Jump-starting The Green Car MarketWhen BYD Auto launches one of China's first mass produced fully electric sedans later this year, it will be trying to conquer the world rather than save it.But such is the explosive growth of China's car market and thirst for petrol that the two goals are likely to become ever more synonymous.Senior government leaders have initiated a major push for hybrid and electric vehicles in a bid to bypass car makers overseas and avoid an environmental meltdown at home.The consultancy McKinsey and Company estimates that China's car market will grow tenfold between 2005 and 2030,which will drive up demand for diesel and petrol from 110 million tonnes to 500 million tonnes.That will mean a sharp rise in carbon emissions from a country that has already overtaken the United States as the world's biggest source of greenhouse gases.