BIOMASS INTEL

Much has been made about the sustainability of biomass-derived energy in recent years, read about indirect land use change and carbon accounting errors here and here.  But with RPS and RFS goals looming and global uncertainty surrounding Peak Oil, the international scramble to secure biomass feedstock sources is on.  To do it right, countries, regions, and states governments must wrangle with evolving sustainability standards while accounting for growing water shortages.

While the carbon, land, and food-price impacts of biomass are hotly debated topics, less is known or understood about its connection to water.  In an article by Dominguez-Faus et al. published in “Environmental Science and Technology” in 2009, researchers examined the water footprint of biofuels and found that dedicated energy crops are huge water hogs.

In the Midwest, competition over decreasing water supplies and increasing irrigation demands for corn crops has led to protracted legal battles between Nebraska and Kansas (see Kansas v. Nebraska & Colorado, 538 U.S. 720 (2003)).  The region is already experiencing severe water deficits, which includes the Ogallala Aquifer, the lifeblood of the region’s agricultural industry stretching from South Dakota to Texas.  It is uncertain what demands a mature biofuel industry will place on such regions.

The chart below, taken from the study, lists the water requirements for energy production by different processes:

Energy Return of Water Invested (EROWI).

While climate change, Peak Oil, and other environmental limits necessitate a shift away from fossil fuels, as the chart above shows, water inputs will remain a thorny issue for biomass advocates.  Most regional water sources, both national and international, are subject to long-standing agreements that depend on mutual restraint.  As the Kansas/Nebraska dispute demonstrates, they are difficult to administer, and with increasing demand, difficult to stick to.  Internationally, water shortages are particularly worrisome as climate change leads to increasing desertification.

One of the thornier challenges for policymakers is how to assess and account for the sustainability of biomass feedstock sources, and in particular, the energy-water nexus.  A start would be to better integrate energy and water policy debates.

Image: Flickr/slgwv