Electric Thermal Energy Storage

GWh scale & cost competitive

Setting new standards in flexible energy storage
The world of energy has come a long way but securing stable energy supply remains a challenge. To overcome this, Siemens Gamesa is developing a cost-competitive, GWh-scale storage solution that can even be used to convert existing power plants into storage facilities.
Contact Siemens Gamesa

Are you interested in this electric thermal storage solution? Please contact our team for further information.

Nominal power
> 30 MW
250 MWh – 12 GWh
Experience since
80% off-the-shelf
Key Facts
  • Cost-competitive to build and maintain by reusing existing components
  • Deployable independent of geography
  • Charging, discharging and storage can be independently scaled
  • Efficiency is maintained: 98% while storing heat, up to 45% at full-electric cycle
  • Capital expenditure is up to ten times lower than batteries
  • Proven and tested: demonstrator will be commissioned in 2019
Recommend for

Large scale energy storage, combined heat and power, and second-life option for conventional power plants.

ETES applications
ETES Base universal stand-alone storage
ETES Add higher flexibility for existing heat cycles
ETES Switch full conversion of power plants into green storage
Three applications to solve various challenges
A cost-competitive, utility-scale energy storage solution
ETES Base: a GWh-scale stand-alone storage solution
This unit can be operated independently of geographic conditions like mountains or caverns. It brings the ability to store and supply electricity, process steam and heat. Input and output power can range from 30 MW up to 750 MW, while storage capacity extends from 250 MWh to 12 GWh. It can make renewable energy dispatchable and base-load capable. It mitigates grid constraints and secures stable electricity supply.
Upgrade of heat cycles for tapping new revenue streams
ETES Add: new flexibility for existing heat cycles
This unit is attached to a fossil fuel power plant or an energy intensive industrial process to flexibilize operation and to broaden revenue base. It builds on existing process equipment. Stored heat can be added to the existing heat cycles without jeopardizing the core process. It offers district heating, process steam, energy cost reduction, ancillary services and electricity arbitrage.
Convert fossil fuel power plants to renewable energy storage
ETES Switch: a second life for power plants
Thermal power stations have the potential to become energy storage plants, reusing existing equipment in combination with new technology. By transforming the conventional power plant infrastructure, this option helps to avoid the negative effects of plant closure. The furnace is replaced by ETES, enabling existing steam cycle and O&M processes to remain in place while at the same time turning a fossil power plant into a CO2-free storage plant.
The road ahead
ETES brings economies of scale and retrofit advantages

ETES costs will be significantly lower than classic energy storage solutions. Even at the pilot stage, a commercial project at GWh scale would be highly competitive compared to other available storage technologies. Economies of scale will bring substantial reductions in capital expenditure, while increasing the storage rating. Implementation of ETES Switch will lead to a further cut in CAPEX of around 50%. What’s more: charging power, storage capacity and discharging power are independently scalable.

Making ETES commercially available.

  1. The first test site with 5 MWh capacity was implemented in 2014
  2. Proof of system will start operation with a 120 MWh capacity in 2019
  3. A pilot plant with an output of around 50 MW will follow in 2020
  4. Commercial rollout is planned with an output of several hundred MW
A proven and reliable technology
The concept of electric thermal energy storage has been extensively tested since 2014. Technical specifications were set at 700 kW charging power and 5 MWh storage power. Running at these levels the project achieved 95% heat storage efficiency, optimizing the control algorithm with a 10% improvement in storage. This process has helped to identify storage and insulation materials for use in the demonstrator, and led to 60 patent families so far.
The test worked with simple processes of heat and steam.
The 24-hour thermal energy storage site will be commissioned in 2019, in Hamburg. Its storage capacity of 120 MWh will be available day and night. Approximately 1,000 tons of rock-fill will provide 30 MWh of electric energy at temperatures of 480°C. The heat is then re-converted into electricity through steam. A generator rated at 1.5 MW will produce energy for up to 24 hours. The erection of this plant is being funded by the German Ministry for Economic Affairs and Energy.
The Hamburg site will show the commercial opportunities offered by ETES.


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