- 60%: The increase in land efficiency possible with elevated agrovoltaic systems
- 250 MWh: the electricity generated annually from a 194 kilowatt voltaic array
- 20%: the average reduction in crop yield from a field under a voltaic array
Agrovoltaics (or agrophotovoltaics) is not a wholly new concept, but it is one that is about to experience a resurgence. First developed in 1981 by Adolf Goetzberger and Armin Zastrow, agrovoltaics is a technique of using the same land for both agricultural purposes and for the generation of solar energy. Normally, land can only be used for one purpose at a time. Either land is used for an array of solar panels that generate energy, or land is used to grow crops. Normally a landowner or farmer would need to make a choice as to which one to use their land for, but with agrovoltaics they are essentially able to do both.
There are three different agrovoltaic methods that can be used. One method is to have the solar arrays on the ground, placed a distance apart so that crops can be grown in the space between them. Another method is for the solar arrays to be mounted on stilts, with the crops then growing beneath the panels. The last method is a greenhouse solar array, where the panels are placed on the roof of a greenhouse.
A pilot project by the Fraunhofer Institute for Solar Energy Systems is testing an elevated solar array system over a one-third hectare section of cropland in Germany. The study has placed a 194-watt solar array at a height of five metres above the field. This height meant that farm equipment was able to operate beneath them with no problems. The solar panels used are bifacial PV modules that catch both rays from above the refracted rays from below. Underneath they are growing potatoes, clover, celery and wheat. The study is scheduled to last three years, and the first results of crop yields and energy generation have just been revealed.
Land use efficiency increased by 60%
In comparison to a control field that didn’t have a solar array, the yield was lower for each crop, with wheat, potatoes and celery all yielding somewhere in the region of 18% and 19% less. Clover fared much better, yielding just 5% less than the control. The electricity generated by the array was considerable. In the first year it produced almost 250 MWh of electricity. The lower crop yield was more than made up for by the electricity generation, which was able to provide 40% of the test farm’s needs.
The use of this agrovoltaic method increases the land efficiency by more than 60%. For example, if instead of using one hectare of land for solar and one hectare for crops you use a solar array across the two hectares, the results are an overall increase in efficiency.
Fraunhofer’s goal is to make this type of technology market ready and for a variety of applications. The initial results are promising, and it seems like the agrovoltaic technique could be used on for large scale agricultural and energy needs.
There are other smaller scale examples of agrovoltaics, such as the Japanese farmers growing mushrooms while generating energy, or the successful small-scale farm in Massachusetts growing crops beneath solar panels installed 3m overhead. Agrovoltaics has passed the proof of concept phase, and for densely populated areas or simply for more efficient use of the land, this is a solution that could really take off.
Further Reading: Related Start Ups and Organizations
- Vestas (http://www.vestas.com only global company dedicated entirely to wind energy)
- Sunfloat (http://www.sunfloat.com/home/ mission to give solar systems up to 50% better performance and install them worldwide in unused waters and rivers near urbanised areas.)
- GBM Works (http://www.gbmworks.com/ GBM Works is developing a new silent and cost-effective method for installing windturbine foundations offshore.)
- Desert Control (http://desertcontrol.com/ To cultivate desert into farmland normally takes 7–15 years, but Desert Control found a way to convert sandy soil into fertile land in 7 hours.)
- Windmanufactur (http://www.windmanufactur.com/ small wind turbines (SWT) systems that supply the best price performance ratio and the cheapest total price for everyone and every country’s mass markets.)
- SmartAgri (http://tiino.in/ SmartAgri a Wireless Sensor Network (WSN) based, real-time monitor and control for effective farm irrigation and management of other vital farming resources.)
- Mobile Solarkraftwerke Afrika (http://www.solarcontainer.org mobile solar power plant, they will be the first green and de-central energy provider in Africa to help the environment and people while generating sustainable profit.)
- Lumenaza (https://www.lumenaza.de/ green electricity solutions for individuals, farmers and cooperatives.)
- Ecoligo (www.ecoligo.com Financing platform for solar projects in developing countries)
- Landmapp (http://www.landmapp.net/ affordable land rights documentation to rural communities)
This series of articles has been prepared with the support of our partner Viessmann — they’re celebrating 100 years of their company this year (2017) and are actively involved in positively shaping the next 100 years.