HAMBURG – Coal power plants can have a green future by becoming massive storage facilities for renewable energy, Hasan Özdem, the head of technology management and large storage at Siemens Gamesa Renewable Energy (SGRE), told New Europe in an interview at the site of an electric thermal energy storage in Hamburg on September 26, a pilot facility which is still partially under construction.

SGRE celebrated the topping-out ceremony of its Electric Thermal Energy Storage (ETES) facility in Hamburg-Altenwerder in the context of the Global Wind Summit, comprising WindEnergy Hamburg expo and the global WindEurope conference.

According to Siemens Gamesa, this innovative storage system can help to make the supply and demand for electricity from renewable energy sources more flexible. The facility can store up to 30 MWh of energy and boasts maximum scalability at a low investment cost.

Walking through the pilot facility, which is currently in the final construction phase, and all of the storage facility’s buildings and main components have already been completed, Özdem noted that there is a current debate about shutting down coal power plants because they are polluting the environment.

“But we believe that they have a very good place in the green future by turning them into batteries which are necessary in the future. So utilities have this problem: They invested 20-30 years of money and investigation in those power plants and they are very efficient and now they have to shut them down without any major technological reason. They just shut them down because of the pollution. And we thought why not just take away this pollution character and keep them running,” Özdem said.

He noted that coal plants could become storage facilities with zero emissions. “It’s going to go down from a pollution energy generation facility into a big storage facility,” he said.

According to Siemens Gamesa, the simple thermal principle of the storage facility is based on known components that are used in a new combination. For example, fans and heating elements from series production are used to convert the electrical energy into a hot air flow. The same applies to reconversion: a highly dynamic Siemens steam boiler is used as standard in a steam turbine to produce electricity at the end of the storage chain. The insulating container filled with a rockfill is the core of the innovation.

“There are multiple advantages to using heat,” Özdem told New Europe, handing over a fistful of rocks used to store heat. “First of all, we cannot only provide electricity but we can provide heat for district heating, which is very popular and infrastructures are available. We can also give out as process steam for industries. We can use heat as a source import from excess heat from other industries so there is like a lot of ways to adapt and use this technology,” he explained.

“The lifetime of these facilities is 30 years as opposed to batteries which is 10 years and when you talk about cost as well, the bigger you build, the cheaper it gets. At the moment, we’re 10 times cheaper than batteries. We’re really starting with big capacity so this technology is not competing with batteries. Batteries are good for quick start and small storage like at homes or smaller wind parks. But when you have 60-70-80 percent of renewable energy, in the night all the solar fuels don’t help you and the wind doesn’t blow,” he said.

With ETES, Siemens Gamesa has developed a storage facility that reduces the construction and operating costs of larger storage capacities to a fraction of the usual level for battery storage. In commercial use, the technology can store energy at a cost of well below ten euro cents per kilowatt hour.

“When its heat, unlike batteries, we can keep it for 24 hours and whenever you need it, we can discharge it. Also, for a longer period because that’s also something you need. For example, the photovoltaic industry, they’re all approaching us and saying: ‘Hey, if we build even bigger parks, like too much energy, can we store every day and discharge every night?’ We’re like: ‘Yes’, and then the business case is getting very strong,” Özdem said, emphasizing, “We have no losses at all so with this technology you can really finally, for example, put a huge field in the desert and power the whole not only nation but also the whole region, if you like.”