German project looks to home photovoltaic systems to help grid

The pilot project that will tap home photovoltaic (PV) systems to help iron out imbalances on Germany's power network

Grid operator Tennet and solar panel maker Sonnen GmbH have launched a pilot project that will tap home photovoltaic (PV) systems to help iron out imbalances on Germany's power network.

TenneT and Sonnen's e-Services subsidiary aim to sign up 6,000 household PV producers equipped with storage batteries by the end of May.

The project will be supported by blockchain technology from IBM, which works as an inexpensive transaction-processing system for tracking and recording encrypted information.



It holds potential to link up small energy "prosumers" and make them independent of centralized power providers.

"A home storage unit for solar power on its own is less valuable than one that can be used collectively," said Philipp Schroeder, director of sales and marketing at Bavaria-based Sonnen.

"We will be able to create a big virtual power line. That is revolutionary."

The two partners aim to initially pool 24 megawatts (MW) of power capacity for TenneT to use as a buffer for variable wind power.

"Balancing" power is so far handled mainly by traditional power plants while surplus wind power is often dealt with by curbing turbine output or throwing output away.

"We want to find out how we can reduce the waste of wind power by storing it in Sonnen batteries that we can access in the North while releasing power from solar energy stored at Sonnen batteries in southern Germany," said Urban Keussen, board chairman of the board at TenneT's German unit.

Germany currently subsidizes renewable power producers with billions of euros a year, regardless of demand.



Because network development lags far behind, a lot of power is wasted because the north houses most of Germany's wind turbines whose output cannot reach industrial users in the south.

New transport lines, funded via grid fees charged to consumers, will take years to build.

Schroeder said he saw big potential for solar pv "communities" filling gaps in the meantime.

Germany has 15 million detached houses and 1.7 million photovoltaic units, but only 50,000 home storage units.

Should 10 percent of all households use solar plus storage in 10 years, that would create capacity of some 6 gigawatts of power, he said, equivalent to six nuclear plants.