Why solar parks should replace agricultural land


At first glance, solar parks are technical installations that devalue the surrounding landscape and nature. At second glance, solar parks offer enormous potential for nature and biodiversity conservation.

Particularly when solar parks are built where intensive farming has been practised, areas of arable land with few species are transformed into high-quality, species-rich plant communities for nature conservation purposes. Solar parks offer a special habitat for plants, insects and small mammals, which are rarely found in the intensively used cultural landscape. Solar parks thus make a significant contribution to the conservation of many native species.

On grassland, the main reason for the decline in biodiversity is too much or too little use. Only a few grasses and herbs can cope with frequent mowing and heavy fertilization. The populations are monotonous and poor in species. If they are not mown at all, competitive grasses and woody plants displace the herbs. Insects also lose an important food source.

Species protection

Solar parks are not subject to agricultural utilization pressure. So that the modules do not shade, or even trees and shrubs have a chance, mowing is carried out at least once a year. There is no fertilization at all. Solar parks thus have a huge potential for diversity, which can be very valuable for the protection of species.

Solar parks are still often greened with seed mixtures consisting of non-native species or easy-care breeding grasses. The resulting monotonous grass deserts offer insects neither pollen nor nectar. However, solar parks with insect-friendly seed mixtures from native species are subject to some legal framework conditions.

According to Section 40 (4) of the Federal Nature Conservation Act (BNatSchG), “the application of plants of alien species in nature requires the approval of the responsible authorities.” This regulation serves, in particular, to protect intra-species diversity (§7, para. 1 no. 1 BNatschG; Art.2 CBD). As of 1 March 2020, plants or seeds in the wild may only be applied within their occurrence areas.

Already before 2020, the local seeds of wild plants (regio seed) are to be used preferentially according to BNatschG. The use of regional wild plant seed from the region for planting outside the settlement area therefore complies with the applicable legal provisions of the Nature Conservation Act.

Regio seed is legally compliant and makes a major contribution to biodiversity. The indigenous plants are the food source for a rich insect fauna. They promote the development of species-rich, nature conservationally valuable habitats. This type of greening with a high nature conservation value does not only lead to an appreciation of the landscape, it can even be the prescribed compensatory action for the intervention in the ecosystem.

Why solar parks?

Solar parks now generate electricity at costs of 4-6 Eurocent/kWh. They no longer need any financial support and will generate even cheaper electricity in the future. Solar parks are therefore economically reasonable for electricity customers. They generate very cheap electricity and also serve the purposes of nature protection.

In comparison with other bioenergy sources, solar parks are also considerably more efficient. Here is a comparison with biogas plants operated with silage maize: A solar park produces approx. 700,000 kWhelect./ha, the biogas plant on the other hand only approx. 10,587 kWhelect./ha. The efficiency is 66 times higher with solar power. If the heat is also used with the biogas plant, the advantage of the solar park still remains with the factor 44.

To date, only about 45 GWp of solar power systems have been installed on roofs and free-field sites in Germany.

For the necessary storage to balance the naturally fluctuating supply of electricity from solar and wind farms, I expect an efficiency of 50%. In order to supply the current annual electricity demand of 500 TWh in Germany, all “renewables” should generate 1,000 TWh/year. Of course, considerably more electricity will be needed across all sectors in the future.

Solar power, wind power, water power, together with short-, medium- and long-term power storage technologies (Power-to-x), can secure a complete power supply from renewable energies until 2050. This study by the Federal Environment Agency already said so in 2013.

Demand problem for land

However, solar parks require land and are, therefore, in competition with agriculture, which cultivates food, feed and renewable raw materials there.

Suggested solution 1: Bioenergy areas

Due to the considerably better efficiency of solar parks, the areas that are used today for the cultivation of silage maize for biogas plants should be used in the future. This could happen step by step as the EEG funding for the biogas plants concerned comes to an end.

A total of 1.35 million hectares of land were used for biogas in 2018. Of this, approx. 900,000 hectares were used for the cultivation of silage maize.

According to the current state of the art technology, 600 GWp of solar power capacity can be built on 900,000 hectares of land, generating 630 TWh of electricity annually. Biogas plants operated with silage maize generate almost 10 TWh of electricity on the same area.

Biogas plants can even continue to be used in combination with solar parks. This enables upcoming power-to-gas technology: Gas storage, demand-oriented electricity and heat supply, the use of installed technology, including local heating network, transformers and grid connection are possible. Only sufficient solar parks with power-to-gas technology would have to be set up in the surrounding area.

Of course, it would also make sense, in the interests of animal welfare and a healthier diet, to avoid mass livestock farming and thus produce and consume considerably less meat. The agricultural area for the production of animal feed is much larger than the above mentioned area of silage maize for biogas.

