Indonesia is a country of more than 10,000 islands, so supplying the entire country with electricity is a big challenge.
More than a million people are not connected to the electricity grid.
"People without electricity live on remote islands, so it is difficult to connect in this situation and it is difficult to install other expensive solutions such as wind turbines," said Luofeng Huang, professor of mechanical engineering at Cranfield University.
Solar energy is an option to provide electricity to the islands. In recent decades it has become much cheaper - the International Energy Agency (IEA) has said that it has become the cheapest option for new power plants.
But solar farms take up a lot of land that could be better used for homes, farms and businesses.
Therefore, scientists and engineers are looking for ways to place solar panels at sea level, providing electricity to the inhabitants of the surrounding lands.
"Floating solar is very convenient because you put it on the water, and if you need more electricity, you can put more solar panels on it," Huang said.
Floating solar energy is already being used in many places around the world, but in lakes, not in the ocean.
The reason is obvious: waves can easily overwhelm them and damage the solar panels.
But research and testing is underway to find ways to keep solar panels working in turbulent waters.
The Dutch-Norwegian company SolarDuck, for example, is working with the German energy company RWE to build a floating solar power plant on a wind farm in the North Sea.
The company says it will be the world's largest floating offshore solar plant, capable of powering hundreds of homes.
The solar panels will be placed on a raised platform a few meters above sea level. The installation, which will be operational in 2026, will use the existing cables from the wind farm to return electricity to the coast.
Meanwhile, Ocean Sun has developed a floating platform where solar panels are placed on a base that flexes with passing waves.
"This slows down the wave and prevents it from breaking," says founder and CEO Borge Bjørneklett.
He said that because the panels are completely flat, it exerts less force. Proximity to seawater also cools the cells, which increases efficiency.
Both Ocean Sun and SolarDuck plan to place solar farms next to wind turbines to smooth the flow of electricity when there is no wind.
Huang believes that both approaches have drawbacks. With the panels raised above sea level, the SolarDuck system can be a more expensive solution.
"If you lift it, you're going to need very strong support, so it's going to cost a lot of money," he said.
SolarDuck disputes this claim.
"Offering our technology at a competitive energy cost is at every step of the design process," said Cohen Burgers, Managing Director of SolarDuck.
"We can also adapt the technology to local environmental conditions to find the best balance between performance and cost," he added.
As for the Ocean Sun system, Huang isn't sure that approach is enough to protect the panels from wave damage.
Bjorneklett admits his company's system may not be suitable for the North Sea with its 9m waves. But the company said the system survived a Category 4 hurricane during tank tests.
"In our opinion, places near the coast are more attractive, with better sea conditions," he said.
Huang's Cranfield University team is working on an alternative offshore solar power plant that it believes will be reliable and cost-effective.
Together with Indonesian academic and commercial partners, they hope to demonstrate the system in the Indian Ocean within 12 months.
Called Solar2Wave, it will feature a moving spike in front of the solar panels, which Huang says reduces the height of waves by about 90%.
The reduced waves then pass through a buffer zone, a small area covered by water, further reducing the strength of the waves before they hit the solar array.
It's important to keep the booth cheap: "Any damage will be done to the booth parts, which are cheap and very easy to replace and maintain," says Huang.
Although the installation and maintenance costs of any offshore solar power plant will be high, in many cases such a facility will be the only way to provide renewable energy in some densely populated parts of the world.
"In Singapore, for example, land prices are very high and already take up most of the roof space," says Björneklett.
"If they can use sea level outside of Singapore, that's the only way to provide affordable renewable energy, and a similar situation exists in much of the rest of Southeast Asia."
Solar farms can also be located in the open sea, where they can serve as a supply hub for electric ships.
More business technology:
The potential is definitely huge,” said Cranfield's Luofeng Huang. "Everyone wants to solve this problem, so we work very hard, and it's like a competition to be the first to come up with a successful design."
