There isn’t much extra space in Singapore, since the entire country is smaller than New York City and fully developed. So when the government decided to install more solar power to help meet the area’s energy needs, they turned to water instead of land: When finished, the country’s new power plant would be the world’s largest floating solar farm.

“The vast majority of photovoltaic installations in Singapore will obviously be on rooftops, but even those are limited,” says Thomas Reindl, deputy CEO of the Solar Energy Research Institute of Singapore, the organization that will be managing the project for the government. “Alternative areas have been explored, and one of the most promising options is inland water reservoirs.”

One of the most promising options is inland water reservoirs.

Since only a handful of demonstration floating solar farms have ever been built anywhere, the project will start by testing out smaller versions of 10 different designs. The best design will be expanded into the full plant, which will eventually generate 3.3. gigawatt-hours of solar energy in a year–and even as much as 4 gigawatt-hours if it turns out to be more efficient than solar on land.

The reservoir will eventually be used to provide drinking water, so one of the challenges of the project will be making sure that none of the components in the solar panels can leach into the water. As each of the test designs run, the agency will also carefully monitor other environmental impacts. In some ways, the solar panels and water may actually help each other: By shading the water, the panels are likely to help reduce evaporation, and the water may help keep the panels cooler so they run more efficiently.

When the system is completed, Singapore hopes that it can be used as a model for other countries with limited space. “Singapore is already one of the major hubs for offshore floating platforms for the marine and oil industries,” says Reindl. “Combining that expertise with solar could also end up in offshore floating PV systems, or even energy islands that generate energy from various sources like solar, wind, and ocean currents.”

The idea of floating solar farms isn’t new. Singapore has been considering the idea for several years, and others, like the French company Ciel et Terre, are developing similar ideas. But it’s only now that the cost of solar tech is low enough to make it a truly viable idea.