alt Hacker NewsFor wind this makes a little bit of sense, but for solar "whenever I want to deliver" is largely once per day as regular as clockwork for several hours and that means you can bridge with BESS.
You can already see it in charts, initially BESS shifts some of that peak midday sun energy to evening usage where it's worth more to us, but gradually competition drives down that evening price and so the BESS cuts deep into the night chasing those higher prices. It's most exaggerated in Australia today, where the reason the power is relatively cheap when you wake up before dawn isn't that somehow coal is less expensive at night - it is because much of that is solar power from yesterday and if they don't sell it to you now for whatever price they can get they've wasted a whole cycle, 'cos the sun, with free power, is coming up like it or not.
> once per day as regular as clockwork for several hours and that means you can bridge with BESS.
If you live in Arizona or in tropical climate maybe. For anybody else it is bullshit.
Solar production fell to few percents of its peak when the sky is covered.
Many European regions can spent multiple weeks during Winter with the sky entirely covered.
BESS is nowhere near the capacity required to even go pass a single day. And it is unlikely to change even over the next 10y.
So hoping to run entirely on Solar + BESS for a multi week Dunkelflaute is living in dreamland, no reality.
What happens in practice is that country like Germany will need to have a backup Gaz that matches its peak consumption in Winter if they want to go full renewable.
The other option is to throw the problem on your neighbours with interconnects. This is what Germany does with mainly Norway, Sweden and France. And this is not a sustainable solution.