Solar installation in the Canton of SolothurnNotify first, then build.

Permit: notification form to the commune

Under Art. 18a RPG, sufficiently well-integrated solar systems on roofs in building and agricultural zones do not need a building permit. In the Canton of Solothurn, the cantonal notification form of the Department of Building and Justice, as at 1 January 2026, is used for this. You submit it with a building description, site plan and elevation plan at the latest 30 days before building work starts to the building administration of your commune.

The commune checks whether the system only has to be notified or whether a building permit is needed. If the system must be notified, the commune informs the client, the Solothurn cantonal building insurance (Solothurnische Gebäudeversicherung) and, where applicable, other bodies such as the fire brigade. We fill in the form and submit it.

Subsidies in the Canton of Solothurn

The federal government pays the one-off payment (Einmalvergütung, EIV) through Pronovo. Since 1 April 2025 there has been no base amount, and add-on systems under 30 kWp receive CHF 360 per kWp. We file the application. On request, we pre-finance the subsidy.

The cantonal subsidy programme does not list photovoltaics as a measure of its own. It names the building envelope, wood heating, heat pumps, solar thermal systems, heat networks and Minergie. Individual communes or energy suppliers may offer their own contributions, and we check that for your address.

According to the canton’s tax manual, the costs on existing buildings are deductible if the building is more than five years old. On new builds they are not deductible, and they later reduce the property gains tax. Feed-in payments are taxable to the extent that they exceed the cost of electricity you buy.

Grid operator and power price

In 2026 the cantonal median is 30.4 ct. per kWh excluding VAT, and the Swiss median is 27.7 ct. BKW supplies 26 communes (27.3 ct.), Primeo Netz 23 (32.0 ct.), AVAG 16 (32.3 ct.) and Regio Energie Solothurn 7 (30.0 ct.). How much self-consumption pays off therefore depends on your utility.

The grid operator pays for the electricity you feed in. The rate differs from one utility to the next, and we calculate with the tariff of your utility.

Building stock

Around 38% of residential buildings in the canton heat with oil. If you replace an oil heating system, you can combine the solar system with a heat pump and use your own power directly for it. A battery storage system also fits well.