Since 1 January 2026 the Winterstrombonus supports PV systems from 100 kWp that produce more than 500 kWh per kW of installed capacity during the winter half-year (1 October to 31 March). This threshold is reached above all by vertical and facade-integrated bifacial systems: they make optimal use of the low winter sun and gain up to 25% additional yield from snow albedo. The specific subsidy amount comes from the Pronovo tariff calculator.
Key Takeaways
5 min read
Key Takeaways
5 min read- Winterstrombonus active since 1 January 2026The new federal programme applies to PV systems commissioned from 1 January 2026. Existing systems are not covered retroactively.
- System size from 100 kWp requiredThe bonus is available exclusively to commercial and industrial systems from 100 kWp, the typical scale for industrial, commercial and logistics buildings.
- Vertical PV as the technical answerFacade-integrated and vertical bifacial modules capture the low winter sun optimally and use snow albedo for up to +25% additional yield.
- Federal subsidy and cantonal bonuses can be combinedVertical PV systems can claim the GREIV integration bonus, cantonal facade programmes (e.g. GR: CHF 300/kWp) and the Winterstrombonus at the same time.
Flat-roof PV produces over 70% of its annual energy in the summer months. That is not a technical problem but a structural challenge for the grid: demand peaks and supply shortfalls occur in winter, not in summer. The Winterstrombonus, in force since 1 January 2026, addresses exactly this point. It creates a financial incentive for systems that produce electricity when the grid actually needs it.
What is the Winterstrombonus?
The Winterstrombonus is a new element of the Einmalvergütung (EIV) under the Mantelerlass (Electricity Act 2025). It targets PV systems whose design delivers an above-average share of their annual production in the winter half-year.
Key facts of the programme:
- Valid for commissioning from 1 January 2026
- Systems from 100 kWp
- Production threshold: more than 500 kWh per kW of installed capacity during the winter half-year (1 October to 31 March)
- Target group: alpine sites, facade systems facing south-west or south-east, steeply tilted systems
- Subsidy amount: the specific amount comes from the Pronovo tariff calculator.
The threshold of 500 kWh/kW in the winter half-year corresponds to a share that conventional flat-roof systems as a rule do not reach. This is where vertical PV comes in.
Vertical PV as the technical answer
Why do vertical and steeply tilted facade systems reach the winter production threshold while flat-roof PV falls short? The answer lies in the geometry of the sun’s path and in the bifaciality of modern modules.
Optimal angle of incidence in winter. In December and January the sun in Switzerland sits low on the horizon, typically 15 to 25 degrees above it. For a vertical or steeply tilted surface this light strikes the module almost perpendicularly. A flat-roof system (10-15 degrees) receives the same light at an unfavourable grazing angle.
Snow albedo with bifacial modules. Bifacial modules generate electricity on both sides. In winter, snow on the ground, the road or the roof surface below reflects sunlight onto the rear of the modules. Depending on site and snow cover, this albedo effect delivers up to +25% additional yield compared with single-sided modules, a figure well documented by Fraunhofer ISE studies on bifacial gains as a function of ground albedo.
Combined subsidy logic. A vertically integrated PV system (BIPV) qualifies simultaneously for the GREIV integration bonus (CHF 400/kW) and, with sufficient winter production, for the Winterstrombonus. Two cantonal programmes reinforce this framework particularly strongly:
- Canton of Graubünden: CHF 300/kWp for vertical and facade-integrated systems, one of the most generous cantonal schemes in Switzerland.
- Canton of Lucerne: CHF 100/m² for systems with a tilt of 75 degrees or more.
Real project in Landquart GR: A 23 kWp bifacial system on a 50 m long partition wall delivered 11’332 kWh of annual production and received total subsidies of CHF 10’730. The project shows that even smaller facade areas can secure significant subsidy contributions when site, orientation and subsidy logic fit together.
For the system solution, design variants and technical details, see our solution page on vertical PV.
Checking eligibility, step by step
Clarifying Winterstrombonus eligibility
Check the system size (>= 100 kWp)
The Winterstrombonus is available exclusively to systems from 100 kWp. Smaller systems are not eligible but can be supported through KLEIV and cantonal programmes.
Calculate the winter production potential
Site, orientation (south-west or south-east is optimal), tilt angle and any albedo surfaces below determine whether the threshold of 500 kWh/kW in the winter half-year is achievable. This calculation belongs in a preliminary study.
Consult the Pronovo tariff calculator
With the technical parameters of the planned system, the Pronovo tariff calculator gives you the specific subsidy amount. It is binding for the application. Registration in the portal must take place before construction starts.
Start planning with winter optimisation built in
Facade integration, bifacial modules and orientation towards low sun angles are part of the system design from the outset. Subsequent changes to a project that has already been approved are not possible under the EIV.
For a complete overview of all federal subsidy programmes (GREIV, KLEIV, HEIV and the bonus structure), see our Subsidy Guide 2026. It covers every programme and explains the full application process.