As countries shift away from fossil fuels, companies are focusing on developing and improving technologies for cleaner fuels.

One such company is Toshiba, which is developing and improving on the perovskite photovoltaic cells created by a Japanese scientist in 2009.

A perovskite solar cell harvests sunlight and is thin and transparent enough to coat machines and objects such as electric vehicles, vending machines, smartphones, clothes and curtains. This new solar cell could replace the existing crystalline silicon cells that dominate today's photovoltaic market.

Over the past decade, Toshiba has managed to increase the power conversion efficiency of its perovskite solar cells to 14.1%, the highest in the world. This compares just over 20% for conventional solar panels.

If perovskite solar cells become cheaper, they could be a vital technology for a carbon-neutral economy. "We could be able to install solar cells anywhere," said Kenji Todori, a senior expert at Toshiba.

A team of researchers at Stanford University said that if the manufacturing process of perovskite cells can be fine-tuned further, the average price of electricity generated this way could be dragged down to roughly 2 cents per kilowatt-hour. If this comes true, perovskite cells would be one of the cheapest sources of renewable energy.

But the creator of the perovskite cells, Tsutomu Miyasaka, professor at Toin University of Yokohama and a Nobel Prize in chemistry candidate, is not optimistic about the future of Japanese research in this field.

"In China, there are at least 10,000 researchers specializing in this technology, more than 10 times the number in Japan," he said. Despite being in the lead decades ago in the development of solar energy, Japanese manufacturers have now lost out to foreign rivals.

But Japan has now another focus -- tidal power. As an island, this is a plentiful source of energy for Japan. At the Goto Islands in the west of the country, where currents are fast and powerful, the Ministry of Environment and renewable energy producer Kyuden Mirai Energy are piloting Japan's first tidal power generation system.

A turbine to generate electricity from tides.

Tides are predictable, unlike wind and sunlight, so they can be "trusted to keep producing stable amounts of electricity without being affected by weather conditions," said Masakatsu Terasaki, an executive at Kyuden Mirai Energy. It is estimated that Japan can generate energy, from tides, equivalent to the amount that 20 nuclear reactors can produce.