves soil and crop residue undisturbed
except for the crop row where the seed is placed in the ground;
Potential environmental benefits:
* Reduces soil erosion caused by tillage and exposure of bare soil to
wind and water;
* Reduces water lost to evaporation;
* Improves soil quality by improving soil organic matter;
* Reduces sediment and fertilizer runoff.
Agricultural conservation practice: Cover crops;
Description: A close-growing crop that temporarily protects the soil
during the interim period before the next crop is established;
Potential environmental benefits:
* Reduces erosion;
* Reduces nitrate leaching;
* Integrates crops that store nitrogen from the atmosphere (such as
soy), replaces the nitrogen that corn and other grains remove from the
soil;
* Reduces pesticide use by naturally breaking the cycle of weeds,
insects, and diseases;
* Improves soil quality by improving soil organic matter.
Nutrient pollution reduction:
Agricultural conservation practice: Crop rotation;
Description: Change in the crops grown in a field, usually in a planned
sequence. For example, crops could be grown in the following sequence,
corn-soy-corn, rather than in continuous corn;
Potential environmental benefits:
* Integrates crops that obtain nitrogen from the atmosphere (such as
soy), replaces the nitrogen that corn and other grains remove from the
soil;
* Reduces pesticide use by naturally breaking the cycle of weeds,
insects, and diseases.
Agricultural conservation practice: Nutrient management;
Description: Use of nutrients to match the rate, timing, form, and
application method of fertilizer to crop needs;
Potential environmental benefits:
* Reduces nutrient runoff and leaching.
Agricultural conservation practice: Subsurface fertilizer application;
Description: Injection of fertilizer below the soil surface;
Potential environmental benefits:
* Reduces runoff and gaseous emission from nutrients.
Agricultural conservation practice: Controlled-release fertilizers;
Description: Use of fertilizers with water-insoluble coatings that can
prevent water-soluble nitrogen from dissolving;
Potential environmental benefits:
* Reduces nutrient runoff and leaching;
* Increases the efficiency of the way nutrients are supplied to and are
taken up by the plant, regardless of the crop.
Agricultural conservation practice: Controlled drainage;
Description: Water control structures, such as a flashboard riser,
installed in the drainage outlet allow water level to be raised or
lowered as needed;
Potential environmental benefits:
* Minimizes transport of nutrients to surface waters.
Irrigation techniques:
Agricultural conservation practice: Subsurface drip irrigation systems;
Description: Irrigation systems buried directly beneath the crop apply
water directly to the root zone;
Potential environmental benefits:
* Minimizes water lost to evaporation and runoff.
Agricultural conservation practice: Low-energy precision-application
systems;
Description: Irrigation systems that operate at lower pressures and
have higher irrigation-water application and distribution efficiencies;
Potential environmental benefits:
* Minimizes net water loss and energy use.
Agricultural conservation practice: Reclaimed water use;
Description: Water recovered from domestic, municipal, and industrial
wastewater treatment plants that has been treated to standards that
allow safe reuse for irrigation;
Potential environmental benefits:
* Reduces demand on surface and ground waters.
Multiple benefits:
Agricultural conservation practice: Wetland restoration;
Description: Restoration of a previously drained wetland by filling
ditches or removing or breaking tile drains;
Potential environmental benefits:
* Reduces flooding downstream;
* Filters sediment, nutrients, and chemicals;
* Provides habitat for wetland plants, amphibians, and birds.
Agricultural conservation practice: Riparian buffer zones;
Description: Strips or small areas of land planted along waterways in
permanent vegetation that help control pollutants and promote other
environmental benefits;
Potential environmental benefits:
* Traps sediment;
* Filters nutrients;
* Provides habitat and corridors for fish and wildlife.
