Alcohol is the best known--and most hyped--alternative fuels. In lower concentrations, it's an octane booster and a replacement for the methyl tertiary-butyl ether (MTBE) that replaced tetra-ethyl lead in earlier gasoline blends. It also makes it possible to run engines with high compression ratios without pre-ignition. In higher concentrations, it turns into a clean-burning fuel. Since alcohol has about 24% lower specific heat than gasoline (26.7 versus 34.9 kJ/kg), though, you need to consume more of it to extract the same energy.
A great deal of controversy swirls around energy budgets and the economics associated with fuel-alcohol versus petro-fuel production. There also are sociological and ecological concerns about taking arable land out of food production, bio-engineering monoculture corn or cane, and (in Brazil, in particular) cutting down rainforests.
And, there's controversy between conventional farmers, who want to grow corn for alcohol, and hemp advocates, who want to produce alcohol from what midwesterners call "ditchweed." The latter group claims that corn requires intense cultivation and lots of water, while wild hemp grows everywhere. They also insist nobody can smoke enough ditchweed to get high.
The ups and downs of alcohol fuel in Brazil are instructive in terms of public and industry response to government intervention. In the 1980s, Brazil's military government started encouraging alcohol-powered cars. By 1988, more than 88% of new vehicles in the country ran on a blend of ethanol and gasoline.
But then the government pulled its subsidies to cane farmers, who immediately decided to sell their sugar on the international market instead of to the fuel refineries. Alcohol shortages ensued, and most of the Brazilian public abandoned ethanol cars. (Interestingly, the taxi fleets stayed with alcohol cars because maintenance costs for them were lower than those for gasoline taxis.)
Subsequently, Brazil's government introduced a law that forced oil companies to add alcohol to gasoline, and interest picked up again. On the carmaker side, Volkswagen got in early with the flex-fuel TotalFlex Golf in 2003. With the availability of cars like the Golf that could adjust themselves to the amount of ethanol in the fuel (up to 85% ethanol), flex cars began outselling traditional gasoline models.
The Christian Science Monitor reports that by last August, 62% of new cars sold in Brazil were flex. Those sales may be encouraged because the flex vehicles cost no more than gasoline-fueled cars. And while ethanol engines get 24% lower mileage, thanks to that difference in specific heat, the ethanol fuel usually sells at somewhere between a third to half the price of gas. The Monitor also says that at trade-in time, the flex cars keep their value better.
What's not happening in Brazil, at least yet, are flex hybrids. But they're appearing in the U.S. At the Washington Auto Show last January, Ford demonstrated its Escape Hybrid E85 research vehicle, a version of its Escape Hybrid with a flexible-fuel engine capable of running either gasoline or ethanol blends of up to 85%.
There are the usual ironic gotchas, of course. The Detroit Free Press reported that because ethanol evaporates at lower temperatures than gasoline, "the Escape Hybrid E85 doesn't meet the U.S. 'partial zero emissions vehicle' standard," which is the case with the regular version. But dealing with setbacks is part of the fun of being in on the Next Big Thing.