Financing the public and private energy infrastructure towards a low carbon energy future will require significant investment of both public and private funds. Novel sources of finance and subsidies are required in the short and medium terms to help tackle and cope with climate change. As has been clearly demonstrated by the Stern Review (UK, 2006), the cost of inaction on climate change far exceeds the cost of action. It is crucial that finance be available now to fund the great transition to a sustainable energy infrastructure. This is covered in more detail in the Economics chapter.