Agricultural conservation practice: Precision agriculture;
Description: A system of management of site-specific inputs (e.g.,
fertilizer, pesticides) on a site-specific basis such as land
preparation for planting, seed, fertilizers and nutrients, and pest
control. Precision agriculture may be able to maximize farm production
efficiency while minimizing environmental effects. Key technological
tools used in this approach include global positioning systems,
geographic information systems, real-time soil testing, real-time
weather information, etc;
Potential environmental benefits:
* Reduces nutrient runoff and leaching;
* Reduces erosion;
* Reduces pesticide use.
[End of table]
Source: GAO analysis.
[End of section]
Appendix III: Comments from the U.S. Department of Agriculture:
USDA:
United States Department of Agriculture:
Research, Education, and Economics:
Agricultural Research Service:
Office of the Administrator:
James L. Whitten Federal Building:
Room 302-A:
1400 Independence Avenue, SW:
Washington, D.C. 20250-0300:
An Equal Opportunity Employer:
Ms. Anu Mittal:
Government Accountability Office:
Director, Natural Resources and Environment:
441 G. Street, NW:
Washington, D.C. 20548:
Dear Ms. Mittal:
Thank you for the opportunity to review the U.S. Government
Accountability Office Draft Report, Energy-Water Nexus: Many
Uncertainties Remain About National and Regional Effects of Increased
Biofuel Production on Water Resources (GAO-10-116).
The Department of Agriculture (USDA) has reviewed the GAO Draft Report
and is in general agreement with its findings. We are impressed with
its comprehensiveness, the broad scope of topics covered, and accurate
assessment of those issues. We agree with the report's general
contention regarding the uncertainties of the availability of water
resources to sustain increased biofuel production. Moreover, several of
the specific issues cited”such as the potential for ground water
contamination from benzene production in underground storage tanks
(UST)”provide great insight into the many infrastructure deployment
challenges currently facing biofuels production and distribution. The
report also does an excellent job laying out the parameters that frame
the link between bioenergy and water resource management, thus
providing an excellent starting point for the establishment of research
and development needs to address water availability and quality issues
related to increased production of biofuels. Some substantive comments
on the report are as follows:
1. We note that some topics stray from the overarching issue of
bioenergy production and water management. For instance, the report
discusses details of conservation tillage practices, the need for
planting and harvesting equipment, and decisions that a grower might or
might not make related to production and environmental concerns. Some
of these questions may or may not be relevant depending on the
biofeedstock to be produced or may be more dependent on regulatory
control. Condensing and shortening these areas could improve the focus
of the report.
2. The report documents the move toward advanced biofuels development
and notes that many producers are beginning to adopt feedstocks that
use less water. The report fails to adequately recognize the degree to
which industry is already moving along a more sustainable development
path.
3. The Draft report allocates significant space and attention to grain
based ethanol production, even as concentrated efforts and policies are
focusing on next generation biofuels.
USDA's technical and specific comments are attached.
Again, thank you for the opportunity to review.
Sincerely,
Signed by:
[Illegible] for:
Edward B. Knipling:
Administrator:
Enclosure:
[End of section]
Appendix IV: Comments from the Department of Energy:
Department of Energy:
Washington, DC 20585:
November 12, 2009:
Mr. Mark Gaffigan:
Director:
Natural Resources and Environment:
U.S. Government Accountability Office:
441 G Street, NW:
Washington, DC 20548:
Dear Mr. Gaffigan:
Thank you for the opportunity to comment on the draft GAO Report
titled: "Energy-Water Nexus: Many Uncertainties Remain About National
and Regional Effects of Increased Biofuel Production on Water
Resources" (GA0-10-116). The Department of Energy (DOE) appreciates the
effort put forth by GAO with regard to this report and is in general
agreement with GAO's findings and approves of the overall content of
the report, but would like to take this occasion to reiterate its
assertion that certain sections of the report would benefit from
further revision.
First, statements regarding the likely need for additional nutrients
and pesticide inputs on marginal lands (page 11) and the role of
biofuels in motivating farmers to return Conservation Reserve Program
(CRP) land to row crop production (page 12) are speculative. It could
be noted that alternative views exist and that it is too early to make
projections for CRP conversion and for whether or not additional inputs
are needed.
