At RWE’s gas-fired power station in Moerdijk, a cutting-edge inertia battery system with a capacity of 7.5 MW/11 MWh is set to be operational by 2025. This innovative battery will protect the electricity grid from frequency fluctuations by delivering or absorbing power almost instantaneously. Over a two-year study in collaboration with TenneT, the battery’s contribution to enhancing grid stability will be thoroughly evaluated. This is the first time such a technology has been deployed in the Netherlands.
As the energy transition progresses, the share of electricity generated by gas and coal power plants is diminishing. These traditional plants not only generate power but also stabilise the grid through their rotational inertia. This inertia, linked to a consistent 50-hertz frequency, helps maintain grid stability.
However, as fewer traditional power plants are used, grid stability is becoming a challenge with increasing frequency fluctuations. The Moerdijk inertia battery addresses this by providing “extra inertia” and compensating for the lack of stabilising energy from conventional power plants.
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RWE is a global leader in the energy transition, with battery storage systems totaling approximately 700 MW in operation and over 1 GW under construction.
By developing and utilising pioneering technologies—alone and in collaboration with partners—RWE is at the forefront of innovation. This includes groundbreaking converters used in the Moerdijk inertia battery project.
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This inertia battery serves dual purposes. First, it temporarily stores surplus energy and releases it back into the grid when needed. Second, it stabilises the grid by rapidly supplying or absorbing small amounts of power to balance supply and demand.
Advanced software monitors and adjusts the battery’s output in milliseconds to meet the grid’s needs. The innovation lies not in the batteries themselves but in the highly reactive, grid-forming converters that control the voltage and frequency.
Construction of the battery system was completed in 2025, with operations starting in mid-2025. Following this, the two-year research phase will begin to assess the system’s impact and benefits for the energy grid.