25.1 Will an ordinary prairie grass become the next biofuel?

CHAPTER 25 BIOFUELS

GAS FROM GRASS

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The town of Marcus, Iowa, using money made from its ethanol plant production, has invested in its first biodiesel truck stop. Alternative fuel stations are largely clustered in the Midwest, where ethanol production is highest.

CORE MESSAGE

Biofuels represent a potential replacement for fossil fuels and might be especially important fuel sources for transportation. Biofuels offer many advantages but they also involve trade-offs—such as using cropland and fossil fuel inputs to grow biofuel crops—increasing the need for more research and development. Adjusting how we make biofuels can address many of these concerns and will help us meet the energy needs of the future.

GUIDING QUESTIONS

After reading this chapter, you should be able to answer the following questions:

  • What are biofuels and what are potential biofuel sources?
  • What are the trade-offs of using biofuels as an energy source?
  • What is the current controversy of “food versus fuel” and what are some possible solutions to address it?
  • What are the challenges and potential benefits of making fuel from cellulose?
  • What roles do conservation and energy efficiency play in addressing our mobile fuel needs, and what are some ways we can pursue these?

WHERE IS THE CEDAR CREEK RESERVE?

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The Cedar Creek Ecosystem Science Reserve in Minnesota has established more than 1100 long-term experimental plots and 2300 permanent observational plots distributed across 22 old fields.
University of Minnesota ecologist David Tilman (right) and the Nature Conservancy’s Joe Fargione (left) study how clearing land for crops releases CO2.

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The rain stopped, and the plants began to die. In 1987, a massive drought struck Minnesota. At the Cedar Creek Ecosystem Science Reserve, David Tilman helplessly watched the grasslands he had been cultivating for more than 5 years—part of a project to test how different amounts of nitrogen and other resources affect growth—wither away.

But while some areas thinned out and became barren, others kept the auburn and green of healthy prairie grasslands. For some reason, certain plots were less affected by the drought. Tilman, a bow tie-sporting ecologist at the University of Minnesota, decided to find out why. Little did he know, his simple plan to study grass in Minnesota would unexpectedly lead him to a new and potentially better type of biofuel—a substance that provides the energy needed to power engines—made from a mixture of prairie grasses.

“We weren’t thinking about biofuels at all,” recalls Tilman. “When you have a new idea, you start imagining what might happen, but you never know what will really happen until you try the experiment.”