Second, the section on storage and distribution is appropriate but
could be expanded. This section would provide a clearer overview of
risks of biofuels if they were put into context. The inclusion of a
brief description of the risks associated with storing and transporting
petroleum products would be a useful comparison to the risks of
biofuels storage and distribution. The EIA suggests that the report
recognize the dramatic expansion of El0 motor fuel over the past few
years and the governmental and industry efforts to address the
associated risks of handling ethanol blends. The Department of
Transportation and its Pipeline and Hazardous Material Safety
Administration (PHMSA) division, in conjunction with industry groups,
are engaged in efforts to deal with the associated risks in handling
ethanol blends.
Third, it should be noted that in EIA's Annual Energy Outlook 2009
[hyperlink, http://www.cia.doe.gov/oiaf/aeo/index.html] projections
there is a growing use of biomass-to-liquids (BTL) fuels (5 billion
gallons by 2030) to satisfy the EISA 2007 cellulosic biofuels mandate.
EIA believes it might be worth mentioning that the production process
for BTL requires no continuous water inputs (water is used for cooling
but in a closed loop system).
Moreover, pyrolysis oils which are also being currently considered as
cellulosic biofuels use no process water as well. The table in the
Appendix that summarizes the potential environmental benefits of the
agricultural practices is very useful. The inclusion of a similar table
summarizing the pros and cons of the various biofuel conversion
processes discussed in the text would be a useful addition.
Finally, DOE believes it would be appropriate to raise the issue of
price reform for water in this report. Price sends an important signal
to consumers. Distorted prices are resulting in overconsumption of
water because the full cost of water is not always passed on to the
consumer. In areas where water is too inexpensive to monitor,
incomplete data on water use exists.
DOE trusts that GAO will consider these suggestions, but does not deem
it necessary that the report be revised on account of the three issues
raised. Thank you again for the opportunity to comment on the draft
Report. We look forward to working with GAO as we continue our efforts
to develop the potential of biofuels.
If you have any questions, please contact me or Ms. Martha Oliver,
Office of Congressional and Intergovernmental Affairs, at (202) 586-
2229.
Sincerely,
Signed by:
Jacques Beaudry-Losique:
Deputy Assistant Secretary for Renewable Energy:
Office of Technology Development:
Energy Efficiency and Renewable Energy:
[End of section]
Appendix V: Comments from the Department of the Interior:
United States Department or the Interior:
Office Of The Secretary:
Washington, DC 20240:
November 12 2009:
Ms. Anti Mittal:
Director, Natural Resources and Environment:
U.S. Government Accountability Office:
441 G Street, N.W.
Washington, D.C. 20548:
Dear Ms. Mittal:
Thank you for providing the Department of the Interior the opportunity
to review and comment on the draft Government Accountability Office
report entitled, "Energy-Water Nexus: Many Uncertainties Remain about
National and Regional Effects of Increased Biotite! Production on Water
Resources" (GAO-10-116).
The GAO report explicitly makes no recommendations: however, we would
like to provide technical comments and some general comments. We hope
these comments will assist you in preparing the final report. if you
have any questions or need additional information, please contact Donna
Myers, Chief, National Water-Quality Assessment Program, United States
Geological Survey, at (703) 648-5012.
Sincerely,
Signed by:
Anne J. Castle:
Assistant Secretary for Water and Science:
Enclosures:
[End of section]
Appendix VI: GAO Contacts and Staff Acknowledgments:
GAO Contacts:
Anu Mittal, (202) 512-3841 or mittala@gao.gov:
Mark Gaffigan, (202) 512-3841 or gaffiganm@gao.gov:
Staff Acknowledgments:
In addition to the contact named above, Elizabeth Erdmann, Assistant
Director; JoAnna Berry; Mark Braza; Dave Brown; Muriel Brown; Colleen
Candrl; Miriam Hill; Carol Kolarik; Micah McMillan; Chuck Orthman; Tim
Persons; Nicole Rishel; Ellery Scott; Ben Shouse; Jeanette Soares;
Swati Thomas; Lisa Vojta; and Rebecca Wilson made significant
contributions to this report.
