Improving energy efficiency (EE) is one of the most promising approaches for achieving cost-effective global greenhouse gases (GHG) reductions. However, it is severely underrepresented in the Clean Development Mechanism (CDM) portfolio. Just 10 percent of the emission reduction credits traded in the carbon market is from EE projects. In particular, small, dispersed, end-use EE measures-which entail significant GHG mitigation potential, along with other clear, local, and direct sustainable development benefits-have been largely bypassed by the carbon market. The modalities of traditional CDM have been set for individual, stand-alone, emission reduction projects that are implemented at a single point in time. While CDM rules allow "bundling" of several of these projects together for registration purposes, the specific sites where they will occur must be known ex-ante and they must all occur at the same point in time. These conditions generally cannot be met by most dispersed demand-side EE programs, whose emission reductions occur over a period of time and in numerous locations (households/industries/cities). In addition, participants in energy-efficiency programs may not be known at the outset because the program may depend on gradual take-up of incentives.