Solar energy is the most abundant renewable energy resource and therefore logically represents the most important renewable energy resource for the future. The IEA roadmap for solar energy set a target of ca. 22% of global electricity production from solar energy by 2050, with 50% being produced from concentrating solar thermal (CST) power systems. Achieving this target will be possible only if the costs of producing electricity from solar energy are significantly reduced and cost effective energy storage technologies can be developed.
A major challenge is to achieve continuous, low-variability power generation from renewable energy sources, for stand-alone applications or for integration with domestic power grids. Solar mirror collection fields can collect thermal energy during the day and run a heat engine to convert it into electricity, but cannot provide power at night. However, if some of the heat is used to remove hydrogen from a metal hydride, the reverse reaction where hydrogen absorbs back into the metal hydride can then occur at night, releasing heat for power generation. This thermal battery allows solar energy to provide 24 hour power generation. By combining a high temperature metal hydride with a low temperature metal hydride, a coupled pair reversible metal hydride thermochemical solar energy storage system is created. Concentrated solar thermal coupled to a high and low temperature metal hydride has the potential to provide a continuous supply of electricity to remote areas in Australia and around the World.
I will discuss the use of CST worldwide and will present some results on the properties of metal hydrides that are suitable for CST applications, focussing on high temperature hydrides.