Storage Solutions

Wind and Solar Power – Even on Still, Cloudy Days?


People need energy 24/7. Even when wind turbines stand still and the sun is hiding behind the clouds. The key to a secure renewables supply regardless of the weather? Energy storage. Surplus renewable energy can be stored as power, gas, or heat. And used later when needed.

Gas storage facility in East Frisia

Discover which storage technologies we’re developing and how they work

Tomorrow’s energy system will need flexible backup solutions to balance out the increasing amount of volatile wind and solar energy. At Uniper, we believe that, alongside gas storage, new technologies such as power-to-gas and batteries will also play an important role. This is why Uniper invested early in our own pilot projects, such as M5BAT or WindGas Falkenhagen. These projects will help us remain a reliable partner for the secure supply for our customers well into the future.

Dr. Stefanie Kesting, Director Uniper Innovation

M5BAT: a unique battery storage system

Power-to-power (P2P) battery storage represents a flexible solution. In the past, battery systems were not suitable for large-scale applications. Together with RTWH Aachen University and other partners, we developed a prototype whose hybrid design incorporates five different battery technologies and 25,000 battery cells.

In September 2016 we began with M5BAT test operations.

60 minutes

The time that the M5BAT battery system can supply power to 10,000 households in the event of a power outage.

The battery can store several megawatt-hours of eletricity and is designed to be used in conjunction with on-site renewables production at industrial facilities. 

Battery storage systems can be charged and discharged very quickly – within seconds. Due to their compact design, battery storage systems can also be moved to other locations in the grid if required. These flexibilities allow new applications, especially in the distribution grid, in which battery storage systems could contribute to so-called active grid nodes, controlling the voltage and local power flows. A new business case for batteries might be the optimization of renewable portfolios to reduce the risk of high balancing costs. An interesting opportunity might also be hybrid storages, i.e. enhancing existing hydroelectric pumped storage plants with batteries, which together create an interesting flexibility option regarding both, power and energy. Our close cooperation with Uniper is a very great and unique opportunity for us to develop strategies jointly and to test these strategies in real-world operation. We are proud that our joint effort in the M5BAT project with Uniper and other partners was rewarded as one of the pioneer projects as a driver for progress by the KlimaExpo.NRW.

Prof. Dr.-Ing. Albert Moser, Chair of Power Systems and Power Economics (IAEW) at RWTH Aachen University

Falkenhagen: transforming surplus renewable power into hydrogen and methane

We’re also working on transforming surplus renewable power into hydrogen or methane. The technology is called power-to-gas (P2G) or wind gas. The resulting gas can be used for a variety of industrial processes, as a vehicle fuel, and as a fuel for generating power and heat. We were one of the first companies in the world to operate a P2G demonstration unit. The three-year trial was conducted in Falkenhagen in northeast Germany. The unit used electrolysis to transform surplus electricity from numerous nearby wind turbines into hydrogen. During the trial, several million kWh of wind gas was fed into the natural gas pipeline system.

The trial showed that renewable energy could be stored efficiently as gas, thereby decoupling energy production from energy consumption. The technology works well. It responds reliably to the sharp fluctuations in wind conditions, is market-ready, and promises to become even more efficient and affordable. P2G’s solid performance encouraged us to go a step further by adding additional equipment that enables the unit in Falkenhagen to produce methane. In theory, the quantity of methane that could be fed into the natural gas pipeline system is unlimited. This means that large quantities of wind energy could be transformed into methane for later use, which would have a positive impact on the earth’s climate. The P2G methane trial at Falkenhagen is part of a European research consortium called STORE&GO, which will run through 2020.

Contributing to a stable and secure supply

The development of innovative storage technologies is still at an early stage. Our portfolio already helps keep the energy supply stable and secure and can balance out the fluctuations in renewables production. Below are our fleet’s average ramp-up times broken down by technology.

90 seconds

Ramp-up time for pumped-storage hydroelectric stations

< 5minutes

Ramp-up time for run-of-river hydroelectric stations

< 30 minutes

Ramp-up time for newest gas-fired power stations

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