Load balance in the power grid is managed mainly through fossil fuel peaking generation plants that respond passively to the load changes. With increased deployment of intermittent renewable power generation, conventional power plants play more important role in frequency control, as they are considered as flexible power generation units. This requires power plants working more flexibly, responding faster and more frequent (start-ups/shut-downs) for maintaining the power network stability. IMAGES project explore a new technology which will address the challenges. The project conducted feasibility study for suitable way of integrating Thermal Energy Storage (TES) to the power plant operation (steam-water loop) and investigate how the plant dynamics respond to the cycle of energy storage. The concept is demonstrated via an animation presentation (watch video on YouTube channel) which illustrated the idea of TES integration into the plant water-steam loop.
The feasibility study is conducted via simulation study which covers two types of power plants: a 600 MW supercritical coal fired power plant and a 375 MW oil fired subcritical power plant. Our simulation results suggested that it is feasible to take heat from the steam for storage and this stored thermal energy can be used by feedwater preheaters. If a suitable storage material can be designed to be able to store thermal energy in a controllable way, the steam can be also fed to the low pressure turbine.
It is expected that the research outcomes will present a new route to avoid excessive investments in new peaking fossil fuel power plants that have very low load factors, and to allow the power plants operating at its rated power output. Finally, this should help to improve power generation efficiency and reduce carbon emissions.