Cities are crucial sites for achieving socio-technical transitions in technology and infrastructure systems. Raising building energy efficiency (BEE) through new construction or retrofitting holds particular relevance to sustainability transitions since this requires diffusion of new technologies and energy management practices. In pursuit of this, city policymakers around the world are increasingly utilising mixes of multiple policy instruments.

In April 2010 the Tokyo Metropolitan Government launched the Tokyo Cap-and-Trade Program to reduce energy consumption-related CO2 emissions at the city level. This is the world's first cap-and-trade programme to cover buildings in the commercial, industrial and public sectors. Its main aim is to reduce CO2 emissions from energy consumption in existing buildings in urban areas; therefore, it is called an ‘urban cap-and-trade programme’.

The Shenzhen ETS is the first urban-level “cap-and-trade” carbon emissions trading scheme to operate in China. This paper gives an overview of the economic and emissions situation in Shenzhen and focuses on the development of the Shenzhen ETS regulatory framework. It is devised as an ETS with an intensity-based cap, output-based allocation and a market for trading of allowances. The design of the Shenzhen ETS attaches great importance to coordinate the dynamic relationships between economic growth, industrial transition and emissions control.

Heat pumps are relatively simple appliances. They share similar components to refrigerators and air conditioners and effectively move an external source of heat to where it is needed, such as in buildings for heating or the production of hot water. Their key value is efficiency; for each unit of electricity consumed to operate them, they produce multiple units of usable heat. Because of this, they require much less energy input for a similar heating outcome compared to combustion technologies, making them naturally cleaner and generally cost effective to run.