I recently did some research found something call
solar stirling plant which generates free energy.
from the sample model I've manage to DIY ...  it does seem to work
the energy that this produce is a lot more than solar panel because the
engine runs on hydrogen gas, so when it's heated up by sunlight, It'll generate a good amount of energy

the best part is the cost to build one of these is way cheaper than solar panel

http://mycheapenergy.blogspot.com/