[End of section]
Footnotes:
[1] Pub. L. No. 110-140, § 201 (2007). The act authorizes the
Administrator of the Environmental Protection Agency (EPA), in
consultation with the Secretaries of Agriculture and Energy, to waive
the RFS levels established in the act, by petition or on the
Administrator's own motion, if meeting the required level would
severely harm the economy or environment of a state, a region, or the
United States or there is an inadequate domestic supply. Throughout
this report, the RFS levels established in the act are referred to as
requirements, even though these levels could be waived by the EPA
Administrator.
[2] For additional information on the effects of biofuel production,
see GAO, Biofuels: Potential Effects and Challenges of Required
Increases in Production and Use, [hyperlink,
http://www.gao.gov/products/GAO-09-446] (Washington, D.C.: Aug. 25,
2009).
[3] Other major sources of freshwater withdrawals in the United States
are thermoelectric (39 percent), public water supply (13 percent), and
industrial (5 percent) uses. The remaining withdrawals consist of
mining (1 percent), domestic (1 percent), aquaculture (1 percent), and
livestock (1 percent) uses. S. Hutson et al., "Estimated Use of Water
in the United States in 2000," Circular 1268, U.S. Geological Survey
(2004).
[4] The RFS applies to transportation fuel sold or introduced into
commerce in the 48 contiguous states. However, the Administrator of EPA
is authorized, upon a petition from Alaska or Hawaii, to allow the RFS
to apply in that state. On June 22, 2007, Hawaii petitioned EPA to opt
into the RFS, and the Administrator approved that request. For the
purposes of this report, statements that the RFS applies to U.S.
transportation fuel refer to the 48 contiguous states and Hawaii.
[5] Pub. L. No. 110-140, § 201 (2007).
[6] Wu, M., M. Mintz, M. Wang, and S. Arora. "Consumptive Water Use in
the Production of Ethanol and Petroleum Gasoline," Center for
Transportation Research, Energy Systems Division, Argonne National
Laboratory (Argonne, Ill., January 2009.)
[7] According to the National Corn Growers Association, across the
United States the acres of corn irrigated represent 21 percent of the
total irrigated crop area. The volume of water used in corn irrigation
represents 7 percent of all irrigation water.
[8] McGuire, V.L., "Water-level changes in the High Plains aquifer,
predevelopment to 2007, 2005-2006, and 2006-2007," USGS SIR 2009-5019
(2009).
[9] Maupin, M.A., and Barber, N.L., "Estimated withdrawals from
principal aquifers in the United States," USGS Circular 1279 (2000).
[10] Increased corn cultivation could also result in soil erosion,
which reduces fertility by reducing nutrient-rich topsoil. It also
contributes to sedimentation, which fills channels in deep areas of
waterbodies, affecting aquatic life and recreation. Sediment can also
carry contaminants, such as fertilizers and pesticides.
[11] The algae themselves do not reduce oxygen; instead, when the algae
die, bacteria deplete oxygen as the algae decompose.
[12] Dried distiller's grain, a byproduct of ethanol production used in
animal feed, also contains high levels of phosphorous and contributes
to overenrichment of surface and marine waters.
[13] Diaz, Robert and Rutger Rosenberg, "Spreading Dead Zones and
Consequences for Marine Ecosystems," Science, vol. 321 (2008): pp. 926-
929.
[14] Alexander, Richard, Richard Smith, Gregory Schwarz, Elizabeth
Boyer, Jacqueline Nolan, and John Brakebill, "Difference in Phosphorous
and Nitrogen Delivery to the Gulf of Mexico from the Mississippi River
Basin," Environmental Science and Technology, vol. 42, no. 3 (2008):
pp. 822-830.
