Canadian Solar Inc., the world\'s fifth largest solar module maker, plans to build a plant in Japan as early as fiscal 2013 to become the first foreign manufacturer to produce solar panels in the country, company sources said Saturday. The Ontario-based firm is among domestic and overseas companies vying to strengthen their position in the Japanese market as a new government incentive program starting this July is expected to spur demand for green energy in the wake of the Fukushima Daiichi nuclear disaster. Canadian Solar expects to invest several billion yen for the new plant with an annual production capacity of 150 megawatts of solar panels.