The Regional Greenhouse Gas Initiative is a multi-state program that since 2009 has helped cut carbon pollution from power plants in half in nine states. Photo via NRDC

A new report says the Regional Greenhouse Gas Initiative has put $4 billion into Northeast economies since 2009.

The carbon-trading program limits greenhouse gas emissions from fossil fuel-fired power plants in nine Northeast and Mid-Atlantic states, including New York. It requires plants to pay for the carbon they give off, and lets the states choose how to invest those proceeds.

Since the program launched, electricity prices in the region have fallen even as customers in non-RGGI states have seen higher prices. And, the nine states have cut carbon pollution by 51 percent.

Source: NRDC