全球智库信息集成服务系统

Over the last ten years, four Chesapeake Bay states—Maryland, Pennsylvania, Virginia, and West Virginia—introduced nutrient trading programs to provide wastewater treatment plants with flexible options for meeting and maintaining permitted nutrient load limits. At least one other bay state, Delaware, also convened a work group to discuss developing such a program. Through these programs, wastewater treatment plants may purchase credits or offsets generated by other wastewater treatment plants or farms that reduce the nutrients they release to impaired water bodies. States are also exploring options for construction and urban stormwater programs to buy and sell credits and offsets.

To date, most credit transactions have occurred between buyers and sellers in the same state. Efforts to enact the recent Chesapeake Bay total maximum daily loads (TMDLs), however, could provide more opportunities for interaction by trading partners from different states. For example, regulated entities could seek credits or offsets from other states when the supply in their own state has been exhausted. In addition, entities in states that do not have a trading program could seek credits or offsets from entities in states that do have such a program.

Although the elements of many of the trading programs are identical or very similar, such as calculation platforms, included pollutants, and allowable participants, there are several differences as well. Examples are the time period that defines the life of a credit or offset and the varying types and values of trading ratios. States may need to address these and other differences before permitting more cross-state transactions. Regardless of how these differences are resolved, government regulations require credit transactions to be documented in the public record.

The World Resources Institute (WRI) has compiled into comparison tables the key design elements of the four state trading programs. The tables comprise a reference document for policymakers and others addressing the programs’ differences. These design elements are grouped into twelve categories based on their common characteristics. All the information is current as of May 2011; was paraphrased directly from the statute, regulation, policy, or guidance documents; and has been reviewed by trading experts. Nonetheless, this information will undoubtedly change as the states refine their strategies for implementing the TMDLs.