Generating Additional Revenue with PV Curtailment
From Loss to Revenue Stream: PV Curtailment Becomes a Lucrative Business Model
Kriens/Immensee, December 11, 2025c – What was previously considered a nuisance in the industry is now becoming a new source of income: The curtailment of photovoltaic systems is developing into a lucrative business for operators. sun2wheel AG and convoltas AG demonstrate with a new marketing model that flexible PV systems can achieve multiples of the usual feed-in tariffs in the balancing energy market. This opens a new chapter in the Swiss solar industry.
Switzerland has ambitious goals for expanding solar energy and is heading toward a fivefold increase in solar power production. On sunny days, systems already produce more electricity than the grids can absorb. Instead of curtailing these surpluses without compensation, operators can now market their flexibility in a targeted manner and get paid for it.
Solar Power Surplus: From Problem to Opportunity
The technology newly developed by sun2wheel bundles numerous PV systems throughout Switzerland into a large virtual power plant. sun2wheel and convoltas market this potential under the name “Profit-Plus” for the first time systematically. “When there is excess power in the grid, we curtail PV systems and turn it into a lucrative business model for system operators,” says Sandro Schopfer, CEO and co-founder of sun2wheel.
Surprisingly Lucrative Returns in Test Operation
Since June 2025, the system has been in productive use within Swissgrid’s PV4Balancing pilot project. The results are impressive: The partners achieved around CHF 10 in additional compensation per installed kilowatt of capacity. This increases the return on a photovoltaic system by over 20 percent. The electricity from photovoltaics is only curtailed for 4 to 8 hours per month, mainly on weekends or during changeable weather. “Given declining feed-in tariffs, our customers now earn more with flexibility than with pure grid feed-in. So it’s not surprising that we already have more than 100 large-scale systems under contract,” explains Fabian Gloor, Sales Director at convoltas.
Example of a curtailed system
sun2wheel as First Provider in the Balancing Energy Market
sun2wheel is the first provider that can offer PV systems in the balancing energy market outside the PV4Balancing pilot project. This is made possible by an AI-based process that sun2wheel developed together with partners. This is an important step, as previously only large-scale systems could be marketed due to required sensors and high installation effort. Thanks to the newly developed software, medium-sized systems can now also be integrated for marketing. Plans are in place to open the solution to small residential systems in the future.
Demand for Flexibility in the Power Grid is Growing Rapidly
Sandro Schopfer puts it in perspective: “We need not only more photovoltaics but also more flexibility. Our software ensures that systems are integrated into the virtual power plant within minutes, without any upfront costs for the PV system owner.” The technology also supports the requirements of the 3% rule (see box) by automatically controlling production peaks or storing energy in electric vehicles or batteries. For the first time, operators can actively market this curtailment instead of having to accept it without compensation.
Flexibility Increases Benefits and Grid Stability
The collaboration between sun2wheel and convoltas in the “Profit-Plus” product shows how technological innovation and market mechanisms can work together to advance the energy transition. When solar power is not only produced but also flexibly controlled and compensated, operators, grid operators, and the entire power supply benefit. This makes flexibility the new currency of the Swiss solar industry.
The Significance of the 3% Rule
The so-called 3% rule allows distribution grid operators in Switzerland to permanently curtail the feed-in capacity of photovoltaic systems by up to 30% of installed capacity without compensation – which corresponds to about 3% of annual production. The rule was introduced to avoid grid overloads on sunny days but leads to unused solar power for many system operators. Intelligent control and marketing systems like “Profit-Plus” from sun2wheel and convoltas can specifically manage these curtailments, make them economically viable, or avoid them entirely – for example, by using production peaks from photovoltaic systems to charge electric vehicles or battery storage.
About sun2wheel AG
Founded in 2020, sun2wheel AG develops energy management systems for the intelligent networking of decentralized energy resources. The platform optimizes self-consumption and load management while simultaneously enabling the marketing of flexibility in virtual power plants. sun2wheel connects PV systems, storage, and e-mobility into an integrated energy ecosystem. www.sun2wheel.ch
About convoltas AG
convoltas AG is a Swiss energy general contractor that plans, builds, and operates large-scale photovoltaic systems, battery storage, electromobility solutions, and holistic energy systems. Since 2019, convoltas has developed into a leading provider in the renewable energy sector, offering a complete value chain from project development to monitoring. The focus is on scalable, economically attractive, and grid-serving energy solutions for industry, commerce, and real estate portfolios. www.convoltas.ch