"Doing nothing will result in a major power deficit"

If Switzerland were to fully rely on heat pumps and electro-mobility – and no other measures are instituted – there is a risk that an enormous power deficit would occur in the winter. This is the conclusion drawn in an Empa study. The study is fuel for debate, and has received a great deal of praise as well as criticism. "Mission accomplished," sums up Empa researcher Martin Rüdisüli.

If we rely on heat pumps and electric vehicles to protect the climate, we will not have enough power in the winter. Is that the key message of your study?
There are several messages. But in principle this is the main one. If we increasingly heat our homes with heat pumps, drive electric vehicles, and do so without nuclear power and lots of photovoltaics – as is the current vision – we will have a major power deficit in the winter. That is the case if we do nothing, for example if we do not produce additional renewable energy and if we do not find additional efficiency measures or storage options.

How did you reach this conclusion?
We expect heating energy demand to decrease by about 40 per cent thanks to refurbishment measures. In the future, heat pumps will cover 75 per cent of the remaining heat demand. In the area of mobility we assumed that about 20 percent of kilometres driven will be with electricity – that is almost two thirds of all journeys. Bottom line, power consumption will increase by 25 per cent.

The Federal Energy Strategy 2050 expects a decrease in power consumption. Your study anticipates higher consumption. Why?
It's difficult to forecast how total consumption will develop in the future. We did not want to depend on prognoses and chose a simpler approach. We looked at the current consumption values and asked ourselves: What if we continue as currently envisaged without implementing additional measures?

What additional measures would be needed to bridge such a power deficit?
Mainly options to store energy over a day as well as seasonally. I am not thinking only about power storage. The different areas would have to be coupled – battery storage, pumped storage, heat storage as well as power-to-gas.

You see your study as food for thought. Does that mean your study is primarily provocative instead of realistic?
On the contrary. The study is extremely realistic. Real measured data was used rather than average values or prognoses. But it is a "what if story" just the same. Our study indicates: If we do not institute measures that go beyond those that are currently in place, we will have to import lots of electricity or produce it with gas-fired combined-cycle power plants.

Your study anticipates that in the future all electric vehicles and heat pumps will be using electricity at the same time. This conclusion has drawn criticism because load management has not been included in the consideration.
Load management truly has great potential. Load management also helps improve utilisation of stochastic renewable energies such as solar power. We would like to look at these possibilities in an additional study. In this first study we primarily analysed what would happen if we only implement the envisioned measures – and do nothing else.

Did your study achieve its objective?
Totally. There was a great deal of feedback – mostly positive. We indicated that the winter could become a problem if we continue to uncritically pursue the relatively simple route that is accepted today.