Power plants energy production from

Most electric power plants produce electricity from steam that is used to rotate a power-generating turbine. The heat contained in the steam after it condenses is lost to the environment. In many industrial processes steam or heat is produced during production, but the mechanical energy in the steam or heat is not utilized. 

Real power plants operate differently from the Carnot cycle but the big picture is the same An energy source at high temperature is used to supply heat to a process, whose net result is to produce an amount of work. In industrial production of power the heat source is either a fossil fuel such as coal or a nuclear fuel. In either case a chemical or nuclear reaction releases heat at an elevated temperature, which acts as the high-temperature reservoir. Invariably, part of this heat must be rejected to the surroundings but at a lower temperature. As a result, only a fraction of the heat released by the fuel is converted into work. The Carnot efficiency gives the maximum possible fraction of work that can be extracted, given the... 

Excise taxes placed on specific energy sources tend to reduce the demand for these energy sources in both the short and the long run. The federal government imposes excise taxes on almost all petroleum products and coal (see Table I). The federal government also imposes excise taxes on many transportation uses of methanol, ethanol, natural gas, and propane and imposes a fee on electricity produced from nuclear power plants. 

Alternatives to fossil fuels, such as hydrogen, are explored in Box 6.2 and Section 14.3. Coal, which is mostly carbon, can be converted into fuels with a lower proportion of carbon. Its conversion into methane, CH4, for instance, would reduce C02 emissions per unit of energy. We can also work with nature by accelerating the uptake of carbon by the natural processes of the carbon cycle. For example, one proposed solution is to pump C02 exhaust deep into the ocean, where it would dissolve to form carbonic acid and bicarbonate ions. Carbon dioxide can also be removed from power plant exhaust gases by passing the exhaust through an aqueous slurry of calcium silicate to produce harmless solid products ... 

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