The number of solar panels in use will keep growing for decades. Some will be on trains, ships, planes and integral with road surfaces. Probably most will be installed on rooftops and in deserts where they are not in competition with other land uses. A lot will be on farmland, where they can detract from agricultural production. Currently in the UK they tend to combine solar and livestock, often with the added goal of increasing biodiversity. Another possibility is to grow fruit, vegetables or arable crops in association with the panels. The Fraunhofer Institute have been running a trial on a third of a hectare plot at Heggelbach near Lake Constance, growing a variety of crops under the solar panels. The panels are more widely spaced than usual to allow sufficient light to reach the crops, and high enough for a combine harvester to work under them. The combined solar and agricultural productivity of the land should allow increased income for farmers. Other trials have taken place in USA, India and Japan. The Japanese project is growing 40 tons of cloud-ear mushrooms per year under a 4MW solar installation, which I would think must be one of the most productive dual uses of land anywhere and produce a good income for the farmer.
It seems to me that the best place to combine solar panels and agriculture is in the hot arid tropics where the shading is likely to help plant growth and reduce transpiration. The vegetation may also help keep the panels from overheating and so aid the efficiency of the solar panels. Doing a web search I’ve only come across a couple of small trial projects in India and USA. I’m sure other projects exist. They ought to. The potential benefits are huge. I would really like to see a large scale project doing both electricity and food production at a commercial scale, and doing proper scientific evaluation. The solar power might in part be used to drive irrigation, perhaps from solar desalinated seawater. The steel structure supporting the solar panels could also be used to hang shade netting, horticultural fleece or be integral to glass or plastic greenhouses, all of which could help increase crop production while reducing water use. Pioneering projects that I’ve blogged about in Somalia and Jordan could be expanded to incorporate solar panels directly over cropping areas. I think this may be one of the most beneficial technological combinations in the fight for food, energy and climate security. If anyone reading this blog knows of such projects perhaps they would send me a link. Thanks.