Google Inc has developed a prototype for a new mirror technology that could cut the cost of building a solar thermal plant by half. Mr.Bill Weihl said The Internet search engine company, which has been investing in companies and doing research of its own to produce affordable renewable energy, wants to cut the cost of making heliostats, the fields of mirrors that track the sun."There is a decent chance that in a small number of years, we could have a 2-X reduction in cost," he said. Global companies are increasingly investing in green technology as the world grapples with global warming and governments strive to implement regulations that could limit greenhouse gas emissions. Google has invested in two solar thermal companies, eSolar and BrightSource, with which it has discussed the new mirror technology.