A little pioneering spirit would not harm us
Die Welt recently reported on the “first dark doldrums”. Is something like this also possible in Switzerland?
Switzerland also has days with little wind and sunlight, of course; however, around 60% of the electricity supply here comes from hydropower, which offsets this. Germany made the decision to switch off all nuclear power plants, although energy policy was not ready for this step. In Switzerland, we have also set the goal to phase out nuclear energy, but we have not set a binding deadline for it.
Ramping up climate-damaging power plants seems an unfortunate solution.
Absolutely. In Switzerland, however, we do not have any of the coal power plants that still account for a significant share of the electricity mix in Germany. Of course, we too need to be able to compensate for seasonal fluctuations, as photovoltaics from the Swiss Plateau supply around 75% of the annual produced energy in summer and 25% in winter.
How does this compensation work?
There are two main components. The reservoirs of our hydroelectric power plants are large energy storage systems and offer seasonal flexibility in the production of electricity. In addition, our connection to the internation al electricity grid allows us to import electricity in winter and export it in summer. Historically, this has come about because other countries have an excess of electrical energy during the winter. As our neighbouring countries will focus more on winter production in future, e.g. from wind farms that benefit from the stronger winds in winter, there will continue to be synergies.
What about more short-term fluctuations?
Of course, these still exist – on the production and consumption side. We compensate for this mainly with hydropower, as it is relatively easy to change production. Nuclear power plants, on the other hand, supply so called “base energy”. These tend not to be run up and down because it also increases cost efficiency: high capacity utilisation means lower costs per kilowatt hour.
How does one identify the current electricity demand?
Supply and demand are compared in advance on the basis of requirements predictions via the electricity market. This means that tomorrow’s electricity production is already being planned today. During the day, these forecasts and schedules of the power plants are once again adapted via the electricity market. However, it also requires a realtime comparison, as forecasts are always flawed. Imbalance in consumption and production leads to a change in frequency due to physical circumstances. This can be measured anywhere in the grid and used as a signal to adapt production at short notice.
Your research also includes not-centralised approaches.
At the highest voltage level, there is actually only one stakeholder responsible for the state of the transmission grid: Swissgrid. There are various opera tors at the lower voltage levels, but even there the grid is mainly operated centrally. In future, the grid will have to be regulated more dynamically due to the distributed resources. This also includes controlling the consumer side. If many larger devices could be integrated into the control of the electricity grid, there would be new room for manoeuvre: an electric car does not always need to be charged exactly when it is plugged in. Ideally, such control signals are determined in a decentralised manner.
Can grid operators control when electricity flows?
Yes and no. It would actually be an opportunity to relinquish some control over certain flexible consumers such as electric cars. In return, they benefit from certain ad vantages, such as lower energy costs. Some thirdparty providers are already testing this. This is tricky in terms of data security and privacy, as data need to be exchanged in order to optimise the use of this flexibility.
What would be an alternative?
Regulating consumption with finely adjusted electricity rates. The prices would reflect the current situation in the electricity grid and automated chargers would react dynamically to this without receiving direct control signals or sharing a lot of information.
So is it better to use electricity guzzlers on a low rate?
Precisely. But always bearing in mind that electricity customers and grid operators have different motivations. The operators aim to minimise peak consumption so as to avoid having to expand their systems, while customers simply want to minimise their costs. Bringing together these “target functions” is not that easy.
You recently came to the conclusion that a fossil-free energy supply is technically feasible.
We have modelled the resources required for a stable Swiss electricity grid, always looking at various scenarios and showing which alternatives are available. It turns out that we can do without fossil fuels and nuclear power plants. Providing a factual basis for the political debate was important to us. It goes without saying that this requires a strong expansion of renewable energy sources and that imports and exports are also important.
As a technical expert, what motivated you to take this position?
In the past, I have mainly dealt with purely technical issues. After my return from the USA, part of my work focused on energy system modelling, i.e. what the electrical energy system could look like in 2050, for example, which automatically involves a political aspect. But is it not also the role of science to comment on such questions with facts? It was important for me to point out that a clean energy future for Switzerland in various ways is possible.
And where are we today?
Even if the expansion on roofs is progressing well, wind energy and alpine photovoltaics in particular are struggling. Solar power in the mountains does not have to encroach on unspoilt landscapes. There needs to be a tradeoff between energy production and landscape protection. Some pioneering spirit, like in the early 20th century, would not harm us.
What do you think of the “power supply gap”?
The term is unfortunate because it implies a deficiency. Swiss energy policy has always been designed to ensure that we are integrated into the European grid and export in summer and import in winter. It makes sense to make the most of synergies with our neighbouring countries, also in future, in order to keep costs as low as possible. Importing in winter is therefore not bad perse, but makes economic sense.
So, no power outages?
In complex power grids, power failures or blackouts can occur frequently, unfortunately. There have also been examples in Europe in recent years; however, this has more to do with the stability of the grids, as they are extremely dynamic systems. This is challenging and will certainly not get any easier with renewable energies, but it is also incredibly exciting.
