The trouble with renewable energy sources is they use up land!
And lots of it!
If we look upon solar as a competitor to other land uses, this might lead to a new unfortunate round of food vs. fuel debate. But if we combine the obvious benefits of solar energy with other land uses, farmers and communities might benefit in multiple ways
One form of multiple land use is in pollinator-friendly projects. Here, we couple solar panels with perennial grasses and wildflowers, which provide habitat for pollinators.
This can build soil health, improve local water quality, and boost agricultural yields of nearby pollinator-dependent crops thanks to the increased abundance of native pollinators. This may well serve to reduce opposition to solar projects.
Even the economics of the project may benefit. Pollinator-friendly areas need less maintenance, and lower ambient temperatures may result in higher solar panel efficiencies.
Land underneath solar panels can also be used for sheep grazing. This will reduce mowing to just once a year
We can construct the panels somewhat higher above ground and at a larger distance apart. This increases opportunities for multiple land use.
Irradiation and rainfall will better reach the soil; this will promote biodiversity, all the more so if the land underneath the panels is not fertilized. In peat meadow areas, harvesting solar energy could go hand in hand with nature conservation
On water, floating panels might be double-sided: capturing light both from above and from the reflection on the water
In Germany the Fraunhofer Institute mounted bifacial solar modules for electricity production with some extra distance, 5 metres above the land, which allows tractors to pass underneath.
The agrophotovoltaic system proved suitable for the practice and costs as much as a small solar roof system. The crop production is sufficiently high and can be profitably sold on the market. Among the first crops tested were winter wheat, potatoes, celeriac and clover grass
Multiple land use will increase profits and enhance nature
As a rule of thumb, we can put the solar energy harvested in such projects (with panels spaced somewhat apart) at 80% of the maximum yield. But they may be double-faced and then also collect light reflected from the soil. We can also put the agricultural yield at 80% of the maximum yield, as some light is being captured by the solar panels. The sum of these two exceeds 100%, meaning that multiple land use will be economically viable
How will nature develop in a solar park where the panels are somewhat spaced apart? Can we treat the area in such a way that it can be turned into a natural area in 15 years’ time? While having had a profitable function in the meantime?
We need to allow ourselves time to develop optimal solutions but it is an exciting development in thinking about future solar farms
Are you a fan of large solar farms?