Water plays a critical role in many aspects of this life cycle. Water is also important for conversion of feedstocks into biofuels. In  particular, water is used for heating and cooling as well as for processing. 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. This will happen because corn requires  high applications of fertilizers relative to soybeans and other potential  biofuel feedstocks, such as perennial grasses. 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. 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. 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. 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. 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. 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. For example, technologies such as dry cooling systems are often  prohibitively expensive and can increase energy consumption. 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. 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. However,  according to the National Research Council, the current  evapotranspiration rates of crops grown on such lands is not well known. Cultivation of algae. 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. Conversion. 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. 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. Agency Comments and Our Evaluation

We provided a draft of this report to USDA, DOE, DOI, and EPA for review  and comment. USDA also  provided technical comments, which we incorporated as appropriate. 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. 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. Reduces pesticide use.
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.