Public support for a commercial solar plant depends on its capacity: up to 100 kWp, an investment grant for self-consumption and a feed-in tariff for the surplus; above that, support obtained through a CRE (French energy regulator) call for tenders. Amounts, thresholds and schemes change regularly: check them at the date of your file, before signing a quote.
Which grants exist for a commercial solar plant?
Three families of support coexist: investment and production support set by decree for small capacities, CRE calls for tenders for larger installations, and local or tax incentives that vary with your territory and status.
The table gives the general logic by capacity band. The exact thresholds, amounts and opening periods of the schemes change: do not sign a quote without checking them.
| Capacity | Support in general | Point of attention |
|---|---|---|
| Up to 100 kWp | Investment grant for self-consumption and feed-in tariff for the surplus | Amounts set by decree, revised regularly |
| From 100 to 500 kWp | Feed-in tariff or CRE simplified call for tenders depending on the period | The applicable scheme is changing: confirm at filing |
| Above 500 kWp | CRE calls for tenders | Ranking on the price offered, twenty-year contract |
How does selling the surplus work?
You consume your production first, and the surplus fed into the grid is bought back under the tariff or contract that applies to your installation. This buy-back price is lower than the price at which you buy electricity: profitability therefore rests first on the share you consume yourself.
With full sale, all production is resold and nothing is consumed on site. This structure suits sites that consume little during the day or roofs of buildings with limited use.
Which local grants and tax advantages?
Regions, departments and inter-municipal bodies sometimes open investment grants for solar energy, with their own criteria: business sector, company size, building type. They are occasional and depend on your territory.
For local authorities, local investment support grants may fund part of a project. On the tax side, the treatment of the investment (depreciation, VAT) depends on your status: have your accountant validate it before committing.
Are car parks subject to an obligation?
Yes, for large outdoor car parks. The APER law (law accelerating renewable energy production) requires photovoltaic canopies over at least half the surface of outdoor car parks above 1,500 m²: by 1 July 2026 for those above 10,000 m², by 1 July 2028 for those from 1,500 to 10,000 m².
The canopy can be financed by rent paid by the plant operator, or serve the self-consumption of your buildings. Both structures should be costed before choosing.
How do you estimate return on investment?
There is no single payback period: it varies with each of these inputs. Be wary of figures presented without assumptions; a serious proposal details them and costs them on your own consumption.
At Eneffic, we study your roof free of charge, size the plant on your daytime consumption and check the grants applicable at the date of your file. You know before any commitment whether your project holds up.
The 4 inputs of the calculation
Expected output
Depending on region, orientation, tilt and shading.
The self-consumed share
It depends on your daytime consumption curve.
Cost and grants
Installation, connection and grants applicable at the date of the file.
Price trends
The more expensive the purchased electricity, the more valuable the electricity avoided.
Key takeaways
Capacity determines the scheme
Grant and feed-in tariff for small installations, call for tenders above.
Check the rates at the date of the file
Amounts and thresholds are revised regularly.
Self-consumption drives profitability
The more of your output you consume, the less you buy from the grid.
