Archive for the ‘Biomass Energy 101’ Category

Jul

01

Biomass Environmental Benefits

Biomass energy brings numerous environmental benefits—reducing air and water pollution, increasing soil quality and reducing erosion, and improving wildlife habitat.

Biomass reduces air pollution by being a part of the carbon cycle (see the box below), reducing carbon dioxide emissions by 90 percent compared with fossil fuels. Sulfur dioxide and other pollutants are also reduced substantially.

Water pollution is reduced because fewer fertilizers and pesticides are used to grow energy crops, and erosion is reduced. Moreover, agricultural researchers in Iowa have discovered that by planting grasses or poplar trees in buffers along waterways, runoff from corn fields is captured, making streams cleaner.

In contrast to high-yield food crops that pull nutrients from the soil, energy crops actually improve soil quality. Prairie grasses, with their deep roots, build up topsoil, putting nitrogen and other nutrients into the ground. Since they are replanted only every 10 years, there is minimal plowing that causes soil to erode.

Finally, biomass crops can create better wildlife habitat than food crops. Since they are native plants, they attract a greater variety of birds and small mammals. They improve the habitat for fish by increasing water quality in nearby streams and ponds. And since they have a wider window of time to be harvested, energy crop harvests can be timed to avoid critical nesting or breeding seasons.

All of these benefits are described in comparison with food crops such as corn, wheat, and soybeans. Compared to undisturbed natural habitat, energy crops are not as good. But the strength of biomass is that it is much closer to the natural world than our modern industrial agriculture. The harvest of prairie grasses is not so different than the fires that periodically swept across the plains. Plantations of poplar and maple trees may not be the same as varied forests, but are certainly closer than pesticide-laden monocrops. Nonetheless, the environmental benefits of biomass hinge on whether energy crops are managed with sustainable agricultural practices. Just like food crops, they can be mishandled, with productivity increased by greater chemical inputs. If biomass energy turns out to have unforeseen environmental effects, we must be willing to alter our methods to reduce these effects.

Jun

17

What is Biomass Energy?

Biomass is a renewable energy source because the energy it contains comes from the sun. Through the process of photosynthesis, chlorophyll in plants captures the sun’s energy by converting carbon dioxide from the air and water from the ground into carbohydrates, complex compounds composed of carbon, hydrogen, and oxygen. When these carbohydrates are burned, they turn back into carbon dioxide and water and release the sun’s energy they contain. In this way, biomass functions as a sort of natural battery for storing solar energy. As long as biomass is produced sustainably—with only as much used as is grown—the battery will last indefinitely.

From the time of Prometheus to the present, the most common way to capture the energy from biomass was to burn it, to make heat, steam, and electricity. But advances in recent years have shown that there are more efficient and cleaner ways to use biomass. It can be converted into liquid fuels, for example, or cooked in a process called “gasification” to produce combustible gases. And certain crops such as switchgrass and willow trees are especially suited as “energy crops,” plants grown specifically for energy generation