The electric power industry is the generation, transmission, distribution and sale of electric power to the general public.
The electrical industry started with introduction of electric lighting in 1882.Throughout the 1880s and 1890s, growing economic and safety concerns lead to the regulation of the industry. Once an expensive novelty limited to the most densely populated areas, reliable and economical electric power has become a requirement for normal operation of all elements of developed economies. By the middle of the 20th century, electric power was seen as a "natural monopoly", only efficient if a restricted number of organizations participated in the market; in some areas, vertically-integrated companies provides all stages from generation to retail, and only governmental supervision regulated the rate of return and cost structure. Since the 1990s, many regions have opened up the generation and distribution of electric power to provide a more competitive electricity market.
However, transmission and distribution are harder problems since returns on investment are not as easy to find.Źródło: https://en.wikipedia.org/wiki/Electric_power_industry
Power in an electric circuit is the rate of flow of energy past a given point of the circuit.In alternating current circuits, energy storage elements such as inductors and capacitors may result in periodic reversals of the direction of energy flow.
The portion of power that, averaged over a complete cycle of the AC waveform, results in net transfer of energy in one direction is known as active power (sometimes also called real power).