Photo: Mikal Schlosser

The cities can become fossil-free, if they think 'smart'

Friday 11 Mar 16
by Iben Julie Schmidt


Henrik Madsen
Professor, Head of section
DTU Compute
+45 45 25 34 08


CITIES is short for ‘Centre for IT-intelligent Energy Systems in Cities’.

  • The project is to develop methods and IT solutions for the analysis, operation, planning, and development of fully integrated energy systems in urban areas. The aim is to create a society that is completely independent of fossil fuels.

  • The project is funded by Innovation Fund Denmark and runs from 2014 to 2019.

  • The project takes the form of a partnership involving a wide range of international players from the university environment, industry and both public and private sections of the energy sector.

  • DTU is represented by DTU Compute, DTU Civil Engineering, DTU Management Engineering, DTU Electrical Engineering, and DTU Energy.

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Read also the article 'Clean water on green power' about how a research collaboration between Krüger and DTU Compute makes the wastewater treatment plant Kolding Centralrenseanlæg function as energy storage.

Cities are major energy consumers and thus also CO2 emitters. However, it is precisely the many different urban infrastructures and energy units that may be the key to the development of a fossil fuel-free society, says DTU professor.

Denmark is to be independent of fossil fuels by 2050. This is the government's long-term climate policy target. But a number of Danish cities and local authorities are currently trying to outdo one another in setting new and more ambitious green goals. Thus, the capital Copenhagen has declared that it will be fossil-free already by 2025. But is it possible?

“From a technological perspective, it’s not as difficult as you may think,” says the DTU researcher Henrik Madsen from DTU Compute, with a fair degree of optimism.

What is required, however, is the capacity to think outside the box and apply new, intelligent technologies to interconnections in the energy sector. This is precisely the purpose of a major research project entitled CITIES (please see box) and led by Henrik Madsen.

“In January 2014, it was demonstrated that the entire electricity consumption can be covered exclusively by renewable energy for several days. Here, wind energy covered up to 120 per cent of Denmark’s total electricity consumption. Of course, there is still a long way to go before we can ensure the supply of sustainable energy all year round, but it is definitely possible,” he explains.

Energy systems are connected 

The point is that all energy systems must be connected via intelligent IT solutions to alternate between the different energy sources, depending on what is available and most appropriate at any given time.

For instance, in very windy conditions, excess electricity production is used to heat up water in the district heating system. In this way, the energy can be stored for up to several days, whereas electricity must be used immediately. And it is not only the electricity grid and the district heating system that must be connected.

When you also integrate natural gas, biofuel plants, and other infrastructures such as wastewater treatment plants as well as—not least—the individual households that may, for example, store energy in the masonry, you can be sure of a flexible energy system, where energy can be stored for hours, days, or months, and this will ensure a stable energy supply and the optimal use of the renewable energy.

More intelligent control

The challenge will be to link up all the small, decentralized units that will supply the energy we require in the future, taking over from the small number of large and centralized providers that characterize the sector today. A major part of the solution is to be found in an IT-based ‘smart’ utilization of the ever-increasing volume of data available thanks to more modern technologies, in a new and intelligent form of planning and management.

“The focus of CITIES is on towns and cities, because these urban areas already have much of the infrastructure and complexities that will come to distinguish the coherent energy solutions of the future. However, the systems and the mathematical models we create must, in principle, be able to encompass and integrate information at all levels: from the washing machine in the user’s home to national or continental energy planning, optimization and management,” explains Henrik Madsen.

New technologies are developed

And this is where the mathematics start to become seriously complex.

However, advanced algorithms and mathematical models with many types of data is exactly what DTU Compute excel at. And the CITIES research project also involves a wide range of companies that are to help develop the new technologies such as Smart Meters—which, via regular measurements in the residence, provide important data about energy consumption and requirements—or new smartphone apps that can provide users with tips and hints for how to save energy.

“CITIES will not only bring us closer to a fossil fuel-free future, it will inevitably result in the development of all kinds of new technologies and intelligent solutions that may become important export goods for Denmark,” adds Henrik Madsen.