A company in Germany has developed what it claims is the world's smallest hydropower plant. The Blue Freedom charging kit consists of a 4.7 inch (12 cm) diameter micro turbine, a 5W generator and a 5,000 mAh lithium-polymer internal battery. The whole kit would fit into a large coat pocket. The plastic turbine slides out of the base and is left to dangle at the end of a cable in running water while the unit's base stays ashore, generating enough power to charge a mobile device directly by way of its USB ports. It can also store energy in the integrated battery for later use. The device would be useful for campers, but most particularly for those without access to a power grid in developing economies, who still need to charge mobile phones, or LED lights after dark.
Having demonstrated its prototype, the company is just getting into commercial production. Orders are coming particularly from India and Africa.
Price is currently €300, but is expected to fall with production.