Agri-photovoltaics is considered a promising solution for the expansion of renewable energies, even in areas heavily used for agriculture. Because it combines solar energy and agriculture on the same area. However, agri-PV will only become established if this dual use is also economical. Two experts explain in an interview whether this is the case and what factors determine it.
Solar systems and agriculture do not have to be competitors for land, because with agricultural photovoltaics, fields, gardens or orchards can be used twice. Theoretically, such systems could even cover our country’s entire electricity needs with solar systems integrated into arable land, orchards or vineyards. But agricultural photovoltaics is still in its early stages; there are only a few pilot systems in Germany so far.
In an interview, two experts from the Research Center Jülich explain to us why this is, what prospects agricultural photovoltaics has in Germany and what is important. Dr. Matthias Meier-Grüll works at the Institute of Life and Geosciences and Chantal Kierdorf works at the Institute of Climate and Energy Systems.
What is Agri-PV – and why is it more than just electricity from the fields?
Matthias Meier-Grüll: Agri-photovoltaics – Agri-PV for short – combines solar energy and agriculture on the same area. The solar modules are positioned in such a way that further agriculture is possible underneath or in between – for example arable farming or fruit and vegetable cultivation. The space is not lost, but is used twice. In times of climate change, the energy crisis and increasing space shortages, this is a decisive advantage.
Depending on the design, the systems can even provide additional benefits: They provide shade, protect against hail or heavy rain, collect valuable rainwater, can help retain water in the soil and promote biodiversity. At the same time, clean electricity is generated directly in the region. Many people are therefore more likely to accept Agri-PV in contrast to classic open-space systems, where agricultural use is completely eliminated.
A current study by the Thünen Institute comes to the conclusion that Agri-PV is significantly more expensive than classic ground-mounted photovoltaic systems. What does this study say – and what does it not say?
Chantal Kierdorf: The study compares the costs of various agricultural PV systems with classic ground-mounted photovoltaic systems. To do this, they compare the so-called levelized cost of energy, or LCOE for short. This is a technical term for the average cost per kilowatt hour generated over the entire lifespan of a system.
The authors come to the conclusion that agri-PV systems are currently between 4 and 148 percent more expensive than conventional ground-mounted PV systems – a range that shows that costs can vary greatly depending on the system, location and design. They also come to the conclusion that the costs for maintaining the agricultural area under the Agri-PV system amount to 8,000 to 75,000 euros per hectare – also a wide range – which cannot be covered by the agricultural yield.
What is important, however, is that the study does not examine whether specific agri-PV projects are economically viable or worthwhile for agricultural businesses. It compares agri-PV with ground-mounted PV based on certain assumptions and cost assumptions from 2023. Already today, 3 years later, one can assume that cost reductions due to lower prices will change this picture. In addition, Agri-PV is technologically much younger than classic ground-mounted PV, which has been optimized over many years. This should also be taken into account when classifying.
Agri-PV is often discussed primarily in terms of electricity costs. What other factors are relevant?
Chantal Kierdorf: Electricity production costs are there to compare the costs of different energy sources. This makes sense, but it falls short when it comes to Agri-PV because important additional benefits are not taken into account. A crucial point is that the agricultural area is preserved and can continue to contribute to the regional food supply. This strengthens security of supply and regional added value – beyond specific harvest yields.
There are also operational and systemic synergies. Depending on the design, an agri-PV system can generate electricity more evenly throughout the day – not just at midday, but also more strongly in the morning and afternoon. This relieves the load on the power grid and makes feed-in easier to plan. At the same time, partial shading can reduce water consumption and relieve pressure on plants during hot periods. On farms, the electricity generated can also be used directly or in combination with storage. This can have a significant impact on the economic viability of a project.
Regulatory framework conditions also play a role. In contrast to classic open-space systems, with Agri-PV the status of the area as agricultural land is retained. This can enable tax advantages or certain compensation payments. The potential additional benefits are of course highly dependent on the location and the project, but influence the actual economic evaluation – this is not taken into account in pure electricity cost comparisons.
Of course, the price per kilowatt hour remains an important benchmark. However, if we want to assess agri-PV, we must take into account that it can vary significantly depending on the system, location and marketing. For a comprehensive assessment, the additional effects should therefore be taken into account – for agriculture, the energy system and regional development.
What does Agri-PV need now to make it better and cheaper faster?
Matthias Meier-Grüll: In order for Agri-PV to become cheaper more quickly, one thing is needed above all: more practice. We know this effect from classic photovoltaics. The more systems are built, the more costs fall – because processes are standardized, technology is improved and experience is gained. This market ramp-up is still in its early stages for Agri-PV.
This requires targeted support during a transition phase. According to calculations by the Association for Sustainable Agri-PV, Agri-PV would only require a comparatively small share of the funds set aside in the Renewable Energy Sources Act – EEG for short – to promote renewable electricity generation. In Germany, the EEG regulates, among other things, how electricity from renewable sources is paid for. Compared to other funding areas, the need for Agri-PV would be manageable.
At the same time, we as researchers have a responsibility: We have to provide scientific support to commercial projects in order to better understand which plants work particularly well with which photovoltaic systems. Initial results already show that certain combinations can improve both electricity yields and agricultural yields. The modules change the microclimate beneath them – they provide shade, reduce water evaporation and can relieve plants during heat periods. In order to reliably evaluate such effects, we need more practical projects in different regions and with different cultures. At the same time, we need to better understand the underlying biological processes – such as photosynthesis, i.e. the conversion of light into plant energy.
With this knowledge and cleverly designed funding, Agri-PV can become a stable form of multiple use of land in the long term – for energy production and agriculture alike.
Source: Research Center Jülich