What are green energy and renewable energy?

Energy from renewable sources is replenished naturally, for example solar, wind, wave and geothermal energy. Green energy generally emphasises lower environmental impacts, but its definition depends on the framework used. Nuclear power has low operational greenhouse-gas emissions but uses non-renewable fuel and requires radioactive-waste management; it should not be equated with renewable energy.

The aim of greener energy production is to supply energy with lower environmental impacts. No energy technology is entirely free of impacts across its life cycle. Renewable options can reduce reliance on fossil fuels and help reduce the greenhouse-gas emissions that drive climate change, while requiring consideration of materials, land use and local ecosystems.

Examples of renewable energy

Solar energy

Conventional electricity supplies have relied heavily on fossil fuels such as coal, oil and gas. These energy sources face challenges including price volatility, import dependence in countries with limited domestic resources, and environmental impacts. Governments, organisations and businesses have therefore invested in research and deployment of solar energy.

Wind energy

Over recent decades, alongside solar power, wind power has made substantial advances in electricity generation. Supportive policies, technological progress and investment have helped improve its competitiveness and contribution to energy supply.

Wave energy

Wave energy and tidal energy are different marine energy resources. Wave technologies capture wave motion, whereas tidal technologies use tidal flows or water-level differences. Performance, cost and environmental effects depend on the technology and site; a conversion efficiency above 90% or universally negligible environmental impact cannot be assumed.

Compiled information

US EPA: What is green power?

US Department of Energy: Marine energy basics