Subtitles section Play video Print subtitles Graphene is the wonder material that just keeps on giving. Actually, it's the reported wonder material that keeps on promising it can give but so far has been a bit flakey, promising advances in electronics, fabrics, construction materials, information systems and countless other fields, but singularly failling to deliver commercially viable products. Graphene is great. In fact it's better than the inherently imperfect technology currently used to produce it, which makes it, for now, a bit useless. And now there's yet another incredibly useful thing that graphene has found to be capable of - it can generate electricity from saltwater. A team of researchers from China found that, by placing a droplet of saltwater on a graphene film and then dragging it along, they could generate a small voltage difference. More drops moved faster generated a linear increase in the amount of voltage producecd. So what's caused it? Well the team foudn that when the drop was still, the charge distribution between the graphene on either side of the drop was equal. When it moved, it created a charge difference - the electrons desorbing from one side of the strip and absorbed into the graphene at the other. This means that with a regular flow of salt water over the strip, a constant, potentially useful charge can be created. The amounts are pretty small - in the test, one droplet created about 30 millivolts. But it can be scaled up, with some serious advantages. Most hydroelectric and tidal power systems are monumental engineering feats, requiring millions of tonnes of concrete and large scale destruction of ecosystems and shorelines. Nano materials such as graphene require much less engineering and infrastructure, and therefore damage. And because graphene can be created from more or less anything carbon based, from wood to dog poo, it would be relatively cost effective too. But like all other graphene related advances, manufacturing is the major stumbling block. We simply can't make enough graphene in large, continuous quantities to be industrially viable. Yet.