Electricity Generation

Electricity generation is the process of converting some form of energy into electricity. For electric utilities, it is the first process in the delivery of electricity to consumers.

Electricity has been generated for the purpose of powering human technologies for over 100 years, from various sources of energy. The first power plants were run on water power or coal, and today electrical power generation relies mainly on coal, nuclear, natural gas, hydroelectric, and petroleum with a small amount from solar energy, tidal harnesses, wind generators, and geothermal sources.

Electricity is most often generated by electro-mechanical generators, primarily driven by heat engines, usually turbines, but also by other means such as the kinetic energy of flowing water and wind. Small electricity generators are often powered by reciprocating engines burning diesel, biogas or natural gas. Diesel engines are often used for back up generation, usually at low voltages. Biogas is often combusted where it is produced, such as a landfill or wastewater treatment plant, with a reciprocating engine or a microturbine, which is a small gas turbine.

There are many other technologies that can be and are used to generate electricity though, with solar photovoltaics being the most significant alternative currently. Photovoltaic panels convert sunlight directly to electricity. Although sunlight is free and abundant, solar electricity is still usually more expensive to produce than large-scale mechanically generated power due to the cost of the panels.

Until recently, photovoltaics were most commonly used in remote sites where there is no access to a commercial power grid, or as a supplemental electricity source for individual homes and businesses. Recent advances in manufacturing efficiency and photovoltaic technology, combined with subsidies driven by environmental concerns, have dramatically accelerated the deployment of solar panels.

Electrochemical electricity generation is also important in portable and mobile applications. Currently, most electrochemical power comes from closed electrochemical cells (”batteries”), which are arguably utilized more as storage systems than generation systems.

Open electrochemical systems, known as fuel cells, have been undergoing a great deal of research and development in the last few years. Fuel cells can be used to extract power either from natural fuels or from synthesized fuels (mainly electrolytic hydrogen) and so can be viewed as either generation systems or storage systems depending on their use.