Sustainable development of energy, water and environment systems

Due to the problems related to energy supply and the threatening consequences of the global climate change the need for inevitable changes in energy supply is becoming more and more obvious. This includes not only a change of the energy sources, but also in energy carriers and technologies for their conversion into useful forms of energy, and a change in the ways energy is being used. Based on present knowledge, the only energy sources that satisfy the sustainability conditions are the renewable energy sources - direct solar insulation and its consequences (wind, hydro, biomass). As the renewable energy sources cannot be utilized directly in most of applications there is a need for energy carriers which can be produced from renewable energy sources and which can satisfy all the energy needs at the end use, again satisfying the sustainability conditions. Electricity is one such energy carrier which may be used in most but not in all applications. There is a need for other energy carriers in the form of fuels which can be stored and be used in transportation and for covering needs for electricity in the periods when the renewable energy sources are not sufficient. This is a role that hydrogen can fulfill in a future energy system - hydrogen satisfies the sustainability conditions, can be produced from renewable energy sources and together with electricity can satisfy all the energy needs. Papers selected from the Dubrovnik Conference on Sustainable Development of Energy and Water Systems deal with different aspects of sustainable hydrogen production and utilization, but also with renewables which may be used in hydrogen production. The 4th Dubrovnik Conference on Sustainable Development of Energy, Water and Environment Systems, held in 2007, was dedicated to the improvement and dissemination of knowledge on methods, policies and technologies for increasing the sustainability of development, taking into account its economic, environmental and social pillars, as well as methods for assessing and measuring sustainability of development, regarding energy, transport, water and environment systems and their many combinations. Sustainability being also a perfect field for interdisciplinary and multi-cultural evaluation of complex system, the Dubrovnik Conference has during the first decade of the 21st century become a significant venue for researchers in those areas to meet, and discuss, share, and disseminate new ideas.