Converting Biomass Into Energy
The process of biomass energy use stored solar energy. A process of photosynthesis in growing plants is possible due to energy from the sun's rays. Biofuels include bioethanol, biobutanol and biodiesel.
Several plants can be used for biofuels including hemp, corn, sugarcane, switchgrass and sorghum. The plant species is not critical to the product and biomass may even include animal waste to be used as fuel.
Biomass process use plant materials to produce electricity using steam turbines. The process may also be used to produce heat by direct combustion.
Dead trees, yard clippings, wood chips can be used in biomass processes. Municipal solid waste is a potential fuel for biomass energy and could solve the problem of waste disposal as well as the need for energy production.
What is Biomass?
Wood is an example of biomass. Energy can be created from wood through burning or pulping. Solid waste from city trash collection, manufacturing waste and even landfill gas can become biomass fuels. When you buy gasoline for your car you may notice a sign on the pump stating 10% ethanol has been added to the petroleum based gas.
The production of ethanol in the U.S. has led to concern as the use of corn to produce ethanol has led to rising prices and warnings of a potential shortage of corn in the food chain should too much of the crop be purchased for ethanol production.
The addition of ethanol to gasoline is a contested issue. There are studies showing long term damage to vehicle engines may be caused by ethanol and even environmentalists are now questioning the value of this product. These are the environmental groups that pushed ethanol as an addition only a few yeas ago.
There are several methods used to convert plant materials in biomass processes. Some are commonly used while other methods are experimental at this time. In thermal conversion the mechanism used to create biomass energy is heat.
The methods used are separated by the extent of the chemical reactions that occurs. Biomass can be converted into fuel that is more easily transported and used through chemical processes.
Using biochemical conversion processes, the enzymes of bacteria and naturally occurring organisms break down the biomass. This may be a process of fermenting and is the conversion we often refer to as "composting".
Gardeners know if you create a deep pile of kitchen peelings, leaves and grass cutting and moisten the pile with water on occasion, the heat from the sun will lead the clipping to decompose naturally and within a few months the biomass that was waste becomes a rich, friable soil to be used in the garden.
Other biomass processes involved methods that speed up the natural decomposition of the plant matter. Through use of chemicals and applied heat biomass can become fuel quickly.
Fuels derived from biomass create carbon monoxide, nitrogen oxide and volatile organic compounds (VOCs). These can be more substantial than the pollutants released when burning fossil fuels.
A leading contributor to climate change is thought to be black carbon. Burning biomass fuels released a high amount of black carbon due to incomplete combustion.
Biomass Power Plant
Biomass processes depend on a source of natural plant matter. The size of a biomass power plant is dictated by the biomass fuel in the region. Transporting the fuel materials is not desirable as the dead plant matter is bulky and uneven in size.
When fuel shipments are necessary, ships and rail cars are the primary transport. The power plants must be high efficiency to balance the small size of the facility.
When fuels are grown through agriculture they biomass is harvested and fields replanted which makes biomass a renewable energy resource.
The difficulties of dealing with natural fuel products are part of the biomass process. Just as farmers long ago learned the value of rotating crops to protect the land, it is know agriculturally grown biomass fuels may contain increased levels of carbon that naturally builds up in the soil over many years.
The biomass processes used to create power release more carbon dioxide than the same amount of biomass would release through normal decomposition.
In a forest, a dead tree will decompose slowly over years and the carbon released into the environment will have less impact than the same tree used as fuel in a biomass power plant.
In the 1990s a biomass-carbon-neutral proposal was put forward and considered the standard. Today we understand that using harsh forestry cutting tactics previously in place where trees were cut without restriction is not good environmental management.
The strategy suggested is to protect standing forests and grow biomass plants meant to be harvested. Fifty years of study revealed that even fifty years after clear cutting, forests had not recovered their ability to store carbon in their roots and in the ground.
Pros and Cons
The processes for generating energy from biomass are expensive to operate. Gases emitted can damage the ozone layer and contribute to global warming. Compared to fossil fuels, biomass processes have several disadvantages.
However, biomass processes used renewable fuels. They generate heat and electricity and there is a vast source of plant fuels available to use.
As technology progresses, biomass fuel processes have the capacity to not only increase energy production but to decrease problems of waste management.
Cost effective is not an issue in distributing the power produced with biomass as the resulting electricity is distributed locally and requires no transportation of pipeline distribution channels.
Biomass energy is not new; through the years we have used wood to burn in our fireplaces and wood stoves. In some area of the world, peat is fuel source readily available and organic gardeners have created compost from biomass for generations.
Biomass has great potential and could produce more energy than either wind or solar processes. The challenge is finding ways to recycle waste products into energy, clean up the environment by using animal waste in a productive way and in developing methods that limit pollution caused by biomass.