'Dark doldrums' highlight supply challenges for Germany's fossil power phase-out

Germany's coal plants provided the bulk of the country’s power consumption amid a period of cloudy short days and little wind in early January, foreshadowing the challenges lying ahead as the country phases out coal and other fossil sources, Ralph Diermann writes in the Süddeutsche Zeitung. The "Dunkelflaute" (dark doldrums) at the beginning of the year caused coal plants owned by operator Leag, for example, to run at full capacity. “Coal and gas plants together secured Germany's power supply" between 6 and 10 January, Diermann writes. On these days, wind and solar power combined never exceeded a capacity of 10 gigawatts (GW), while the national power consumption ranged somewhere between 51 and 74 GW, with a similar situation arising between 15 and 17 January.

According to data from Germany's weather service DWD, similar conditions occur up to 13 times a year for more than 48 hours. "What does that mean for the coal exit?," Diermann writes, quoting researcher Albert Moser of RWTH Aachen as saying "we need additional gas power plants that can deliver power over an extended period of time when renewables are not up to the task." This would not clash with decarbonisation plans as fossil natural gas could gradually be replaced with CO2-neutral alternatives such as hydrogen, Moser said. According to a study commissioned by think tank Agora Energiewende*, the country's gas capacity needs to grow from its current 32 GW to 73 GW by 2050, mostly through small and decentral installations. But finding investors willing to invest in this "safety net" could be challenging, which is why making greater use of renewable power traded throughout Europe to exploit feed-in spikes elsewhere may be a better option.

Germany is phasing out nuclear power by the end of 2022 and coal power no later than 2038. Swift renewables expansion is seen as key for filling the gap left behind by decommissioned coal and nuclear plants. But even though renewables already covered nearly half of the country's power consumption last year, Germany is still struggling to achieve the expansion rates needed to guarantee a frictionless substitution. Reserve options like hydrogen production likewise depend on a much higher renewable power capacity.

*Like Clean Energy Wire, Agora Energiewende is funded by the Stiftung Mercator and the European Climate Foundation.