Property owners who constructed a photovoltaic installation in Germany at the start of the 2000s feed all of their electricity into the public power grid. However, feed-in tariffs will soon no longer be paid for these old systems. According to the German Solar Association, this will affect a good 10,000 PV installations in 2021, with this figure rising by a factor of 20 by 2026. By 2033, feed-in tariffs will have expired for more than a million solar systems.
Self-consumption presents an attractive option for the continued operation of small and medium-sized domestic rooftop installations in particular. Around 20 to 30 percent of the solar power generated can typically be used on-site. Homeowners can even increase the proportion of electricity consumed on site to between 30 and 40 percent by choosing to turn their dishwashers or washing machines on during the middle part of the day.
And this pays off because the solar power generated by old rooftop PV systems that are no longer eligible for the feed-in tariff is still significantly cheaper than grid-supplied electricity despite the pro rata EEG levy. Self-consumption can be increased to as high as 70 percent through the use of battery storage systems. “Thanks to the falling cost of storage devices, it won’t be long until it is worth storing the electricity produced by systems of over 20 years of age,” says Franz Pöter from Solar Cluster Baden-Württemberg.
Increasing the proportion of self-consumption is especially lucrative for those who already have an electric car. If an electric car is charged using solar power produced on its owner’s roof at a cost of four cents per kilowatt hour, driving costs will fall to below 1 euro per 100 kilometers. A greater level of self-consumption is also profitable in buildings with heat pumps.
PV installation owners can sell any electricity not consumed on site to direct marketing companies. Previously, this was only possible with capacities greater than 30 or even 60 kilowatts, but this is now changing and the first providers for small system operators have already entered the market. Numerous start-ups as well as established utility companies are preparing to act as mediators between consumers and small-scale generators producing electricity on their roofs.
Visitors to Intersolar Europe 2020 can find out more about how to keep operating old solar systems profitably in the post-EEG era by attending various forums and entering into discussions with experts and exhibitors.