Commercial solar in the Canton of SolothurnNotify 30 days ahead.

Rules for businesses in the Canton of Solothurn

For solar systems on roofs in building and agricultural zones that are sufficiently well integrated, the notification procedure under Art. 18a RPG also applies in the Canton of Solothurn. The cantonal form of the Building and Justice Department goes, with a building description and plans, to the building administration of your commune at the latest 30 days before work starts. The commune checks the documents and also informs the Solothurn cantonal building insurance (Solothurnische Gebäudeversicherung). We fill in the form for you.

There is currently no cantonal solar duty for new buildings. The revised energy law, which provided for partial own-power generation at new buildings, was rejected by voters on 9 February 2025. Whether a commune sets its own requirements in the zoning plan or in a special land-use plan, we clarify at the site visit.

Subsidies and one-off payment

The cantonal subsidy programme names the building envelope, wood heating, heat pumps, solar thermal systems, heating networks and Minergie. Photovoltaics is not on the list. For your system, the federal one-off payment (Einmalvergütung) through Pronovo is therefore what counts. From 100 kWp the one-off payment for large systems applies, below that the one for small systems. If you do not use any of the electricity yourself and build between 2 and 150 kWp, you can receive a high one-off payment. We calculate which option suits your business. Subsidies can be pre-financed on request. You will find details on the cost structure in the guide.

For tax purposes, the general depreciation rules apply to business assets. Clarify the details with your tax adviser.

Self-consumption in your business

In the canton, businesses are supplied by BKW, Primeo Netz, AVAG and Regio Energie Solothurn, among others. The commercial tariff differs from utility to utility, so we read out your load profile and size the system for daytime consumption. Commerce, industry and farming benefit when machinery, cooling or ventilation run during the day. A battery storage unit can dampen load peaks. Further basics are under solar systems for businesses.