Smart infrastructure as a driver for sustainable smart cities
Today, 73 % of all European citizens are living in cities. Until 2050, this percentage will be growing up to 80 %. Cities have been accountable for two thirds of the CO2-emissions in Europe. This makes it mandatory that cities need to become more sustainable if the EU climat targets shall be reached.
Traditionally, the infrastructure of cities has been set up with independent, separated systems for electricity, heating, cooling, mobility and broadband communication. Digitalization and an increasing share of electrification in the heating, cooling and mobility sector are paving the way to sector coupling and an integrated approach for city quarters. Smart infrastructure integrates electricity, heating, cooling, mobility and broadband communication. It does not increase the efficiency of each sector separately, but it realizes synergies between the sectors and thus optimizes the overall efficiency of the system.
Additionally, such smart infrastructure enables and supports smart customers services for the urban space inhabitants like e.g. e-car sharing or a digital end customer platform. To be more specific, let us have a closer look at the supply of heating and cooling for buildings. Traditionally, two separated systems have been installed, one system for the heating (e. g. a heat boiler, a cogeneration unit or district heating) and the other for the cooling supply (e. g. a cooling unit or district cooling). New, highly energy efficient buildings require less heating at lower temperatures and less cooling at higher temperatures.
The rapprochement of the supply temperatures enables a single, two-pipe system to supply both heating and cooling. This simple two-wire system (with a warm and a cold pipe) is also known as a cold heating network. Cold heating networks use central generation units for maintaining the temperatures of the warm and the cold pipe in a defined range suitable for operations. In each building, heat pumps are used for the generation of the desired temperature levels for heating, hot tap water and cooling. The heat pumps are supplied through the city quarter electricity grid and controlled via the local broadband grid.
In a European tender in 2018, E.ON won the concession to build and operate such a cold heat network for Berlin TXL. Going one step further includes adding a local electricity grid supplying e-chargers for e-cars and other electromobility services with decentralized, renewable energy generation and an overall energy management system. Adding a battery system and combing it with a multilayer thermal storage system allows to significantly reduce the peak load of the overall city quarter electricity demand, Additionally, it enables the provision of grid services for the supplying electricity grid operator.