In the ninth session of the United Nations Commission on sustainable development(CSD9) in New York in april 2001,a sustainable energy system was defined as one that ensures and affordable access to energy for present and future generations in an environmentally sound,socially acceptable and economically viable way.On the other hand, OECD/IEA suggests having a working definition of sustainable development in the context of energy policy-making,namely,development that lasts and that is supported by an economically profitable,socially responsive and environmentally responsible energy sector with a global,long-term vision(IEA, 2001).

In the ninth session of the United Nations Commission on sustainable development(CSD9) in New York in april 2001,a sustainable energy system was defined as one that ensures and affordable access to energy for present and future generations in an environmentally sound,socially acceptable and economically viable way.On the other hand, OECD/IEA suggests having a working definition of sustainable development in the context of energy policy-making,namely,development that lasts and that is supported by an economically profitable,socially responsive and environmentally responsible energy sector with a global,long-term vision(IEA, 2001).