The integration of fluctuating renewable energy sources requires bulk storage of electricity to ensure grid stability and to match supply and demand. At present, PHES covers 99% of the world's bulk storage as measured by power. The main advantages of PHES are high efficiencies of 80-90% and comparatively low environmental impacts as measured by global warming potential and high ratios of energy stored over energy invested. The main disadvantages are environmental opposition, site-dependent capital costs, and uncertainty about the profitability in markets with high shares of fluctuating renewable energy sources. An alternative to PHES is CAES, which in its diabatic form is proven through the plants in Huntorf, Germany (321 MWel, since 1978) and McIntosh, USA (110 MWel, since 1991). Both plants store the compressed air in salt caverns. The main drawbacks of diabatic CAES are low efficiencies of 45-50% caused by rejecting the heat of compression and the need to resupply the rejected heat by the burning of fossil fuels. AA-CAES retains the heat of compression in a thermal-energy storage (TES), avoiding the need to burn fossil fuels and allowing efficiencies of 65-75% to be attained.

To study AA-CAES with a combined sensible/latent TES and rock caverns through simulations and experiments and to carry out a sustainability analysis in terms of environmental and economic factors.

Implications for research

Implications for practice

High-Temperature Combined Sensible/Latent-Heat Storage Based on Novel Materials for Electricity Storage Using Advanced Adiabatic Compressed Air Energy Storage

Leader of the joint project

Deputy leader of the joint project

The joint project consists of three research projects

Design and Optimization of High-Temperature Combined Sensible/Latent-Heat Storage

Analysis of AA-CAES cycles exploiting Combined Sensible/Latent Thermal Energy Storage and Novel Materials

Aluminium-silicon based phase change material structures for high-temperature latent heat storage