Biomass

Biomass energy generator

Biomass energy generator of Dockside Green, John Newcomb [CC BY 3.0], via Wikimedia Commons

What is biomass?

Biomass is biological material derived from living, or recently living, organisms. It most often refers to plants or plant-based materials but animal waste can also be considered biomass.

Biomass is a source of energy as it can be used to generate electricity.  Plant biomass material is heated in a power plant, the heat generates steam from water, the steam drives a turbine that powers a generator that produces electricity.  Animal wastes can be broken down in a tank called a digester, releasing methane gas that can be used to heat water, releasing steam that drives a turbine which powers a generator, as above.  Watch this video.

Biomass doesn’t include fossil fuels.  Fossil fuels such as coal, oil and gas are also derived from biological materials that absorbed CO2 from the atmosphere many millions of years ago and they are essentially carbon stores.  Burning fossil fuels releases this stored carbon as CO2, thereby increasing its concentration in the atmosphere and producing the greenhouse effect.

Biomass takes carbon out of the atmosphere while it is growing, and returns it as it is burned.  If it is managed on a sustainable basis, biomass is harvested as part of a constantly replenished crop. This is either during woodland management or coppicing or as part of a continuous programme of replanting with the new growth taking up CO2 from the atmosphere at the same time as it is released by combustion of the previous harvest.

This maintains a closed carbon cycle with no net increase in atmospheric CO2 levels.

Biomass Facts

  • If you’ve ever been near a campfire or a fireplace, you’ve witnessed biomass energy through the burning of wood.
  • Biomass has been around since the beginning of human civilization when people burned wood for heating and cooking.
  • Wood was the biggest energy provider in the world in the 1800’s.
  • Rubbish can be burned to generate energy as well. This not only makes use of waste for energy, but reduces the amount that goes into landfills. This process is called Waste-to-Energy.
  • Farmers create energy from animal manure using tanks called digesters. The digesters produce biogas, which can be used to generate electricity.
  • Biogas can be captured and sold as fuel if not used to generate electricity on site.
  • Biomass is a renewable energy source because the CO2 released by burning biomass is absorbed again by biomass crops.