This brief presents public policy tools available to provide support for research, development, demonstration, and deployment (RDD&D) of technologies that reduce greenhouse gas emissions. An emissions price induced by a cap-and-trade program can provide an incentive to “pull” new technology into the marketplace, while public funding for technology can provide a “push” with the two approaches more powerful in tandem than either alone. Economic theory provides the rationale for public expenditure on RDD&D, which can compensate for several market failures that would otherwise generate sub-optimal investments from the private sector. The appropriate policy tool depends on the stage of development for a particular technology and the scale of a project. Direct public expenditures, channeled through organizations such as the Department of Energy or the National Science Foundation, have a long history of funding earlier stages of research and development, and make up the bulk of current technology dollars. Some technologies to address climate change, such as next-generation nuclear power and carbon capture and storage, require a larger investment for early projects than private industry is likely to make, and could benefit from public funding of demonstration projects. The federal government can also provide inducements for private industry to invest in RDD&D with mechanisms such as investment tax credits. Indirect policies that can support technology deployment include standards that require a minimum performance or a market share requirement, and programs that identify and certify top efficiency performers in the marketplace. Funding sources for technology programs include appropriations from general revenues and dedicated revenues, perhaps from climate- or energy-related sources such as allowance auctions or dedicated energy taxes. Regardless of the source, funding must flow through and to multiple institutions that manage, select, and perform the actual RDD&D options. Each institutional option has strengths and weaknesses.