Renewable

Renewable is a term used for natural resources or energy flows that are replenished naturally on a human timescale and can be sustained indefinitely with responsible management. In energy planning, renewables derive from sources expected to be replenished continuously, unlike finite fossil fuels.

The major renewable energy sources include solar, wind, hydro, geothermal, biomass, and certain ocean energies such as tides and waves. Solar energy is harvested with photovoltaic panels or concentrating collectors. Wind energy uses atmospheric motion to drive turbines. Hydropower relies on flowing water, and geothermal taps Earth's internal heat. Biomass converts organic matter into electrical or thermal energy, and ocean energy exploits tidal and wave motion.

Renewables offer lower greenhouse gas emissions during operation, reduced air pollution, and greater energy security through diversification. They create jobs in construction, installation, and maintenance. Challenges include intermittency and geographic dependence, the need for energy storage or backup capacity, land and water use, and lifecycle environmental impacts from manufacturing and end-of-life disposal of equipment.

Policy and deployment involve incentives, auctions, and standards to promote investment in renewables. Grid integration and transmission upgrades are often needed to handle variability, along with storage, flexible demand, and market reforms. Local factors, environmental considerations, and community engagement also influence siting and development.

In many regions, renewables have grown to constitute a substantial portion of electricity generation and are central to climate and energy transition goals. Ongoing advances in efficiency, storage, and smart grids are expected to further expand their role across power and, increasingly, other sectors.