Integrating Water Sustainability into the Low Carbon Fuel Standard

TitleIntegrating Water Sustainability into the Low Carbon Fuel Standard
Publication TypeReport
Year of Publication2008
AuthorsFingerman K, Kammen DM, O'Hare M
Date Published09/2008
InstitutionUniversity of California, Berkeley
CityBerkeley, CA
Keywordsbiofuels, California, low-carbon fuel standard, water

The “water footprint” or “embedded water” of a product is seen as the amount of water consumed during its life cycle (Chapagain and Hoekstra, 2004). As the State of California implements the Low Carbon Fuel Standard (LCFS), a more complete view of environmental and social sustainability demands consideration be given to the effects that various pathways would have on water resources.

While the role of biofuels in a climate protection strategy is unclear owing to the global warming consequences of both direct and indirect land-use, water use remains another central issue and could be, in the words of a recent report, the “Achilles heel” of biofuel production (Keeney, 2006). This study projects the effects on California water resources from some scenarios of in-state feedstock and fuel production.

Many analyses of the water implications of bioenergy only take into account consumption by biorefineries. Because the feedstock cultivation phase of the biofuel production process is by far the most water-intensive part of the bioenergy life cycle, our analysis quantifies these consumptions as well. We find that on average over 1500 gallons of water are consumed (i.e. removed from productive use for a given hydrologic cycle – see Box 1) in the production of a single gallon of corn ethanol in California – with feedstock cultivation accounting for more than 99% of this use. In comparison, the amount of water required to produce the average daily diet in North America is 1330 gallons, the average in Western Europe is 1240 gallons, while in Sub-Saharan Africa, this figure is less than 500 gallons (Serageldin, 2001).

In some scenarios, the cultivation of biofuel feedstocks could serve to reduce the strain on California water resources insofar as thirstier crops are displaced by energy feedstocks. Often, however, a tradeoff exists between minimizing greenhouse gas (GHG) emissions and avoiding effects on a variety of other environmental criteria (Zah, Boni et al., 2007; Spatari et al., 2008). For example, developing understandings of indirect landuse change may bring increasing incentives not to displace current cultivation for bioenergy production (Delucchi, 2002, Searchinger et al., 2008, Jones et al., 2008). This could bring about extensification of agriculture onto currently uncultivated lands, which would mean applying irrigation water where none was required before, and so offsetting none of the new water consumption with reductions from displaced crops.

Our research shows that biofuel production in California could either increase or decrease the sustainability of the state’s water resource use. It also makes clear the feasibility and importance of estimating the water consumed in production of fuels from various feedstocks grown in different regions of the state. We suggest that rule-making under the LCFS consider water resources in hopes of pursuing a broader sustainable fuel system for California. We further suggest the incorporation of water sustainability as a task under the Alternative and Renewable Fuel and Vehicle Technology Program (AB 118) and other relevant renewable fuel legislation. Options available to the Air Resources Board in incorporating water sustainability into LCFS policies include:

(a) Ignore water resources, delegating this consideration to water programs
(b) Determine a “price” for water in Global Warming (GW) units and add it to Average Fuel Carbon Intensity (AFCI)
(c) Charge a tax on water use for biofuel production
(d) Establish a go/no-go rule for maximum water consumption per MJ of all fuels allowed under the LCFS
(e) Categorize counties/regions in California based upon water scarcity, establishing go/no-go rules for each county/region.

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