Advantages and Disadvantages of Biomass
Advantages of Biomass
The most important advantage of biomass is that it is everywhere and very easily available. In the agriculture industry, residuals like bagasse (fibers) from sugarcane, straw from rice and wheat, hulls and nutshells, as well as manure lagoons from cattle, poultry and hog farms are usable. Similarly, the timber industry has a lot to offer. Wood wastes like sawdust, timber slash and mill scrap are considered organic materials. Even in cities, paper and yard wastes are usable. Fully utilized biomass reduces pollution in underground water bodies by offsetting the amount of waste in landfills. Methane and other poisonous gases that form from dead organic matters can be found in landfills and water treatment plants. These can be captured and converted in to fuels suitable for generating electricity.
Rural economies will grow because of the development of a local industry to convert biomass to either electricity or transportation fuel. Because biomass feedstocks are bulky and costly to transport, conversion facilities will be located where the crop is grown. That means more people have chances of getting employed. Farmers will see their income rise thanks to these new markets -- for both agricultural wastes and crops that can be grown sustainably on marginal land. As new markets are created, the rural economy will become more diversified.
Energy producers and consumers will have available a renewable energy option with uniquely desirable characteristics. Biomass has the greatest potential of any renewable energy option for baseload electric power production. It is also the renewable resource with the most promise for producing economically competitive liquid transportation fuels. Co-production facilities will allow the production of electricity when it is needed and ethanol when it is not -- acting, in effect, as "seasonal peaking" facilities. The energy security of a nation will be significantly enhanced. With sustainable agricultural practices, biomass fuels could replace half or more of the nation's entire current level of gasoline consumption. Burning new biomass contributes no new carbon dioxide to the atmosphere because if we replant harvested biomass, carbon dioxide is returned to the cycle of new growth. Bioconversion and thermal conversion techniques for transforming biomass into fuels are currently under development at NREL and other research laboratories. These new technologies will reduce our reliance on oil and coal with no net addition of carbon dioxide to the atmosphere. New thermal conversion techniques coupled with chemical catalysis are making it possible to exploit the previously discarded lignin fraction by converting it into valuable chemicals that we now get from non-renewable fossil sources.
Agricultural land that might otherwise be converted to residential or industrial use -- because we will need fewer and fewer acres to meet the market demand for food -- can be used to grow biomass crops that will restore soil carbon, reduce erosion and chemical runoff, and enhance wildlife habitat. Perennial energy crops can be harvested without damage to the root structure and thus continue to serve as a soil stabilizer and stream buffer and habitat for wildlife. The use of biomass will greatly reduce greenhouse gas emissions. Fossil fuels remove carbon that is stored underground and transfer it to the atmosphere. In a combustion system, biomass releases carbon dioxide as it burns, but biomass also needs carbon dioxide to grow -- thus creating a closed carbon cycle. In a gasifier-fuel cell combination, there is a net reduction of carbon dioxide. In addition, substantial quantities of carbon can be captured in the soil through biomass root structures, creating a net carbon sink.
Disadvantages of Biomass
- The burning method of biomass is not clean. It is similar to the burning of fossil fuels and produces large amounts of carbon dioxide. However, it produces much less harmful pollutants (e.g. sulfur), as the main elements found in organic materials are hydrogen, carbon, oxygen and nitrogen.
- It takes considerable energy to produce biofuels from certain feedstock, resulting in less than desirable energy returns on energy invested (EROEI).
- Biomass collection is difficult.
- Biomass crops not available all year.
- Still an expensive source, both in terms of producing the biomass and converting it to alcohols
- On a small scale there is most likely a net loss of energy--energy must be put in to grow the plant mass