Sheep keeping a solar park short has been common practice for years. What is newer is livestock as part of the plant concept: cattle graze between tall or vertical module rows, laying hens use the modules in their range as protection from birds of prey and sun. Since June 2024 there has been a dedicated technical rule for this, DIN SPEC 91492.
For investors there is a question behind this that affects the business case: is this an ordinary solar park with animals as vegetation management, or a special solar installation (besondere Solaranlage) within the meaning of the EEG? In the first case the animals change nothing about revenue. In the second there is access to grassland and, for some designs, a surcharge. In return the hectare carries less capacity, the frame costs more and the support depends on evidence that the livestock farmer has to supply. We do not currently offer an agrivoltaics project with livestock; this article is an assessment of the concept.
Is a solar park with sheep already agrivoltaics?
No. In a solar park with sheep, grazing is as a rule vegetation management. The plant is an ordinary ground-mounted plant, bids in the tender on one of the usual site categories and receives the award value without a surcharge. The EEG mentions grazing there only as one of five nature conservation criteria, of which a park must meet at least three: a maintenance concept with no more than two cuts a year or strip grazing with an adapted stocking density (§ 37 (1a) no. 2 EEG). Which land an ordinary park may use is set out in Eligible land: where can a solar park be built in Germany?.
Agrivoltaics within the meaning of the EEG is a special solar installation where farming continues on the same land. For grazing animals one category is relevant: grassland that is not peat soil, with simultaneous use as permanent grassland (§ 37 (1) no. 3 (c) EEG). The difference from an ordinary park shows in three places.
- Land: a special solar installation may stand on permanent grassland that is open to an ordinary park only through the general categories, for example in a less-favoured area or along motorways and railways. Peat soils, Natura 2000 sites and protected habitat types remain excluded.
- Remuneration: the award value comes from the same tender as for any other park. A surcharge exists only for certain designs.
- Obligations: farming must continue over the entire support period and is confirmed by an expert every three years.
Whether the information memorandum says agrivoltaics, pasture PV or solar park with grazing tells you nothing about this. What matters is the site category in which the plant received its award. The general classification of agrivoltaics is set out in Investing in agrivoltaics: dual land use, revenues and tax leverage at a glance.
What does the EEG require of an agrivoltaics plant on grassland?
That the land is permanent grassland (Dauergrünland) and continues to be farmed as such. The Bundesnetzagentur set the requirements in a determination (Festlegung) of 1 July 2023. Permanent grassland is land on which grass or other herbaceous forage grows and which has not been part of the crop rotation for at least five years; permanent pasture is included. Farming must be taking place at commissioning and must not be significantly restricted by the solar plant in intensity, type, duration or timing. Four points of the determination matter for projects with animals.
- Mowing or grazing: both are permitted. Switching from grazing to mowing and from intensive to extensive use also remains allowed.
- No switch from arable land to grassland: arable land sown with grass for the construction of the plant is not permanent grassland within the meaning of the determination. The five years must lie before commissioning.
- Species: if a particular species grazed the land before construction, grazing with that species must remain possible. The expert report at commissioning confirms that the grazing planned in the farming concept is possible.
- Evidence: an expert report on the state of the art at commissioning, then in every third year an expert confirmation that the grassland was farmed over the past three years. Aerial images, photographs, payment records from farm subsidies or extracts from the field record (Schlagkartei) are sufficient. Nobody has to prove a particular yield level.
The authority expressly rejected requirements on grazing management, such as periods without animals. Nor does the land have to be in the farm subsidy scheme. What is required is actual continuation: according to the reasoning, farming and solar plant form an inseparable unit. Plants above one megawatt bid in the tender for first-segment solar plants; smaller ones receive the statutory value under § 48 (1) sentence 1 no. 5 (c) EEG.
Which standard counts: DIN SPEC 91434 or DIN SPEC 91492?
For the EEG, the older one. The determination refers statically to DIN SPEC 91434 in its May 2021 version. It describes agrivoltaics in general and lists permanent grassland with grazing as a category of its own without elaborating on it. DIN SPEC 91492 of June 2024 fills that gap for livestock. The Bundesnetzagentur could not include it in 2023 because it had not yet been adopted. In its notes on the bid date of 1 December 2026 the authority does not name a newer determination for grassland.
The new standard is useful all the same, because it names what matters with animals.
- Two categories: high-mounted from 2.10 metres of clearance, where the animals use the land under and between the modules, and ground-level or vertical.
