Photovoltaics and agriculture can benefit from each other

Agriphotovoltaics should make it possible to harvest electricity and food on one field at the same time. The areas under the photovoltaic systems are not lost for food production. Grain, fruit and vegetables continue to grow there. Work is currently underway to reconcile agriculture and the energy transition. Electricity above, straw below: with agriphotovoltaics, electricity generation should no longer compete with food production. So-called ground-mounted systems, where panels are installed on greenfield sites - or even on fields - are viewed critically and meet with resistance.

More than plants with roofs

It sounds simple the Agriphotovoltaik - plants with a solar roof over it - plants are sensitive, Photovoltaik is it also. Essentially it depends on the plant, lettuce, hops and potatoes thrive under the shade of photovoltaic panels better than under the blazing sun, wheat, corn, as well as fruit or berries and the wine rather worse. The solar panels can also benefit from the plants under them. Indeed, at high temperatures, the efficiency of the panels decreases. Especially in hot areas, the plants under the system can cool the electronics. 

The increasing demand for renewable energies leads to increasing competition between agricultural land and areas for solar parks. A lucrative solution would be Agri photovoltaics, which enable double use of agricultural land. Fruit growing, such as apples/pears/cherries or berry crops, arable farming, such as potatoes, asparagus and vegetables in connection with photovoltaics are optimally combined in order to generate solar power and food at the same time.

Profitability of AGRI-PV depends on electricity generation.

Electricity generation is much more crucial to the economic viability of the system than the yields from agricultural production. For example, the Heggelsbach farm community with its AGRI-PV pilot project used about 70 percent of the energy itself, mainly for charging electric vehicles and for the milking and cooling systems. A very high specific yield of over 1,200 kWh per installed kilowatt unit is possible and presentable on average in southern Germany, for example. This makes the agriphotovoltaic system already competitive with smaller rooftop solar systems in terms of electricity production costs, but somewhat more expensive than pure ground-mounted systems. One has to compare the double benefit.

The light intensity or shading and the light homogeneity with the respective edge effects are checked and analyzed. The respective needs of agricultural products and crops are taken into account and summarized. For this purpose, semi-transparent and bifatial solar modules are used with a transparency that is individually adapted to the corresponding agricultural culture. To this end, a large number of initial research projects are currently underway.

The water availability and its use in the Agri-PV system is adapted to the growth conditions of the crops of agricultural cultivation. What is important here is a homogeneous distribution of the rainwater for the crops under the PV system. Additional technical equipment can be advantageous here. In addition, there are always certain areas under an agri-PV system that are not covered or covered by the solar modules.

The ability to dismantle the Agri-PV system will always be guaranteed for the farmer, so that the possibility of agricultural use is retained for agricultural operations and cultivation after the system has been dismantled. Both during construction and dismantling, care is taken to ensure that compaction does not have any damaging or negative effects on the soil. Here special vehicles are used on the mobile routes. Also, when assembling the system outside of the growing season.

There are various substructure systems that allow both temporary and permanent fixation in loose rock and soil. These create a secure subsoil that takes into account all static and stability-relevant aspects during assembly and construction. In any case, the foundation is built in such a way that it can be dismantled without leaving any residue. Ramming or screwing is usually used, based on the respective soil reports.

According to § 35 BauGB, outdoor PV systems are not privileged, ie they are not normally provided for here. Therefore: Building rights on the property must be established via a development plan process, taking into account the regulations of the state development programs, regional development programs and land use plans: Duration usually 12 - 15 months, not inconsiderable costs, restrictions due to area planning, competition in the use of agricultural land. After successful completion of the B-plan process, a building permit must be applied for - and this will be approved.

Permitted in the external area according to § 35 BauGB are, among others, projects which: "serves an agricultural or forestry operation and occupies only a subordinate part of the farm area," "because of its special requirements for the surroundings, because of its adverse effect on the surroundings or because of its special purpose is to be carried out only in the external area,...". The place of construction is bound to the purpose connection to the agricultural area, which already exists and continues to be used at the same time. The connection to the public network and the public traffic areas are already given. It is not an open space solar plant, the plant is to be removed after use. A building permit can be granted, as there is therefore a privilege under building law. No development plan procedure is required to create building law. The facility can be approved directly through building code procedures.

Significant savings due to omission of the B-plan procedure. Considerable time savings in implementation. Better design options for the municipality if the decision is positive in principle. But: basic consideration of public concerns, e.g. landscape and land use plan environmental, soil and nature protection. However: permissibility of projects according to § 35 BauBG para. 1, if projects do not conflict with public interests.