CAP和貿易是一種基於市場的控製汙染的方法。它通過發出一定數量的排放許可來有效地限製允許的總排放量。許可證可以通過受監管的各方進行交易，從而為減少排放提供了經濟激勵措施。
Work at the Nicholas Institute for Environmental Policy Solutions aided in the design aspects around emissions trading systems for the Northeast’s Regional Greenhouse Gas Initiative (RGGI)—the country’s first regional cap-and-trade program designed to reduce power plant emissions—and California’s cap-and-trade program, the country’s first to cover multiple economic sectors. A key challenge for any cap-and-trade system is preventing emissions allowance prices from rising beyond the reach of potential purchasers.
兩個程序都使用津貼儲備概念，由杜克大學研究人員於2008年開發，以防止排放津貼的價格上漲如此之高，以至於他們將對潛在買家以及通過這些成本的客戶造成極大的經濟困難。