- Loss of land of no more than 15 per cent of the project area. Permanently installed fences without an agricultural function count towards it, mobile pasture fences do not.
- Stocking of at least 85 per cent of a reference area. Less is permitted if the farming concept justifies an improvement, for example in animal welfare.
- Protection in both directions: animals must not injure themselves on the plant. Cables and frame must be secured against chewing, biting and rubbing.
- An agricultural use concept signed jointly by farmer and operator, with a use plan for the first three years.
For investors this means: planning to DIN SPEC 91492 is a quality feature for the interaction of animal and technology. It does not secure the status as a special solar installation. That depends on the grassland definition of the determination and on DIN SPEC 91434, to which the farm subsidy rules also refer.
What does a hectare earn depending on the design?
Considerably less electricity than an ordinary park, because more space remains between the modules. We calculated three designs at the same site in central Germany, with hourly profiles from PVGIS and the exchange prices of 2025: the ordinary park with 1,000 kilowatts per hectare, a high-mounted plant with 600 kilowatts and vertical bifacial module rows with 250 kilowatts per hectare. The densities follow assumptions by Fraunhofer ISE for ground-mounted plants, high-mounted plants and vertical modules.
| Design | kWp per ha | Revenue per kWp | Revenue per ha |
|---|---|---|---|
| Vertical bifacial | 250 | €66.1 | €16,500 |
| High-mounted | 600 | €55.5 | €33,300 |
| Ordinary park | 1,000 | €52.7 | €52,700 |
Per hectare the high-mounted plant reaches 63 per cent and the vertical one 31 per cent of the electricity revenue of an ordinary park. Per kilowatt the picture is different. Vertical modules generate in the morning and evening, when electricity is worth more: only 17 per cent of their generation fell into hours with a negative price in our calculation, against 25 per cent for the south-facing plants. Their revenue per kilowatt was therefore around a quarter higher. The calculation contains no shading between rows and assumes that the rear side delivers 90 per cent of the front. Both assumptions favour the vertical plant. How orientation affects revenue is covered in detail in South, east-west or vertical: which solar park layout pays off for investors.
The low density has a price that does not appear in comparisons per kilowatt: the land. For every 1,000 euros of lease per hectare and year, one kilowatt carries 1.00 euro in the ordinary park, 1.67 euros high-mounted and 4.00 euros vertical. For the vertical plant that is 6 per cent of annual revenue, for the ordinary park just under 2 per cent. An agrivoltaics lease therefore has to be well below that of an ordinary park per hectare. In return the lessor keeps the farming. What should be in the lease is described in The land lease of a solar park from the investor's side: why it is a Mietvertrag, what the rent costs per kilowatt and how you step into the contract.
Does the agrivoltaics surcharge cover the extra cost?
For high-mounted plants it does not. The surcharge of 0.5 cents per kilowatt hour goes today only to special solar installations that are, in the wording of the law, horizontally mounted; the Bundesnetzagentur speaks of high-mounted agrivoltaics, meaning a clearance from 2.10 metres. It applies to awards in the years 2026 to 2028. Vertical and ground-level plants do not receive it. The rule comes from the May 2024 version of the EEG, because the more generous provisions of the Solarpaket I were never applied for lack of approval by the European Commission (§ 101 (1) EEG). According to the Bundesnetzagentur's notes this also holds for the bid date of 1 December 2026 as long as the approval is missing.
The tall frame costs more. Fraunhofer ISE puts the substructure of high-mounted plants below four metres at 243 to 306 euros per kilowatt against 76 euros for a ground-mounted plant, and site preparation and installation at 137 against 67 to 100 euros. Together that is 221 to 284 euros of extra cost per kilowatt. For ground-level systems, among which we count the vertical ones, it gives 97 to 167 euros for the substructure and 93 euros for installation, that is 31 to 101 euros more than for a ground-mounted plant. The energy agency of Rhineland-Palatinate arrives at 600 to 800 euros per kilowatt for a plant mounted two metres high with livestock, against 450 to 600 euros for a ground-mounted plant. That confirms the order of magnitude for the tall frame. For vertical systems it gives around 700 euros, more than the Fraunhofer ISE range suggests.
| Design | Extra cost | Surcharge covers |
|---|---|---|
| Vertical (2027 draft) | €31 to €101 | 51 to 167 % |
| High-mounted | €221 to €284 | 16 to 21 % |
The surcharge brings the high-mounted plant 3.72 euros per kilowatt and year, because it is paid only on the kilowatt hours outside negative-price hours. Discounted at 5 per cent over 20 years that is 46 euros per kilowatt, a sixth to a fifth of the extra cost. Converted to every kilowatt hour generated, the tall frame costs 1.8 to 2.3 cents; the surcharge is 0.5 cents. The surcharge alone therefore does not carry a high-mounted plant over a pasture. The reasons for this design lie with the land: the farmer only makes it available with grazing, the municipality only agrees to dual use, or the grassland would not be admissible for an ordinary park at all.
