A Model for the Valuation of Carbon Price Risk
Modeling the price risk of CO2 emission allowances is an important aspect of integral corporate risk management related to emissions trading. In this paper, a pricing model is developed which may be the basis for evaluating the risk of emission certificate prices. We assume that the certificate price is determined by the expected marginal CO2 abatement costs in the current trade period as well as by the long-term marginal abatement costs. The price risk is modeled on the basis of a mean reversion process. Due to uncertainties about the future state of the environment, we suppose that within one trade period erratic changes in the expected marginal abatement costs may occur leading to shifts in the price level. In addition to the parameter estimation, it is also an objective of this work to modify the mean reversion process so that such abrupt changes in the expected reversion level can be displayed. Because of the possibility of transferring spare allowances to a subsequent period we take into account the fact that the expected long run marginal abatement costs act as a lower limit for the price in the trading period.