Generator that runs without fuel or gas

https://www.youtube.com/watch?v=7lFxMaCqLoM

These two men from Nigeria, Gabriel and Moses claimed to have invented a locally made 900w power generator. The power generating plant does not require fuel or gas to work. What they did not mention in their brief expression is whether the generator runs on water or not.

Having watch the video, the question that comes to mind is whether the generator can work efficiently or if it will last. Again, if it works perfectly, do they have the talent to standardise it. Non the less, they need fund to upgrage and produce in large quantity.