NAS report on biofuels and water use and pollution


This morning the National Academy of Science released a report on the water-use and water-pollution implications of biofuels. A press statement from Jonathan Kaplan, NRDC's Sustainable Agriculture Project Director, will be is available on our web site shortly. The Institute for Agriculture and Trade Policy also has a good press release on the report available here.

The data in the chart below gives some sense of the urgency around water issues. While it's difficult to tease out exactly what role shifts in cropping patterns played in the surge in nitrogen loading in the Raccoon River, there can be no doubt that meeting the demand for corn for ethanol played a big part. The NAS report does a very even handed job of discussing the complexity of isolating and predicting the impacts of crop production for biofuels, but also is about as blunt as the NAS can be that our current path is unsustainable.

Below are my thoughts on the report, but before offering those up, I would also recommend last week's NPR's Science Friday, which included a good segment on biofuels. The guests included Dan Kammen from the Energy and Resources Group at UC Berkeley, Evan Ratliff, the author of the recent Wired article on biofuels, and Tim Appenzeller, an editor from National Geographic Magazine who edited the Magazine's recent article of biofuels. As I've mentioned before (here and here), these articles were good but failed to cover the policies needed to get biofuels right. This radio piece does a pretty good job of covering that territory for the general public especially during the caller questions portion.

So about that NAS report...

Top-line take away: The NAS report makes it clear that unless Congress acts decisively through the Farm Bill and comprehensive energy bill, increased biofuels production will increase water pollution from agriculture and intensify many regional and local water shortages. The report also details many agricultural practices, technologies, and alternative crops such as prairie grass that could help reduce total water-use and water-pollution while we increase the production of biofuels. But to deliver on the promise of biofuels, Congress must dramatically increase funding for Farm Bill conservation programs and reform them to get more conservation per dollar. We also need to shift our biofuels policies to improve environmental and energy security performance rather than simply increasing the volume of production.

The details: The NAS report provides a detailed discussion of corn and cellulosic ethanol and biodiesel and their water-use and water-quality impacts. The report also covers the technologies and practices that exist or are being developed that could help mitigate these impacts and general policy directions that could also help. The report does not do any forecasting of expected impacts under potential scenarios, nor does it make specific policy recommendations. However the report does reach the following conclusions:

“Staying the current policy path would likely result in the continued trend of expansion of corn-based ethanol production, driven by the economics of input costs and ethanol prices supplemented by the subsidy.” (Page 45.)

“If projected future increases in use of corn for ethanol production do occur, the increase in harm to water quality could be considerable.” (Page 45.)

“With the rapid expansion of ethanol production, some local communities and governments have not anticipated withdrawal levels or discharge volumes and have suffered the resulting water draw-downs and water treatment requirements. Mitigation will require effective withdrawal rules and enforcement and/or enhancement of existing state/federal rules on point discharge.” (Page 47.)

The Farm Bill: The report also calls out the Conservation Reserve Program, the Conservation Security Program, and the Environmental Quality Incentives Program as three programs that can contribute to managing and mitigating water-use and water quality impacts. As noted in the report, the ability of NRCS to target these programs where they will produce the greatest environmental benefits was reduced in 2002. (Page 46.) Congress should restore and increase targeting and other measures to get more benefits per dollar in the Farm Bill currently being debated. The report also notes that the conservation programs of the Farm Bill currently receive about $4 billion per year. (Page 46.) By comparison, the main ethanol tax credit is worth $0.54 per gallon and by the end of 2007, the US will have capacity to produce about 7 billion gallons per year, meaning that the direct subsidies for ethanol will be worth well over $3.5 billion. To counter balance the economic pressure to increase corn yields created by these subsidies and high oil prices, Congress needs to dramatically increase funding for these conservation programs.

The Energy Bill: The report does not directly refer to the comprehensive energy bills that the Senate passed in June and the House passed in August and that should be reconciled through conference this fall. However the report does state:

“Expansion of ethanol production to meet President Bush's call for 35 billion gallons annually by 2017 will drive increased corn production until marketable future alternatives are developed.” (Page 11.)

“All else being equal, the conversion of other crops or non-crop plants to corn will likely lead to much higher application rates of nitrogen (Figure 3-1). Given the correlation of nitrogen application rates to stream concentrations of total nitrogen, and of the latter to the increase in hypoxia in the nation’s waterbodies, the potential for additional corn-based ethanol production to increase the extent of these hypoxic regions is considerable. Since the dead zone in the Gulf of Mexico is already on the order of 10,000 square kilometers, the economic stakes are high.” (Page 23.)

“If taxpayer money can be spent on subsidies, it can also be used to provide incentives to encourage both the technology and the production of product and feedstock to meet public objectives. Performance subsidies could be designed to be paid when specific objectives such as energy-conversion efficiency and reducing the environmental impacts of feedstock production—especially water quality—are met.” (Page 46.)

The Senate energy bill would require 36 billion gallons of biofuels by 2022, and it is generally assumed that the final bill will also include a major increase in the renewable fuels standard. It is critical that any increase in the renewable fuels mandate include requirements for cellulosic biofuels and also performance standards and environmental safeguards.

Cellulosic biofuels: The report repeatedly describes the potential for cellulosic feedstocks to use less water and fewer chemical inputs and reduce soil erosion but also major unknowns surrounding the cultivation of these crops at the scales needed to supply a major ramp up of biofuels production. Cellulosic feedstocks and the technologies to convert them to liquid fuels are necessary to achieve large increases in biofuels production without the massive water-use and water-quality impacts that would result from corn. However, cellulosic biofuels are not sufficient to achieve a massive increase in biofuels while also reducing the total stress on our aquifers and pollution loading in our watersheds. We also need Farm Bill and energy bill policies that will establish environmental safeguards and performance standards to ensure that biofuels deliver on their environmental promises.

Factoids and quotables:

  • "Over the last 40 years, the volume of the Chesapeake Bay’s dead zone has more than tripled, and in many summers comprises almost a quarter of the water in the mainstem Bay." (Page 23.)
  • The growing of corn to make ethanol consumes about 200 times more water than the processing of that corn into ethanol. (Page 38.)
  • Refining corn into ethanol currently consumes about 4 gallons of water per gallon of ethanol. Technologies exist to reduce this at least to 2 gallons per gallon. Biological processing of cellulose into ethanol is expected to start much higher but eventually be about the same. Thermochemical processing may be significantly lower. For comparison gasoline requires about 1.5 gallons of water per gallon of gasoline. (Pages 35-37.)