Given the Japanese feed-in tariff and current prices for solar PV modules, the economics of open field mega-solar projects favor a simple fixed tilt installation using cheap, reliable, 60-cell 250 watt polycrystalline modules, typically with a conversion efficiency of slightly better than 15%.
One or two axis trackers? Thin film modules? Concentrating lenses with high efficiency PV cells? Expensive storage solutions? None of these make economic sense under normal circumstances, at least in the Japanese market. Here are some ideas that may make sense, either today or in the very near future.
An "East West" installation achieves a much flatter power curve -- more even production during daylight, and thus can be preferable where the aim is self-consumption, or where power is sold onto the grid at market-based prices in a region where other solar output depresses mid-day pricing. As you can see from the photos below, East-West installations can also pack a large number of modules onto a limited size site and so are ideal for an environment where modules are cheap and land is expensive.
IBC Solar recently completed a 6.36MW open field East-West installation in Kaiserlautern, Germany -- the largest so far in that country. The plant will supply 2 nearby industrial users.
2. Water-based Installations
Another recent innovation is to install a large solar installation on a pond, lake or reservoir. The site can continue to be used for irrigation, flood control or other purposes, so any revenue from a solar lease is purely additive -- pennies from heaven for the owner of the pond. Also, if the modules are installed on floats relatively close above the surface of the water, the water exerts a cooling effect on hot days, and can significantly improve output.
Ciel et Terre, a France-based company, has the leading current system of floats for this type of installation. Their first Japanese system was installed in Okegawa, Saitama in a West Holdings project. A number of others are now in the planning stage.