Solar sharing.

The development of technology to produce at the same time the power and crops using the solar cells of film-like passage of light , laboratory Watanabe Associate Professor Suwa Tokyo University of Science , Faculty of Systems Engineering, of Chino was begun . Demonstration experiment to generate electricity and cover the plastic greenhouse , make sure that it does not interfere with the growth of nearly vegetables . It is an attempt to help the farmers outside the prefecture facing the harsh environment , such as TPP ( Trans-Pacific Partnership Agreement ) , momentum to the spread of solar energy .
Research proceeds as next-generation solar cells same laboratory in development , " organic solar cells " . Conversion efficiency is inferior as compared to solar cells using silicon widely used in such as residential , but there is light cheap advantages material cost , and it can also be semi-transparent. It is expected if the established technique for producing at high speed by using a machine such as a rotary press , the manufacturing cost and decreases further .
Venture companies in the United States , the same laboratory procurement product film-like , translucent kind of organic solar cells called " organic thin film type" . Experiments were carried out to grow tomatoes and cover the plastic greenhouse outdoors , growth is slightly delayed , but it was demonstrated that crop yields does not change . Even experiment to grow lettuce of leafy vegetables over the hydroponic equipment for indoor , it was confirmed almost the same results .
According to Watanabe, Associate Professor , one of the three primary colors of light , has a photosynthesis using the red and blue light is mainly plant . Technology in development , how the solar cells covering the farmland is generated by the light green mainly , to transmit light of red and blue necessary for photosynthesis . The combination of solar cells and a special phosphor sheet to enhance the red light to encourage photosynthesis , they also succeeded in experiments to increase crop yields .
Technique for growing the crop farmland , to the solar power at the same time is called a " solar -sharing " , can be expected management stabilization if farmers electricity sales . Last year , the Ministry of Agriculture, Forestry and Fisheries was accepted conditionally solar cell installation in the farmland .
Currently , Case Studies throughout the country , the center is a method of providing a framework to farmland on , put solar panels on the gridiron like . Watanabe Associate Professor explained, " and the like cover the vinyl house if organic film-like , can be introduced more easily " with the other hand . The low conversion efficiency emphasizes the advantage to be " compensated in the area" .
Future , the lab intends to work on the development of organic solar cells with high conversion efficiency , want to measure the practical application in industry-university cooperation . The " durability is an issue organic , but the production cost drops sufficiently below the limit , and I do exchange every year as agricultural film ," said Watanabe, Associate Professor technology that lead to the solution of the food problem and "Environmental and energy issues you are talking with " want to send to the world as .
It might be a good way of stable income is opened also for farmers to be able to put to practical use at low cost .



光を通すフィルム状の太陽電池を使って農作物と電力を同時に生産する技術の開発に、諏訪東京理科大システム工学部（茅野市）の渡辺准教授の研究室が乗り出した。ビニールハウスにかぶせて発電する実証実験で、野菜などの成長をほぼ妨げないことを確認。ＴＰＰ（環太平洋連携協定）など厳しい環境に向き合う県内外の農家を支援し、太陽光エネルギーの普及にも弾みを付ける試みだ。
　同研究室が開発中の太陽電池は、次世代型として研究が進む「有機系太陽電池」。住宅用などに普及しているシリコンを使った太陽電池に比べ変換効率は劣るものの、材料費が安く軽い利点があり、半透明にすることも可能だ。輪転機のような機械を使って高速で生産する技術を確立すれば、製造コストもさらに下がると期待されている。
　同研究室が米国のベンチャー企業から、「有機薄膜型」と呼ばれる有機系太陽電池の一種で半透明のフィルム状の製品を調達。屋外でビニールハウスにかぶせてミニトマトを育てる実験を行い、生育は若干遅れるものの、収穫量は変わらないことを実証した。屋内の水耕栽培装置を覆って葉物野菜のサンチュを育てる実験でも、ほぼ同様の結果を確認した。
　渡辺准教授によると、植物は光の三原色のうち、主に赤と青の光を使って光合成をしている。開発中の技術は、農地を覆う太陽電池が主に緑の光で発電し、光合成に必要な赤と青の光を透過する仕組み。光合成を促す赤色の光を強める特殊な蛍光シートと太陽電池を組み合わせ、収穫量を増やす実験にも成功した。
　農地作物を栽培し、同時に太陽光発電をする手法は「ソーラーシェアリング」と呼ばれ、農家が売電すれば経営安定化が見込める。農林水産省は昨年、農地への太陽電池設置を条件付きで容認した。
　現在、全国での導入事例は、農地上に骨組みを設け、すのこ状に太陽光パネルを置く方法が中心。これに対し渡辺准教授は「フィルム状の有機系ならビニールハウスを覆うなど、より簡単に導入できる」と説明。変換効率の低さは「面積で補える」と利点を強調する。
　研究室は今後、より変換効率の高い有機系太陽電池の開発に取り組み、産学連携で実用化を図りたい考え。渡辺准教授は「有機系は耐久性が課題とされるが、製造コストが下がれば、農業用フィルムのように毎年交換すればいい」とし、「環境・エネルギー問題や食糧問題の解決につながる技術として世界に発信したい」と話している。
　安価で実用化できると農家にとっても安定収入の道が開かれていいかもしれませんね。