Solar sharing with agriculture
Vishnu Mohan | 23 Apr 2014

Farmers in Japan can now generate solar electricity while growing crops on the same farmland. The previous laws prohibiting solar generation on farmland has been suitably amended to pave the way for installation of PV systems on existing crop producing farmland in Japan.

-          This co-existence or double generation is known as “Solar Sharing” in Japan. 
What gets nicely transpired through a research done by a retired agricultural machinery Engineer, is the fact that any excess of sun light beyond a point is of no use for existing plants.  In other words, the rate of photosynthesis increases as the irradiance level is increased; however at one point any further increase in the amount of light for the plant does not cause any increase in the rate of photosynthesis.  This aspect literally brought the need to also combine PV systems with farming. 

-          Creation of a couple of testing fields with different shading rates with different crops was tested out by this Engineer.  The structures he created are made of pipes and rows of PV panels, which are arranged with certain intervals to allow enough sunlight to hit the ground for photosynthesis.

-          Based on the tests conducted at his solar testing sites in Chiba Prefecture, the Engineer recommends about 32% shading rate for a farmland space to reach adequate growth for crops.  In other words, there is twice as much empty space for each PV module installed.

-          Farmers can now look forward to enhanced income by combining agriculture with solar.

-          Some questions were raised regarding the stability and durability of the PV structure for solar shared family.  The Engineer stated that his systems, which are made of thin pipes without concrete footings, even withstood strong winds and earthquakes during the Fukushima Tsunami disasters in 2011.  These systems are extremely lightweight and installation of PV panels is spaced out, allowing air to flow through between the panels.  This will eliminate concern that the panels will receive wind load and be blown away, therefore, reducing the need for complicated and expensive mounting hardware.

-          The Engineer has also suggested that solar shared farming for ranches in the U.S. He stated that a few benefits of PV systems over grass on pasture: the PV system can provide shade for cattle or sheep to rest underneath and because of higher soil moisture level, the shading will reduce irrigation expenses.

-          The Engineer believes that solar-shared farming makes again for farmers to provide two important products from nature and will revitalize the farming sector.

Concerned people can do well to debate the above issue for bringing such technology to Indian agriculture scenario as well.

Going by the above, a pilot project can be planned in India and depending on its success; introduction of the above mentioned models can then be made feasible in different parts of the country.  If Indian agricultural farmers are getting scope to enhancing their earning potential by not only producing food for the masses but also producing electricity, then their status as true heroes of the country will be strengthened further.