The last five years has seen a revolution in how governments, people and industry view energy. The advantages of biomass energy have come to the forefront in this discussion.
Advantages of Biomass Energy
The most common practical expression of biomass energy is in the form of biofuels. Biodiesal and bioethanol are already being used to supplement gasoline products in an effort to cut emissions and wean America off oil products.
Biofuels are essentially nontoxic and biodegrade readily. Every gallon of biofuels used reduces the hazard of toxic petroleum product spills from oil tankers and pipeline leaks (average of 12 million gallons per year, more than what spilled from the Exxon Valdez, according to the U.S. Department of Transportation). In addition, using biofuels reduces the risk of groundwater contamination from underground gasoline storage tanks (more than 46 million gallons per year from 16,000 small oil spills, according to the General Accounting Office), and runoff of vehicle engine oil and fuel.
The U.S. transportation sector is responsible for one-third of our country's carbon dioxide (CO2) emissions, the principal greenhouse gas contributing to global warming. Combustion of biofuels also releases CO2, but because biofuels are made from plants that just recently captured that CO2 from the atmosphere-rather than billions of years ago-that release is largely balanced by CO2 uptake for the plants' growth. The CO2 released when biomass is converted into biofuels and burned in truck or automobile engines is recaptured when new biomass is grown to produce more biofuels. Depending upon how much fossil energy is used to grow and process the biomass feedstock, this results in substantially reduced net greenhouse gas emissions. Modern, high-yield corn production is relatively energy intense, but the net greenhouse gas emission reduction from making ethanol from corn grain is still about 20%. Making biodiesel from soybeans reduces net emissions nearly 80%. Producing ethanol from cellulosic material also involves generating electricity by combusting the non-fermentable lignin. The combination of reducing both gasoline use and fossil electrical production can mean a greater than 100% net greenhouse gas emission reduction.
Biomass generated electricity is another active area of research and production. Biomass electricity is typically generated through boiler/steam turbine plants, but with three key differences: the fuel is renewable, there is less than 0.1% sulfur (an acid rain ingredient) in biomass fuels, and less air pollutants are produced. More specific environmental benefits for biomass power are:
• Reduced Sulfur Dioxide Emissions - Most forms of biomass contain very small amounts of sulfur, therefore a biomass power plant emits very little sulfur dioxide (SO2), an acid rain precursor. Coal, however, usually contains up to 5% sulfur. Biomass mixed with coal can significantly reduce the power plant's SO2 emissions compared to a coal-only operation.
• Reduced Nitrogen Oxide Emissions - Recent biomass tests at several coal-fired power plants in the U.S. have demonstrated that NOx emissions can be reduced relative to coal-only operations. By carefully adjusting the combustion process, NOx reductions at twice the rate of biomass heat input have been documented.
• Reduced Carbon Emissions - Plants absorb CO2 during their growth cycle when managed in a sustainable cycle, like raising energy crops or replanting harvested areas. Biomass Power generation can be viewed as a way to recycle carbon. Thus, Biomass Power generation can be considered a carbon-neutral power generation option.
• Reducing Other Emissions - Landfills produce methane (CH4) from decomposing biomass materials. Decomposing animal manure, whether it is land-applied or left uncovered in a lagoon also generates methane. Methane, which is the main component of natural gas, is normally discharged directly into the air, but it can be captured and used as a fuel to generate electricity and heat.
• Reduced Odors - Using animal manure and landfill gas for energy production can reduce odors associated with conventional disposal or land applications.
Biomass energy is not the perfect solution to our current energy and environmental concerns. The advantages of biomass energy, however, far outweigh those of fossil fuels.