The ethanol industry faces a challenge: under the federal Energy Act, passed last December, the industry is required to produce 30 billion gallons of ethanol a year by 2020. Today it produces about 7 billion gallons. And once that much fuel is produced, there is the challenge in ensuring consumers can use it all. But if ethanol were blended into every gallon of gasoline sold, in the standard 10 percent ratio, it would consume only about half of the 30-billion-gallon requirement. So far, the Department of Energy (DOE) has proposed two potential solutions: Sell more E85 ethanol, though it is a niche market today. Raise the standard blend from 10 to 15 or 20 percent. Unlike the standard blend, called E10, which all cars can use, only specially equipped cars can run on E85 ethanol. About five million of those cars are on the road today. According to DOE estimates, it would take 100 million E85 cars to provide a big enough market to absorb the additional 15 million gallons of ethanol in E85. Currently, automakers (mostly those based in Detroit) are building about 1 million new E85-capable cars every year. And they have promised to raise that to about 3.5 million a year by 2012. Still, getting to 100 million E85 cars by 2020 is a tall order. It would also take between 30,000 and 60,000 million gas pumps capable of dispensing E85. Today, there are only about 1,500. So the DOE, along with some automakers, is testing the potential to raise the standard ethanol blend to 15 or 20 percent, and making that blend universal for all gasoline sold in the United States. In Brazil, all gasoline sold in the country contains at least 25 percent ethanol. But there are some problems with increasing ethanol blends. Ethanol contains less energy than gasoline, so increasing the amount of ethanol in gasoline will likely result in lower fuel economy. Increasing standard fuel blends from zero to 10 percent ethanol, as is happening today, has little or no impact on fuel economy. In tests, the differences occur within the margin of error, about 0.5 percent. Further increasing ethanol levels to 20 percent reduces fuel economy between 1 and 3 percent, according to testing by the DOE and General Motors. Evaluations are underway to determine if E20 will burn effectively in today's engines without impacting reliability and longevity, and also assessing potential impact on fuel economy. In our own tests at Consumer Reports, we found that E85 reduced fuel economy by about 27 percent overall in a Chevrolet Tahoe. Interestingly, this is a lower reduction than the fuel's lower energy density would theoretically suggest. General Motors research fellow Kevin Cullen suggests that E85's higher octane rating is allowing the engine's computer control system to advance ignition timing to compensate for the lower energy density in the fuel and making up a little bit of the energy loss. Andy Karsner, undersecretary for energy efficiency and renewable energy at the federal Department of Energy,...