Price Volatility and Banking in Green Certificate Markets

There is concern that prices in a market for Green Certificates (GCs) primarily based on volatile wind power will fluctuate excessively, leading to corresponding volatility of electricity prices. Applying a rational expectations simulation model of competitive storage and speculation of GCs the paper shows that the introduction of banking of GCs may reduce price volatility considerably and lead to increased social surplus. Banking lowers average prices and is therefore not necessarily to the benefit of “green producers”. Proposed price bounds on GC-prices will reduce the importance of banking and even of the GC system itself.The paper benefited from presentations at Copenhagen University, Stockholm School of Economics and University of Iceland. Thanks are due to Lars Bergman, Torstein Bye, Pauli Murto and participants in the Nordic Energy Research Program (NERP).