Some prominent news sources are focusing on the negative environmental effects of federal mandates requiring the use of billions of gallons of ethanol in transportation fuels. According to these reports, the initiative is turning former conservation areas into cornfields, degrading water quality and reducing wildlife habitat and biodiversity. University of Illinois plant biology professor Evan DeLucia, the director of the Center for a Sustainable Environment and an expert on how land use changes influence greenhouse gas emissions, spoke to News Bureau life sciences editor Diana Yates about the pros and cons of producing biofuels.
New reports from The Associated Press and elsewhere point to a host of environmental problems associated with federal mandates for ethanol in gasoline. Is it time to give up on the idea of substituting plant-based ethanol for gasoline?
A number of people have been beating up on bioenergy production for a lot of different reasons. And one thing I find a little bit perplexing is I think folks are missing the big problem. The big problem is the rapid acceleration of global climate change caused by the ever-increasing levels of carbon dioxide in the atmosphere, fueled by our insatiable consumption of fossil fuels. This is the big gorilla in the room, and this is where we need to find solutions.
It's quite reasonable to say that corn ethanol has a number of very serious environmental consequences. However, corn ethanol is not the only source of ethanol. Many people are working very hard to develop sustainable, second-generation biofuels made from perennial plants or forest waste that will carry with them ecological benefits as well as displacing fossil fuels. So I worry that when people read these articles they see "ethanol," and they lump it all into one category.
The 2007 Renewable Fuel Standard set a target for corn-ethanol production and we've hit that target. This means that the remainder of our renewable fuel supply must come from biodiesel and from second-generation feedstocks such as perennial grasses. And so the argument that the rapid expansion of additional corn acres is dangerous for us is probably not accurate because we're probably there already.
The AP report says that corn ethanol will achieve only a 16 percent decrease in carbon dioxide emissions by 2022. Is this an insignificant reduction that warrants an end to the federal mandate?
While there is no question that corn ethanol poses a number of environmental challenges, we should not turn our back on the 16 percent displacement of fossil fuel that it offers. At least until we develop more sustainable sources of bioenergy. And, that 16 percent will increase as grain yields increase.
What are the environmental downsides of corn ethanol?
Any time you convert Conservation Reserve Program lands to row-crop agriculture, you're going to take a big ecological hit. These lands tend to be covered in native grasses or woody plants. You're not tilling them every year, you're not harvesting grain from them, so you're not dumping a lot of nitrate on that landscape. These kinds of systems tend to build soil organic carbon. And because they're perennial and often more diverse than the surrounding intensive agricultural land, biodiversity tends to be higher. There is no question in my mind that if you go from that kind of system to a system where you're annually tilling and putting high nitrogen inputs in, you're going to see a big environmental hit. You're going to see it in increased nitrate losses to groundwater. You're going to see it in lost carbon from soil to the atmosphere. And you're going to see it in terms of a reduction of biodiversity. There's no question about that.
What I'm questioning is, going forward, is it reasonable to expect more of that to happen? And the answer is I don't think that is what we're going to see.
You said that corn ethanol isn't the only kind of ethanol. What else is available to meet the federal mandates?
So-called second-generation biofuels are where the future lies. Making biofuels from the non-edible parts of plants, the leaves and stems, will make biofuels much more ecologically sustainable. If you were going to take that 35 percent of the corn crop and replace that with high-yielding grasses like switchgrass or Miscanthus, you would convert the rain-fed Midwest from a net source of greenhouse gases to a net sink of greenhouse gases, plus you would greatly increase ethanol production because the yield of these other grasses is so much higher than the yield of corn. So there would be a huge benefit. The big "if" is whether we can do this affordably.
Is anybody making cellulosic biofuels now?
Yes. There are a number of test plants around the country that use various types of chemical decomposition processes. You can break cellulose apart chemically. It's just not gotten to the point where it's economically feasible at a big scale.
Are there still years of development before we get to production on a large scale?
Everybody's hoping it's just around the corner. That's the holy grail of this whole thing. The challenge is cost. The folks who work in this field knew it was a tough problem from a biochemical perspective. They just didn't realize how tough a problem it was. So that cost point is still pretty high and when that cost point comes down then there's more incentive for second-gen biofuels.
So what do you say to people who are dubious about the prospects of cellulosic sources of ethanol and who are worried about the damaging environmental impacts of corn-based ethanol? Why not just suspend corn ethanol production until cellulosic sources are proven to be economical?
Well, because corn ethanol is displacing fossil fuel, so there's still a benefit from a greenhouse gas perspective. Remember, ethanol has also been used as a fuel additive and has displaced the use of lead in fuels, and so we don't want to go back to leaded fuels. The Energy Independence and Security Act of 2007 also talked about revitalizing and maintaining agricultural economies in rural America, and it has done that. I wouldn't advocate expanding it, but there are a number of reasons why I think we should hold onto it while we're in the development phase for these other crops.
We've got to keep our eye on the big picture, which is climate change. We can't lose sight of that.