Siemens Gamesa Renewable Energy (SGRE), known for its wind turbines used in both large onshore and offshore projects, in June began operation of an electric thermal energy storage (ETES) system in Germany (Figure 1). The technology is designed to store large quantities of energy, using volcanic rock as the storage medium.
“The technology employs an electric heater to charge the storage and a conventional heat recovery steam cycle to discharge the storage,” Veronica Diaz Lopez, who handles external communications for Siemens Gamesa, told POWER. “For charging, electricity is converted into hot air and blown through the storage, which is filled with volcanic rocks.”
The project includes about 1,000 metric tons of volcanic rock. The electrical energy is converted into hot air by means of a resistance heater and a blower that heats the rock to 750C/1,382F (Figure 2). “In the storage the heat is transferred from the air to the rocks and stored,” said Lopez. “During discharging, the flow direction through the storage is reversed and cold air enters the storage from the opposite end. In the storage, the air is heated up by the rocks and leaves the storage as hot air. The hot air is guided through a boiler where the energy is used to produce steam. The steam runs a steam turbine, which in combination with an electric generator, produces electricity.”
The system is installed at the Trimet SE aluminum smelter site in Hamburg-Altenwerder. The ETES pilot plant can store up to 130 MWh of thermal energy for a week, and its storage capacity remains constant throughout the charging cycles, according to SGRE. The company said the plant has a generator rated at 1.4 MW that produces energy for up to 24 hours. SGRE wants to use the storage technology in commercial projects, with plans to increase the storage capacity and power output as the technology is developed. SGRE said its goal is to store energy in the range of several GWh in the future. “Currently we are planning to do the commercial rollout in the mid 2020s,” said Lopez.
“Decoupling generation and consumption of fluctuating renewable energy via storage is an essential contribution to implementing the energy system transformation,” said Andreas Feicht, state secretary at Germany’s Federal Ministry of Economics and Energy, which funded the project known as Future Energy Solutions (FES). “We therefore need cost-effective, efficient, and scalable energy storage systems.”
Recent Comments