Fossil fuels, such as coal, oil, and natural gas, are non-renewable energy sources because they are formed from the remains of ancient plants and animals and take millions of years to replenish.

As of 2021, China has the highest installed capacity of solar PV systems in the world, with over 300 gigawatts (GW) of installed capacity.

Energy efficiency policies aim to reduce energy consumption by promoting the use of energy-efficient technologies and practices, thereby reducing the demand for energy.

Installing energy-efficient light bulbs is an example of an energy efficiency measure because it reduces the amount of electricity needed to light a room.

Carbon dioxide (CO₂) is the primary greenhouse gas emitted by the burning of fossil fuels. It is a major contributor to climate change.

Renewable energy sources, such as solar and wind, do not produce air pollution when they generate electricity. In fact, they can help to reduce air pollution by displacing the need for fossil fuels.

The photovoltaic effect is the process by which sunlight is converted into electricity. This process occurs when photons from the sun strike a semiconductor material, such as silicon, and knock electrons loose, creating an electrical current.

Nuclear power plants do not generate electricity from renewable energy sources. They use nuclear fission to generate electricity, which is a non-renewable process.

Wind power is the term used to describe the process of converting wind energy into electricity. This process occurs when wind turbines capture the kinetic energy of the wind and convert it into electrical energy.

Increasing the use of natural light is not a type of energy efficiency measure for buildings. It is a passive solar design strategy that can help to reduce the need for artificial lighting.

Hydropower is the term used to describe the process of converting the kinetic energy of flowing water into electricity. This process occurs when water flows through a turbine, which spins a generator to produce electricity.

Energy efficiency measures can help to reduce air pollution by reducing the demand for energy, which in turn reduces the amount of fossil fuels that are burned.

Bioenergy is the term used to describe the process of converting biomass into energy. Biomass is organic matter from living or recently living organisms, such as plants, animals, and waste materials.

Nuclear power is not a type of renewable energy technology. It uses nuclear fission to generate electricity, which is a non-renewable process.