The answer is obviously no, the sun is not the only source of clean energy. Check below the other options
It has been used for hundreds of years to
-Pump water with windmills
Today wind turbines produce electricity
-smaller turbines can produce 50 Kilowatts of power
-larger turbines can produce 1 to 2 Megawatts
Water motion rotate turbines that generate electricity
Energy is released without using up water
Bio means Life, bio energy is energy released by living things. It can be methane from decaying biomass at landfills or bio fuels such as ethanol alcohol made from corn and other plants.
Home fire places burn wood (although not very efficiently) a renewable source of bio energy
The centre of earth is cooking at 9000 degree Fahrenheit. That energy escapes to the surface in the form of steam and hot water that can be harnessed to produce electricity.
Geothermal power plants need water of only 225 degree to 360 degrees to produce power.