The United Nations Environment Programme calls for more district energy in cities in a report released yesterday as part of The District Energy in Cities Initiative, in support of the Sustainable Energy for All (SE4All) EE Accelerator Platform.
Accelerating the uptake of energy efficiency and renewable energy in the global energy mix is the single biggest contribution to keep global temperature rise under 2 degrees Celsius (°C) and to reap the multiple benefits of an inclusive green economy. Cities account for over 70 percent of global energy use and, 40 to 50 percent of greenhouse gas emissions worldwide. Half of cities’ energy consumption is for heating and cooling. Any solution for the climate and energy transition must explicitly address sustainable urban heating and cooling, as well as electricity. One of the least-cost and most efficient solutions in reducing emissions and primary energy demand is the development of modern (climate-resilient and low-carbon) district energy in cities.
Modern district energy systems combine district heating, district cooling with combined heat and power (CHP), thermal storage, heat pumps and/or decentralized energy. They are increasingly climate resilient and low carbon, allowing the:
■ Recovery and distribution of surplus and low-grade heat and cold to end-users (e.g., previously unused waste heat from industry or power stations, waste water and use of natural water reserves such as lakes, rivers);
■ Storage of large amounts of energy – such as surplus wind power or surplus heat in the summer – at the lowest cost compared to other energy storage options; and
■ Integration and balancing of a large share of variable renewable power – for example, through conversion to heat and stored for use seasonally or during peak thermal demand.
A transition to low-carbon district energy systems could avoid over 35 gigatons of carbon dioxide (CO2) emissions at low cost by 2050 – equivalent to 58 per cent of the global CO2 emissions reductions required to keep the global temperature rise to 2-3°C. Modern district energy systems could result in a 7 per cent reduction in overall capital investment in the power sector by 2030 – an investment savings of US$795 billion by replacing the use of electricity for heating and cooling and thereby reducing peak and overall power demand.