In a story reported by CNN, Britain's biggest solar-powered boat debuted Tuesday on a lake in London's Hyde Park. The Serpentine SolarShuttle -- powered entirely by the sun -- cruises at 5 miles per hour and carries 42 passengers. Almost no pollutants are given off during the trip because the shuttle has two silent engines -- meaning there are no carbon emissions and it is also charged fully by the sun. It is expected the boat will save nearly 5,000 pounds of carbon-dioxide per year, compared with a diesel boat of a similar size, according to Gavin Gomes, a spokesman for Sputnik Communications, a London-based energy company. When the ferry is idle, surplus electricity generated by the solar panels will be fed back into the national transmission network.