Municipal building regulations inhibit the expansion of renewable energies

Solar systems change the townscape. That can be problematic.
Credit: Solarimo

Municipalities with high legal requirements for the construction of photovoltaic systems have been shown to produce less solar power.

Securing energy supplies, coping with climate change and expanding renewable energies are high priorities in Germany. However, municipalities often pursue their own goals: municipal building regulations in particular, for example to protect the historical townscape, conflict with the expansion of renewable energies. A research team led by Prof. Dr. Stefano Carattini, professor of economics at Georgia State University, Atlanta, USA, and Prof. Dr. Andreas Löschel, professor for environmental / resource economics and sustainability at the Ruhr University Bochum, examines. The study shows that many municipalities have issued building regulations that regulate the installation of photovoltaic systems. These communities have 10.4 percent less solar power than communities in the comparison group. The study is on 24. October 2022 published as a CESifo working paper in Munich.

In Germany, the Renewable Energy Sources Act and the resulting increase in solar systems in the past two decades have made a decisive contribution to greatly reducing the price of solar power. As a result, the share of renewable energies in the energy mix has increased significantly. "However, the expansion goals are immense and clearly exceed the historical trend," says Andreas Löschel. “In our current study, we are researching for the first time whether building law requirements, in particular building design law, represent a decisive obstacle to the expansion of solar energy."

Plans, statutes, regulations and a survey

The introduction of a building regulation (period 0) reduces the installation of photovoltaic systems in the following years. The percentage reduction in solar power output can be read on the vertical axis. In the years before the introduction of a building regulation (negative signs), there was no relative change in the installed solar power output compared to the comparison group.
Credit: Löschel et al.

The researchers examined the role of land use plans, design statutes and regulations that are issued by municipalities and directly or indirectly affect the installation of photovoltaic systems. They have linked data from all solar systems in Germany that come from the Federal Network Agency's market register for the years 1991 to 2020. They also included the results of a survey among all German municipalities and cities. In it, they systematically collected information on the municipal requirements and legal requirements relating to the installation of solar power systems.

15 percent of the municipalities have regulations that affect solar systems

The study shows that a good 15 percent of the municipalities in the sample have issued one or more regulations regarding the installation of photovoltaic systems. Precise legal requirements are the most common. "In the survey, we differentiate between three common regulations," explains Béla Figge from Georgia State University: "First, that solar systems must not be visible from the street. Second, solar systems must not reflect light on other buildings or the street. Third, that solar systems must be integrated into the roof or walls.“Variations of these three regulations are widespread, but bans on photovoltaic systems and local funding programs are relatively rare.

"We can show that communities that have legal requirements regarding photovoltaic systems have 8.9 percent fewer photovoltaic systems and 10.4 percent less solar power," said Löschel. Small and medium-sized solar systems between five and ten kilowatts are most affected.

Too much invisibility is not good either

In order to alleviate the conflict of objectives between maintaining the townscape and expanding photovoltaics, the researchers propose, among other things, to quickly develop solar systems that are designed to be more visually appealing and can be integrated into the existing building structure. Too much invisibility is not cheap either: previous studies by Stefano Carattini show that there are so-called peer effects. Neighbors can also be inspired and build solar systems - but the systems must be visible for this.

Source/Credit: Ruhr University Bochum

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