Volker Quaschning on Self Consumption Solar in Germany

Volker Quaschning just pointed to an interview (in German) where he talks about solar installations for self consumption in Germany.

I agree with most of his points and would like to reproduce some of them here in English.

For one, he does not approve of the CDU and FDP braking policy. I don’t approve either. And he suspects that the motive for them is that they want the big utilities to be able to run their coal plants another forty years.

I am not sure about that last part. It may very well be that environment minister Altmaier is sincerely worried about costs. There is no way I would know.

Quaschning also said that the next phase of the solar revolution in Germany does not depend on feed-in tariffs. As long as solar installations did not make sense economically without a feed-in tariff, politicians have a way to take the speed out of the market. But once that barrier is gone and solar kicks ass in the market without any friendly government help there is not much the government could do to slow things down, even if they are motivated by the dark desire to keep coal alive.

As pointed out before, the rising surcharges actually help with that. Electricity generated for self consumption is not part of the surcharge base right now. And even the new proposals of changing that will only affect installations over 2 MW capacity, as with the existing ecotax, where 2 MW is also the threshold.

Quaschning notes that there is a market potential between 100 and 200 GW in Germany. While the 32 GW existing capacity is world record for now, that is still only a small part of the potential, there are still a lot of roofs left.

That is especially true for roofs facing East or West. Until now, the main factor was getting the most electricity, so South facing roofs were used. With East and West in the mix, you get less energy, but more evenly distributed over the day.

The problem will be to get the prices for batteries down, which is a necessary step for getting larger percentages of self consumption. There Tesla Motor’s development of cheaper electric cars will come in handy. Those car batteries should be able to double for providing solar energy after dark to some extent.

The rest of the surplus electricity will go mostly into heating water, which doesn’t make much sense from the point of global warming, but is better for the individual user than just throwing the electricity away.

Published by kflenz

Professor at Aoyama Gakuin University, Tokyo. Author of Lenz Blog (since 2003, lenzblog.com).

2 thoughts on “Volker Quaschning on Self Consumption Solar in Germany

  1. Well, yes and no. Solar reaching grid parity makes sense to use for own demand. Same as things are wired in Japan, you only get feed-in money for what you do not cosume. We have 3.2kW peak on the roof. Saving energy during daytime became just that much more lucrative.

    This clean energy displaces demand that incumbent utilities would otherwise cover. Their time to break even or after that, their profit margin, gets thinner during daytime.

    On batteries, no joy until the number of cycles improves until you need a new one. If you take a 27kWh lithium to 1000 cycles, I estimated each kWh costs you 600 yen, vs 41 for solar FIT and 23 off the regular grid. So batteries are great for emergency power but not for everyday use. Ultracapacitors may be a choice, they have nearly unlimited cycles.


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