Energy supply in “smart cities“


The world’s cities are already consuming 80 percent of all the power we generate. And energy consumption is increasing, as more people want to live and work in cities. How can cities and the people who live in them make sure that energy is used efficiently in future?

Interconnection is the key

Many German research centres are hunting for answers to this question. One of the buzzwords is ‘interconnection’: if the energy supply is interlinked with all the other components of city life such as its population, transport, buildings and water and food supply, it can be designed in a much more efficient way. In such ‘smart cities’, an electric car knows exactly when its owner will want to drive it. This means the car can plan when it next needs to recharge, ensuring it does so at a time when electricity is at its cheapest. The car also knows where there are free parking spaces, so the driver does not have to search for one. This saves energy and time.

Digital concepts for smart cities

The Fraunhofer Institute for Industrial Engineering IAO in Stuttgart is working on a solution for this kind of intelligent energy supply. Information and communication technologies (ICT) are at the heart of its ‘Triangulum’ project. Together with European partners, the IAO researchers are working on a concept that will digitally interlink the individual components of a city. The project partners are first testing their idea in selected European cities.

Pilot projects in major European cities

In one part of Manchester in the UK, for example, conventional cars will soon be a thing of the past. Local residents will use only electric vehicles to get from A to B. The necessary power will come from a self-sufficient and digitally-controlled energy network. This independent energy network is not connected to the city’s central energy supply grid. It will efficiently coordinate energy production and consumption at the local level, providing the area’s population with heat and electricity. Surplus energy will be stored in a fuel cell.

A new ‘smart’ district is also being planned in the Dutch city of Eindhoven. A digital tool will allow residents to rent electric cars and reserve parking spaces. The idea is as follows:

  • households and providers of utility services will be interlinked, a method known as “smart grids”
  • supply and demand can be precisely matched
  • resources can be saved

Self-organizing electricity networks

Many of the models for smart cities of the future rely on renewable energies such as solar and wind power to generate electricity. But what happens when there is no wind and the sun is not shining? Will the city then face a blackout? Currently, such fluctuations are balanced out by the power grid operator, but city districts with self-sufficient grids will not have any such operators in future. One idea is for households themselves to use special ‘smart meters’ to compensate for the fluctuations. Depending on current supply and demand levels, they will either increase or reduce the power consumption of electrical devices. How well this will work in practice has been put to the test by a group of researchers at the Max Planck Institute for Dynamics and Self-Organization in Göttingen. Physicists in the ‘Network Dynamics’ research group used a mathematical model to simulate what happens when measurement and control instruments in households react to fluctuations. They discovered that smart meters can indeed balance out the variations. The solution has other advantages, too: millions of these small, intelligent devices cost less than central infrastructures, and are also less prone to cyber-attacks.

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