Sunlight is the ultimate source of clean energy as it is available anywhere, albeit only during daytime. Its use to store power in a battery through a solar panel has become widespread.

More households are tapping the power of the sun through solar appliances, especially with the high cost of electricity these days.

For some low-income families that cannot afford electricity or off-grid remote communities, they use a solar bottle bulb that refracts sunlight inside a house for lighting.

The device made up of a liter-sized plastic bottle of soda filled with clean water and installed though the roof was propagated by the Liter of Light foundation. The latest version of the easily-assembled SBB has a solar panel wired to a battery and LED bulb that is enclosed in a plastic bottle making it portable and usable at night.

Still, scientists continue to make new technology that harnesses the sun's unlimited energy. A group of nuclear physicists from South Korea recently replicated the experiment made by their Chinese counterparts early this year for that purpose.

The team of scientists from Seoul National University and the Korea Institute of Fusion Energy reproduced heat or plasma of more than 100 million degrees Celsius for some 30 seconds at the reactor of the Korea Superconducting Tokamak Advanced Research facility.

The incredible feat was made possible through the process called nuclear fusion, or the combination of atomic nuclei through extreme heat. But the team is not stopping there and will try to make the same temperature last longer or up to 50 seconds by the end of the year and, eventually, for 300 seconds by 2026.

"This is not the end of the story, we must move on to 300 seconds — 300 is the minimum time frame to demonstrate steady-state operations, then this plasma can work forever," KSTAR director Yoon Si-woo, said, according to New York Post.

What the Korean scientists ignited was a miniature sun as nuclear fusion is the same process that occurs in the sun. The difference is that the heat in the sun's core is only 15 million degrees Celsius.

Aside from Chinese and Korean scientists, American and European physicists are also conducting similar experiment of recreating a mini-sun to produce heat for conversion into electricity.