Electricity production from coal

A lower cost system is achieved if electricity and steam is generated from a coal-fired power plant and then routed to a high-temperature electrolysis plant for steam decomposition with an overall thermal efficiency of 35 - 38 % (based on 35 % efficiency of electricity production from coal) [55]. 

A tremendous increase in energy efficiency together with certain limitations regarding comfort and lifestyle permits a second age of fossil fuels. The carbon capture in coal power plants facilitates a long-term electricity production from coal. 

From an economic standpoint, electricity production from a new natural gas plant versus a newly built coal-fired plant heavily favors natural gas, because natural gas-fired plants are cheaper to build. However, older coal-fired plants built 20 to 30 years ago are often more profitable than newly built gas plants, because — among other reasons — coal is cheaper than natural gas, and the older plants have long since paid for their capital investments through depreciation. 

An energy cost would also be paid for the processes that remove the sulfur along with environmental problems from disposing of it. About 5% more coal would be needed to keep electricity production from these power plants at current levels if most of the sulfur is scrubbed out. 

In case of CHP production, this factor was reflected in the allocation by assigning 430 allowances for every GWh of electricity produced by CHP in 2003. This benchmark was based on an estimate of the displaced electricity production from a coal-fired plant and its sole purpose was to recognise the contribution of CHP in the allocation at the installation level. Eligibility was based on a written document stating how many GWh were supplied to the electricity grid or on the statement of a statutory representative in case of own consumption (electricity consumed inside the installation, not supplied to the grid). For the purposes of this bonus, a reserve of 1.5% of the total projected emissions was deducted. 

The production of electric power from coal is a mature and well-established technology in the industrialized countries of the world. However, with the advent of stricter environmental controls on effluents from power plants, especially with respect to snlfnr oxides, new types of combustion/ pollution control technology are emerging. In fact, the increased utilization of coal in place of oil and gas for combustion applications in the United States is motivating near-term development and implementation of alternative technologies for electricity generation from coal. 

Energy storage systems will also affect the environment, although not always beneficially. In operation most do not pollute or disrupt an ecosystem and so are environmentally benign. On the other hand, construction of CAES or pumped hydro is disruptive, and manufacture of the other systems frequently entails waste products that are toxic. In balance, however, energy storage systems will prove to have less environmental impact than electricity produced from coal-, nuclear-, or gas-powered or hydroelectric generators. 

Terrestrial applications aimed at an economic SOFC system for the production of electrical power from coal and air at an overall efficiency of 60% or greater. With a conceptual 100 kW coal-burning fuel cell power system (Figure 2.10 [120]), coal could be gasified using the heat and combustion products emerging from the fuel cell stacks. 

Today, over half of the US electric energy production is based on the combustion of coal at net efficiencies of about 35%. Sixty percent of the world s fossil reserves are coal, and of this amount 80% is located within China, former Soviet Union and North America. Since electric power production from coal is expanding world wide, it is advisable to approach the problem of CO2 emissions control by pushing the efficiency of power production from coal as close as possible to the theoretical natural limit. 

Environmental considerations also were reflected in coal production and consumption statistics, including regional production patterns and economic sector utilization characteristics. Average coal sulfur content, as produced, declined from 2.3% in 1973 to 1.6% in 1980 and 1.3% in 1990. Coal ash content declined similarly, from 13.1% in 1973 to 11.1% in 1980 and 9.9% in 1990. These numbers clearly reflect a trend toward utilization of coal that produces less SO2 and less flyash to capture. Emissions from coal in the 1990s were 14 x 10 t /yr of SO2 and 450 x 10 t /yr of particulates generated by coal combustion at electric utiUties. The total coal combustion emissions from all sources were only slightly higher than the emissions from electric utiUty coal utilization (6). 

For central station power generation the open cycle system using electrically conducting coal combustion products as the working fluid is employed. The fuel typically is pulverized coal burned directly in the MHD combustor, although in some plant designs cleaner fuels made from coal by gasification or by beneficiation have been considered (8—10) (see Fuels, synthetic). 

Whereas near-term appHcation of coal gasification is expected to be in the production of electricity through combined cycle power generation systems, longer term appHcations show considerable potential for producing chemicals from coal using syngas chemistry (45). Products could include ammonia, methanol, synthetic natural gas, and conventional transportation fuels. 

Most electricity from biofuels is generated by direct combustion. Wood fuels are burned in stoker boilers, and mill waste lignin is combusted in special burners. Plants are generally small, being less than 50 MW in capacity. There is considerable interest in combustion of biomass in a process called cofiring, when biomass is added to traditional fuels for electricity production. Cofiring is usually done by adding biomass to coal, but biomass also can be cofired with... 

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