New electric grid-scale energy storage system

Abstract

Energy storage appears to be the only solution to rectify intermittency of renewable energy over grid utility. While energy storage technologies are still in their development stage, battery storage systems are rapidly moving into a technological lock-in state termed as battery lock-in. Meanwhile, there are numerous unresolved challenges on batteries used as grid-scale energy storage which poses significant risk.

This thesis focuses on innovating alternative solution for grid-scale energy storage other than batteries used as grid-scale energy storage. Secondly, the system intends to alleviate the intermittency of renewable energy, such as wind energy and solar photovoltaic farms connected to the grid. The final objective of this design is to reduce the cost and risk associated with electric energy storage systems and to ensure stability in electric grid networks.

The present innovation stores power from the electric grid in a thermal fluid system integrated with a regeneration step to match power demand. This innovation consists of a thermally insulated tank where electric heaters and the hot side cylinders of Stirling Engines are embedded within the body of the thermally insulated tank. A wide range of liquid state heat storage materials can be used in this system. The heat storage material within the thermally insulated tank is heated when power is fed to the electric heater and the energy stored is released as electricity when the Stirling engines are made to run. In addition to the unit components, an auxiliary electric storage unit known as supercapacitor electric storage is attached to the system where it stores excess electricity from the Stirling engines and supplies it to the electric heater.