There are days in Germany when the sun does not shine, and the wind does not blow. Their renewable energy engineers call these days dunkelflaute, meaning ‘dark lull or calm’. They occur during winter high pressure systems, when the sky is overcast, days are short, and winds are calm. This in a few words is why Germany needs dunkelflaute batteries for dark days.
Dark Days and Dunkelflaute Call for Renewables
Dunkelflaute days present challenges to German utilities, that rely on renewable wind and solar energy. They have to fall back on battery storage, energy imports, or gas / hydro renewables which usually cost more.
Perhaps the answer may be further afield, asks Petra Stock writing on The Guardian website. Possibly they should consider what is happening ‘down under’ in Australia, where long duration batteries are proving their point at a new solar farm.
The ‘proof of the pudding’ is rolling out at Limondale in New South Wales, with consent of tribal land owners. This does not however mean that anybody there needs dunkelflaute batteries for dark days. The region has a cold, semi-arid climate, although the skies can be ‘somewhat cloudy’ in winter according to Wikipedia.
So What’s The Connection With Dunkelflaute Then?
Germany needs longer-term energy storage than its current two-plus hour battery farms can deliver. The Limondale project will deliver eight hours of back-up energy when complete. This could put it in the same league as more expensive hydro-pumped storage.
The gigantic project rolling out in Australia will have capacity of over 50 megawatts and 400 megawatt-hours, making it the longest-duration grid-scale battery operating in Australia.
Put differently, the 872,000 solar panels will generate enough electricity on-line to power 105,000 average homes for a year. This output equates to pumping 50 megawatts into the grid for eight long hours. How’s that for dunkelflaute batteries for dark days?
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