The first of a series on climate change, this evaluation assesses International Bank for Reconstruction and Development (IBRD) and International Development Association (IDA) experience with key win-win policies in the energy sector. It focuses on energy price reform and policies for energy efficiency, both of which offer potentially large gains at the country level together with significant reductions in greenhouse gas emissions. The next phase will look at the project experience of the Bank (including the carbon funds) and the International Finance Corporation (IFC) in promoting technologies for renewable energy and energy efficiency. Transport and forestry issues will also be evaluated. The record levels of energy prices in 2008, although they have been relaxed, provide an impetus for clients to seek more sustainable and price-resilient growth paths. The Bank can proactively help interested clients to assess the domestic benefits of price reform and efficiency policies, explore design options, and finance their implementation. This will require a reorientation of the Bank's internal incentives, and adoption of a systems approach to energy and climate. These efforts will complement the crucial steps developed countries must take to reduce their own greenhouse gas emissions and to provide financial and technical help for mitigation by developing countries, consistent with United Nations Framework Convention on Climate Change (UNFCCC) commitments and the Bali action plan.