Business Green: Wherever there is commercial opportunity, criminality soon follows. That is the somewhat dispiriting conclusion to be drawn from the annual fraud risk report from consultancy PricewaterhouseCoopers (PwC), which will warn later today that the emerging low-carbon economy is facing a growing threat from fraudsters. “Just because it’s green, does not mean it’s all good,” said Jon Williams, partner, head of sustainability and climate change at PwC. “That is the advice for companies …