Question: what are the 4 main types of renewable energy?
Answer: 1) Solar energy. Sunlight is one of our planet's most abundant and freely available energy resources. ... 
2) Wind energy. Wind is a plentiful source of clean energy. ... 
3) Hydro energy. ... 
4) Tidal energy. ... 
5) Geothermal energy. ... 
6) Biomass Energy.