There are various types of waste to energy technologies, including pyrolysis, gasification, combustion, esterification, fermentation, and anaerobic digestion. Some of these waste to energy technologies use chemical or biochemical processing and others use thermal processing. Municipal waste to energy technology can meet households energy needs, while waste-created biofuels can power automobiles.
Pyrolysis and gasification are probably the most cost-effective modern waste to energy technologies. To further maximize cost-effectiveness, they can be performed together. Pyrolysis requires an external source of heat, which can be provided by the process of gasification. This combination of processes is self-sustaining, which reduces the costs, therefore making both of them increasingly cost-effective
Anaerobic digestion is another currently available type of waste to energy technology. In this method the waste is placed into digesters specially constructed for this purpose, where oxygen cannot get through. In this way the waste can break down quicker, which releases methane and other greenhouse gases. It is possible for heat to be created in this process because of extensive microbial activity in decomposing biomass.
Fermentation is another waste to energy technology, which can create ethanol out of biomass, using organic or cellulosic material. During the process of fermentation, the sugar found in the waste gets changed to alcohol and carbon dioxide, much like in the wine-making process. Fermentation normally occurs when there is no air present.
Another kind of waste to energy technology is something called esterification. Biodiesel is the result of this process. The feedstock used will determine esterification’s cost-effectiveness. Other factors that contribute to the effectiveness of esterification include the amount of oil in the feedstocks, the transportation distance, and various others.
Waste to energy technologies have been declared by the Environmental Protection Agency as having the least impact on the environment out almost all energy sources. Mature technology and strict regulations helped waste to energy plants be efficient and green at the same time. Every year about 12-15 percent of America’s solid waste is turned into electricity, which amounts to over 100,000 tons daily and provides 2.8 million homes with electricity.
So, if the process is effective then why is only a fraction of the trash burned? Well, this comes down to economics. In some locations some waste to energy technologies make more sense than others. Hydro, nuclear power, and coal are still cheaper energy generation methods. But waste to energy technology has many other benefits like landfill reduction. Also, waste to energy technologies do not produce greenhouse gases which are then released into the atmosphere, and they help reduce usage of fuels by reducing transportation of waste for long distance.
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