Sustainable Urban Energy Solutions

Mother Earth is running short of fossil fuels, and climate change is a threat to human civilisation. At the same time the population grows, and people move to the cities. This is a challenge, but also an opportunity.

In modern cities we have cost effective Urban Energy Solutions, which can provide the population with energy services with little or no use of fossil fuels. The problem is how to organise it.

In last century it was a well known fact that a modern city should have infrastructure for traffic, electricity, gas, water, waste water and waste collection.

In modern smart cities we can ad intelligent grids for district heating and district cooling – all depending on the climate zone.

District heating and Cooling – also known as district energy, is a precondition for cost effective use of renewable energy and efficient generation of energy, such as combined heat and power (CHP).

Energy planning

Developing these urban solutions is however difficult. It requires a strong energy policy and local long-term energy planning and collaboration.

Cities in the Nordic Countries have a long tradition for planning district energy and serves as a model for other cities in the world.

The EU has adopted this concept and agreed in May 2009 on a very ambitious directive for Renewable Energy, stating:

  • that member states shall elaborate national actions plans for renewable energy,
  • that local authorities shall consider district heating and cooling for more efficient use of renewable energy and
  • that buildings shall be almost independent of fossil fuels taking into account the more efficient use of renewable energy via district heating and cooling if feasible.

District Energy

In the optimization of the whole energy system, the district energy systems have some important qualities:

  • they can shift between all sources for heating and cooling
  • they can store hot and cold water from fluctuating energy sources for days
  • they can use low quality heat sources
  • they can use free cooling from natural sources

There is a wide range of other urban energy solutions, which goes hand in hand with the district energy. We could mention: waste-to-energy, CHP, large scale solar water heating, off shore wind energy farms, geothermal heating and efficient building systems.

More to come

In the next month I will go more into detail with these opportunities and invite readers to discuss how to implement them in the most cost effective and sustainable way for the society.

Large scale solar water heating can compete with oil boilers, even without any subsidy or tax. The cost of heat from large scale plants is 15 % of the cost of small scale building integrated plants.

Image: Marstal, Denmark, 18.000 m2 solar water heating


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