For vertical rows the extra cost according to Fraunhofer ISE is small and the revenue per kilowatt higher. In return there is no surcharge today. The land requirement is four times that of an ordinary park. Here the lease decides.
What is established for sheep, cattle and laying hens, and what is open?
Practice with sheep is established, and for cattle the benefit of shade. Open are, for cattle, the results of the German trial plants and, for laying hens, the classification under the EEG.
Sheep: proven as maintenance, rarely the reason for agrivoltaics
Sheep do not need a special design, but they need clean workmanship. The Bavarian State Research Centre for Agriculture gives a lower module edge of at least 80 centimetres for commercial breeds, everywhere on the site including hollows. Cables must be laid out of reach or protected, because sheep gnaw at them and get caught in them. As a grazing fee the same publication gives 150 to 400 euros per hectare as an industry figure, at least 300 euros from the shepherds' point of view and 801 to 855 euros according to a calculation by KTBL. The figures date from 2010 to 2014; we have not found more recent official values. In an ordinary park, 300 to 855 euros per hectare correspond to 0.30 to 0.86 euros per kilowatt and year, that is 0.6 to 1.6 per cent of the annual revenue in our calculation.
Whether lambs grow worse under modules was measured by Oregon State University over two years. The pasture under the modules produced 38 per cent less herbage. Liveweight gain per hectare remained comparable because the forage was of higher quality.
Cattle: shade is documented, loads on the frame
Cattle place higher demands on the frame than sheep. DIN SPEC 91492 requires that the supporting structure is protected against mechanical damage, for example from rubbing with horns. The animals must also be able to move upright under the plant. The trial plants of the agrivoltaics model region Baden-Württemberg on permanent grassland comprise, besides a ground-level reference plant, two vertical systems and one high-mounted tracking plant; two sites are grazed by cattle. The project had not published results on forage yield and animal behaviour by November 2026.
The benefit of shade is documented. In 2019 the University of Minnesota compared dairy cows on pasture with and without the shade of a solar plant. In the afternoon the cows in the shade breathed more slowly (66 instead of 78 breaths per minute) and had a lower body temperature; there was no difference in milk yield. The trial ran with 24 cows and a plant of 30 kilowatts. It is an indication, not proof for large parks.
Laying hens: permitted in the range, a special case under the EEG
With laying hens two areas of law meet. Egg marketing law has allowed solar panels in the open-air run since November 2023 if the competent authority approves, animal welfare is maintained and the hens can move freely (Annex II of Delegated Regulation (EU) 2023/2465). The run must be mainly covered with vegetation, and no more than 2,500 hens per hectare are permitted. Bavaria derives from this that, seen from above, no more than 49 per cent of the run may be covered by modules. It recommends a minimum height of 55 centimetres.
The EEG is the second hurdle. A hen run is a special solar installation on grassland only if the land is permanent grassland and continues to be farmed as such. A run newly laid out on arable land does not meet this on our reading of the determination: the switch from arable land to grassland is excluded; for the arable category the cultivation of crops is missing. Then there is the sward. Hens scratch away the vegetation near the house; where no grass stands permanently, proving grassland farming becomes difficult. A project with laying hens can therefore be an ordinary solar park under the EEG even if it is presented as agrivoltaics. The information memorandum should name the site category of the award.
What the modules do for the animals is being studied by Nürtingen-Geislingen University at two farms with a good megawatt each. Fraunhofer ISE names range behaviour, the distribution of the hens under the plant and the consequences for the sward as open questions. The project ran until the end of 2025; we had not found a published final report by November 2026. Housing orders during avian influenza are regulated: under the EU regulation the eggs may continue to be marketed as free-range during such a restriction. For the EEG, the wording of the determination looks at the farming of the grassland over three years, not at the individual day in the run.