PTES instead of batteries? Westinghouse and Echogen launch a pioneering project in Europe

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In response to the growing demand for renewable energy storage and Europe’s energy transition, U.S.-based companies Echogen Power Systems and Westinghouse Electric Company have signed a memorandum of understanding with the Slovak state-owned hydropower operator Vodohospodárska Výstavba. The aim of the agreement is to prepare and implement Europe’s first industrial-scale, grid-level Pumped Thermal Energy Storage (PTES) system.

What is PTES Technology?

PTES systems work by converting electricity—generated from hydropower, wind, or solar—into heat, which is stored in special tanks, and then converting that heat back into electricity when needed. Unlike battery technologies, PTES offers much longer energy storage durations (ranging from 6 to even 100 hours) and greater operational flexibility, all at a lower cost per unit of energy.

A key distinguishing feature of Echogen’s solution is the use of supercritical carbon dioxide (sCO₂) as the working fluid. Thanks to its physical and thermodynamic properties, sCO₂ enables high conversion efficiency and helps lower storage costs at the gigawatt-hour scale.

Slovakia as a Laboratory for Europe’s Energy Future

Slovakia has a well-developed hydropower infrastructure—on rivers such as the Danube, Váh, and Orava—which makes it an ideal location for a first deployment of this scale. The project will store excess energy from hydropower plants and use it during peak demand, contributing to grid stability and reducing reliance on fossil fuels.

“This is a huge opportunity to become one of the most efficient organizations in Europe in the use of hydropower energy,”
said Peter Molda, CEO of Vodohospodárska Výstavba.

A Milestone for Energy Transition by 2030

Under the signed memorandum, the parties commit to conducting a feasibility study and a Front-End Engineering Design (FEED) phase, which will conclude with optimization of the technology layout. The goal is to launch the installation by 2030, leveraging local supply chains and Slovak labor.

“This is a breakthrough step for clean energy in Europe. Our sCO₂ technology enables the creation of flexible, reliable, and sustainable energy infrastructure,”
emphasized Rob Bernard, Chief Commercial Officer at Echogen.

PTES Advantages According to Echogen and Westinghouse

Echogen’s storage system offers not only high efficiency but also versatility—it can work with energy from any source: renewable (wind, solar, hydro), thermal, or conventional. Key benefits of the technology include:

  • Energy storage for hours, days, or even weeks
  • Lower levelized cost of storage (LCOS)
  • Reduced consumption of critical resources (like lithium or cobalt, essential for batteries)
  • High durability across operating cycles and minimal degradation

A previous collaboration between Echogen and Westinghouse resulted in a 50 MW / 1.2 GWh PTES project in Alaska with Golden Valley Electric Association—one of the largest known PTES systems in the world. The new agreement with Slovakia aligns with the companies’ global strategy for deploying long-duration energy storage.

“Everybody loves batteries, but they struggle with longer-duration storage. PTES fills that gap,”
commented Phil Brennan, CEO of Echogen.

Source: solarquarter.com

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