Skip Navigation

Biomass Energy

campfireHave you ever sat by a campfire or fireplace? If so, you've see biomass energy in action!

Biomass means "natural material." When biomass energy is burned, it releases heat, just like the wood logs in your campfire.  Biomass energy uses natural materials like trees and plants to make electricity. It can also mean waste products like trash.  It is the second-most common form of renewable energy we use in the United States, providing enough electricity to power more than two million homes.

In Cedar Rapids, Iowa, a company called BFC Gas & Electric recycles more than 150 tons of biomass material every day to produce electricity for about 4,000 homes.

Some of the material they use includes:

  • Leftover wood from sawmills
  • Leftover paper and wood waste from paper mills
  • Corn stalks, corn cobs and seed corn from farms
  • Paper and cardboard that can't be recycled in other ways
  • Fast-growing crops and trees


Area farmers grow the switchgrass and then sell it to  local utilities for energy, as seen in this picture. The switchgrass is burned along with coal to make steam for the generators.


In Wisconsin, people are using electricity made at the local trash dump! When trash decomposes, it gives off a gas called methane. A machine called a microturbine captures the methane gas and uses it to run a small jet engine to produce electricity.

Anaerobic digesters

child plugging his noseHow about electricity from cow manure? Animal waste gives off methane gas too, and dairy farms in Iowa and Wisconsin are microturbines and a machine called a "digester" to turn the methane into electricity.

The most recent digester signed on to supply renewable energy to Alliant Energy customers is in Dane County, Wisconsin and is operated by Clear Horizons. The digester is the first in the state to be shared by three farms. Between those three farms, about 2,500 dairy cows will provide about seven million gallons of manure for the digester a year. The facility is expected generate over 17 million kilowatt-hours annually.


Links for teachers and parents: