Businesses and consumers could see energy bills increase by 20% on top of market rises to pay for the cost of meeting the EU's 2020 emissions target.

The warning comes from Ernst & Young, which estimates that the UK needs to find £100bn for the investment needed to achieve the target of cutting green emissions by 20% by 2020.

"Customers face a triple whammy of rising fuel and oil prices, the cost of climate change mitigation and, on top, the additional investment required to become more energy efficient," said Simon Harvey of Ernst & Young.

The UK currently gets less than 5% of its power from renewable sources.