We use a stochastic dynamic framework to compare price collars (price ceilings and floors) in a cap-and-trade system with uncertainty in the level of baseline emissions and costs. We consider soft collars, which provide limited volume of additional emission allowances (a reserve) at the price...

Current and proposed greenhouse gas cap-and-trade systems allow regulated entities to offset abatement requirements by paying unregulated entities to abate. These offsets from unregulated entities are believed to contain system costs and stabilize allowance prices. However, the supply of offsets...