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Space is a big problem in Japan. The small, mountainous island nation has limited flat ground for building, and what there is comes at a premium.

Its other huge issue is energy, which the country struggles to produce and pays to import enough to satisfy its needs.

One solution: massive solar farms floating on bodies of water. This week, Kyocera Corporation and Century Tokyo Leasing Corporation announced they had begun work on what they say will be the world’s largest floating solar installation by the amount of power produced.

A rendering of the installation.
A rendering of the installation.

The companies plan to create a giant geometric block of 51,000 individual solar modules floating on the surface of the Yamakura Dam reservoir in Chiba Prefecture, some 70km (43 miles) from Tokyo. They’ll cover an area of 180,000 square meters. And once they’re up and running in 2018, they’ll have a capacity of 13.7 megawatts.

The company behind the Yamakura project has already completed much smaller projects, like this one in Hyogo Prefecture around Kobe.

Japan’s energy problem is long-lived, but is particularly acute right now.

The country managed to build up its high-tech, energy-hungry culture with few natural resources, like indigenous coal or gas. It tackled the problem through building nuclear power stations, but had to take them all offline when its Fukushima plant was damaged by the devastating earthquake and tsunami of 2011. Since then it’s brought some plants back online. But at the start of last year it was producing only 9% of its own energy. The rest comes in the form of expensive imports: Japan is the world’s biggest importer of liquified natural gas.

Investing heavily in renewables, and particularly those that utilize space on rooftops or lakes, is part of Japan’s plan to become less reliant on imports.

Advocates of floating solar say it has several benefits. It uses “dead” space on the surface of water bodies, and is easy to assemble. Rather than using heavy machinery required for ground-mounted installations, the panels are clipped together and pushed out from the bank of the lake.

This 200 kilowatt plant in England was constructed in one week:

Kyocera has also said the plant will bring benefits to the water itself by reducing evaporation and algae growth by shading the area.