Volker Quaschning is a leading German renewable energy expert. He has done some presentations in the last couple of days, most of them at a congress of the German solar industry association. Now the slides of these presentations are available at his website.
Many of them are excellent. I would like to reproduce some of them here. But since he has no Creative Commons or similar license on them, I feel restrained by copyright from doing so.
But I can summarize some of the very interesting ideas in these presentations.
For one, Quaschning shows the next step for solar in Germany once 52 GW are reached and new installations won’t qualify any more for the feed-in tariff.
That next step will be solar rooftop with maximum own consumption. And to do that, installing some batteries is only one option. Another would be to use electricity in oversupply to heat some water, which then can be used for heating a building or taking a shower. He shows that by doing this, a house with a 5 kW solar PV installation can use about 80% of the electricity, up from 30% without doing that (slide 13 of this presentation). And this kind of thing will be cheaper for costumers than buying some batteries.
He also calls for keeping up or even slightly increasing the installation speed of over 7 GW per year. I agree with that as well. And since the new ceiling of 52 GW has a built-in function of getting everybody install quicker (so as to take advantage of the feed-in tariff before it runs out), for the next couple of years that goal should be achieved.
The question is what happens after the feed-in tariff runs out.
The slides 14 to 16 of another presentation simulate what happens with 50 or 70 GW solar PV capacity in the mix. They show that with higher penetrations of 50 GW solar will cut into the baseload, and with 70 GW it will be enough to completely supply all electricity in Germany at peak time slots.
That in turn means that fossil fuel power plants will have trouble staying in the market, so there is a need to get power to gas and gas backup plants running until 2020.
I also learned from slide 7 of this presentation that a 70 meter sea level rise would be enough sink Berlin. I have lived for close to ten years there and rather disapprove of that happening.
Slide 15 of the same presentation is on the advantages of a decentralized energy shift. Since it does not depend on building more grid capacity, it can be done much faster. That, of course, is a big advantage, considering that the clock is ticking on global warming.
Fortunately, as slide 16 of that presentation shows, there are 129.5 GW of solar potential only using Germany’s roofs. There are still a lot of buildings to cover. At a moderate speed of 7 GW per year that would keep people busy for another ten years.