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Solar power has had a difficult start on Earth thanks to inefficient panels and high costs. But in space, scientists believe it could transform the way we generate energy.

Now, the space-based solar power – once merely the stuff of science-fiction – could be available sooner than expected if Japan has its way.

Within 25 years, the country plans to make space-based solar power a reality, according to a proposal from the Japan Aerospace Exploration Agency (Jaxa).

Solar power has had a difficult start on Earth. But in space, scientists believe it could transform the way we generate energy. By the end of this year, Japan expects to perform a ground experiment in which a beam of hundreds of watts will be transmitted over about 164ft (50 metres)

The agency has outlined its plans to create a 1-gigawatt commercial system for space-based solar power, which would provide about the same output as a nuclear power plant.

In a recent IEEE article by Susumu Sasaki, a professor emeritus at Jaxa, he outlined the agency's plans create a 1.8 mile long (3 km) man-made island in the harbour of Tokyo Bay.

The island would be studded with 5 billion antennas working together to convert microwave energy into electricity.

The microwaves would be beamed down from a number of giant solar collectors in orbit 22,400 miles (36,000 km) above the Earth.

The microwaves would be beamed down from a number of giant solar collectors in orbit 22,400 miles (36,000 km) above the Earth. Pictured are artist's impressions of what the system may look like

To collect the solar energy, two large mirrors would be positioned to direct light onto photovoltaic panels 24 hours a day.

A separate substation on the island would send electricity coursing through a submarine cable to Tokyo, to help keep the neon lights of Shibuya shining.

'A combination of technical and social factors is giving it currency, especially in Japan,' said Professor Sasaki.

'On the technical front, recent advances in wireless power transmission allow moving antennas to coordinate in order to send a precise beam across vast distances.

'At the same time, heightened public concerns about the climatic effects of greenhouse gases produced by the burning of fossil fuels are prompting a look at alternatives.'

Japan has a particular interest in finding a practical clean energy source: The accident at the Fukushima Daiichi nuclear power plant prompted an exhaustive search for alternatives.

However Japan lacks both fossil fuel resources and empty land suitable for renewable power installations.

By the end of this year, researchers expect to perform a ground experiment in which a beam of hundreds of watts will be transmitted over about 164ft (50 metres).

Each panel will transmit 400W, so that the total beam will carry 1.6 kW. In this early-stage experiment, Jaxa hopes to achieve a power output of 350 W.

Shimizu Corporation plans to install a 250-mile-wide field of solar panels on the moon's equator (concept image pictured). Energy from these panels would be sent to Earth using microwaves and laser lights and the company claims the system would be an 'almost inexhaustible' source of power

'Some people have a grisly mental image of roasted seagulls dropping from the sky. In fact, the beam wouldn't even be intense enough to heat your coffee,' said Professor Sasaki.

In a separate project, a Japanese firm last year revealed plans to cover the moon in a huge swathe of solar panels and use them to power homes here on Earth.

Shimizu Corporation's Luna Ring project would stretch almost 6,790 miles (11,000km) around the moon's equator and a field of solar panels would form a belt.

Energy captured by these panels would then be sent to Earth using microwaves and laser lights could be beamed directly to countries where it is needed. 

According to the plans, the project would produce around 13,000 terrawatts of continuous solar energy. At present, the world's population consumes about 15 terawatts of power each year.

The company claims the plans would not only provide an 'almost inexhaustible' energy supply, it would stop the rise of global warming caused by carbon dioxide from current energy sources.

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This graphic explains Shimizu Corporation's master plan for its Luna Ring scheme. According to the plans, the project would produce around 13,000 terawatts of continuous solar energy which could be sent directly to countries when needed