In recent years, most cities have experienced rapid population growth. Concurrently, international policies have called for substantial reductions of greenhouse gas emissions. Additionally, the resilience of energy-supply systems has become more important. Consequently, solutions to exhaust locally-available sources must be developed to minimize the fraction of fossil fuels for heating, cooling and electricity. This article shows an example of designing a low-temperature heating and cooling grid based on locally-available renewables and waste heat and introduces general hypotheses concerning smart energy planning in urban development zones. Taking an urban development area in Vienna, Austria, as example, it is shown that wastewater, geothermal and (office) waste heat, solar energy, and the heat content of ambient air can play an important role within a climate-friendly urban energy concept and that heating and cooling demand can be covered completely on-site. From an environmental point of view, the concept is promising, as greenhouse gas emissions and the non-renewable primary energy consumption can be reduced by over 70% compared to conventional gas heating, while, based on current (fossil) energy prices, it is economically not fully competitive. The gap could be closed e.g. by CO2 taxes on fossil energy sources or (temporal) subsidies for renewables. Additionally, reservations of stakeholders in the energy sector against this innovative approach must be dismantled.
Special Issue on Cutting-Edge Technologies for Renewable Energy Production and Storage