Suggested solution 2: Agrar-photovoltaics

Worldwide, there are promising approaches to combine solar parks and agricultural use on one area. If, however, the focus is on agricultural use, this means higher expenditure on technology. It also follows that, depending on the type of agricultural use, there are different kinds of use. Both aspects lead to higher costs for the construction and operation of the solar park and consequently higher electricity prices, which no one wants to pay.

I argue in favour of subordinating agricultural use to electricity generation in solar parks. This keeps construction, operation and electricity costs absolutely competitive.

People in a solar park are always a risk of damage to the technology. The use of independently operating agricultural machinery within a solar park is an alternative. Adapted to the microclimatic conditions under and beside the module tables, agro-robots can cultivate mixed crops that also promise more yield security than monocultures. Agricultural engineering will certainly be able to develop these agro-robots in 5-10 years if there is a market for them.


In Germany, solar parks are an essential building block for the generation of renewable energy. They are considerably more efficient and ecologically more reasonable than the cultivation of renewable agricultural raw materials for biogas plants. Consequently, it makes sense to gradually use bioenergy agricultural land for the construction of solar parks.

Requirements of species protection and food production are taken into account by biodiversity concepts and future use with farm robotics. If we want to install 600 GWp PV capacity over the next 20 years, domestic module production could even be profitable. It is now up to legislation to create the necessary conditions.

Desirable conditions

  • Even spatial distribution of the facilities throughout Germany to create a biodiversity network that can be used by insects, small mammals and birds (Stepping Stone Corridors).
  • Creation of financial participation opportunities for citizens in the vicinity of solar power plants.
  • Simplification of the authorisation procedure where multiple use is ensured. Multiple use means: Biodiversity concept for species protection or use for plant and animal production.
  • Corresponding adjustments to the EEG, Regional Planning (Regional Plan, Regional Development Plan) and approval procedures.
  • Adaptation of the legal requirements for the use of agricultural land in connection with solar power plants.
  • Adapting the system of EU agricultural subsidies to this upcoming type of multiple land use.


The future is uncertain and I am in favour of a gradual approach that allows mistakes, as well as openly and honestly informs and involves all citizens. With new knowledge, in a few years‘ time completely new paths may emerge that are still unimaginable?

I take the liberty of gazing deep into the glass ball already today:

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Agriculture 5.0 in 2050 in Germany

In 2018, there were about 16.6 million hectares of agricultural land. In the year 2050, approx. 2-4 million hectares will be used for solar parks. These generate approx. 2,000 to 4,000 TWh of electrical energy per year. Together with wind, hydropower, electricity storage and intelligent grids, the entire cross-sector energy demand is covered cost-effectively and more than adequately. Electricity generation and storage are carried out as locally as possible. Expenditure on electricity thus remains in the region. Huge power lines are superfluous.

In greenhouses, also on many roofs, vegetables and herbs thrive. If you don’t have a green thumb, farmbots can help you with your work.

Most of the food is produced in bioreactors. This is an old idea of NASA for the supply on long space flights, rethought on the spaceship earth. Bacteria shorten the carbon cycle and produce carbohydrates, proteins and fats directly from CO2. Food technologists supplement this with micronutrients and bring it into edible, appetising forms. The Bavarian radio station explains very clearly what this could look like.

The remaining area of 12-14 million hectares is managed extensively and sustainably with agroforestry systems, afforested or converted into nature parks. Who would like to have more on the plate, has a fishing and or hunting licence. Edible wild plants are abundant in the forest.

This is how it could look in 2050, if we gradually and constructively deal with the diverse demands of nature and species conservation, the energy transition, the consequences of climate change and a growing world population.

The projects Energy Transition, Agricultural Transition, Nature Conservation and thus the preservation of a biosphere worth living in confront the entire human race with an enormous challenge. It is certainly a worthwhile endeavour.


My thoughts may seem hard to digest at first glance. There is no question that we need a paradigm shift in many areas of our lives. Preserving the biosphere in such a way that all of today’s inhabitants of the earth can live well in it will not exist without changes in our way of life.

To produce food directly from bacteria, without detouring through plant cultivation and animal husbandry. This seems more reasonable than optimising old ideas and procedures and is actually nothing special. Beer and wine are already produced today with the help of bacteria in bioreactors. Food and bacteria have always had a very close relationship. They have always been bacteria that both produce and digest food:

  • Soil bacteria make nutrients available to plants
  • In photosynthesis, it is also bacteria that convert light into energy. Chloroplasts were once free-living phototrophic bacteria that now live inside plant cells
  • At the end of the food chain there are bacteria. This time in the digestive tract and in the body cells. Mitochondria provide energy there
  • Mitochondria were also once free-living bacteria, which now live in all body cells. (For information: Chloroplasts and mitochondria are so-called endosymbionts)

Photovoltaics is more efficient than photosynthesis in generating energy from sunlight. Bioreactors provide the bulk of food. This means less land and no monocultures on the field, or mass animal farming.

