The Role of Power-to-X in a Sustainable Energy System Based 100% on Renewables

To stop global warming, all sectors must become climate neutral. To reach this aim energy use must be reduced, efficiency must be increased and the remaining energy demand must be covered by renewables. This 100 per cent renewables supply will lead to a regular and cyclic energy over supply. However also sectors which can not be electrified directly must be connected to electricity sector. Power to Liquid (PtL) is one possible sector coupling technology. PtL production can be operated in times with renewable energy excess. In times of less renewable production a reduction of the actual production of a PtL plant, this can help to stabilise the power supply in the public grid and the market values of renewable energies. This enables the substitution of fossil by synthetic carbon neutral fuels, first of all in aviation and maritime transport. Today it is allowed to substitute 50 per cent of the fossil kerosene in aviation by synthetic kerosene. To reach this drop-in quota and increase it in future further a consistent and accelerated expansion of renewable energies must be realized. Of course, it must be expanded to reach a 100 per cent synthetic fuel quota for the remaining hydrocarbons which have to be used in aviation, maritime transport and other sectors. Note, synthetic fuels are only carbon neutral if the CO2, which is needed for the production, is kept in a closed CO2 cycle. In addition, synthetic kerosene is burned in the engines of a plane. This will lead to non CO2 effects, which will lead to global warming, too. Therefore, using synthetic kerosene can only lead to carbon neutral aviation, and if further ecological and social aspects are not being negelected, a transformation into a truly sustainable energy system is feasible.