Wood to Wheels: Put a Tree in Your Tank

By Marcia Goodrich | Published

By the time it does, researchers at Michigan Tech aim to have examined the entire journey, from harvest to tailpipe and back again, with the goal of creating a source of ethanol that’s sustainable, environmentally safe and economical.

The university’s Wood to Wheels, or W2W, project has brought together scientists and engineers from multiple disciplines to research ethanol-powered transport from a 360-degree perspective.

Since Michigan Tech is surrounded by vast tracts of timberland, the project is an excellent fit. “Because of our location, we felt we had a vested interest in looking at this issue,” said David Shonnard, a professor of chemical engineering and director of the Wood to Wheels Graduate Enterprise. “Any human activity has consequences, and as we move toward biofuels, we want to minimize the negative impacts.”

It all starts in the woods. Researchers will evaluate how Great Lakes forests and wildlife would be affected should enough biomass--wood and other plant material--be harvested to sustain an ethanol production facility.

“We’re looking at Minnesota, Wisconsin and Michigan, the three upper Great Lakes states,” said Ann Maclean, an associate professor of forest resources and environmental science. “As a nation, we need to reduce our dependence on foreign oil, and we need to reduce emissions. Ethanol can provide a substitute for gasoline, and it’s a very clean-burning fuel, but as we develop it, we need to assure that the process doesn’t harm the environment.”

Forestry experts will also look at which tree species are best suited to be harvested for ethanol, possibly developing hybrids.

The second phase of Wood to Wheels will be the manufacturing process. Wood, unlike the conventional raw material for ethanol, corn, grows abundantly without human intervention and has the potential to yield much more fuel per acre. It’s also different from corn in that it’s much tougher to turn into ethanol.

“Nature uses enzymes to break down the cellulose compounds in wood,” Shonnard said. But the natural process is slow, so he and his graduate students are examining the use of engineered enzymes to improve production.

Shonnard disagrees with a number of scientists who contend it requires more energy to produce ethanol than it actually yields. Some of their studies are flawed, he says, since they include all the energy involved in producing ethanol, but do not allocate a portion of those environmental burdens to any of the other products produced in the process.

“When you make ethanol, you make lots of other products,” Shonnard notes. For example, when corn is converted into ethanol, animal feed, corn oil and other products are also produced.

Similarly, ethanol production in the Great Lakes could be tied to another well-established industry.

“We’re running tests on wood samples from pulp mills in Wisconsin, and we hope to receive funding for a commercial-scale demonstration facility to produce ethanol as part of the pulp-making process,” Shonnard said. “Ultimately, we’d like to help American manufacturers better compete against foreign mills.”

The effort is part of a larger collaboration, including a partnership with American Process, Inc. The firm consults with pulp mills to help maximize their efficiency. “We’re actively engaging with industry, and that’s where we need to be if we’re to make the significant discoveries that will drive this research,” Shonnard said.

The ethanol-production process should be an excellent deal from an energy as well as a business standpoint. Shonnard calculates that producing ethanol from wood will only require a small amount of energy from fossil fuel, about 5 percent to 7.5 percent of the energy contained in the ethanol produced. The figure for gasoline is significantly higher: at 20 percent, it takes about one gallon of fuel to produce five gallons of gasoline from petroleum.

But fuel is only one side of the ethanol equation. The other side is the vehicle.

Gasoline engines wear out quickly when powered with ethanol, so a team of mechanical engineering faculty is looking at the entire vehicle, with the goals of improving fuel economy and engine life while maintaining driveability.

They will also focus on controlling emissions. Ethanol has a green reputation, but exhaust remains an issue. Just like gasoline, ethanol sends the greenhouse gas carbon dioxide out the tailpipe.

Unlike gasoline, however, ethanol production is part of a process that can help clean up CO2. Trees remove carbon dioxide from the atmosphere, so scientists theorize that, as biomass harvested for ethanol regrows, it will mop up the carbon dioxide produced by ethanol-powered vehicles. Ideally, no additional CO2 would be added to the atmosphere, so ethanol would not contribute to global warming.

Finally, Wood to Wheels will also look at the economic and social ramifications of developing an ethanol industry in the upper Great Lakes.

“The transition to biofuels is becoming an imperative,” said Barry Solomon, a professor of social sciences. “It has huge implications for land use and settlement patterns, particularly in those parts of the country that produce the natural resources, such as corn, switchgrass and trees.

“We’re interested in the public’s views on biofuels, especially ethanol, and whether they are supportive or not. Public perception could influence the pace of development.”

Currently, Wood to Wheels is funded in part by a $1.75-million National Science Foundation grant. Ideally, W2W will be sustained as Michigan Tech’s first Enterprise focussing on graduate students, with funding from a variety of sources aimed at sustainable ethanol technology.

“If we wean ourselves off fossil fuels, we need to look at the consequences of that,” Shonnard said. “As individual researchers, none of us can do that by ourselves. We’re attempting to integrate parts of a very complicated puzzle.”

Michigan Technological University is a public research university, home to more than 7,000 students from 60 countries. Founded in 1885, the University offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, forestry, business and economics, health professions, humanities, mathematics, and social sciences. Our campus in Michigan’s Upper Peninsula overlooks the Keweenaw Waterway and is just a few miles from Lake Superior.