Storing surplus electricity production in chemical form
Power-to-X (also P2X and P2Y) are electricityconversion, energy storage, and reconversion pathways from surplus renewable energy.[1][2]
Power-to-X conversion technologies allow for the decoupling of power from the electricity sector for use in other sectors (such as transport or chemicals), possibly using power that has been provided by additional investments in generation.[1] The term is widely used in Germany and may have originated there.
The X in the terminology can refer to one of the following: power-to-ammonia, power-to-chemicals, power-to-fuel,[3]power-to-gas (power-to-hydrogen, power-to-methane) power-to-liquid (synthetic fuel), power to food,[4]power-to-heat. Electric vehicle charging, space heating and cooling, and water heating can be shifted in time to match generation, forms of demand response that can be called power-to-mobility and power-to-heat.
Collectively power-to-X schemes which use surplus power fall under the heading of flexibility measures and are particularly useful in energy systems with high shares of renewable generation and/or with strong decarbonization targets.[1][2] A large number of pathways and technologies are encompassed by the term. In 2016 the German government funded a €30million first-phase research project into power-to-X options.[5]