Lesson 1: Forms of Energy – We learned that chemical energy is energy that is stored and released in the bonds between atoms. Then we learned that nuclear energy is the energy stored in and released from the nucleus of an atom. The energy released from the Sun comes from nuclear fusion. During nuclear fusion nuclei of atoms join together and release large amounts of energy. During nuclear fission the nucleus of an atom breaks apart and energy is released. Energy used in nuclear power plants to make electricity comes from nuclear fission.