Power-to-Heat Gets Going in Germany

Article published in Renewables International

What to do about all that excess electricity at times of low or negative spot market prices? Use it to generate heat in a district heat network!

Increasingly, firms and communities are investing in power-to-heat or P2H systems in Germany. Last year, there were negative prices on the power exchange on 25 days, up from 15 days in 2012 and only 6 in 2011 (report in German).

A recent project at Südzucker, a foodstuffs (sugar) producer, is a good example (report in German). It needs to offer 10 MW of uptake capacity and be able to ramp by 2 MW per minute. It is connected to the medium-voltage grid. The entire storage tank only takes up, however, 60 square meters. “A lot more sites are available for P2H than previously thought,” one expert from Enerstorage, Südzucker’s contracting partner, is quoted.

It should be noted that the signals for power storage as heat are not negative wholesale market prices, but ancillary services. In other words, power is taken from the grid when the frequency rises.

The P2H process uses is highly efficient and inexpensive – nearly 100 percent according to a report on a similar facility in Augsburg (in German). Connected last fall, it also has an uptake of 10 MW.

Wikipedia provides of list of the some two dozen P2H facilities in Germany along with more in the pipeline (in German). It also points out that Denmark is a leader in the technology, having opened numerous such systems in the 2000s. The Danes, of course, needed P2H sooner; they already have roughly 40% wind power alone, compared to around 20% wind and solar combined last year in Germany.

by Craig Morris