Bio-energy, Sustainable or Not?
By vivi, 2010/4/15
In this Environmental Science and Sustainable Development (ES & SD) section, we mainly focus on the sustainability concerns, and those bioenergy that are unsustainable or even a threat, such as cellulosic ethanol in America.
Generally, biofuels can be divided into liquid biofuels (bioethanol, biodiesel, and other liquid biofuels), gas biofuels (biogas, biopropane, synthetic natural gas, syngas) and solid biofuels (wood, charcoal, biomass pellets). Which from the very beginning, people just put a prevailing trend to all these rising energy which are renewable. However, as time goes by, many controversial cases happened and showed not all bio-energy are environment-friendly or economic-benefit.
For example, Corn Biofuel (i.e. butanol, ethanol, biodiesel) is especially harmful because:
Row crops such as corn and soy cause 50 times more soil erosion than sod crops (e.g., hay) or more, because the soil between the rows can wash or blow away. If corn is planted with last year's corn stalks left on the ground (no-till), erosion is less of a problem, but only about 20% of corn is grown no-till. Soy is usually grown no-till, but insignificant residues to harvest for fuel.
Corn uses more water, insecticide, and fertilizer than most crops. Due to high corn prices, continuous corn (corn crop after corn crop) is increasing, rather than rotation of nitrogen fixing (fertilizer) and erosion control sod crops with corn.
The government has studied the effect of growing continuous corn, and found it increases eutrophication by 189%, global warming by 71%, and acidification by 6%.
Farmers want to plant corn on highly-erodible, water protecting, or wildlife sustaining Conservation Reserve Program land. Farmers are paid not to grow crops on this land. But with high corn prices, farmers are now asking the Agricultural Department to release them from these contracts so they can plant corn on these low-producing, environmentally sensitive lands.
Crop residues are essential for soil nutrition, water retention, and soil carbon. Making cellulosic ethanol from corn residues -- the parts of the plant we don’t eat (stalk, roots, and leaves) – removes water, carbon, and nutrients.
So before following bio-energy blindly, to take more attention to sustainability concerns seems pressing important. Carbon emissions, climate change, life-cycle impacts, biodiversity and species impacts, impacts on use of degraded lands etc. become public’s topic. Thus, in current society, to implement sustainable bioenergy production, we need environmental tools (e.g. impact assessment tools, agricultural tools, water resource tools, threatened species tools, invasive species tools etc.) and socio-economic tools (e.g. food security tool, gender tools, climate adaptation tools, economic tools etc.) working collaboratively, and give full play to the compilation of tools and approaches (Keam, S. and McCormick, N. 2008).
More information is available: http://data.iucn.org/dbtw-wpd/edocs/2008-057.pdf
Reference:
Keam, S. and McCormick, N. (2008). Implementing Sustainable Bioenergy Production; A Compilation of Tools and Approaches. Gland, Switzerland: IUCN. 32pp.
Alice Friedemann (2007) Peak Soil: Why cellulosic ethanol, iofuels are unsustainable and a threat to America, Culture Change
