The boats operate on 12v and have a battery bank to provide the power to the lights, ‘fridges, pumps etc. These batteries are re-charged by the engine whilst the boat is underway. The boats also have a 220v circuit and this is powered either by a shore supply cable or, on the luxury boats, by onboard generators/invertors. The 220v shore supply is available in ports and in some towns and villages, and, like the water, it is often free in towns and villages, but is charged for in ports. The 220v is not a necessity, but powers luxury items such as air conditioning, and any personnel items you may wish to bring (e.g. Hair dryers).