Thin Film solar superstar, Nanosolar, has shipped their first panels. Their 430 MW plant in California will be the largest in the world and allow them to sell at less than $1/Watt per panel, or about $2/Watt in a complete system. According to the Energy Department, building a new coal plant costs about $2.1 a watt, not including the costs of fuel and emissions. Is this a watershed for solar energy? It may be difficult for vacuum deposited thin film solar manufacturers to compete with Nanosolar, which uses nanoparticle ink jet printing in atmosphere on metal foil, roll to roll. Their plant reportedly is costing about 15 million dollars to build, compared to about 350 million for a vacuum deposited solar cell plant. Nanosolar is tight lipped about their efficiency, but Copper Indium Gallium Selenide (CIGS) cells have reached 19.5% in the laboratory.