Building a Sustainable Future in Cities

With around 55% of the global population residing in cities in 2019, urban buildings are high emitters.

The operation and construction of buildings accounted for 35% of world energy demand in 2019, which will keep increasing, with 50% growth expected by 2050. Emissions reach 38% of total global share.

Renewable energy currently accounts for only 20% of urban energy use, with around two-thirds of this in the buildings sector.

Integrating renewables into buildings is greatly influenced by city planning and vision for both immediate- and long-term development objectives.

Smart design in new construction is a must. However, most efforts to reduce buildings’ energy use need to centre on improving efficiency and promoting renewable energy for existing structures.

Municipal governments can influence the decisions of builders, owners and users of buildings through a variety of regulations and incentives.

Cities can make it a requirement that existing buildings adhere to minimum requirements for energy performance expressed in a variety of ratings systems.

The systems may also be reflected in municipal building codes or ordinances that require the integration of renewable energy into buildings.

Ramping up the share of renewables is central to making urban energy use more sustainable – a strategy that needs to be paired with efforts to increase the efficiency with which energy is used in buildings.

Energy used for heating and cooling purposes accounts for half of global final energy consumption and generates 40% of energy-related CO₂ emissions.

Renewables-based electrification is a key pathway to the decarbonisation of heating and cooling.

The flexibility of the urban power system to integrate more variable renewables (VRE) can be enhanced with demand-side appliances such as heat pumps which provide heating and cooling services for individual houses or an entire urban area through their integration with district heating and cooling networks.

Scaling up the deployment of heat pumps may benefit from policies such as including minimum performance standards and redesign of tariffs.

In densely populated urban areas where space for utility-scale plants is scarce, decentralised solar PV systems can be integrated in new and existing buildings.

Solar thermal systems can be placed on roofs, facades, balconies and any outside building area.

For commercial and service buildings that have high and constant thermal demand, solar water heating systems are often used to achieve cost savings.

With climate change, buildings’ cooling demand keeps rising. A number of measures can help decarbonise the sector, e.g:

• improved insultation and building thermal envelopes
• better technical efficiency (such as through the use of heat-pumps)
• increased renewable energy to power cooling systems.

Dubai and Boston are among the cities that use electrically chilled water integrated with cold storage for district cooling system, providing potential to utilise renewable electricity.

Smart grids allow higher shares of variable renewables and improve system efficiency.

An estimated 20–30% of energy consumption in buildings could be saved through optimised operation and management, without major hardware changes within buildings.

District heating and cooling based on renewable energy can reduce electricity bills, benefiting low-income families while increasing their access to clean and affordable energy.

See how two cities in China used geothermal and wind resources in district heating and cooling, extending energy access, lowering prices and bringing health benefits to their communities.