Solid Oxide Cells and Stacks for Reversible Operation at High Current Densities

摘要

Renewable energy sources such as solar and wind power are fluctuating by nature, and energy supply is therefore not fully controllable. Certain countries and communities have already incorporated significant share of fluctuating renewable energy in their energy system e.g. reaching a share of electricity supply from wind of 43% as reported for the Danish energy grid for 2017, which in turn also lead to periods where the supply of wind power exceeds the electricity consumption. In that perspective there is already at present a starting need for efficient, flexible and durable energy conversion and storage solutions, and the need for increased capacity of energy conversion and storage will increase steadily on the path to an energy supply aiming for substituting all fossil fuels and turning to an energy supply based 100% on renewable energy. Among a variety of energy conversion technologies reversible solid oxide cells (SOC) are a good candidate to tackle this challenge of efficient energy conversion and storage. Their capability to operate reversibly, i.e. in 'electrolysis mode (SOEC)' or 'fuel cell mode (SOFC)', allows using the surplus energy of wind and solar farms to produce H_2 or syn-gas (which then can be stored) and re-using the gasses to generate electricity (and possibly heat) on demand.