Under which conditions is it still Green Energy? Photovoltaics on organic soils: A scenario analysis for Germany

Abstract Solar parks generate emission-free electricity, but installations on drained organic soils can lock in substantial greenhouse gas (GHG) emissions from peat oxidation. Therefore, combining ground-mounted photovoltaics (GM-PV) with rewetting is emerging as a multifunctional climate mitigation strategy in temperate peatland regions. Despite growing interest, data on GM-PV on organic soils (Peatland-PV) remain limited. To address this gap, we conducted a geospatial analysis of Germany's Peatland-PV plants, quantifying associated water table depths (WTD) and GHG fluxes. Based on these findings and socioeconomic projections from the literature reflecting different policy frameworks, we developed three exploratory scenarios of future expansion under three rewetting regimes each. Peatland-PV solar panels covered 1,019 ha of organic soils in Germany as of 1 January 2026 and could expand to 2,604–8,031 ha by 2045 according to our model. We found that most existing sites are deeply drained (median WTD ca. −0.5 m), resulting in annual soil emissions of 39 kilotons (kt) CO₂-eq from the panel–soil intersection area. The future GHG balance of the Peatland-PV sector depends on expansion rate and rewetting policy, rather than geographic location. Continued drainage of Peatland-PV plants could sustain nationwide organic soil related GHG emissions of 89–274 kt CO₂-eq yr ⁻¹ by 2045, while rewetting may reduce these emissions by 21–49%. Our scenarios indicate that Peatland-PV may initially contribute to net climate cooling mainly due to avoided fossil emissions, but under continued drainage a crossover point could occur 2039, at which soil emissions exceed mitigation benefits from renewable energy production.