Germany Finances Major Push Into Home Battery Storage For Solar

mdsolar writes with this bit of news from Green Tech Media "The German government has responded to the next big challenge in its energy transition – storing the output from the solar boom it has created — by doing exactly what it has successfully done to date: greasing the wheels of finance to bring down the cost of new technology. ... Now it is looking at bringing down the cost of the next piece in the puzzle of its energy transition — battery storage. ... KfW’s aim, according to Axel Nawrath, a member of the KfW Bankengruppe executive board, is to ensure that the output of wind and solar must be 'more decoupled' from the grid. ... This is seen as critical as the level of renewable penetration rises to around 40 per cent — a level expected in Germany within the next 10 years. ... According to Papenfuss, households participating in the scheme will spend between €20,000 and €28,000 on solar and storage, depending on the size of the system (the average size is expected to be around 7kW for the solar array and around 4kWh for the battery)."

Comments

skeptical of home batteries for large-scale use

[Trepidity]

I agree with the general drive towards decoupling immediate production vs. use with better energy storage, but even with improved battery technology, everyone having batteries in their house is a particularly inefficient (and high-maintenance) way of doing it. Better approaches need quite large sinks for excess energy. For example, pumped-storage hydro is good for very large amounts. For medium-sized amounts, especially transient spikes, Denmark is experimenting with (PDF) dumping the excess production into district heating, since the heat reservoir handles fluctuations better than the grid does.

Better prediction and integration between sources can also help. For example, Denmark is largely managing its fluctuating wind energy these days not by literally storing it, but by predicting much of the variation, and offsetting discretionary production within the integrated Nordic energy market. What mostly happens is that on high-wind days, Sweden and Norway just reduce production at their hydro plants, and use the excess Danish wind power instead. In a sense the excess wind therefore gets stored as potential energy in the hydro reservoirs, but just by not producing the hydro in the first place, rather than pump-storage.