Technologies and interventions in the field of energy form a core part of the smart and sustainable cities. Aimed at improving energy efficiency, generating low carbon energy, modernizing the infrastructure and creating high quality living environment for citizens, these measures are introduced into different spatial contexts – on a building, district and city level. As a result, they can be divided in two types:

• Energy efficiency in buildings, which covers retrofitting of old buildings as well as construction of new buildings, the use of renewable energy sources, smart building services, etc.
• Energy system integration, which provides solutions on a larger scale such as district heating and cooling, photovoltaics, geothermal energy, waste management, etc.