Corn ethanol curse strikes again? Algae fuels have large footprint

Could algae-based biofuels suffer the same fate as the now much-discredited corn-based ethanol? They might, if we don’t find ways to reduce algal fuel’s environmental impact, according to a new study.

After the race to turn corn into fuel helped spark a global spike in food prices, clean-energy proponents turned their sights to so-called “second-generation” biofuel stocks. These include non-food crops like switchgrass and algae, as well crop waste and lumber waste. Algae have been widely considered to have especially great potential, since they can be grown in marginal areas that don’t compete with prime food-growing farmlands.

But there’s a problem — or, rather, several problems — with that idea, according to a team of researchers from the University of Virginia. Their new study finds that growing algae for fuel is more energy- and water-intensive than other biofuel crops, including switchgrass, canola and corn. Oh, and it also produces more greenhouse gas emissions than those other sources.

“Given what we know about algae production pilot projects over the past 10 to 15 years, we’ve found that algae’s environmental footprint is larger than other terrestrial crops,” said Andres Clarens, the study’s lead author.  “Before we make major investments in algae production, we should really know the environmental impact of this technology.”

One solution could be to grow algae in ponds behind wastewater treatment facilities. That way, producers could use the wastewater as a source for phosphorus and nitrogen, two nutrients that algae needs. That strategy would also prevent those nutrients from, as they now are, being discharged into local waterways.

Another plus is that feeding algae with phosphorus and nitrogen from wastewater reduces the biofuel’s fossil fuel footprint, since those nutrient are currently produced using petroleum.

It’s a situation the Virginia researchers have seen before.

“People were investing in ethanol refineries, but then we realised that it takes a lot of petroleum to grow corn and convert it to ethanol,” Clarens said. “By the time you get done, you’ve used almost as much petroleum to make ethanol that you would have if you just put the oil straight into your car.”

Today’s limitations, though, doesn’t mean algae doesn’t have potential. In addition to not competing with food crops, algae tend to yield more energy than other biofuel crops like corn or switchgrass. Their high fat content also promises to make refining more efficient than with other fuel stocks.

Still, significant hurdles still stand in the way of algae becoming a cheap and easy source of fuel. And those hurdles need to be removed soon before we put too many eggs in algae’s basket.

Both governments and energy companies are already spending hundreds of millions of dollars for algae research. Last year, for example, ExxonMobil said it was investing $600 million into the quest for algal biofuels. And just last week, the US Department of Energy announced it was directing $78 million in economic stimulus funds into algae fuel research.

“If we do decide to move forward with algae as a fuel source, it’s important we understand the ways we can produce it with the least impact, and that’s where combining production with wastewater treatment operations comes in,” Clarens said.