Electric power is the rate at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second.
Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is usually supplied to businesses and homes by the electric power industry through an electric power grid. Electric power is usually sold by the kilowatt hour (3.6 MJ) which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a running total of the electric energy delivered to a customer.
Electrical power provides a low entropy form of energy and can be converted into motion or other forms of energy with high efficiency
Electric system, Wkipedia:
An electric power system is a network of electrical components used to supply, transfer and use electric power. An example of an electric power system is the network that supplies a region's homes and industry with power?for sizable regions, this power system is known as the grid and can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating centres to the load centres and the distribution system that feeds the power to nearby homes and industries. Smaller power systems are also found in industry, hospitals, commercial buildings and homes. The majority of these systems rely upon three-phase AC power?the standard for large-scale power transmission and distribution across the modern world. Specialised power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners and automobiles.
Electricity responsible for traffic control
Undoubtedly, one of the most interesting uses of electricity in everyday life is a traffic light. There are even special systems that allow long phase justification of the amount of light waiting to drive through the intersection cars. This is a very interesting solution, but it also can be subject to failure. Then it is necessary to help electricians to solve problems, and control traffic can be much more difficult than the use of traffic lights. Electricity can make the traffic jams formed especially in large cities are less burdensome for enjoying the busy streets of people. However, you need time to time to monitor these intelligent systems to ensure their trouble-free operation.