Germany’s transmission system operators began procuring synthetic inertia as a new ancillary service in early 2026, driven by the accelerating retirement of thermal power plants that once provided natural rotational stability to the grid. Battery systems fitted with grid-forming inverters can qualify by holding network frequency within 0.2 Hz of the 50 Hz standard.<\/p>\n
The financial upside is real, though analysts disagree on its magnitude. Philipp Hazel, a senior analyst at Aurora Energy Research, puts the IRR uplift for large battery projects at one to two percentage points \u2014 and frames the revenue as bankable and free of market-price risk. Ahmed Elbaz, head of BESS at Enpal, is more conservative, estimating a gain closer to 0.9 percentage points based on a market coupon of around \u20ac10,000 per megawatt.<\/p>\n
The market design is transparent: system operators publish a fixed tariff and any pre-qualified asset may deliver inertia at that rate. Because batteries can run inertia contracts in parallel with arbitrage or frequency-response income, the earning streams are largely additive. Marie-Sophie Braun, head of markets and regulatory at Kyon, says the service’s low interference with other dispatch strategies lets owners assemble multi-layered financial portfolios. Contract durations of two to ten years add a rare long-term anchor to what are typically short-cycle ancillary markets.<\/p>\n
Despite the commercial promise, no battery asset is yet actively delivering the service \u2014 pre-qualification of grid-forming inverters remains the outstanding technical hurdle. Regulatory momentum is building: since June 2026, grid-forming capability has been mandatory for connections to Germany’s 220 kV and 380 kV extra-high-voltage network, and an extension to the 110 kV tier is under consideration.<\/p>\n