What is any energy resource that can be used in place of fossil fuels called nuclear energy?

An energy resource that can be used in place of fossil fuels, such as nuclear energy, is often referred to as a "renewable" or "alternative energy" source. Nuclear energy specifically derives from nuclear reactions, primarily fission, to generate electricity. This type of energy is considered low-emission compared to fossil fuels, as it produces minimal greenhouse gases during operation. Other examples of alternative energy sources include solar, wind, hydroelectric, and geothermal energy.