Electricity and economic
The selection of electricity production modes and their economic viability varies in accordance with demand and region. The economics vary considerably around the world, resulting in widespread selling prices, e.g. the price in Venezuela is 3 cents per kWh while in Denmark it is 40 cents per kWh. Hydroelectric plants, nuclear power plants, thermal power plants and renewable sources have their own pros and cons, and selection is based upon the local power requirement and the fluctuations in demand. All power grids have varying loads on them but the daily minimum is the base load, supplied by plants which run continuously. Nuclear, coal, oil and gas plants can supply base load.
Thermal energy is economical in areas of high industrial density, as the high demand cannot be met by renewable sources. The effect of localized pollution is also minimized as industries are usually located away from residential areas. These plants can also withstand variation in load and consumption by adding more units or temporarily decreasing the production of some units. Nuclear power plants can produce a huge amount of power from a single unit. However, recent disasters in Japan have raised concerns over the safety of nuclear power, and the capital cost of nuclear plants is very high. Hydroelectric power plants are located in areas where the potential energy from falling water can be harnessed for moving turbines and the generation of power. It is not an economically viable source of production where the load varies too much during the annual production cycle and the ability to store the flow of water is limited.
Due to advancements in technology, and with mass production, renewable sources other than hydroelectricity (solar power, wind energy, tidal power, etc.) experienced decreases in cost of production, and the energy is now in many cases cost-comparative with fossil fuels. Many governments around the world provide subsidies to offset the higher cost of any new power production, and to make the installation of renewable energy systems economically feasible. However, their use is frequently limited by their intermittent nature. If natural gas prices are below $3 per million British thermal units, generating electricity from natural gas is cheaper than generating power by burning coal
Tasks for the electrician during the formation of the building
Electricians, in addition to repair defects associated with the current also have other jobs. Very often help electrician is needed to properly design the electrical network in the proposed facility. Also during the construction electrician with his team in control of the electrical installation of the network, because only authorized persons may perform such work. It is very important to install the appropriate wiring to the building during the operation met its functions. Therefore, this electrician is responsible for the oversight of electricity on site and very often his help is invaluable, because it allows the reception of installations, without which the building does not meet the required functions.
Turbines and electricity
Almost all electrical power on Earth is generated with a turbine of some type. Turbines are commonly driven by wind, water, steam or burning gas. The turbine drives an electric generator. Power sources include:
Water is boiled by coal burned in a thermal power plant, about 40% of all electricity is generated this way.7
Nuclear fission heat created in a nuclear reactor creates steam. Less than 15% of electricity is generated this way.
Renewables. The steam is generated by:
Solar thermal energy (the sun as the heat source): solar parabolic troughs and solar power towers concentrate sunlight to heat a heat transfer fluid, which is then used to produce steam.
Geothermal power. Either steam under pressure emerges from the ground and drives a turbine or hot water evaporates a low boiling liquid to create vapor to drive a turbine.
Large dams such as Hoover Dam can provide large amounts of hydroelectric power; it has 2.07 GW capability.
Gas Natural gas is burned in a gas turbine, turbines are driven directly by gases produced by combustion. Combined cycle are driven by both steam and natural gas. They generate power by burning natural gas in a gas turbine and use residual heat to generate steam. At least 20% of the worlds electricity is generated by natural gas.
Water Energy is captured from the movement of water. From falling water (dam), the rise and fall of tides or ocean thermal currents. Each driving a water turbine to produce approximately 16% of the worlds electricity.
Wind The windmill was a very early wind turbine. In a solar updraft tower wind is artificially produced. Before 2010 less than 2% of the worlds electricity was produced from wind.