If the switch to renewable energies is to succeed, there needs to be more electrification and networking of buildings and mobility both regionally and locally. A conversation with Dr Kristina Orehounig, Head of the Urban Energy Systems department at the Swiss Federal Laboratories for Materials Testing and Research (Empa).

Dr Orehounig, what challenges does the Swiss energy system face?

At national level, the expansion of renewable energy sources is definitely a challenge, because Switzerland is lagging behind in this domain. Managing to increase energy efficiency whilst consuming electricity more carefully is another area that is just as important. It is clear that we will have to import energy in the future as well, although the question is in what form and when. Networking with surrounding countries will continue to play a central role. The best framework for this would, of course, be an energy agreement, or at least an electricity agreement, with the EU. Especially if hydrogen technologies become more widespread and the corresponding infrastructure is built up in Europe. Switzerland should be a part of this too.

Is the situation different at regional and local level?

If the switch to renewable energies is to succeed, then ensuring more electrification of buildings and mobility, both regionally and locally, are among the most important measures to be taken. In a broader sense, we are talking about sector coupling, i.e. connecting the energy, heat and transport sectors. One example is to use waste heat from cooling and industrial processes wherever possible. There is still considerable potential in this area. Similarly, renewable energy needs to be generated locally – in other words, production and consumption should occur in the same place. In addition, measures for increasing energy efficiency must be pursued.

Kristina Orehounig, Head of the Urban Energy Systems department at the Swiss Federal Laboratories for Materials Testing and Research (Empa).
Kristina Orehounig, Head of the Urban Energy Systems department at the Swiss Federal Laboratories for Materials Testing and Research (Empa).

Is there a production technology that will dominate in the future?

It will prove impossible for one single technology to solve the climate problem and phase out today’s nuclear energy technology, but there will be a range of different technologies, as is currently the case. Hydropower will certainly continue to play a dominant role in the future. The same applies to solar energy, whose importance is constantly increasing. Geothermal energy, biomass and wind energy also play a less significant but nonetheless important role in Switzerland. One of the major challenges is that renewable technologies have their energy potentials at different times, so they are not always available when we need them. This means that the energy transition can only succeed if storage and energy conversion technologies are increasingly used together as a system. This is the only way we can close the energy gap in the winter months. More specifically, the aim is to network the various energy sources and consumers with each other and to integrate a wide range of storage technologies into this system.

How can your «Energy Hub Approach» help to solve these challenges?

The Energy Hub Approach is designed to regulate energy flows as effectively as possible within a system – be it a neighbourhood or an entire city – and to balance peak loads. Consequently, in the not too distant future, we will have hubs consisting of some buildings, e.g. historic buildings, that still consume energy, but with many other buildings that are energy positive and able to supply energy. In other words, they will be designed to provide renewable energy. The desired balancing effect can be achieved by means of an electricity grid or a heating grid. What is more, we will use both short-term storage in the form of batteries and long-term storage, for instance in geothermal reservoirs. Taking economic criteria into account, this will enable an entire neighbourhood to supply its own energy. Perhaps not all the electricity it needs, but a large part of it.

You mention neighbourhoods and buildings. Is production shifting to the cities?

Our cities and building parks are ideally suited for generating solar energy. The use of geothermal energy by means of heat probes is also relevant, although the possibilities for drilling the necessary holes in urban areas are limited. In addition, waste heat from incinerators and industrial or air conditioning plants is increasingly being fed into heating networks. The role of cities is at least as important when it comes to energy consumption. This is illustrated by the proportion of one-third of households that makes up nationwide consumption. Not least because fossil fuels are still used in cities in some cases. The fact that another third of Switzerland’s total consumption is due to mobility shows the extent of leverage that exists in our cities. This demonstrates how crucial it is to push ahead with the electrification of mobility and to use renewable energy sources as much as possible. Demand-side management must also be expanded so that energy consumption corresponds to availability and is better matched to the relevant energy potential.

Our cities are ideally suited for generating solar energy. The role of cities is equally important when it comes to energy consumption.

Dr Kristina Orehounig, Empa

Will there be solar panels and wind turbines on most houses in the future?

If we want to switch to renewable energies rapidly, then the thing we need most of all is roof space for solar production. In the current scenarios, it is assumed that about a quarter of roof surfaces will have to be equipped with photovoltaic systems by 2050. Alpine solar and wind power plants will also be needed. There are solutions for small-scale installations of wind turbines in urban areas, but widespread expansion is questionable due to the noise they cause and the wind potential.

Do you have a solar system on your roof yourself?

Yes, there is a solar system on the roof of the house we have just moved into. As tenants, we don’t use the energy generated ourselves though; it is fed directly into the grid. Having said that, we have bought into a large-scale project operated by an energy provider on school roofs. This way, we can obtain enough energy to meet our needs as a family. Here, too, the problem is that solar power is not always available, especially in the evenings.


Silvia Zuber
Silvia Zuber

Project Manager

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