The economic feasibility of using Georgia biomass for electrical energy production
Shumaker, George A.
McKissick, John C.
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The purpose of this study is to re-evaluate the economic feasibility of current technology for pyrolysis and gasification as methods for producing energy from Georgia’s biomass resources. The study also evaluates the feasibility of converting dairy waste into methane for electrical generation. The basic process is to convert the biomass resource into “bio-gas” and “bio-oil” or “syn-gas” and “syn-oil” that can be used as fuel to produce electricity. Georgia has a large amount of potential biomass feedstocks available for conversion into energy. There may be in excess of 13 million tons of material that could possibly be converted each year. Estimated annual electricity use in Georgia during 2006 was about 137.2 billion kilowatt hours. If all 13 million tons of bio-mass were converted into electricity using the best technology explored in the study, it would produce about 8.6 percent of the estimated Georgia electricity use. While that is an impressive amount, the likelihood of utilizing all available bio-mass for electricity production is unlikely. The cost of delivery of the biomass to a conversion facility would require a sales price of the electricity well above the current prevailing sales prices. The properties and characteristics of each potential bio-fuel have important implications to the feasibility of individual biomass sources. In order to optimize feasibility, feedstocks must provide generators with an abundant supply at the lowest cost of delivery possible. In addition, the heat content (BTU) of feedstocks varies depending upon the type of biomass, so a high energy fuel is critical. Biomass sources also differ in ash and moisture content. This affects the energy value of biofuels, since the chemical make-up of ash generally has no energy value and the amount of water in bio-fuel affects, in a decisive manner, the available energy within every bio-fuel. Gasification and pyrolysis are similar technologies that convert carbon laden products into component products that can be used as fuel. There are three main products produced from the processes: hydrocarbon gas or “syn-gas”, hydrocarbon oils “syn-oils” that can be further processed and char and ash, the solids residual. The gasification system will produce a greater volume of syn-gas while the pyrolysis system will produce a greater volume of the oil product. The cost of producing electricity with both the gasification and pyrolysis systems modeled in this study are above the current rates for electricity sold in Georgia. For that reason it appears that neither gasification nor pyrolysis technology, similar to that modeled here, are viable sources of electricity at the present time. The reasons for the relative high cost of electricity production with these technologies are many but a few of them include the high capital cost of the technology relative to electrical power generated. The high capital cost raises the fixed costs of operation and places a large financial burden of the venture. It is possible that larger scale operations or different technologies than those modeled in this study can drive unit costs of production down enough to be competitive. The basic findings are that while it is technologically feasible to accomplish the task, it is not economically feasible to convert biomass into electricity in Georgia at the present time. The exception is that large dairies or smaller dairies that pool their manure may be able to produce electricity at competitive rates.