Siemens Gamesa to construct Hot Rock grid storage plant

Siemens Gamesa to construct Hot Rock grid storage plant

The wind turbine manufacturer Siemens Gamesa has begun the development of a prototype 30MW/hr scaled facility prior to the construction of a much larger, gigawatt-scale thermal energy storage system. The planned large-scale system is due to be completed and operational by 2019.

Siemens Gamesa Energy Storage Project

The site will use industry standard heaters and fans that will be powered when surplus energy is supplied to the grid to heat approximately 1000 tonnes of rock to temperatures of 600 degrees Celsius. The heat will then be utilized to drive a 1.5MW steam turbine, feeding electricity directly back to the grid.

Located in northern Germany, the site is expected to store enough thermal energy to generate electricity for up to 24 hours. Developers believe the initial efficiency of the system will be in the region of 25% but potentially will rise to closer to 50% if the technology is scaled up. Siemens Gamesa believes the stored energy, at higher scales, will cost less than $0.12 per kilowatt hour.

Energy Storage Development

Siemens Gamesa has been researching and developing the project for close to three years and has highlighted that the focus of research and development in the business has been on insulated containers to house rock fills, creating a virtual battery system. Siemens Gamesa believes the Future Energy System (FES) is a more cost-effective alternative to batteries for large-scale energy storage.

At Altenwerder, Siemens Gamesa is working with local utility company Hamburg Energie to examine the commercial prospects of the technology in energy markets and Technical University Hamburg-Harburg to model the thermodynamic characteristics of the technology. If the first stage proves successful, the next step would be a commercial-scale plant that could potentially deliver electricity for several days.

“The thing with batteries is they do not allow for upscaling with sufficient economies of scale,” he said. “When you go from a 10-megawatt to a 20-megawatt battery system…you double the cost. In the case we’re looking at, you do have economies of scale: If you double the power, you won’t have to double the price.”

The scalability could extend to long-duration storage, too.

“The biggest advantage that this system will have is the size and duration of the storage compared to electrochemical batteries,” said Hong Durandal, business analyst with MAKE Consulting. “Thermal storage would be able to store large chunks of renewable energy when it is being produced in excess and discharge it when it’s needed without worrying too much about the degradation of the system.”

Thermal storage beats batteries for renewable energy time-shifting and capacity-firming applications that require more than 4 hours of continuous discharge, he said.

“We will see in the near future how the capex plays out,” he commented.  

Source: Green Tech Media