The Cellulosic Solution

It's doubtful that Tom Stephens knew his boyhood chores would someday mesh with his profession as an adult.

Barbara McClellan

July 1, 2007

5 Min Read
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It's doubtful that Tom Stephens knew his boyhood chores would someday mesh with his profession as an adult.

“When I was a boy (growing up in farm country), I liked driving the tractor,” recalls General Motors Corp.'s group vice president-global powertrain & quality.

“I particularly liked fixing it. I never thought (someday) we'd be using corn and stems and stalks for fuel.”

With gasoline prices at historic highs and expected to keep climbing, biofuels such as E85 ethanol, a blend of 85% ethanol and 15% gasoline, hold massive potential to help reduce America's dependence on petroleum and slow down global warming, Stevens says during a media briefing at the $62 million U.S. BioEnergy Woodbury ethanol production plant near Lake Odessa, MI.

Indeed, GM is revving up its new image, from producer of fuel-thirsty vehicles to developer of advanced powertrain technologies and environmentally friendly corporate citizen.

Among the auto maker's efforts, it is embracing a “yellow” campaign with its current offering of 14 cars and light trucks and vans in the U.S. that can run on corn-based E85, and a pledge to build 400,000 additional units annually if the necessary infrastructure is in place.

The company already has 2 million flex-fuel vehicles (FFVs) on the road in the U.S. In Brazil, FFVs make up more than 95% of GM's fleet, and in Europe the Saab 9-5 BioPower model is a best-seller.

By the end of 2006, Stephens says there were more than 6 million flex-fuel-capable vehicles on U.S. roads. If all those vehicles were running on E85, “we would displace the need for 3.6 billion gallons (13.6 billion L) of gasoline per year,” he says.

Domestic auto makers could displace 22 billion gallons (83 billion L) of gasoline annually over the next 10 years, and all OEMs could increase the savings to 37 billion gallons (140 billion L), he says. E10, consisting of 10% ethanol, could save an additional 10 billion gallons (38 billion L).

But beyond fueling automobiles, experts say ethanol is a renewable energy source that provides the U.S a means of self-reliance. Global energy demand is growing 1.6% per year, necessitating collaboration between government, the auto industry, energy suppliers and academia.

“We will go from 205 million barrels of oil per year to 335 million barrels by 2030,” Stephens says, quoting U.S. Department of Energy statistics.

There is no silver bullet. The wide range of vehicle usage today requires a comprehensive powertrain technology strategy.

A blending of liquid fuels with electricity and hydrogen will serve as the in-vehicle energy carriers for the foreseeable future, with hydrogen being the advanced propulsion goal for the long term, Stephens says.

GM has been building toward this vision with an array of concepts, from its Sequel fuel-cell hydrogen car to the Chevy Volt electric plug-in hybrid-electric vehicle. And that's why the auto maker is supporting advances in research to commercialize and increase ethanol production through non-food, cellulosic energy sources.

Corn-based ethanol has been around for a while, at least in small quantities. Ford Motor Co. was the first to introduce it as an alternative fuel in the '85 Taurus, and U.S. auto makers until recently have used it in a 10% blend with gasoline to satisfy federal fuel economy regulations.

Research into making E85 from cellulosic sources — such as unused corn stalks; municipal, agricultural and forestry wastes; native grasses and other non-food plants — also is ongoing. But it has taken on new urgency in the U.S., with 114 ethanol plants now in operation, producing 5.6 billion gallons (21 billion L) annually.

Additionally, some 87 ethanol plants are under construction or expansion that will provide another 6.4 billion gallons (24 billion L) of capacity.

Indeed, cellulosic ethanol, combined with the billions of gallons of corn-based ethanol already produced today, potentially could replace up to 30% of the nation's demand for energy by 2030, the National Renewable Energy Laboratory reports.

Similarly, Stephens says a GM/University of Toronto study supports DOE projections the country potentially could produce 90 billion gallons (341 billion L) of the combined ethanol biofuels in that timeframe, representing “60 billion adjusted energy gallons (227 billion L) of fuel.”

Michigan's Woodbury operation, alone, which opened in September and is one of six plants nationwide operated by the U.S. BioEnergy Corp., is expected to produce 50 million gallons (189 million L) of ethanol and 160,000 tons (145,149 t) of dried distillers grain each year.

Thus, there is the need for non-food sources, say industry experts gathered in Woodbury by GM. The problem is cellulose in renewable materials used to make cellulosic ethanol must be pre-treated and then broken down into sugars before they can be fermented.

Cellulose is an energy-rich carbohydrate that is the main structural component in green plants, found in stems, stalks and leaves. One of the primary technical and scientific challenges of making biofuels from cellulose involves designing a low-cost method for releasing sugar.

The pros and cons of the various cellulose materials and their pre-treatment processes currently are being evaluated in various research efforts that are under way around the country, including six DOE-funded pilot plants, with the goal of discerning which is the most efficient and scalable.

“It's possible to get this cellulosic ethanol industry within the next five years,” DOE Under Secretary for Science Ray Orbach said late last year.

Bruce Dale, director of the Biomass Conversion Research laboratory at Michigan State University, says he has been working for more than 30 years on ways to turn cellulose into ethanol.

His patented technology for pre-treating corn stalks, grasses, wood and other biodegradable materials currently is being used by an Iowa corn ethanol plant now being adapted for cellulosic ethanol as one of the six DOE test facilities.

Dale says cellulosic ethanol could be produced for $1.30 per gallon in the near future and about $1 per gallon by 2020. Another plus is that grain-based ethanol reduces greenhouse gas emissions by 29% and cellulosic ethanol by 86%, he says.

Says GM's Stephens: “We need to develop every option. ‘If not us, then who?’ really applies here.”

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