(Japanese article is here.)
On July 6, 2014, I went to Smart Life Power Plant, a newly built solar sharing power plant in the town of Izunokuni, Shizuoka prefecture.
It takes about 3 hours to get there by train from my place in Tsukuba, Ibaraki prefecture. A small one-day trip.
I finally got off at a small station on Izuhakone railway line. The power plant should be 2.3 km from the station, so I decided go on foot. After some 30 minutes of walking, the power plant came into view:
... a bit closer:
Even though I arrived well before the scheduled start of the tour, a small crowd was already there. When you click on the photo to enlarge it, you can see people standing under the panels.
I received materials at the registration desk and went in, and there I could see Mr. Iwahori from Hatsudenman - the company that constructed the plant - already absorbed in conversation with visitors. It's the group in the middle of the picture, standing on the border between rice field and taro potato field.
Afterwards, Mr. Iwahori gave a detailed explanation to all of us and patiently answered our questions.
Mr. Iwahori talking:
Here is an overview of the Smart Life Power Plant.
Size (generation capacity):
Block A 44 kW (“selling capacity”)※1
Block B 44 kW (“selling capacity”)※2
Block C under construction
※１、２：The actual generation capacity is slightly higher, but the amount of electricity to sell to the grid (utility company) is 44 kW. This is what I mean by "selling capacity" (which is most probably not correct expression but I couldn't find anything better.)
Date of grid connection (selling electricity started):
Block A, B July 3, 2014
Block C some time in the future.
Land category: farmland (rice paddy and a [non-rice] field)
Block A, B : rice, taro potatoes (now being grown)
Block C : field wasabi(=hatawasabi) (planned)
Shading rate: 38%
Height from the ground: 3.5 m
1. It's big!
First of all, Smart Life Power Plant is, as a solar sharing power plant, very big. Generation capacity of blocks A, B, C combined is well over 100 kW. It is the largest solar sharing power plant I've seen/heard of so far.
2. It's not dark despite higher shading rate
The shading rate is 38 %, which is somewhat higher than recommended level in solar sharing (up to 32 %), but it didn't feel particularly dark. Obviously this is due to the fact that sunlight comes not only from above, but also from the sides. Rice and taro potatoes under the panels were growing well.
As for myself, I wouldn't raise the shading rate that high, but my frank impression was that the field was surprisingly bright even at shading rate as high as 38%.
Next we just have to wait for the harvest and see whether the yield is lower, and if yes, how much. (Ministry of Agriculture guidelines stipulate that the yield cannot drop by more than 20%)
3. Solar sharing on farmland
The special feature of this power plant is that it is built over land that is registered as “farmland.” If you want to do solar sharing on farmland in Japan, you need permission from local agricultural committee. This is a substantial challenge to overcome.
From what I heard, it was indeed the case with this power plant as well and it took a great deal of effort to get the permission. The hard thing was to prove that the crops will grow even with reduced sunshine, because scientific data are scarce. Eventually research data on light saturation point did help to persuade the committee.
In April 2013, Japan’s Ministry of Agriculture released Guidelines that allow solar sharing on farmland and set basic rules to follow, so one would think that getting local committee's permission is easy, but that seems not to be the case yet.
By the way the land for our power plant in Tsukuba is categorized as “miscellaneous,” so we are spared of any farming-related bureaucracy. Lucky us. (Well, we're not allowed to buy farmland anyway. )
This was the first time I saw solar panels generating electricity installed over a rice field. Solar sharing on a rice field is still rare in Japan.
It felt strange to see metal pipes (that support the construction) rise out of the water, because rice field is covered in water. Here’s how it looks like:
Another thing that popped up in my mind was that in case some maintenance or repair works on panels are needed in the months between planting (May) and harvesting (September), it must be really hard to do (e.g. you can't put a stepladder in without damaging rice plants around). But maybe that's not any issue at all - I don't know.
I hope the crops - both rice and taro potatoes - at the Smart Life Power Plant will keep doing well. From time to time I might ask Hatsudenman for an update!
Absolutely unrelated postscript:
This has absolutely nothing to do with the power plant I visited, but I can’t help not mentioning it. When I walked from the station to the site, I again realized how bad walkability in Japan is. At one point the sidewalk simply disappeared and I had to walk on the road along the cars. It could have been such a nice walk otherwise. In Japan car drivers are first-class citizens, pedestrians are second-class. It's not easy to get used to it. Japan would be so much nicer place to live were there more sidewalks around.