The share of global energy used by cities is rising fast. In the early 1990s, cities used less than half of the global energy supply. Today, it is nearly two-thirds. Because of this growth, any decisions made for the future of energy and climate needs to build on a robust understanding of urban energy systems.
A sustainable urban energy system needs low carbon technologies on the supply side, and efficient distribution infrastructure as well as lowered consumption on the end-user side. Cities therefore need to shift from the current unsustainable fossil fuel energy generation towards using renewable energy sources, not only because of looming resource depletion but also to curb the negative externalities such as pollution and greenhouse gas emissions. At the same time, energy consumption must be reduced by changing consumption patterns and adopting energy saving techniques.
Photovoltaics, wind power, biogas and combined heat and power production are just some of the examples that cities around the world have already experimented with as reliable ways to achieve a more sustainable energy supply mix towards a greener urban economy.