One of the biggest challenges in the energy sector is how to balance electricity generation with consumption in the most efficient way possible. One answer lies in the deployment of innovative energy storage systems – and one such project could soon be built in Slovakia.
The concept is called pumped thermal energy storage (PTES) – a technology that converts electricity into thermal energy and, when needed, back into electricity. Simply put, the principle is similar to that of pumped-storage hydroelectric plants, such as Čierny Váh in Slovakia. When there is surplus electricity, water is pumped from a lower reservoir to a higher one. When energy is needed, the water is released back through turbines to generate electricity.
Memorandum signed
This July, Westinghouse Electric Company, the American company that might build the next nuclear power station in Slovakia, signed a memorandum of understanding with the state-owned Vodohospodárska Výstavba (VVB) to assess the feasibility of building such a system. If realised, it would be the first commercial PTES project in Europe.
“Westinghouse’s ground-breaking pumped thermal energy storage technology provides utilities with a reliable and scalable solution for storing energy over extended periods,” said Dan Lipman, President of Energy Systems at Westinghouse, during the signing ceremony. “Our PTES system will enable Slovakia to store hundreds of megawatt hours of clean electricity during low-demand periods and discharge it when needed most, increasing system reliability and potentially reducing overall energy costs.”
Westinghouse developed its PTES system in cooperation with Echogen, a supplier of supercritical carbon dioxide (sCO₂)-based power systems. The solution uses an electrically driven heat pump to draw electricity from the grid and transform it into stored thermal energy, which can later be converted back into electricity using a heat engine. The system is designed for 100 MW-plus applications requiring at least eight hours of energy storage.
Where it could be built
VVB, which operates several hydroelectric power plants in Slovakia, sees this as a major opportunity to become one of Europe’s most efficient organisations in terms of maximising the use of electricity generated by hydroelectric power plants on the Danube, Váh and Orava Rivers.
The agreement outlines a two-month pre-study to analyse the project’s economic and environmental feasibility, and sets the framework for a 12-month front-end engineering and design (FEED) study to determine the system’s configuration. The Westinghouse PTES is expected to become operational by 2030, involving local suppliers and creating opportunities for similar projects across Europe and beyond.
The main advantage of the system is that, unlike pumped-storage hydroelectric plants, it is not dependent on specific geography. It only requires a sufficiently large plot of land with suitable geological conditions and access to a high-voltage power grid.
The most logical solution would be to locate the storage facility directly next to one of the major power plants – for example, near the Gabčíkovo hydropower plant, writes Pravda.
