Lee Lynd, Thayer School of Engineering

Oil is out. Whether it runs out in 10 years or 100, there will be a time in the foreseeable future when we cannot get any more oil. What then will fuel our cars? And maybe we shouldn’t wait for the oil to be gone before we make a switch to a new energy source. Regardless of your feelings on global warming, there is no doubt that burning fossil fuels has been frighteningly destructive to this planet, with most of the damage done by the transportation sector. Finding a cleaner, sustainable fuel source for our vehicles could really make this world a better place for everyone,

At the forefront of this movement is Lee Lynd, professor of engineering at Thayer School, who believes that we can grow our transportation fuel. Lynd is co-leader of a project entitled The Role of Biomass in America’s Energy Future (RBAEF), lead jointly by Dartmouth and the Natural Resources Defense Council (NRDC). The project is sponsored by the U,S, Department of Energy, the Energy Foundation, and the National Commission on Energy Policy. The basic idea is that any organic matter, or biomass, can be broken down and fermented to form ethanol, using the same processes that produce the alcohol in our beer, wine and vodka, According to a joint statement by the NRDC and the Union of Concerned Scientists this past February, ethanol has at least as much potential as hydrogen to lead us toward a sustainable transportation sector. Lynd sees the amazing potential of his work, saying “At the very least we hope to change the world,” speaking of himself and colleague Professor Charles Wyman.

The RBAEF project has taken a broad-based approach, looking at many potential biomass sources and evaluating them based on sustainability, land requirement, and fuel content. Lynd is also working in his lab to improve the process of converting biomass to ethanol by isolating and manipulating microorganisms. On another front, RBAEF is investigating the policy and economics of increasing the supply and demand for ethanol.

According to Lynd, improvements must be madein three major fields for ethanol to weigh in as a gasoline replacement: biomass productivity, land use efficiency, and vehicle fuel efficiency.

A relatively small amount of ethanol is currently being produced domestically for a variety of uses, including 10% ethanol gasoline blends that many of our newer cars can burn (seen mostly in the Midwest). This supply is made almost exclusively from corn kernels, but ethanol produced this way, even when heavily subsidized, is significantly more expensive than gasoline, with little room for improvement (Valley News, July 2004). Lynd contends that we should make ethanol instead from cellulosic biomass, or the tough, fibrous or woody part of plants. Agricultural and forestry wastes, paper pulp, and grasses are just a few examples of potential sources of such material. Cellulose contains more energy than simple starches (like those found in
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corn kernels), is far more abundant, and requires much less energy input to produce. The trouble is that cellulosic biomass is more difficult to break down than simple sugars, Thankfully, Professor Lynd is leading a team of biologists and bioengineers to improve our ability to break down cellulose.

The most promising feedstock appears to be perennial grasses, particularly switch grass, which is native to the Midwest prairie. Based on Lynd’s estimates,switch grass could produce more ethanol per acre than corn kernels with no improvements, but with a concerted effort switch grass productivity could increase by 2 to 3 times in the next 20 to 30 years, greatly outperforming any simple starch feedstock.

No fuel based on corn (or any row crop) as we grow it today could be called sustainable, because our current agricultural practices rely heavily on large energy inputs through machinery and chemicals, and lead to soil degradation. Growing perennial grasses, however, would prevent erosion, require minimal chemical inputs, and actually rebuild soil fertility by adding organic matter. Ethanol produced from such grasses also has the potential to be carbon neutral. By pulling as much carbon (in the form of carbon dioxide) out of the air while growing as will be released in its subsequent burning, this fuel would not contribute to global warming. So now we have a source of ethanol, but where do we get the land on which to grow it?

Currently 400 million acres of agricultural land are used to feed this nation. Lynd optimistically claims that we could use 20 times less land to meet the same need if we reached the height of efficiency. This would require major lifestyle changes on all of our parts, which is not what Lynd suggests. He means only to point out that there is room for improvement in our agricultural efficiency. Perennial grasses could be co-produced on the same land as animal or human food. Demand for grasses as an ethanol feedstock would also create competition for agricultural land, producing an incentive for land use efficiency.

Hybrid electric vehicles can currently achieve 50 to 60 miles per gallon, nearly three times the national average of about 20 mpg. With rising gas prices, and the passing of the SUY fad, the United States should follow the rest of the world in pursuing smaller, more efficient vehicles. Fuel efficiency technology has a lot of room to grow, and with the right ingredients, the average vehicle fuel efficiency could rise drastically in the next 10-20 years.

Under Lynd’s “motivated” scenario, a doubling of biomass productivity, with a reasonable doubling or tripling of vehicle fuel efficiency, and the integration of animal feed and ethanol feedstock production would require essentially no new agricultural land to fuel entire US light duty vehicle fleet.

So when do we start?

Clifford “Cliffo” Orvedal ‘05 is an Engineering major and Environmental Studies minor and working towards an MEM at Thayer. He hopes to work in alternative energy.