Energy is certainly the most important resource, factor of production, commodity in the world economy, and human beings always try to obtain it in increasing quantities to ensure their own survival, to obtain more goods and services, to improve their quality of life and well being. Every stage of development is defined by a specific amount of energy. A mode to confirm this link is the positive relationship between Gross Demand Product per capita and Total Primary Energy Consumption per capita. Obviously, the consumption of energy is linked to the population dynamics too. It is forecasted that the world population will be 8 billion people in 2025. Increased population means increased energy consumption. But it is unrealistic to snatch energy unlimitedly and at the same time, energy generation and utilization have, in every case, an environmental impact and cause exhaustion of resource. Based on this background the Authors aim to forecast the probable world energy demand in the future. According to the Authors' scenario, the world energy demand will be 18 Gtoe in 2025, in which 8 Gtoe for developed countries (7.1 Gtoe in 2005) and 10 Gtoe for developing countries (4.3 Gtoe in 2005). In this scenario China and India play a significant role because of their prominent economic growth and population proportion in the future, which means a revolution in the world energy market and then a new international order in the future. The advent of an international energy policy is expected to demonstrate a deferred refund of contributions that some poor people had to give (their liberty and even life) for the benefit of most rich countries in the past. The Authors regard this international equity with great importance because it can alleviate the heavy problems of the future generations. Giancarlo Santoprete, (Department of Business Economies, University of Pisa, Italy, g.santoprete@ec.unipi.it) graduated in Economy and Commerce and then he became a teacher in various University: Bologna, Pescara, Pisa. At present he is full professor at the Faculty of Economics of Pisa University. He is the founder of the Commodity Science Society. He is a member of national and international scientific associations and directs the series of "Technology and economy of the production and the sources of energy" (Giappichelli Publisher) and series of "Routes in alimentary field" (ETS Editions). He is the author of over 200 papers and various books. For his scientific activity he was awarded by the "Ordine del Cherubino" from the University of Pisa. Juan Wang, (College of Environmental Science and Engineering, Tongji University, China, wangjuan@mail.tongji.edu.cn) is majored in Environmental Management and got her Doctoral degree in Tongji University. At present she is an associate professor in Tongji University. She has published many scientific papers in her research fields (eco-city planning, environmental impact assessment, sustainable development). She also has experience in Antarctic for environmental monitor and related research. Now she is a winner of the scholarship between Italy and China to be a visitor researcher in Pisa University for one year and is studying energy and sustainable development.