Berlin has passed a plan to speed up the installation of PV panels on the city’s roofs with the goal to meet a quarter of its power needs with solar energy by 2050, when the city state also wants to have become carbon neutral.

“The study of potential in the Solarcity master plan showed that we can harvest 25% of the electricity generation [needed] from solar roofs in Berlin,” said Ramona Pol, the Green Party energy minister of the state.

Pop cautioned, however, that to accelerate the city’s solar expansion, Germany’s federal government needs to improve the legal framework for solar power in cities. Berlin already now wants to actively use the existing scope for solar power on the state level, expand information and advice, set incentives and also examine regulatory instruments.

Due to lacking space for land-based solar arrays or wind farms, in addition to past policy mistakes and months of cloudy weather during the autumn and winter, renewables according to the agency for renewable energy (AEE) in 2017 only accounted for 4.9% of Berlin’s power generation. Only a tiny share of that came from solar installations, 0.7% according to a study be the Fraunhofer ISE solar institute.

In the sunny, southern state of Bavaria - despite decades of conservative governments – renewables in 2017 made up 44.1% of power generation, according to the AEE. Solar alone in 2018 accounted for 15.9% of the state’s power generation, the state government said, representing one of the highest solar penetration rates in the world.

To catch up with Germany’s more advanced states in the energy transition, Fraunhofer ISE in its ‘Masterplan Solarcity’ has worked out a catalogue of 27 measures to accelerate the solar expansion in Berlin.

“The implementation of the Solarcity master plan is a joint task for the Senate (Berlin’s government), and also for all actors from business and society in Berlin,” Pop said.

As a first step, the city government has created a coordination point where experts from the energy and solar industry, the housing sector, state companies and researchers meet.

To reach the 25% target, Berlin needs to install some 4.4GW in solar panels on its roofs, up from little more than 100MW now.

The city already supports solar storage systems with generous subsidies covering up to two thirds of the cost when installed in combination with solar panels.

The master plan recommends the installation of solar panels on all new buildings in the city of 3.7m inhabitants, but so far the state government hasn't made that obligatory yet as some smaller southern German cities have.