Peatland PV and floating PV as a direct investment: support, EEG 2027 and the evidence the revenue depends on

Most solar parks in Germany stand on arable land, grassland or former industrial and military sites. To reduce competition with farming and nature conservation, the legislator has defined a group of sites it explicitly wants to promote: the special solar installations (besondere Solaranlagen). They include agrivoltaics over crops or permanent cultures, plants over car parks, plants on drained peat soils that are rewetted, and floating plants on artificial waters such as gravel-pit lakes.

Peatland PV and floating PV appear more and more often in offers to investors, usually with a reference to climate protection and land efficiency. Both are true but say little about revenue. Three questions decide: which support does the plant actually receive, which conditions does it have to meet over its lifetime, and how much more does the site cost than an ordinary ground-mounted plant? This article takes them in turn.

What counts as peatland PV and as floating PV under the EEG?

Both are sub-categories of the special solar installations under § 37 (1) no. 3 EEG. Peatland PV is letter e: plants on peat soils that have been drained and used for agriculture, provided the land is permanently rewetted when the plant is built. What counts as peat soil is defined in § 3 no. 34a EEG by reference to the agricultural area map (§ 11 GAP-Konditionalitäten-Verordnung). The combination is deliberate: a drained peat soil is excluded for an ordinary ground-mounted plant in the tender (§ 37 (1) no. 2 EEG, each time with the words "kein entwässerter Moorboden"). Anyone who wants to build there has to make the land wet again.

Floating PV is letter f: plants on an artificial water body, meaning one created by people such as a gravel-pit or mining lake, or on a heavily modified water body (§ 3 nos. 4 and 5 of the Federal Water Act, WHG). Natural lakes and rivers are excluded. Unlike peatland PV, the statute requires no additional Bundesnetzagentur determination for floating PV; the requirements come from water law. Smaller plants outside the tender fall into the same categories via § 48 (1) sentence 1 no. 5 EEG.

Agrivoltaics, the third well-known form, is also a special solar installation and has its own rules on dual land use; it is covered in Investing in agrivoltaics: dual land use, revenues and tax leverage at a glance. This article stays with peat and water.

What support do peatland PV and floating PV receive, and what does EEG 2027 change?

Peatland PV receives 0.5 cents per kilowatt hour more, floating PV the same remuneration as any other ground-mounted plant. Both bid in the tender for first-segment solar plants, and the award value becomes the reference value (anzulegender Wert) from which the market premium is calculated, as for any other bid; Direct marketing and the market premium: how a solar park earns its money explains the mechanics. For peatland PV this reference value is raised by 0.5 cents after the award (§ 38b (1) sentence 3 EEG in the version in force on 15 May 2024). High-mounted agrivoltaics has a surcharge of its own. Floating PV has none.

There is a reason why a version from May 2024 applies, and many descriptions leave it out. Solarpaket I had planned two advantages for special solar installations: a separate quota awarded first (§ 37d EEG, 1,200 megawatts for 2026) and a ceiling price of up to 9.5 cents instead of 5.9 cents (§ 37b (2) EEG). Under § 101 (1) EEG, both may only be applied once the European Commission has approved them under state-aid law. That approval is still missing; the Bundesnetzagentur pointed this out explicitly for the bid dates of 1 March and 1 July 2026 and applied the general award procedure. In practice, peatland and floating projects therefore compete with every arable solar park for the same award, at the same ceiling price.

How much peatland PV and floating PV is actually being built?

Very little, measured against the tenders. The Bundesnetzagentur's tender statistics show the site type of every bid. We evaluated the ten bid dates since July 2023, when peatland PV first appeared. Over that period 21.5 gigawatts were awarded in total. Peatland PV accounted for 57 megawatts, or 0.27 percent, and water bodies for 7 megawatts, 0.03 percent. The ratio of bids to awards stands out: of 113 megawatts of peatland PV bid, half was successful; in March 2026 a 20 megawatt bid came away empty. Without its own ceiling price and without priority, a peatland project has to hold its own against arable solar parks that build more cheaply, with only the surcharge in its favour.

For floating PV the tender shows only part of the market. Some floating plants supply the gravel or sand extraction on the same lake directly and are therefore paid through the EEG only for the surplus, or not at all; the Fraunhofer guide describes this model as the usual permitting route on lakes with active extraction. In its 2025 guide, the Fraunhofer Institute for Solar Energy Systems (ISE) reports 44.2 megawatts of floating PV in operation based on the market master data register; for comparison, Germany awards ground-mounted plants in gigawatts per tender round. There is no current official total, because the register does not reliably record the site type for older entries.

What does rewetting require of a peatland PV project?