The maltreated nature (soils, plants and animals) will be grateful and can recover. We use the space freed up for solar parks and for agroforestry systems, afforestation, nature parks. This would additionally reduce the CO2 concentration of the air.

It could therefore be a good strategy in several respects to generate electricity in solar parks and food with bacteria in bioreactors.:

  • In the future, extreme weather conditions will make agriculture more expensive, riskier and sometimes impossible. Bioreactors, greenhouses and indoor farming are used to ensure the safety of the food supply in all weather conditions..
  • Agroforestry systems and afforestation reduce the CO2 content in the atmosphere. Flora and fauna recover and offer ecosystem services forever.
  • Additional benefits: If we deal with climate change in this way, it would be easier to get through if we missed the 2°C target.
  • Last but not least, there would be a secure energy supply from renewable sources.

Further Links

In this context, Stefan Brunnhuber’s books seem to be absolutely right:
In his latest book “Die offene Gesellschaft: Ein Plädoyer für Freiheit und Ordnung im 21. Jahrhundert“(published in February 2019) Stefan Brunnhuber describes how the transition can succeed step by step and with the involvement of the critical public.

In 2016, Brunnhuber already described a way to meet the global challenges as a society in: “The art of transformation, how we learn to change the world“.

The director of the Wuppertal Institute, Prof. Dr. Uwe Schneidewind, on WDR’s philosophical radio, is also worth listening to the question: What possibilities are there to deal with the seemingly unsolvable problems of the ecological crisis – and to make the process as meaningful as possible?

The Deutschlandfunk reports in “Forschung aktuell” from 06.05.2019 in a radio report about the UN report on global biodiversity, as well as about the topic of agricultural photovoltaics. Click here to go directly to the podcast.

With the “Barometer of the Energy Transition“, the Fraunhofer IEE annually evaluates the state of the German energy transition. The indicators selected for this purpose describe the energy system in its various technical dimensions: end energy, wind energy, photovoltaics, balancing power systems, bioenergy, power-to-gas, batteries, heating sector, mobility sector and investment activity.

On the basis of the actual values from December of the previous year, scenario modelling is used to calculate target values for 2050 and to identify target paths that will enable the energy system to be transformed into a 100% renewable energy supply.

The Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) does research on methanol production from CO2. The project is called innovative cascade processes for the conversion of CO2 into fuels and chemicals.

Climate change represents an existential, global threat to humanity, yet its delocalized nature complicates climate action. Here, the authors propose retrofitting air conditioning units as integrated, scalable, and renewable-powered devices capable of decentralized CO2 conversion and energy democratization. Crowd Oil – not Crude Oil

Deutschlandfunk reported on CO2 recycling on June 4, 2019. Production of fuels with the help of bacteria. BASF has recognized the potential of Lanzatech, the company mentioned in the article. At the other company mentioned, Electrochaea GmbH, bacteria are also working on the same topic.

Facts and figures on agriculture from the Federal Ministry of Food and Agriculture

Current Facts on Photovoltaics in Germany from Fraunhofer ISE, March 18, 2019

This study by the Research Centre for Energy Networks and Energy Storage (FENES) at the East Bavarian Technical University Regensburg (OTH Regensburg) from 2016 offers a look beyond the horizon:
METASTUDY, Analysis of cross-sector studies on the decarbonisation of the German energy system, On behalf of the Deutsche Energie-Agentur GmbH„.

Author’s note: In 2016, the authors of this study may not have been able to foresee that solar power plants in Germany can already be operated profitably today with electricity sales prices of 4-6 cents / kWh and that agriculture with farm robots can be possible in 5-10 years under, between and alongside the installed module.

Why we are morally obliged to help when someone’s existence is threatened, read and listen to the two political philosophers Christian Neuhäuser and Arnd Pollmann in a report of Deutschlandfunk Kultur from 05.05.2019.

In many situations in life, however, the question of a duty to help is more complicated than in philosophical model cases. What happens when we hear about need and injustice elsewhere? How far does each individual’s personal responsibility go? How does it measure itself, and how high does the common good rank in relation to individual claims and rights? Should this moral duty be extended to every kind of existence – including the biosphere? I say: Yes!

About the author

Ralf Schnitzler was born in Düren, Germany, in 1961, grew up in the Eifel, lives and works in Cologne. He first came into contact with the world of renewable energies in 1982, when he built a biogas plant during his training as a farmer. As team leader Germany for photovoltaic free-field projects, he was active at juwi solar from 2009 to 2012. In addition to his current position as a project developer for solar parks at Bejulo GmbH, he is also a dancer, triathlete, golf player, farmer, graduate agricultural engineer, body philosopher, father of 4 children aged 25-30, etc.

The views and opinions expressed in this article are the author’s own, and do not necessarily reflect those held by pv magazine.

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