Loser: Brew, Baby, Brew

A backyard still that turns sugar into ethanol fuel may look sweet, but under scrutiny it turns sour


This is part of IEEE Spectrum’s SPECIAL REPORT: WINNERS & LOSERS 2009, The Year’s Best and Worst of Technology.

Imagine filling up your car’s tank with cheap ethanol from your very own backyard refinery. All you’d have to do is feed the machine with…sugar. Sweet!

That’s the idea behind E-Fuel Corp., a start-up in Los Gatos, Calif., which recently began shipping its MicroFueler ethanol production system in the United States. The refrigerator-size machine’s solid-state distillation system can produce up to 35 gallons (132.5 liters) of pure ethanol per week, enough to fill two average car tanks. The purchase price is steep—US $10 000, or a third less with a federal tax rebate—but the company contends that the operating costs are low enough to brew ethanol for as little as $1 per gallon (26 cents per liter). Assuming that gasoline averages $3 per gallon and electricity and spare parts cost about $500 per year, a MicroFueler running flat out would pay for itself in three or four years.

E-Fuel says that the arithmetic will get better, because sugar is vastly abundant and oil prices are likely to go up. Further, the company claims the machine will allow users to “greatly diminish their carbon footprint” because replacing gasoline with the homemade ethanol can cut carbon dioxide emissions by up to 85 percent. Finally, a home production approach would solve ethanol’s main problem: distribution.

Its creators call the MicroFueler “revolutionary,” “a game changer,” and “the ultimate ‘green machine.’ ” But is it?

“I’m not sure that the excitement is justified,” says Donal F. Day, a professor at Louisiana State University’s Audubon Sugar Institute, in St. Gabriel. He explains that it takes about 14 pounds (6.4 kilograms) of sugar to make 1 gallon (3.8 L) of ethanol and that raw sugar generally costs at least 20 cents per pound. “That comes to $2.80 for a gallon,” he says, “and it’s not counting a person’s time and effort.” A lot of effort: if you drove 30 miles (48 kilometers) a day and got 13 miles per gallon (18 liters per 100 kilometers), you’d have to lug your weight in sugar every week.

“Making ethanol at home does not make a lot of sense for one’s own economics or the environment,” says Robert W. Howarth, a professor of ecology and environmental biology at Cornell University, in Ithaca, N.Y. Even mass-produced corn ethanol, he says, is only marginally profitable in the United States, despite huge government subsidies. So it’s hard to see how small-scale production using sugar could do any better.

Howarth denies E-Fuel’s environmental claims, saying that “ethanol is a poor fuel in many ways and very inefficient to make.” On top of that, the E-Fuel scheme involves burning fossil fuel just to get feedstock to people’s homes.

Daniel Sperling, director of the Institute of Transportation Studies at the University of California, Davis, says Brazil is probably the only place where sugar ethanol production makes sense environmentally and economically. That’s because Brazilian producers cultivate high-yield sugarcane crops, use the cane waste as fuel to generate electricity, and have a vast distribution network. Ethanol home production in the United States “will always be a niche,” he says, adding that even if it were possible to brew cheaper fuel at home, “not many people are really willing to go to all this effort.”

Indeed, those interested in home ethanol production face some practical problems. Making the weekly maximum of 35 gallons of ethanol requires nearly a quarter of a metric ton of sugar every week. It also requires a fuel producer’s permit from the Alcohol and Tobacco Tax and Trade Bureau, and maybe from state and local authorities as well. (Not that moonshiners would want the MicroFueler. For their purposes, a gas-fired distillery is good enough—and much cheaper.) Federal law also mandates that you keep the machine outside your house for safety’s sake, so you’ll have to think about the insurance implications and the opinions of your neighbors. Finally, you’ll need to have your car tuned for a diet of pure ethanol, which means replacing some parts.

E-Fuel, naturally, stands by its claims. Its chief executive, Thomas J. Quinn, a Silicon Valley executive who has bankrolled the company, says the $1-per-gallon proposition is realistic because it’s possible to obtain sugar for much less than 20 cents per pound. He explains that current U.S. farm legislation permits surplus sugar to be sold to ethanol manufacturers for 2 cents per pound, and that there’s plenty of cheap, 2.5-cents-per-pound Mexican sugar that could be imported tariff-free. He also emphasizes that the MicroFueler can use discarded beer, wine, fruit juices, and other alcoholic or fermentable liquids.

Quinn expects the MicroFueler to sell 200 000 units worldwide, and he’s already planning to market it in Brazil, China, and the United Kingdom. In the United States, he’s establishing a network of dealers to distribute feedstock and help users set up their operations. He’s also getting companies and governments to sponsor a carbon coupon program that lets customers buy discounted feedstock. “MicroFueler customers are not burdened with locating their own sources of feedstock,” Quinn says. “They just need to pump ethanol into their vehicles.”

To be sure, the MicroFueler is a neat machine. Floyd Butterfield, the other cofounder of E-Fuel, designed it as a kind of cross between a gasoline pump and a washing machine that easily connects to standard home power and water supplies. You load sugar or other types of feedstock into the machine’s tank and press a button; the machine does the rest. It uses sensors and a microcontroller to dispense special yeast and maintain the temperature at ideal conditions for fermentation. Then, in the distillation phase, it uses a single solid-state filter rather than the multiple distillation columns found in conventional systems.

E-Fuel is rather secretive about how it forces the liquid through this membrane system. All it says is that the nanoscale pores let the water pass while holding back the larger alcohol molecules. The result is 99 percent ethanol, a much higher purity than conventional distillers obtain.

Day, of the Audubon Sugar Institute, remains skeptical. He argues that if the main feedstock is sugar, the economics remain shaky. The prospects of getting hold of cheap sugar in the coming years are far from certain. In fact, U.S. prices will likely go up, now that two major hurricanes have hit the country’s sugar-producing regions and high fuel costs have pushed many producers out of business. Prices also depend on politics—the subsidies and import limits negotiated between the government and the U.S. sugar industry. As for the cheap Mexican supply, Day says, “Tell me where it is and I’ll go buy some.”

There are just too many economic variables: sugar prices, gasoline prices, government politics, Mexican supplies, and so on. Last summer, with gas reaching $4.11 a gallon in the United States, home distillation might almost have seemed worthwhile. But as of late November, prices were down to less than $2. The current global economic slowdown may help keep prices at those levels, while sugar prices may increase, making ethanol home brewing a sweet deal turned sour.

For more articles, go to Winners & Losers 2009 Special Report.

Snapshot: The 200-Proof Solution

Goal: To produce sugar-based ethanol at home for US $1 a gallon.

Why it’s a loser: The economics don’t add up when all costs are factored in; transporting sugar to people’s homes will burn lots of fossil fuel.

Who: E-Fuel Corp.

Where: Los Gatos, Calif.

Staff: Info not available

Budget: Info not available

When: Started shipping in late 2008