KNX Award winners

KNX city – the sustainable city

What form will communication take in cities in the future?

Information and communication technology (ICT) will be an essential element of smart grids and infrastructure in the future. ICT is a vital component of the holistic solution needed to create a sustainable city. KNX will provide all of the interfaces needed between the city of the future and smart grid communications infrastructures, itself becoming an integral part of the smart grid. Because it brings together buildings, transport, energy generation and infrastructure in a holistic way, KNX can already offer innovative solutions today for making cities more sustainable while exploiting the potential of transdisciplinary approaches.

Energy-efficient buildings are the cornerstone of sustainable cities


Energy-efficient buildings are at the heart of any sustainable city. KNX offers a wide range of solutions for improving the energy efficiency of all kinds of buildings, from private homes to large company premises. These include load management concepts, which always involve sensors and actuators. The sensors gather information, for example consumption figures, or information on the status of a given component, while the actuators respond to this information by triggering an action. Actions can include making or breaking an electric circuit, turning on or off a device such as a heat pump or a household appliance, or switching on or off more conventional power consumers. KNX energy actuators are particularly useful devices here, because they not only measure the power consumption of electric circuits, but also switch them on or off.


KNX touch panels enable the control of various household appliances to switch them on or off electronically. This represents a major benefit over other systems, as of course simply turning the power on or off is not sufficient to properly start up or shut down a typical domestic appliance. KNX also offers a wide range of interfaces for intelligent connections between a KNX system and a heat pump. Wall-mounted home charging points for electric vehicles can also be integrated into KNX networks via actuators, enabling the charging process to be started or stopped from a KNX touch panel. If the building has its own micro power plant, for example a photovoltaic system, any KNX connected charging points can be configured to charge the vehicle using only electricity produced on-site.

With KNX, electric cars are an integral part of intelligent buildings

For a city’s electricity supply, electric vehicles mean an increase in power consumption. Not only that, but electric cars are likely to use the most electricity in the evening, as drivers return home from work and plug their vehicles in to be charged overnight. This happens at a time when private households use the most electricity anyway, so the additional demand from electric vehicles will pose a threat to the city’s reliability of supply. This is because nearby transformers could become overloaded, but also because the excess demand calls for additional generating capacities. Electric vehicles are likely to stand unused overnight for longer than it takes to charge their batteries. In principle it should therefore be possible, instead of charging them in the evening, to charge them at night or even in the very early hours of the morning.


This would help considerably to spread the load more evenly over a 24-hour period. Where different electricity tariffs apply at different times of day, it can even make sense to stop or start the charging process at specific times so that charging takes place when electricity is cheaper, or to make maximum use of the power generated by an on-site photovoltaic system.


KNX infrastructure solutions allow several buildings within a city to be networked with one another as though they were just one building. In the sustainable city of the future this can be very beneficial, for example for building operators or housing associations responsible for several different buildings or sites. If a building operator has already a micro power plant (e.g. photovoltaic system) on one site and would like to build a car park for electric vehicles at a second site, this KNX solution can be used to ensure that the vehicles are only charged if the power plant at the other location is generating enough electricity. The KNX infrastructure solution is of course also suitable for controlling all traditional KNX applications.


The sustainable city of tomorrow needs a seamless flow of communication from the power grid to the city, on into the building or household, and back to the grid. In the sustainable city of the future KNX will be responsible for communication at building level and will also provide all necessary interfaces to the smart grid to facilitate tariff management, power generation management, load management and, where relevant, storage management throughout.

Renewable energy is an integral part of any KNX-controlled smart building

Renewable energy is constantly gaining in popularity compared to traditional energy sources. But renewable energy sources fluctuate, producing electricity only when, for example, the sun is shining or the wind is blowing. This poses challenges for electricity grids. If, for example, on a sunny day electricity is fed into the local grid from photovoltaic systems in quantities far exceeding the load on the grid (i.e. the demand for electricity) at that time, this can cause voltage problems. The other way around, if there is a demand-supply gap because demand is high at a time when renewable power generation is missing or collapsing, this gap must be filled by electricity from conventional power stations that need to be started up at short notice. One potential solution that is frequently discussed is the storage of electrical energy. However, it is hardly realistic to store electricity on the kind of scale necessary.

Power Generation

In future, power generation management and load management will therefore be essential. KNX offers load management solutions that permit the adaptation of conventional electric loads and electric loads from HVAC systems, white goods and electric vehicles according to the amount of renewable energy generated by the building, or in response to a electricity tariff fluctuating in time (determined by the amount of renewable energy produced in that section of the grid), without any loss of comfort or convenience. All solutions available so far have had one thing in common: that they can interact with each other within the building, but not with the outside world. KNX will change all that.