de-DEen-GB

About the project

Storing today’s energy for tomorrow

The energy transition and expansion of renewable energies in Germany call for innovative storage technologies to balance out short-term fluctuations in generation and consumption.

Depending on the availability of wind or sun, renewable electricity generation is subject to strong power fluctuations over the course of a day, while electricity consumption also varies depending on the time of day.
Intelligent, highly flexible storage systems enable these fluctuations to be absorbed and balanced out. With their high power dynamics, battery storage systems are particularly suited to meet these needs. As a result, the integration into the grid of increasing amounts of renewable energies can be improved and dependency on fossil fuel power plants reduced.

M5BATbattery storage system

A unique 5 MW hybrid battery storage system has been built in Aachen. M5BAT is a hybrid of different battery technologies that optimally combines storage capacities for periods of seconds, minutes or hours, whereby the storage system is designed for a total storage capacity of around 5 megawatt hours (MWh).
This highly efficient and modular system offers a wide range of applications irrespective of location and therefore facilitates the integration of renewable energies. In this initial phase, the M5BAT project will be focusing on two particular aspects:

  • Testing the distributed provision of control reserve for stable grid operation
  • Electricity trading and the associated exploitation of electricity price arbitrage

Practical aspects


Construction of the large battery storage system began in August-2015, the commissioning was on Thursday 8th of September 2016. Since that day, the battery system is connected to the local medium-voltage network and used to balance out the energy supply. During this time the trading of capacities on the energy market in real time will also be trialled. The participants in the project are jointly investing €11.4 million in the development and testing of this world-first battery storage system. The project is also receiving funding from the German Federal Ministry for Economic Affairs and Energy to the tune of € 6.7 million.

What can you get out of 5 megawatts and 5 megawatt hours?

Average power consumption of a household
= around 500 watts
M5BAT = 5 megawatts (output)
Can supply power to 10,000 households

M5BAT = 5 megawatt hours (energy)
Can supply power to 10,000 households for about 60 minutes in the event of a power outage (5 MWh / 5 MW = 1 h = 60 minutes)
By way of comparison:
Average duration of a power outage in Germany: 15.91 minutes
(SAIDI value 2012, Source: German Federal Network Agency)

Control reserve is needed for compensation if the actual electricity demand is not equivalent to the expected electricity supply.