"Energy security" is an elastic concept. However, it offers the prospect of linking "hard security" issues, such as territorial protection and supply of vital fuels, in mutually reinforcing ways, with "soft security" issues, such as protection of the environment generally and specifically the limitation of the emissions that lead to global climate change. Such linkages, which could engage a large number of countries and diverse interests, make energy security a good prospect for early action by the L20. Moreover, security of energy supply is once again high on the agenda of most governments because of the current high prices for energy, notably oil. Political action is needed not only because consumers demand it, but also because a large and growing fraction of the world oil supply is under direct control of governments who make supply decisions on the basis of political factors.