Paying to keep the lights on when the wind drops

When wind and solar vanish for days (Dunkelflaute), the grid leans on dispatchable backup. Germany's planned capacity mechanism procures gas plants and recovers the cost through a levy — a forward consumer cost. This panel pairs that cost with a residual-load stress indicator.

Can firm capacity cover the worst residual-load hours? Over the last year Germany saw about 531 hours of low renewable output, the longest low-wind-and-sun spell running 52 hours, against a peak residual load near 40 GW.

To insure against that, a draft German capacity mechanism would tender about 12 GW of firm capacity for 2031 — a provisional figure from a cabinet bill that is not yet law.

1 · The forward cost of capacity
levy, € bn per year — provisional
The capacity mechanism pays plants to be available, not to run. That availability payment is recovered from consumers through a levy. The first year carries the build-out premium; the cost then settles into a steady band as plants come online and amortize.
Annual levy (€ bn) — provisional, upper bound
2 · When renewables can't cover demand
wind + solar share of demand, %
During a Dunkelflaute, wind and solar together cover only a sliver of demand; the rest is residual load that dispatchable backup has to supply — the reason a capacity mechanism exists at all.
During a Dunkelflaute spell Normal conditions
Loading data…