In the medium term carbon pricing thus has the potential to be a transformative force in the energy markets of OECD countries with overall positive impacts on the security of energy supply. The more volatile are electricity prices, the higher is the penalty for low-carbon technologies such as nuclear and renewables. Since the latter have overall good performance in security of supply terms, electricity market liberalisation without measures to address price volatility such as long-term contracts cannot be considered ceteris paribus as contributing to improved energy market security. The cost of supply interruptions may be substantial but it is not infinite, so neither will be the price that countries are willing to pay for avoiding them.