Direct electricity generation

Diversity of use—geothermal energy has three common economic uses—electricity generation, direct use of heat, and GHPs. 

Electrical generator directly coupled to the turbine produces electricity and the voltage is stepped up by the generator transformer which in turn is connected to a switch yard. Generated power is thus transmitted to the electrical power grid. 

EJ = 0.9488 X 10 Btu. Assumes market incentives of 2 /kWh on fossil fuel-based electricity generation, 2.00/10 Btu on direct coal and petroleum consumption, and 1.00/10 Btu on direct natural gas consumption. 

Not all of the gas is wasted. About 300 MW of electricity is generated from landfills. A variety of electric generation systems have been employed by a small number of developers. Most projects use simple technology and are small (2—10 MW). However, an EPRI study has estimated that landfill gas resources in the United States could support 6,000 MW of generation if utilized in 2-MW-sized carbonate fuel cells. Constmction on the world s first utihty-scale direct carbonate fuel cell demonstration was begun in California. If successful, EPRI estimates that precommercial 3-MW plants based on this design could become available by the end of this decade at an installed cost of 17,000/kW. 

The BWR operates at a pressure such that cooling water boils as it passes through the core the steam is dried, exits containment and drives the turbine-generator to produce electricity. This direct cycle is like a fossil-burning power plant. 

In electrical power stations a new measure of the performance is the amount of CO2 produced per unit of electricity generated, i.e. A = kg(C02)/kWh this quantity can be non-dimensionalised by writing A = A( 16/44)(LCV) where (16/44) is the mass ratio of fuel to CO2 for methane and (LCV) in its lower heating value. However, presenting the plant s green performance in terms of A directly allows the cost of any tax on the carbon dioxide to be added to the untaxed cost of electricity production most easily. 

Although biomass used directly for heating and cooking is the thermodynamically most efficient use, followed by use for electricity generation, the economics are much more favorable to convert to a liquid fuel. Economic considerations outweigh thermodynamics as an electricity generator, biomass must compete with relatively low-priced coal, but as a liquid fuel the competition is higher-priced oil. 

Many geothermal reseiwoirs contain hot water at a temperature too low for electricity generation. However, the water can be used to heat buildings such as homes, greenhouses, and fish hatcheries. This heating can be either direct or through the use of heat pumps. 

Having covered the chemical behavior of electrolytes, the text is now directed to their electrical behavior. The importance of the chemical and the electrical behaviors of electrolytes in galvanics and electrolytics hardly needs any elaboration. The term galvanics, used here, implies the generation of electrical energy directly from a spontaneous chemical reaction. 

The second variant is designed for solid state reactants to the exclusion of liquid or gas. This powder variant of Thermostar is described by the Fig. 1.19 (right). The microwave applicator is the same as for the device for liquids heating but the reactant transport is ensured by a metallic screw set within the dielectric pipe. This specific traveling metallic screw crosses all the microwave applicators. The coexistence of this metallic screw with the electric field is ensured by the fact that the major electric field direction is parallel to the major direction and perpendicular to the local curving of the screw. A typical industrial unit for solid or liquid reactants is powered with microwave generators units of 2 or 6 kW for a total microwave power close to 20 or 60 kW. 

Doenitz, W. et al., Electrochemical high temperature technology for hydrogen production or direct electricity generation, Int. ]. Hydrogen Energ., 13,283,1988. 

Electrogenerated chemiluminescence (ECL) is the process whereby a chemiluminescence emission is produced directly, or indirectly, as a result of electrochemical reactions. It is also commonly known as electrochemiluminescence and electroluminescence. In general, electrically generated reactants diffuse from one or more electrodes, and undergo high-energy electron transfer reactions either with one another or with chemicals in the bulk solution. This process yields excited-state molecules, which produce a chemiluminescent emission in the vicinity of the electrode surface. 

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