First Solar (FSLR.NASDAQ), the world’s leading producer of thin-film solar panels, is working with China Guangdong Nuclear Solar Energy Development to build a solar-energy plant in Inner Mongolia, the Wall Street Journal reported. The project was supposed to be undertaken by First Solar alone, but the scheduled construction start date of June 1, 2010 came and went as the US company tried to resolve disagreements with the Chinese government on subsidies and feed-in tariffs. With state-owned Guangdong Nuclear Solar Energy Development – a subsidiary of China Guangdong Nuclear Power – now on board as majority owner and operator of the plant, First Solar expects the first phase, a 30-megawatt demonstration project, to be completed by the end of the year. The plan is to complete the facility by 2020, by which point it would have a capacity of 2 gigawatts, making it the world’s largest solar energy plant. First Solar hasn’t provided details of the cost of the project.