Today, energy production stands for a large share of global carbon emissions. Consequently, reducing our energy use is an important step towards climate neutrality. The report “Reduce, reuse and reimagine – Sustainable energy development in the city” explores how different techniques can be applied to re-use energy, minimising emissions and waste.

Designing and planning the communities and cities of the future will involve not only saving energy, but also developing smart energy-efficient solutions focused on the re-use of energy. Great amounts of energy are currently wasted in our cities.

Did you know that fuel combustion for electricity and heat production and fuel losses account for more than 50 % of the EU-wide greenhouse gas emissions? With modern technology, a large share of energy can be reused.

Great potential to reduce energy

For example, in Germany are great potential to reduce energy consumption, particularly since fossil fuel consumption in Germany’s residential sector is among the highest in Europe. It is possible to achieve an 80 per cent reduction by 2050, over 2008 levels, in final primary energy consumption in Germany’s residential sector if we change the way we reduce, reuse and reimagine energy. The right approach to reducing energy consumption will give cost savings of up €13.34 billion in Germany.

Energy waste costs billions

In the UK, energy wasted in the electrical system – before it even reaches homes and industry – costs billions of pounds. Currently, £9.5 billion is lost every year. According to the Association for Decentralised Energy, this is over half of the amount spent on electricity by all UK homes.

Waste recycling is a familiar concept for most of us. It became common practice in the mid-70s to decrease environmental pollution and reduce the amount of waste. But what does “re-use of energy” mean?

Re-use of energy can be understood as a smart use of excess energy that would otherwise be dissipated unused into the environment. Re-use of energy comprises clever combinations of different types of energy (e.g. heat, electricity). As a result, the re-use of energy increases the efficiency of energy usage to face the challenges of climatic change and limited fossil fuel resources.

How is energy used in European countries?

In order to analyse how to re-use energy, we must first understand how energy is used in European countries today. In the Insight report 14 different countries are analysed: Denmark, Finland, Belgium, Norway, Sweden, Germany, Netherlands, United Kingdom, Czech Republic, Estonia, Lithuania, Poland, Bulgaria and Turkey. In these countries more than 37 per cent of the final energy consumption is related to transport and 19 per cent to electricity. The main share of energy consumption, 44 per cent, is used for heat generation.

In most countries, fossil fuels are still the main source of heat. Increasing our re-use of energy can substantially reduce the share of heat-related carbon emissions.

Different energy sources can be utilised

Direct fuel consumption accounts for the majority of the energy required for transport and electricity. This energy cannot be used a second time. Instead the report focuses on the energy used for heat – the energy that can be re-used.

Most heating energy is supplied by fossil fuels (26%), followed by renewable energies, including the renewable share of waste-based (10%) and derived heat (8%), mainly from district heating grids. The energy sources vary between the different countries. While some countries depend heavily on fossil fuels, for example Sweden hardly uses any fossil fuels for heating. This proves that even a cold country can get by without fossil fuels.

Even in cases where derived heat is being generated by fossil fuel in heating plants that do not generate electricity, derived heat grids offer opportunities to distribute heat from sources other than fuel combustion. For residential consumers in particular, excess energy from various alternative sources that are currently not utilised can supply derived heat in future.

Energy re-use essential for minimising emissions and waste

The technology required for re-use of energy is already available or will be in the near future. Many previously unused energy sources can be tapped in energy re-use.

In view of the current levels of fossil fuel consumption, energy re-use will be an essential component in abandoning fossil fuels in future. There are a number of methods that can be used to re-use energy.

Abandoning fossil fuels to reduce the consequences of global warming forces us to not only optimise the energy consumption of existing technologies, but also to search for new energy sources that were not previously relevant for us. These new sources need to avoid the main problems of the existing energy structure: limited resources and negative environmental impact through emissions to air, water and soil.

Conclusions

Utilisation of the new resources also needs to be technically feasible and economically affordable. Last but not least, the energy sources need to be accepted politically. The generation of heat for industrial and residential purposes will play an especially important role for a sustainable energy supply in the future.

Energy re-use is already established in many contexts but can be expanded in many European cities through a variation of different methods. The change of the energy supply will also increasingly affect construction costs and rents. In view of the anticipated major investments that are required, targeted support will be instrumental in implementation and may mitigate the impact on construction costs and rents.

Ultimately, though, the development of energy costs and the frame conditions at individual sites will be determining factors in the replacement of fossil fuels. Additional financial and structural efforts are needed – particularly in the residential sector. This huge task can only be solved jointly by society as a whole.