In 2007, the Rhode Island General Assembly passed legislation enabling state participation in the Regional Greenhouse Gas Initiative (RGGI). RGGI is the first market-based cap-and-trade program in the United States designed to reduce electric power sector greenhouse gas emissions. Nine states currently participate in the effort: Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont. The program, which began in 2009, establishes a declining regional emissions cap and requires electric generators greater than 25 MW to purchase emissions allowances through quarterly auctions. Participating states invest the auction proceeds in energy efficiency and clean energy programs that deliver economic benefits to consumers throughout the region.