A combined heat and power generating unit is an energy transformation unit that has both the function to produce thermal energy and the function to produce electrical energy.
A combined heat and power plant (CHPP) is an energy transformation unit that consists of combined heat and power generating units, a grid component feeding electric energy into an electricity grid, and a grid component feeding thermal energy into a heating grid.
A power plant is an energy transformation unit consisting of power generating units and a grid component that feeds electric energy into an electric grid.
A power-to-fuel system is an energy transformation unit that implements a power-to-fuel process. A water electrolyser is participating in the power-to-fuel process.