Financial Times: High quality global journalism requires investment. Please share this article with others using the link below, do not cut & paste the article. See our Ts&Cs and Copyright Policy for more detail. Email ftsales.support@ft.com to buy additional rights. http://www.ft.com/cms/s/0/2a9ce14e-a755-11e2-9fbe-00144feabdc0.html#ixzz2QrUuWxrV More than a decade of investment in renewable power generators such as wind farms and solar parks has failed to make the worlds supply of energy any cleaner than it was...