Efficient Conversion of Renewable Energy using Solid Oxide Cells

In a future sustainable society where a large part of the energy demand will be met with renewable energy sources, efficient energy conversion of this energy will play a very important role. For instance, it is necessary to convert electricity coming from wind and solar power to chemical energy for easy storage and transportation. At the point of consumption it is necessary to convert the chemical energy to electricity and/or heat. The project, which is a collaboration between Risø National Laboratory and five Danish universities, concerns so-called solid oxide cells. Such cells are capable of working either as electrolyzers (conversion of electricity to chemical energy) or as fuel cells (conversion of chemical energy to electricity and heat). This technology has the potential to ensure an efficient conversion of energy if it can be made economically viable. This demands that the internal resistance of the cells is reduced considerably. In the project we identify and study a number of central scientific problems – especially concerning interfaces between the different components in the systems – where increased fundamental knowledge is necessary to obtain a smaller internal resistance. We also study the economical aspects of the technology.

Energy conversion using solid oxide cells (SOCs): Fuel is converted to electricity and heat using the SOC in fuel cell mode (SOFC – Solid Oxide Fuel Cell). Electricity is converted to fuel (e.g. hydrogen) using the SOC in electrolyzer mode (SOEC – Solid Oxide Electrolysis Cell).
The inset shows the layered structure of the cell stack. Seen is (from top to bottom): interconnect, corrosion layer, cathode, electrolyte, anode, corrosion layer and interconnect.