This paper explores how guarantees and other risk mitigation instruments such as insurance, hedging products and Put and Call Option Agreements, have been used in emerging markets and developing economies (EMDEs) to mobilise capital for renewable power and energy efficiency projects. The paper presents the latest evidence and data, along with good practice examples of various instrument designs and implementation methods. A series of international case studies illustrates different types of guarantees and risk mitigation instruments applied in renewable energy and energy efficiency projects, and derives key learnings. The paper includes the results of a new OECD survey exploring the relevance of such instruments and identifies challenges and limitations of such financial instruments. Finally, the paper offers recommendations for different stakeholders, including donors, Development Finance Institutions (DFIs), Multilateral Development Banks (MDBs), EMDE governments and offtakers, financial regulators as well as financial institutions and insurance companies.