Special

1st Project Finance for Agricultural Mega Solar Plant Revitalizes Idle Farmland (1) (page 3)

3 former prime ministers gather at mecca of solar sharing

2017/11/20 19:28
Kenji Kaneko, Nikkei BP Intelligence Group, CleanTech Institute
Print Page

Crops grow with no problem if shading rate is 30%

It was reportedly the first project financing intended for an agricultural mega solar plant in Japan. The project cost was about 300 million yen (approx US$2.68 million). Shimin Energy Chiba invested 20 million yen, the Johnan Shinkin Bank provided 220 million yen through project financing and SBI Energy provided 40 million yen through underwriting of the bonds.

"We have grown crops including soybeans under the panels of the solar sharing power plants that we operate and that are connected to low-voltage transmission lines, and the panels have not affected the crop yields," said Mitsuhiro Higashi, who represents Shimin Energy Chiba. "Crops sometimes grow even better in shade."

Each crop has a "light saturation point," and the amount of photosynthesis does not increase further even if the crops are subjected to sunlight exceeding a certain level. It is known that crops of any kind grow without a problem if the shading rate is 34% or less, Higashi said.

Solar sharing projects under the temporary cropland conversion system are renewed every three years if the decline in the crop yield ratio due to shade generated by panels is within 20%. There are some solar sharing projects whose shading rate is much higher than 30% due to the policy to place priority on the power generation business. The agricultural mega solar plant in Sosa City places priority on farming, and the shading rate is reduced to 30%. Therefore, it is estimated that the plant will easily satisfy the criteria.

When I visited Sosa City in mid-September 2017, soybean seedlings were growing steadily under the panels and the pods were beginning to increase in size (Fig. 5, 6 & 7).

Fig. 5: Project financing was formed for the first time for an agricultural solar power plant. (source: Nikkei BP)

Fig. 6: Soybeans are growing steadily under the panels. (source: Nikkei BP)

Fig. 7: The shading rate was reduced to 30%. (source: Nikkei BP)

"The soybeans are not at all inferior to soybeans in fields without panels," said Shigeo Tsubaki, who represents Sosa Solar Sharing GK and is also an executive member of Shimin Energy Chiba. "There is no problem in the productivity of the agricultural work either, when compared to general fields."

He explained that tractors can be used with almost no problems if the height of the mounting systems is set at 2.5 to 3m and the distance between supporting posts is set at 4 to 5m.

Go to next page