For decades, the US and other countries have looked to biofuels to reduce emissions and petroleum imports, but is it a sustainable practice?
Biofuels, according to some, could be the next best choice when it comes to fuels that our current conventional transportation system can use. Unlike petroleum, a fossil fuel that comes out of the ground and emits carbon dioxide, biofuels are based on crops that recover the carbon dioxide emitted when they are burned. The result is nearly carbon neutral, if you include emissions during planting and harvesting. In the US and other countries, the addition of ethanol to gasoline, for example, results in somewhat fewer emissions, as well as reduced dependency on foreign petroleum imports, but is it all good news?
Interestingly, biofuels aren’t new at all, even the Germans were making potato-based rocket fuel back in WWII, and the Ford Model T ran on corn-based ethanol, but can biofuels replace an entire fossil-fuel-based infrastructure? Can biofuels replace coal-, oil- and natural-gas-fired power plants? Can biofuels replace gasoline, diesel, and aviation fuels? The short answer is “Yes, but…” because there is always a “but.” In this case, presented by Ike Kiefer, a US Air Force Journal writer, biofuel “cons” outweigh the “pros” by a significant margin.
Keifer asserts that biofuels have a power density* of “only 0.3 W/m2 (Watts per square meter)” while modern photovoltaic solar panels have a power density of around 6 W/m2. An oil well generates about 27 W/m2, and a nuclear power plant generates better than 50 W/m2. The result is that biofuels require vast amounts of land area to offset other fuel supplies. For example, to replace all oil used in the US for transportation with corn-based ethanol, it would require some 700 million acres of croplands, triple the amount of currently-harvested croplands. This doesn’t include all the other uses for fossil fuels we have in the US, which would require perhaps billions of acres that we just don’t have.
What do you think? Are biofuels a dead end?
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