A permanently high water table, and evidence of it over years. The background is climate protection: drained peat soils release carbon they have stored for millennia. The Federal Environment Agency (UBA) puts emissions from peat soils in 2024 at about 52 million tonnes of CO2 equivalent, around 8 percent of German greenhouse gas emissions; the Thünen Institute arrives at about 50 million tonnes. According to the National Peatland Conservation Strategy, one hectare of drained arable land on peat emits about 40 tonnes a year, rewetted it is 5.5 tonnes. The idea behind peatland PV: the solar plant is meant to make rewetting economically viable, and the support is therefore tied to it.

The details were set by the Bundesnetzagentur on 1 July 2023 (ref. 4.08.01.01/1#4, operative part no. 3). For a project this means, in order:

• Before the bid: the land must be in agricultural use on the bid date, and the bidder declares that the plant will not stand in the way of future rewetting (§ 37 (2) no. 1a EEG).
• During construction: the modules must stand above the peat soil; inverters and cables may be outside. The plant must allow vegetation, must not introduce harmful substances into the soil and must be removable without damage and without residue.
• At commissioning: it is only allowed once the construction work for rewetting has begun. The grid operator must be shown the water-law permit with the target water levels and a confirmation by a qualified expert.
• Target water levels: no more than 10 centimetres below ground in winter and 30 centimetres in summer, the same values the peatland strategy names.
• Within five years of commissioning: evidence, based on measurement, that the target water levels have been reached and the construction work is complete, confirmed by the authority, an engineering firm or an environmental verifier.
• If that fails: confirmation that the measures are continuing, and new evidence after five more years at the latest. According to the reasoning of the determination, this mechanism continues until the water levels are confirmed.

For an investor, the last point matters most. The surcharge and the status as a special solar installation depend on water management that the operator controls only in part: ditches, weirs and pumps can sit on neighbouring land, and a dry summer can lower the water table. The determination sets out how the evidence is to be provided, but it does not say explicitly what happens to the payment claim if the evidence fails for good; the grid operator checks the support conditions. That gap therefore belongs in the purchase agreement, not in the small print: who bears the risk if rewetting does not work as planned, and how is it secured?

Then there are the practical consequences of a wet site. Construction and maintenance on waterlogged soil need different foundations, different vehicles and different time windows, and insurance has to cover risks an arable field does not have. How site risks show up in insurance cover is described in Insuring a solar park or battery storage asset: which policies belong to a direct investment, and who holds them; what happens at the end of the term with decommissioning and its security, in Decommissioning a solar park: who pays, how large the bond is and what it costs.

Where may a floating PV plant be built?

Only on artificial or heavily modified water bodies, on no more than 15 percent of the surface and at least 40 metres from the shore. These limits are not in the EEG but in water law: § 36 (3) WHG bans solar plants on natural water bodies entirely and limits them on all others, measured from the mean water line. The provision is unchanged; in September 2025 the Bundesrat merely asked the federal government to examine wider limits (Drucksache 214/25, resolution). There is no bill on it.

The 15 percent limit sets the size. A gravel-pit lake of 20 hectares carries at most 3 hectares of plant, often less once the shore strip is deducted. Fraunhofer ISE estimates the potential on Germany's roughly 6,000 artificial lakes under these limits at 11.8 to 16.5 gigawatts, but the economically and practically usable potential at only 1.8 to 2.5 gigawatts. Many lakes are too small, too far from the grid or still being mined.

The same guide takes a sober view of the site advantage often attributed to floating plants: cooling by the water raises the yield in Germany by a few percent, depending on design. A floating plant needs a water-law and a building permit; if the power is mostly consumed by the extraction business on the lake, it can be privileged in the outer zone (§ 35 (1) BauGB), otherwise many federal states require a zoning plan. How zoning and land security work for ordinary solar parks is shown in Grid connection, easement, building rights: how to tell whether a direct investment has truly secured its site.

Do peatland PV or floating PV pay off for investors?

Peatland PV can pay off through the surcharge if the extra cost of the site stays below it; floating PV hardly pays off through the tender alone. First, the value of the surcharge. We determined it with our own hourly model: the yield profile of a south-facing plant in central Germany from PVGIS, exchange prices from SMARD. The plant delivers about 1,011 kilowatt hours per kilowatt a year. At 2025 prices, a quarter of that fell into hours with negative prices, in which § 51 EEG pays no market premium and therefore no surcharge.

The surcharge raises the reference value, so it only works as long as a market premium is paid at all. That depends on the annual market value of solar: if it is below the reference value, as in 2025 with 4.5 cents against an award value of 4.79 cents, the grid operator pays the full premium and the full surcharge. If it is well above, as in 2023 with 7.2 cents, the premium is zero and the surcharge is worth nothing that year. How the market value develops and why it falls for solar power is explained in Solar market value: why solar power is worth less and less on the exchange.

