nuclear power vs solar power

nuclear power

noun
  • Power, especially electrical power, obtained using nuclear fission or nuclear fusion. 

  • A nation that possesses nuclear weapons. 

solar power

noun
  • The conversion of energy from sunlight into electricity, either directly using photovoltaics, indirectly using concentrated solar power, or a combination of the two. 

How often have the words nuclear power and solar power occurred in a corpus of books? (source: Google Ngram Viewer )