[15] Gilliom et al., "The Quality of Our Nation's Waters--Pesticides in
the Nation's Streams and Ground Water, 1992-2001," USGS Circular 1291
(2006): p. 172.
[16] While some agricultural residues must be left on the ground to
maintain soil moisture and carbon content, a significant portion of the
total can be removed in many areas. According to a DOE official, in
some parts of the country removal of a portion of the residue is needed
because the excess residue does not degrade quickly enough and
interferes with subsequent crop growth.
[17] National Research Council, Water Implications of Biofuels
Production in the United States. The National Academies Press,
Washington, D.C. (2008).
[18] Water is still lost with closed cultivation due to the cooling
needs of the closed systems, among other uses.
[19] In comparison, the recovery and refining of 1 gallon of crude oil
requires a total of 3.6 to 7.0 gallons of water. Wu, M. et al.,
"Consumptive Water Use in the Production of Ethanol and Petroleum
Gasoline," Center for Transportation Research, Energy Systems Division,
Argonne National Laboratory (Argonne, Ill., January 2009).
[20] DOE's Energy Information Administration's (EIA) Annual Energy
Outlook 2009 projects that there is a sufficient growth in use of
biomass-to-liquids (BTL) fuels to meet the EISA cellulosic biofuel
requirement and that the production process for BTL fuels does not
require continuous water inputs. BTL refers to processes for converting
biomass into a range of liquid fuels, such as gasoline and diesel. In
addition, EIA noted that certain oils currently eligible for inclusion
as cellulosic biofuels also do not use process water.
[21] Reverse osmosis is a filtration process used to purify freshwater
by, for example, removing the salts from it. This process is used to
treat water prior to discharging it from the ethanol plant.
[22] Glycerin results in elevated levels of biological oxygen demand,
which is a measure of how much oxygen it will take to break down the
material. According to EPA officials, biodiesel wastewater with small
amounts of glycerin and efficient recovery of methanol has a biological
oxygen demand of 10,000-15,000 mg/liter, compared to a normal wash
water biological oxygen demand of about 200 mg/liter. With glycerin,
biodiesel wastewater has a biological oxygen demand of 80,000 mg/liter.
Pure glycerin has a biological oxygen demand of 1,000,000 mg/liter.
[23] There are other hazards that may occur from releases of ethanol-
blended fuels. For example, some spills of gasoline with ethanol may
pose an explosion risk. Large-scale releases of ethanol have been shown
to degrade under anaerobic conditions to produce explosive
concentrations of methane. According to EPA, this can pose a
significant challenge for remediation contractors mitigating biofuel
spills. In addition, the methane generated in the subsurface can
migrate into overlying buildings, degrading indoor air quality.
[24] When ethanol is present, the ethanol is consumed by micro-
organisms in the soil before other, more harmful fuel constituents.
This decomposition takes up nutrients and oxygen needed to break down
benzene and related compounds. As a result, the benzene plume extends a
greater distance.
[25] Mackay, Douglas, Nicholas R. de Sieyes, Murray D. Einarson, Kevin
P. Feris, Alexander A. Pappas, Isaac A. Wood, Lisa Jacobson, Larry G.
Justice, Mark N. Noske, Kate M. Scow, and John T. Wilson. "Impact of
Ethanol on the Natural Attenuation of Benzene, Toluene, and o-Xylene in
a Normally Sulfate-Reducing Aquifer." Environmental Science Technology,
vol. 40 (2006): pp. 6123-6130; and Ruiz-Aguilar, G., K. O'Reilly, and
P. Alvarez. "A Comparison of Benzene and Toluene Plume Lengths for
Sites Contaminated with Regular vs. Ethanol-Amended Gasoline." Ground
Water Monitoring & Remediation, vol. 23, no. 1 (winter 2003): pp. 48-
53.
