How can surplus power that can’t be fed into the electric grid be made usable? A fictitious day at the Energy System Integration Platform at the Paul Scherrer Institute PSI.
From top left to top right: As long as supply and demand in the electric grid provide for a surplus of power, excess current is used in the electrolyser to split water into hydrogen and oxygen. Where there is strong expansion of capacity from photovoltaic plants, this surplus normally occurs around midday. The hydrogen and oxygen are stored in tanks (the indicated fill level rises). Later (typically during the early evening or early morning hours), current can be regenerated on demand by means of a fuel cell, and the (local) power demand can be met without putting a strain on the electric grid.
From middle to bottom right: Methane can be produced by combining hydrogen with carbon dioxide. Methane production only kicks in, however, when the storage capacity for hydrogen is exhausted (in video, between noon and 6 p.m.). The methane can be stored and more widely distributed, and it can be used in natural gas vehicles or as an energy source for industry.
Bottom left: Gases from biomass are also suitable for methane production.
Text: Paul Scherrer Institut/Martina Gröschl