It is always due to the intrinsic scarcity of the underlying product and its magnitude is exclusively determined by demand. The diversification of energy sources and suppliers, the development of substitutes such as renewables or nuclear power, the provision of incentives for improving energy efficiency are all effective responses to long-term monopolistic behaviour. Such policy measures fall, however, in the realm of standard commercial practice and do not constitute per se measures to reduce energy supply risk. Private actors concerned about high oil and gas prices should be able to deal with the exercise of monopoly power to the extent that it is predictable and that the commercial competition is being played out on a level playing field.