[26] EIA noted that use of E10 has dramatically increased over the past
few years and that there are governmental and industry efforts, such as
the U.S. Department of Transportation's Pipeline and Hazardous Material
Safety Administration, that work with industry groups to address risks
associated with handling ethanol blends.
[27] Some UST systems are specifically designed to store fuel
containing 85 percent ethanol. According to EPA officials, owners using
blends containing 85 percent ethanol generally work with a licensed
installer to use certified, compatible storage and dispensing
equipment. UST systems comprise many components; however, some of these
components have not been tested for use with high ethanol fuel blends.
[28] Any entity that withdraws more than 100,000 gallons a day (monthly
average) of surface water or 100,000 gallons a day (daily average) of
groundwater requires a water permit.
[29] See the USDA-NRCS 2003 Annual National Resources Inventory
[hylerlink,
http://www.nrcs.usda.gov/technical/NRI/2003/nri03eros-mrb.html].
[30] Low-energy precision-application center-pivot systems discharge
water between alternate crop rows planted in a circle. In subsurface
drip irrigation, drip tubes are placed from 6 to 12 inches below the
soil surface, the depth depending on the soil type, crop, and tillage
practices.
[31] In addition to genetically engineering crops, USDA officials
commented that traditional breeding techniques offer great potential
for decreasing water, nutrient, and pesticide requirements of biofuels
feedstocks.
[32] USDA officials noted that use of precision agriculture may also be
limited in the cultivation of cellulosic feedstocks due to the costs
involved.
[33] Cooling towers are used to control temperatures during the
conversion process by transferring the heat to cooler water. This heat
is then transferred via evaporation to the atmosphere.
[34] In one type of dry cooling system, steam flows through condenser
tubes and is cooled directly by fans blowing air across the outside of
these tubes to condense the steam back into liquid water.
[35] GAO, Energy-Water Nexus: Improvements to Federal Water Use Data
Would Increase Understanding of Trends in Power Plant Water Use,
[hyperlink, http://www.gao.gov/products/GAO-10-23] (Washington, D.C.:
Oct. 16, 2009).
[36] Wu, M. et al., "Consumptive Water Use in the Production of Ethanol
and Petroleum Gasoline," Center for Transportation Research, Energy
Systems Division, Argonne National Laboratory (Argonne, Ill., January
2009).
[37] Similar to ethanol, biobutanol is an alcohol that can be produced
from domestic feedstocks. However, biobutanol has a few advantages over
ethanol. Biobutanol has a higher energy content than ethanol and is
compatible with the existing infrastructure.
[38] Liquid hydrocarbons, such as petroleum, are a class of chemical
compounds containing only hydrogen and carbon. Potentially,
hydrocarbons can be derived from substitutes such as oils from plants
or algae.
[39] Evapotranspiration refers to the water lost to the atmosphere from
soil and water bodies (evaporation) and from plant leaves
(transpiration).
[40] National Research Council, Water Implications of Biofuels
Production in the United States, 2008.
[41] U.S. Department of Energy, "National Algal Biofuels Technology
Roadmap," Draft, 2009. In December 2008, DOE convened a workshop to
discuss and identify the critical barriers currently preventing the
economical production of algal biofuels at a commercial scale. As a
result of this workshop, DOE assembled a draft roadmap that highlights
a number of areas in need of additional research.
[42] H.R. 3598, 111th Cong. (2009).
[43] The Omnibus Public Land Management Act of 2009 requires, in part,
the Secretary of Interior, in coordination with the National Advisory
Committee on Water Information and state and local water resource
agencies, to establish a national water availability and use assessment
program. Pub. L. No. 111-11, § 9508(a) (2009), codified at 42 U.S.C. §
10368(a). This program will, among other things, provide a more
accurate assessment of the status of the water resources of the United
States. The program may address some of the water availability data
needs identified by the experts we spoke with.
[44] [hyperlink, http://www.gao.gov/products/GAO-09-446].
[End of section]
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