Story.Ech2O An eco-car that can travel the world using a fraction of the electricity it takes to power a light bulb, has been unveiled by its British creators. According to the British gas firm BOC, its hydrogen-powered BOC Ech2o needs just 25 Watts — the equivalent of less than two gallons of petrol — to complete the 25,000-mile global trip, while emitting nothing more hazardous than water. Link.