Ground-Mounted Solar Under 3 MWc: What the July 2026 Decree Changes

Decree no. 2026-674 of 27 July 2026, published on 28 July, raises the threshold above which ground-mounted solar plants require a systematic environmental assessment from 1 MWc to 3 MWc.

Between 300 kWc and 3 MWc, projects now go through a case-by-case review instead, where the authority decides within 35 days of a complete file whether a full assessment is needed. The new thresholds apply to projects filed from 28 July 2026.

• Faster development. Skipping a systematic assessment removes months from the schedule, bringing ready-to-build within reach much sooner.
• Lower upfront cost. Tens of thousands of euros of preliminary studies are no longer spent before a site is confirmed.
• Quicker site screening. Developers can validate or drop a site early, and keep a larger pipeline moving.

Projects of this size sit close to the C&I format. With storage on site, they can be structured as merchant or locally contracted assets rather than depending on CRE tenders:

• Higher project value by shifting injection toward high-price hours and away from negative-price hours.
• Diversified revenue from energy arbitrage and grid flexibility services.
• Local PPAs backed by a firmer, more predictable delivery profile than solar alone can offer.

Without tender support, the business case rests on how the asset performs in the market. At this scale, the fixed costs of storage, the route to market through an aggregator and the grid connection weigh more heavily, and the case-by-case review can still ask for a full assessment on sensitive sites.

That makes sizing decisive. The right battery power and duration for a 2 to 3 MWc plant depends on its production profile, its exposure to negative prices and the contracts it will sign. ValuationPro tests these configurations against forecast prices and the site's own constraints, so developers can see which ones hold up before committing capital.

The decree lowers the cost of starting a project. Getting the configuration right is what decides whether it is worth finishing.

Lucas Durupt