In the synthesis volume of its Fourth Assessment Report, the Intergovernmental Panel on Climate Change (IPCC) made it clear that the effects of climate change could become catastrophic if no action is taken to reduce greenhouse gas emissions as soon as possible. The report also boldly concluded that global warming is to a large extent caused by human activities (IPCC 2007). In order to achieve substantial cuts in greenhouse gas emissions, governments are attempting to mitigate energy consumption in several major sectors of the economy.