As an alternative fuel, ethanol derived from corn has hit a serious roadblock. That's because producing corn ethanol itself requires lots of energy-after factoring in pesticides, fertilizers, and fossil fuels used to grow and harvest the corn, ethanol generates only about 1.24 times the energy it takes to produce, according to the United States Department of Agriculture.
Corn has been the favored feedstock for making ethanol in the US because it can be easy to grow and transport-and because growing corn for fuel has been historically subsidized through government tax credits. However, producing ethanol from corn has led to record increases in corn prices, which have in turn affected the world's food supply and those populations that rely on corn as a staple food.
The answer, according to AIC subsidiary RedOx Biofuels, is to make ethanol not from corn alone but from a range of cellulosic materials, including agricultural and industrial waste. In essence, the most promising source from which to make ethanol, according to RedOx's Chief Executive Officer Kim Ogaard-Nielsen, is trash.
"We simply can't grow enough corn to make the ethanol necessary to meet future demand," says Ogaard-Neilsen. In fact, because of corn's limited supply and its drawbacks as an energy-intensive feedstock, the US government plans to cap corn ethanol production at 15 million gallons per year starting in 2015. A far more realistic-and economical-solution is to make ethanol from non-food sources that are already in abundant supply, says Ogaard-Neilsen. For example, using the entire corn plant-or corn stover-rather than just the grain could increase existing yields from 440 gallons per acre to 656 gallons per acre, according to Purdue University researchers.
Taken a step further, using unwanted, hard-to-dispose-of waste materials such as rice straw and even sewage sludge could dramatically cut costs for ethanol producers, making cellulosic ethanol production much more economically feasible since feedstocks typically account for 50% to 80% of total production costs.
"RedOx's technology for generating biofuels out of cellulosic waste represents an exciting breakthrough for making biofuels more efficient," says Ogaard-Nielsen. Using an electrochemical process called Mediated Metal Redox (MMR), virtually any organic material can be broken down and converted from cellulose into fermentable starches and sugars, and thus into ethanol and other valuable fuels and plastics.
Applied to ethanol, MMR could avoid the need to convert food into fuel—a practice that has become highly controversial, Ogaard-Nielsen says. "Because the MMR process has the potential to convert every part of the plant—including lignin, the skeletal component of all plant matter that can't be digested by humans or used traditionally to make ethanol—into a usable form, the argument for biofuels becomes much, much stronger."
Sources:
USDA, "Estimating the Net Energy Balance of Corn Ethanol, "Agricultural Economics Report No. (AER721), 24 pp, July 1995.
Makers of ethanol receive a tax credit of $.51 per gallon under the Energy Policy Act of 2005.
Energy Information Administration (EIA), Annual Energy Outlook 2007.
Purdue University Agricultural and Biological Engineerings's Biofeedstock and Particulate Technology Research Group, "Transportation Logististics of Biomass for Industrial Fuel and Energy Enterprises," October 2007.
Overview: RedOx MMR
Our approach uses an electrochemical synthesis process to break down ligno-cellulosic materials, with little or no secondary waste and no chemical pretreatment. [More]
White Paper: Fuel From Waste
Independent analysts evaluate the economics of making fuel from urban and agricultural waste using RedOx's MMR technology. [More]