German engineering behemoth Siemens, working with the Technical University Hamburg Harburg, has revealed it is working on a thermal storage solution to be paired with wind energy, which it hopes “will set a future standard in efficiency.”
Siemens announced its most recent research project this week, revealing that it was working alongside Technical University Hamburg Harburg (TUHH) and urban utility company Hamburg Energie to develop a thermal storage solution to be paired with wind energy. The research has resulted in a process which uses excess wind energy to heat rock-fill, protected by an insulated cover. On the reverse side, when stored electricity is needed, a steam turbine converts the heat energy back to electricity.
“The simple principle of this store promises an extremely low-cost set-up,” Siemens noted in its press release this week, adding that this predicted low cost has resulted in the project receiving research funding from the German Federal Ministry for Economic Affairs and Energy.
Siemens is currently running a test setup of its new storage solution, named Future Energy Solutions (FES), in an attempt to further increase the efficiency of its design. Specifically, Siemens and colleagues are investigating the best arrangement of the rock fill and the form of the surrounding insulating container, components which Siemens describe as “crucial” to the processes efficiency. Current testing has the energy store — the temperature at which the rocks are heated to store the energy — at 600 degrees Celsius. The store is charged when a fan uses an electrically-heated air flow to heat the stones to the requisite temperature, and in turn, when discharging, the hot stones heat the air current which in turn heats a steam boiler, with its pressure driving a generator via a steam turbine.
“The technology of our FES store deliberately uses mainly tried and trusted technology,” explained Till Barmeier, Siemens’ project manager. “Because we are working here with tested thermal components and a series-ready steam turbine, we will be able to offer a practical solution within a few years. Our complete experimental system will be operational in just around 15 months.”
The researchers are looking to next test the complete energy conversion in spring 2017 — from electricity to heat storage in the rock fill, and back again. The full size of their test-bed will be 36 MWh, and the container will hold approximately 2,000 cubic meters of rock-fill.