The last row follows from the logic of the draft: if the market premium becomes two-sided, the operator pays back the difference between market value and reference value in high-price years. A reference value 0.5 cents higher reduces that repayment by the same amount. The surcharge then works every year, but the plant also loses the high-price years in which, under current law, it keeps the full exchange revenue. At an award value of 4.79 cents, 0.5 cents is a little over a tenth more per remunerated kilowatt hour. Against this stand extra costs that no official register shows: foundations on wet soil, hydraulic works for rewetting, expert reports and measurements over ten years. How high they are in a given project is something the provider has to disclose; without that figure the surcharge cannot be assessed.

For floating PV the gap is wider. Fraunhofer ISE calculated levelised costs of electricity for floating plants of 9.0 cents per kilowatt hour facing south and 9.8 cents facing east-west, even though it assumes a low real cost of capital of 2.5 percent. The volume-weighted award value of the last tender was 4.79 cents. A floating plant that sells its power only through the tender thus covers roughly half its costs, according to this one study. It is more likely to carry itself if a local offtaker buys the power at a higher price, such as the extraction business on the lake under a supply contract, or if there is a long-term power purchase agreement; Understanding PPAs: how power purchase agreements make solar park revenues predictable shows how such contracts are structured. In our model, a plant tilted flat towards east and west, as is common on water, delivers 881 kilowatt hours per kilowatt, about 13 percent less than the south-facing plant; the cooling effect is not included. Why a flatter profile is not necessarily worth more on the market is shown in South, east-west or vertical: which solar park layout pays off for investors.

Two counter-arguments belong in the picture. The market is small, so track records are missing: peatland PV has only been eligible since 2023 and 57 megawatts have been awarded; according to the Fraunhofer guide, floating plants total about 44 megawatts in operation. Yield assessments therefore rest more on assumptions than for an arable solar park, and the question of how certain a yield is becomes more important; Reading a yield assessment: what P50 and P90 mean for a solar park direct investment explains how to read an assessment. On the other hand, both forms have an advantage that does not show up in any kilowatt hour: they hardly compete with farming for land, and a peatland project can bring in peatland climate protection funding; the determination explicitly accepts a funding decision under the federal peatland climate protection funding guideline as evidence.

Do the investment deduction (IAB) and special depreciation apply here too?

In principle yes; in detail the classification is open. The investment deduction and special depreciation under § 7g (1) and (5) EStG apply to depreciable, movable assets; the Federal Fiscal Court (BFH) has confirmed that a photovoltaic plant can be one (order of 07.12.2023, IV R 11/21). Modules, inverters and racks of a peatland or floating plant are no different from those of a ground-mounted plant. For the components that exist only here, there is no explicit statement from the tax authorities or the courts: floats and anchoring on the lake, foundations on the peat and above all the rewetting works such as weirs and ditches, which serve the land rather than the plant. The other conditions of the IAB are summarised in Investitionsabzugsbetrag: all §7g EStG requirements, and who can use it.

Which questions should you ask the provider?

With special solar installations, the review shifts from the module to the site. These questions should be answered with documents, not with a presentation:

• Is the plant registered in the award as a special solar installation under letter e or f, and is the peatland surcharge in the award notice or only in the model?
• Is the water-law permit in place, and which target water levels does it set?
• Who operates the ditches, weirs and pumps for rewetting, on whose land are they, and who bears their costs over the term?
• How is the water level measured, by whom, and how is the evidence after five years organised?
• What happens contractually if the evidence fails: is there a guarantee, a price adjustment or a rescission?
• What extra costs does the site have compared with an ordinary ground-mounted plant, and how do they compare with the value of the surcharge?
• For floating PV: who buys the power, at what price and for how long, and what applies if extraction on the lake ends?
• Which conditions does the water-law permit contain on coverage, shore distance, monitoring and time limits?
• How is decommissioning secured, on the water and on the wet soil?
• Does the insurance cover site-specific damage such as storms on the water, ice or subsidence in the peat?

If the questions on rewetting and offtake are answered only with declarations of intent, the project is closer to a development than a finished plant. Further warning signs with providers are collected in How to tell a trustworthy provider of energy direct investments.

How we check special solar installations in our project review

We treat the surcharge as a separate revenue line with its own risk, not as part of the award value. Our model runs one case with and one without the surcharge, and we set the difference against the disclosed extra costs of the site. For peatland PV we read the water-law permit, the hydrological report and the contracts on the hydraulic works; if there is no provision for the case that the water-level evidence fails, that is an open point for us. For floating PV we look at the offtake side first, because it decides the economics, and then at the conditions of the permit. We give no return promises in the process. If you would like a specific offer reviewed, you can bring it to a no-obligation initial consultation.