'Solar Sharing' Might Bring Extra Income to Farmers
Multi-profit-type business stemming from solar sharing
Setting up solar panels over a field of strawberries and Japanese apricots, and sharing the sun between farming and power generation. Such a concept of “solar sharing” is attracting attention as a measure to energize farming and offer new possibilities for “mega-solar” large-scale solar power plants. Amid such circumstances, Renaissance Eco Farm, an agricultural company that developed a system to install solar panels over farmland while ensuring the amount of solar irradiation needed to grow crops, started selling electricity generated on its farmland in Hofu City, Yamaguchi (Fig. 1). Kyudenko, which markets this system, constructed the facility, and another solar sharing approach has been launched above the adjoining farm housing free-range chickens.
Solar sharing changes the existing business model of farming families, which tend to face difficulties to continue farming with just the proceeds from farm products, into a multi-profit-type business model by adding the electricity business leveraging the feed-in tariff (FIT) scheme. Farming families are expecting solar sharing to become a framework to strengthen motivation for farming.
“In the case of a general farm family, sales of electricity are expected to reach seven to eight times the sales acquired from crop harvests," said Masatoshi Motomatsu, executive board member and manager of the Renewable Energy Department in the Sales Division at Kyudenko, which sells and constructs “Solar Sharing System KR,” a solar power generation system developed by Renaissance Eco Farm for solar sharing using farmland and mountain forests. This indicates the possibility that solar sharing could facilitate the reopening of idled plots and improvement in food self-sufficiency. As for problems in operation, which are considered difficult for farming families to handle, Kyudenko will provide support from about 120 regional offices.
Sun shared by farming and power generation
The power generation system used for solar sharing can be characterized by solar panels that are set over the farmland while ensuring the amount of solar irradiation needed to grow crops. The solar panels are laid out in intervals so the field beneath can receive sunlight. The size of this interval is arranged in accordance with the properties of the crops being raised.
As the sun moves from sunrise to sunset, the crops either get plenty of sun or little sun in the shade of the solar panels under changing circumstances. For this reason, varieties that do not require much sun are best suited as crops to be raised under the system. Strawberries, lettuce and citrus are such suitable crops. Even rice could be raised depending on the power generation system design. In other words, the basic concept of solar sharing is that it uses the irradiation that exceeds what the crops beneath the solar panels need to generate power.
A notice issued by the Ministry of Agriculture, Forestry and Fisheries (MAFF) in March 2013 enabled the actual practice of solar sharing. On the condition that crop harvests are reduced by no more than 20% compared with the preceding year, among other conditions, it allows the registration of land zoned for agricultural use to be converted to land zoned for hybrid use only under the posts of the solar panel mounting systems installed on the farmland. The beneficiaries are also subject to submitting a farming program indicating expected crop harvests, etc and reporting on the results of the program.
Before this notice, land owners had to apply for the conversion of the registered land category for all of the farmland on which solar panels would be installed. Conversion from land zoned for agricultural use was rarely approved. And even if the application was approved, problems would come up in terms of farming as the land category was converted from land zoned for agricultural use to land zoned for hybrid use. As a result, solar sharing has been considered difficult to realize.
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Power generation amounts exceed estimates
A power generation facility set up in accordance with this notice can be found in the orchard of Renaissance Eco Farm. It is located in a deforested area in Migita, Hofu City, Yamaguchi. Solar panels are mounted on the pergola-like mounting systems with intervals so that the Japanese apricot trees, basil and strawberries beneath can get sun (Fig. 2).
Its maximum output is 250kW, and all the generated electricity is sold at a fixed tariff of ¥42 (approx US$0.43) per kWh. Power sales of about ¥10 million are projected for the first year. The total construction cost was approximately ¥80 million.
The employed solar panel is a polycrystalline silicon solar cell manufactured by Hanwha SolarOne of Korea. A total of 880 solar panels with 258W of maximum output are used to produce 250.8kW in total. The PV inverter is a product of Yasukawa Electric. The plant started selling electricity June 12, 2013, and has since generated more power than expected.
It is said that there are concerns about safety when simple tube style members are used to assemble mounting systems for a solar sharing approach. In Renaissance Eco Farm’s orchard, however, the mounting system has a robust structure using H-shaped steel for the 3.3m post, with X-shaped reinforcing members added to some of the spaces between posts (Fig. 3). Kyudenko stressed, “We designed it, assuming an instantaneous wind velocity of 36m, since this is a power generation facility after all.”
The X-shaped reinforcing members need to be set in consideration of the position and direction of their layout depending on the crops being raised and the size of the farmland. This is because, for example, they could block tractor routes and other farm equipment when implementing agricultural work.
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Farming families’ fundraising ability, administrative discretion hold key to future development
The future development of solar sharing depends on the fundraising ability of farming families and the discretion of MAFF and other public administrators.
Regarding fundraising, it is easy to estimate power sales generated by the system to be introduced. But it is difficult to predict the agricultural part, which can easily be affected by changes in the weather and the fact that land zoned for agricultural use is difficult to put up for collateral. And it leads to the concern that loans by financial institutions may be hard to come by.
According to Kyudenko, it costs ¥350,000 to 400,000 per kW as an initial investment with solar sharing whereas the cost is only about ¥280,000 per kW for a general large-scale solar power plant. This can be attributed to the cost of the basic construction to erect posts on the typically soft ground of farmland, the cost of the mounting systems to set solar panels at a height of about 4m and the increasingly expensive cost of connecting isolated farmland to the power grid.
Compared with general large-scale solar power plants, which are planned to collect the initial investment over seven to eight years, solar sharing is said to need 14 to 15 years to recoup its costs. Furthermore, if the mounting system was established as a structure in compliance with the Building Standards Act, it would require more cost to meet earthquake resistance standards and other criteria.
In terms of administrative discretion, there is also the challenge of public administrative bodies possibly being reluctant to permit the conversion of land zoned for agricultural use. This point is, however, expected to change due to crop results and other factors in the future.
Application to free-range chicken farm
Renaissance Eco Farm is also operating a solar sharing system combining a free-range chicken farm and solar power generation on an adjoining site (Fig. 4).
Under the C-shaped roof-mounted solar panels is a poultry farm surrounded by chicken wire, with the birds roaming freely. This system’s maximum output is 9.9kW. Given the fact that chickens are being kept inside, the foundation was built high enough to prevent attacks from animals such as weasels.
Inside the farm can be found hens that are about to stop producing eggs, which were bought at a cost of about ¥1,000 each (Fig. 5). Renaissance Eco Farm aims for the effective use of organic waste by using the food waste disposed of at its noodle restaurant as chicken feed.
The hens started to produce eggs again after being transferred to this free-range farm, probably because of the unconstrained environment there. With the value added as being eggs from free-range chickens, the eggs are sold at about ¥30 each.