The international landscape of solar farms and agricultural photovoltaics

Rebecca A. Efroymson, environmental scientist, Oak Ridge National Laboratory; Jonathan M. O. Scurlock, Principal adviser on renewable Energy and climate Change, National Farmers' Union of England and Wales.

Solar photovoltaic (PV) power generation is the most popular form of renewable energy on farms and is being adopted around the world. Food growers and processors around the world have a long history of using solar energy to produce and dry crops, and solar photovoltaics are putting a modern spin on our relationship with the sun. Not surprisingly, some of the best places on Earth to harness solar energy are usually ideal for agriculture and gardening.

However, intelligent design of multipurpose land use can mitigate actual or perceived conflicts between energy and food production. Solar panels can shade crops that get more light than they need, reducing water evaporation; ​they can be installed on agricultural buildings to power the energy needs of farm businesses; ​they can export low-carbon electricity to meet the broader demand for "green" electricity and the transition to a "net zero" global economy.

We use the term "agPV" broadly to describe any combination of agricultural activities and solar power generation, but outside the United States, the term generally refers more specifically to the intimate juxtaposition of solar modules and agricultural land use. Examples include photovoltaic modules mounted several metres up to allow agricultural machinery or large livestock access to the land below, where they provide shelter from storms or excessive solar radiation, and the integration of solar photovoltaics into greenhouses to protect crops. Here is a solar cable 16mm.

We interviewed a range of projects on three continents to report on their goals and future prospects.

About 30% of British farmers have rooftop or ground-mounted solar power. The National Farmers' Union (NFU) aims for every farmer and grows to have the opportunity to become a net exporter of low-carbon energy. The falling capital cost of solar and battery power storage has led to a growing number of solar installations of all sizes, including large-scale 100 hectare (ha) and 1,000 hectare solar farm projects, which are mostly independent of government policy support.

The NFU advises farmers that solar PV can be deployed throughout the field as tiny ground-mounted installations around field edges or near farms, farm buildings and roofs of homes. The NFU encourages solar farm developers to follow best practice guidelines for multipurpose land use, combining sustainable agricultural management such as energy production and grazing with wildlife habitat creation. The NFU's strong preference is to place large solar farm developments on lower quality agricultural land, avoiding the use of the most productive and versatile soils wherever possible. Rooftop solar systems in the UK continue to offer a sound investment, with a simple return on capital of 10 to 25 percent a year at current electricity prices, depending on how much generation is used on site. By the end of 2021, about 70% of the UK's 14 gigawatts of solar capacity was located in the agricultural sector.

In the Netherlands, the Symbizon project in Almele, near Amsterdam, has teamed up a Swedish energy company with Dutch researchers and a private organic farm to build a 700-kilowatt solar park with alternating strips of photovoltaic modules and rows of crops. From spring 2023, the production of herbs will be investigated, with potatoes, beans, beetroot, broccoli and grains likely to be included in this pilot study. Rotating two-sided (double-sided) solar modules will capture reflected light from the soil and crops.

Near Germany, Goldbeck Solar is an innovator in solar agricultural photovoltaic structures. The company has developed a solar photovoltaic arch system that slides on side rails, allowing farmers to shelter or expose a variety of crops. ​Normally oriented east to west for maximum solar output, the arches can span up to 9 meters and be 2.5 to 3 meters tall, allowing some control over temperature, humidity and light. These agricultural PV modules can also provide shelter for livestock from extreme weather, such as heat and hail. The modules are currently being trialled in a four-year Sunbiose project in the Netherlands, which has already successfully grown raspberries under the partial shelter of solar photovoltaic modules.

Agricultural photovoltaics are being tested in East Africa, where their shadows can reduce heat stress and water loss, potentially improving farmers' incomes in poor rural communities. In collaboration with the universities of Sheffield, York and Teesside in the UK, the Stockholm Environment Institute, the World Agroforestry, Energy and Energy Conservation Research Centre, and the African Centre for Technology Research, an experimental facility was opened in Ininia, Kenya, in 2022. About 180 photovoltaic modules, each 345 watts, are installed about three metres above the ground, allowing for the growing of a variety of crops in the strong equatorial sun. The Guardian's Jeffrey Camadi reports that the benefits include increased cabbage, eggplant and lettuce production; ​reduce water loss; ​reduce daytime heat and UV damage.

Japan has seen rapid progress in modest-scale agricultural PV development (less than 0.1 ha), with solar generating 0.8% of the country's total solar power in 2019. Japan likely has by far the largest number of agricultural PV farms, with more than 120 species of plants grown on agricultural PV farms. ​The Solar sharing network provides a directory of 27 species of crops (solar sharing FUN | Japan | solar Shared network solar Shared association ( and its lighting needs. Innovative crop systems include tea, according to Makoto Tajima and Tetsunari Lida of the Institute for Sustainable Energy Policy.

An agricultural PV pilot project in New Zealand is looking for low-growing flowering plants like alyssum to attract bees and reflect light onto rows of double-sided PV modules. Irrigation systems with extreme energy requirements can benefit from farm solar power. In New Zealand, as in the United States, Britain and Australia, sheep and other tiny livestock graze under solar panels, avoiding the need for mowing. As New Zealand journalist Delwyn Dickey points out, the success of such large-scale agricultural PV systems (i.e., solar farms) may depend on adherence to dual land use in the consent process and the willingness of solar development companies to adopt dual land use.

​Obviously, from the close integration of solar PV with agricultural production on a tiny scale to the multipurpose land use of the largest solar farms, the advantages of harvesting solar energy twice are appreciated around the world. The future of agricultural photovoltaics is undoubtedly bright.​

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