The Welfare Effects of Allowance Banking in Emissions Trading Programs

Permitting allowance banking in emissions trading programs can reduce expected compliance costs by giving capped firms flexibility to adjust the time path of abatement and to hedge against future uncertainty. Recent literature suggests that this compliance cost dividend is significant (Fell and Morgenstern Environ Resour Econ 47:275–297, 2010). Allowance banking may yield an environmental dividend (a) if the growth rate of marginal damages from emissions is less than the discount rate and (b) if emissions are lower in the short run as firms bank permits for use in later periods. A discrete, stochastic dynamic programming model is considered to simulate the two dividends of allowance banking in the context of the most recent Federal United States greenhouse gas cap-and-trade legislation. Simulation results show that under a range of parameter values, the environmental dividend has the same order of magnitude as the compliance cost dividend. Under the central set of parameters, allowance banking increases expected present value of benefits by about $350$ million dollars per year of the program. The environmental dividend, however, is completely eliminated if capped firms can borrow permits from future periods without limit.