New thermal energy storage system for CSP

11.11.2014
The mode of operation of the NEST thermal energy storage system. (Graphic: NEST AS)
The mode of operation of the NEST thermal energy storage system. (Graphic: NEST AS)

The Danish company Aalborg CSP A/S and the Norway based company NEST AS have jointly developed a thermal energy storage system, more precisely a direct-steam-to/from-concrete storage system. The new storage system should enable predictable and on-demand power generation for CSP plants.

The new direct-steam storage concept is based on the thermal energy storage technology using NEST’s Heatcrete as storage medium. Heatcrete is a special kind of concrete with superior thermal properties and embedded steel heat exchangers. A heat transfer fluid flows through the serial connected heat exchangers. The whole system consists of several of these heat storage cells. This newly developed system can directly store the heat from steam.

The system is supposed to extend daily steam and power generation to ensure on-demand power production when there is no or limited energy generation during peak demand periods. According to the manufacturer, the solid state energy storage system is more cost-effective than the conventional molten-salt-based systems. This is because there is no need for electrical heat tracing and therefore a low standby power usage.

Due to its scalability, the system is also suitable for off-grid and smaller applications, in which energy supply security is especially important and it can be customised for requirements such as seawater desalination or district heating. Additionally, the heat storage cells are made from raw materials that can be sourced locally for the better part.

“The cooperation between Aalborg CSP and NEST expands the horizon for the CSP market as performance increase will lower the levelized cost of energy (LCOE) of power plants with global technology competitiveness as a result”, said Svante Bundgaard, CEO of Aalborg CSP.

“The direct-steam technology will allow our companies to deliver much needed energy storage solutions for CSP projects and also to industrial plants with process steam requirements. The cooperation is expanding the existing market for our energy storage solutions designed for parabolic trough plants using thermal oil”, commented Jarl Pedersen, Vice President Marketing & Sales at NEST.

Tanja Peschel / NEST AS