The German Solar Industry Association BSW-Solar has done a survey. According to this article (in German) they found that newly built solar capacity is used to about one third for self-consumption. Thanks to this tweet by Peter Crain for the link.
That makes sense, since buying electricity from the grid is much more expensive than producing your own from solar.
The interesting question is if that self-consumption shows up in any statistics. Since it isn’t sold to the grid at any time, it might be difficult to know exactly how much solar energy is generated for self-consumption at any given moment.
That in turn means that all the statistics on the rapid growth of solar electricity production in Germany are actually lower than reality, since they don’t include self-consumption.
With feed-in tariffs for solar going down quickly and phased out in a couple of years (after the 52 GW ceiling will be reached), self-consumption will take an ever growing share of the market. One third right now is already rather substantial.
It will be interesting to see how this part of the market will be included in the statistical reporting in the future.