SOLAR

Solar refers to things related to the Sun, the star at the center of the solar system from which Earth receives light and heat. The Sun is a G-type main-sequence star about 4.6 billion years old, producing energy by nuclear fusion in its core. Its radiation travels through space and reaches Earth at an average distance of about 149.6 million kilometers (one astronomical unit).

Solar energy technologies capture this radiation and convert it to electricity or heat. Photovoltaic (PV) systems use solar cells to convert light directly into electricity. Solar thermal systems use mirrors or lenses to concentrate sunlight to produce heat, which can drive turbines for electricity or provide direct heating. Concentrated solar power (CSP) plants use large mirrors to concentrate sunlight onto a working fluid to generate steam.

Humans have used solar heat for millennia, but modern solar electricity developed in the 20th century with advances in PV materials and manufacturing. The first practical PV cells were created in the 1950s. Since the 2000s, solar power has grown rapidly, aided by public policies and falling costs. Solar installations span rooftops, fields, and large dedicated facilities worldwide.

As of the early 2020s, solar power accounts for a substantial and growing share of global electricity generation, with installed PV capacity exceeding one terawatt. Solar energy can reduce greenhouse gas emissions and dependence on fossil fuels but faces challenges such as intermittency, energy storage needs, land use, and manufacturing environmental impacts. Grid integration and storage technologies are key areas of development.

Solar remains a central component of efforts to decarbonize energy systems, with ongoing research to improve efficiency, reduce cost, and address environmental concerns.