Do you know any non conventional renewable energy source?

[espai afi]

And if you know some could you explain?

[insto]

Piezoelectric. Piezoelectricity is a system that can produce electricity from the conversion of mechanical energy. This energy-generating system is very well applied to public places, such as those installed on a floor of a Japanese train station and also on a disco house floor in the UK. The working principle is that the pressure from the people in that place will be converted into electricity. So, it can be used to meet the electricity needs around the place. I don't know whether this is non-conventional energy or not, what is certain is that it is the latest and most modern energy.