How is power generation understood?
Power generation has to do with the generation of electrical power, and sometimes other forms of power, out of primary energy sources. The term is technically not correct, because the process includes transforming energy between different forms, rather than actually generating it. Generally, the definition is understood. It occurs most commonly in large technical systems called power plants.
Generating energy away from power plants
Smaller systems are used to: provide mobile power generators that have a high demand for energy; as an emergency power supply to ensure security in energy supply; and in the renewable energy sector. Mobile power generator systems and emergency power generators usually consist of a combustion engine with an attached generator. When energy demand is very high, diesel motors are used. Smaller systems ranging from 1 to 2 kW include with an Otto engine. Additionally, there are also very small power generators, with less than 1 kW of power. These have two-stroke engines.
Conventional Power Generators
Power generation from fossil fuels and nuclear power is a process that has several stages, in which the primary energy is first transformed into heat and then into mechanical energy. The desired form of electrical energy is then created within the generator. In order to increase the utilisation of primary energy, the inevitable losses in energy that occur in the form of waste heat can be used be used in suitable facilities as heat. This will increase the overall efficiency of these machines. However, a combined heat and power unit can also be used in order to increase the efficiency of producing heat energy. Combined heat and power is usually applied on a large scale with power plants that are connected to district heating networks. Large power plants generally require longer transportation routes and bigger networks to distribute district heating. This restricts the areas of application for combined heat and power systems in this sector. To avoid these disadvantages, smaller block heating stations can be installed closer to the consumer. Particularly small machines can also be built with motors from the car manufacturing sector. They are usually suited, for example, to supply single or multi-family houses. With these power generating machines, heat is the desired form of energy and the electrical energy is just a high-end side product.
Generating power from renewable sources
Contrary to conventional power plants, the conversion of energy occurs in a small, direct way, even in most large-scale renewable power plants. Hydroelectric power stations and wind turbines generate electricity directly from the energy of movement. In photovoltaic cells, the energy from the suns rays is transformed into electrical energy through solar panels and geothermal systems. A direct transformation of energy also occurs with heat pumps. Thermal energy is brought from one temperature level to another. For a heat pump, the inputted energy in the form of liquid or gaseous fuels is required for the maintenance of the process cycle. This is particularly important when using heat pumps for generating cold air for cooling units (e.g. household refrigerators).
Important milestones during the development of power generators
The history of power generation is tightly connected with the development of industry and is characterised in several large chunks. Until the 1970s, there was a direct relationship between the development of the economy and the consumption of energy. The oil crisis in 1973-1974 moved the focus towards energy saving and this resulted in the discovery that the economy could grow without energy consumption rising. At the end of the 20th century the limit of fossil fuels became known. This was particularly relevant for oil, which is an important resource for the chemical industry and many other aspects of everyday life. The influence of the industrialisation’s massive consumption of fossil fuels on the environment and climate, resulted in a need to change the way power is generated. Even nuclear power generators are not been identified as the ideal alternative to fossil fuels, due to the inherent problems associated with it. In the lead up to the third millennium, rising energy prices, technical challenges, motivations made through environmental policy and governmental subsidies in many countries has increased competitiveness in generating power from renewable sources.
Where are systems used for power generation?
Large power plants are operated by a few utility companies that work over several regions. Medium sized systems are available in industry and at a municipal level, for the regional supply in the case of e.g. public-owned utility companies. Subsidies from the government are available to install and operate systems that generate power from renewable sources. These are used in all sectors and by large utility companies and individual consumers. Wind energy provides an income stream for utility companies and for farmers, who could tap into this new source of income by generating power. In the private sector, power generation usually occurs through use of photovoltaics, thermal power from solar energy and combined heat and power. Additionally, heat pumps are used for geothermal energy, ambient heat and to increase the efficiency of solar thermal systems. The profits from combined heat and power units can be increased by installing heat storage tanks, which can be accessed at times of high levels of consumption.
Who Produces Power Generators?
Examples of companies that produce power generators include ALSTOM, AREVA, AVANTIS, BOSCH, SIEMENS, STIEBEL ELTRON, GENERAL ELECTRIC, MITSUBISHI HEAVY INDUSTRIES, VESTAS, NORDEX, REPOWER, SOLARWORLD, SOLON, SCHÜCO, ENERCON and VW.