Innovative German organic fruit grower Christian Nachtwey produces apples and electricity on the same plot of land, beneath nearly one hectare of solar panels, while simultaneously reducing his carbon footprint and making economic gains.

His apple harvest is largely delivering high-quality yields while the solar panels can generate up to 258 kilowatts of energy under ideal conditions – enough to potentially power 60 households in the surrounding area.

Less fungicide is being applied, and running, investment, and waste management costs have declined on site since 2021, when the system was constructed as part of a unique, research-backed, government-funded, carbon-neutral fruit-growing project.

However, the big question now looming at Nachtwey – a second-generation 65ha farm located in the intensive fruit-growing region of Graftschaft along the south-western edge of Rhineland in the district of Ahrweiler, which Christian operates with his parents, Johannes and Martina – is this: “What happens when the curtains fall on the pilot project?”.

To help avoid negative impacts of climate change – such as rising temperatures, changes in precipitation distribution, and increasingly frequent weather events such as hail and heavy rain – on orcharding in Germany, the Fraunhofer Research Institute for Solar Energy Systems, manufacturer BayWa, together with the German Ministry of Environment, Energy, Food, and Forestry, and Federal Ministry of Food and Agriculture, established the country’s first agri-photovoltaic (agri-PV) system for apples at Nachtwey organic fruit farm.

Five-year plan

The project was launched on a five-year plan.

Another important goal is to counteract land use competition between ground-mounted solar systems and agriculture within the farm sector.

Speaking to the Irish Farmers Journal during a farm visit organised by the European Network of Agricultural Journalists (ENAJ) last September, Christian – whose family is widely known for their commitment to aligning farm practices towards a sustainable future – recounted his experience and thoughts on their next steps.

“The basic idea behind the project is to test the use of solar panels to secure the surface underneath. Solar panels are now that cheap in Germany that it gives growers a real opportunity to use the panel surface in a different way.

“Here we try to protect the apples against sunburn, hail, water, and rain because rain will lead to fungi and, therefore, to apple scab. This is a problem for the region as you can see from this year’s apples and we also have some sunburn issues.

“To try to minimise these problems we need to innovate as farmers to secure our installations to make sure that we have a good possibility to produce apples on the same land as we create solar energy.

“We do not want to have apples and solar panels 100% on separate pieces of land because we are not capitalists. We are dealing with nature, so there will always be a little bit of reduction that we have to deal with.

“This system clearly demonstrates that we can produce normal apples while also producing electricity and have the cover that is needed to secure the harvest,” he said.

In Germany there are two different categories when it comes to agri-PV, for lower and higher installations. Nachtwey’s system is category one which means the edges of the panels must be at least two metres and 10cm above the soil surface.

“In my opinion, it makes even more sense if it is higher above the apple trees, let’s say roughly three, or three and a half, metres to protect the trees, leaves, and apples – or gooseberries, raspberries, or cherries – from harmful weather conditions,” he said.

Practical requirements

The panel design is adapted to the practical requirements of the commercial farm– which also employs 10 permanent and 25 seasonal workers. The canopy provided by the panels is designed to replace protective structures traditionally used in fruit growing, such as hail nets, which are still used to protect other apples in Nachtwey’s traditional-style orchard positioned beside the agri-PV plot.

While up to 22 varieties of apples are grown on the cultivated area at Nachtwey’s (comprising of 80% of total production), eight varieties of apples have been tested under the agri-PV system including Elstar, Pinova, Topaz, Gala, Natyra, and Braeburn all of which appear to perform well, says the entrepreneur.

The Nachtweys sell their fruit mainly through the Landgard Co-operative in Bornheim-Roisdorf; plus to resellers, and through a small farm shop where apples are sold at €3/kg.

While no difference in taste can be detected between the apples grown in the traditional and solar orchards, when asked about the cost comparison between the systems, Christian said: “For agri-PV it’s about €800,000 per hectare, so that is very expensive. It costs €25-30,000 per hectare for a normal hail net system.

“That is a huge difference, but the hail net will only protect against sunburn and hail, not against rain.”

The renewable energy generated above the apple orchard is directly connected to an on-site “trafo-station” (transformer station), considered a vital piece of grid infrastructure to convert and manage the green electricity currently supplied back into the grid by the Nachtweys, and used on their fields.

In addition to public grid supply, in the future the family intends to use their green energy for electrified agricultural machinery, to operate sprinkler irrigation systems to mitigate disease risk, and for electrically-operated cold storage for the apple harvest.

“The trafo-station is an infrastructure that farmers in this region will definitely need in future times to reduce the amount of fossil fuels in the system,” he said.

Irrigation

Expanding on the benefits, Christian added: “Because the panels are at the surface, in our case they are two square meters big, we have a dripping edge on the lower edge of the panels.

So we collect water for periods when there is less water, like in summer, to reach the tree roots. “Because of our irrigation system the leaves also stay dry, so we have reduced problem with fungi, which means we apply less fungicides.

“And we have less frost near the blossom in spring because the cover gives a slightly higher temperature.

“Technically, it’s still a normal orchard with a row where we can drive the tractor to collect the apples, every apple is picked by hand. “So for increasing climate resilience in fruit growing, this is a brilliant, brilliant solution, really,” he said.

Christian believes other farmers in the deep-soil region – which experiences around 2,000 hours of sunshine per year, and about 600mm of rainfall – will need to invest in such developments in the future.

“This system must be driven by farmers because farmers will always focus on the trees first, and the electricity second.

As farmers we want to make sure that the land belonging to us is usable for decades to come.

Hopefully we will be able to set up such a construction ourselves when the project ends but this will depend on government support.

At the moment we have the possibility to do further research for two more years because more is needed for this kind of system.

“To attract others I believe we need 9.5 cent per kilowatt hour from the German government to set up such constructions. We are dealing with so many weather problems that we must make sure our farmers are still enthusiastic to go on.

"Therefore, we need clear, consistently available finance to get support from the banks. If we can sell into the grid at such a tariff then I see a good way to make family-owned farm businesses in this region more resilient.”

The major advantage of farmers participating in research-driven agricultural projects is achieving real and sustainable on-farm solutions.

The challenge, however, is that successful projects often come to an end after just five years, leaving producers asking: ‘what now?’.

That is a key message from organic fruit farmer Christian Nachtwey who is cultivating apples directly beneath solar panels at his 65ha holding situated in Graftschaft, at the south-western edge of Rhineland within district of Ahrweiler, Germany, as part of a novel government-funded, carbon-neutral, fruit growing research project due to officially run its course later this year.

Christian, whose family have earned a reputation for pioneering environmentally responsible farming methods – from building an irrigation reservoir in 1995, to converting to organic in the early 2000s, to installing their first roof-top solar system in 2008, to building a biodiversity orchard in 2012 – says future agri-research projects demand “thinking in decades, not years” to realistically meet increasing needs.

Speaking to journalists during an ENAJ visit to his farm, he said: “Nowadays, a project timeslot is normally five to six years, then the curtain falls – that is nothing in farming.

“If I plant a tree today I must make sure I will have up to 20 or 25 years of apples from that tree.

“If you ask a non-farmer what their business will look like in 20-25 years they will feel insecure.

“But we as farmers have to make decisions like that every day, and that is the difference between industry-thinking and family-owned businesses in agriculture.

“I want to be able to look back in 25 years and say ‘yes, that was a good decision’ because now I have an electric tractor or AI mowers, or whatever I need to sustain my farm.

“Policymakers must recognise that 20-25 years is the minimum amount of time we need as a baseline for all on-farm decision-making because otherwise we are not making serious decisions.”