The greek power system involves power generation by lignite, fuel oil, hydroelectric and natural gas power plants, as well as by renewable energy sources.
It also involves power transmission via the National Interconnected System to the mainland, as well as power supply to consumers via the distribution network.

The load dispatching is effected by the National Center for Energy Oversight, located in Aghios Stefanos, Attica.

Most of the islands are supplied with electric power generated by autonomous fuel oil power plants, while the use of renewable energy sources (wind, solar) is increasingly gaining ground.