It’s good news for solar advocates and bad news for competitors: General Electric is breaking into the solar business in a major way. In April, GE announced it had built a solar module with the highest publicly reported efficiency rate for cadmium telluride thin film — the most popular low-cost solar technology. The commercial module topped out at 12.8%, according to independent testers at the National Renewable Energy Laboratory — nearly 3 percentage points higher than the industry average. (The efficiency rate is the percentage of the sun’s energy a solar panel can convert to electricity.) Those record-breaking solar modules will eventually be manufactured at a U.S. facility set to open in 2013 that will be the biggest solar factory in the country. The news means GE — which already has a wind-energy business worth some $6 billion — could be ready to dominate solar much as it leads the way in wind. “This is the beginning of what we see as a global competition,” says Victor Abate, GE’s vice president of renewables.