Heat pumping technology instead of oil heating, electric cars instead of petrol vehicles: in Switzerland, all the indications are pointing to electricity. What does this mean for the operators of local grids – known as distribution grids? And how are they preparing for further electrification? We put these questions to two specialists from Energie Thun AG, which operates the distribution grid in the city of Thun.
Interview
More and more solar plants, heat pumps and charging stations for electric vehicles are being installed in Switzerland. What does this mean for the distribution grid?
Christoph Woodtli: So far, solar plants have had the greatest impact on the load on the distribution grid. This can be seen in the «midday peak» period, for example: until now, we had to buy a lot of electricity at lunchtime, when electricity consumption is high due to cooking. On a sunny day, this peak demand no longer occurs because solar plants produce a large amount of local electricity. When it rains, on the other hand, there is still a midday peak. This means that the load on the grid fluctuates much more than before.
Is this a problem for your distribution grid?
Roland Schindler: No, not yet. We have invested large sums in the distribution grid in the past, and are now able to capitalise on these investments. In recent years, only a few isolated grid enhancements have been necessary due to solar plants. That is standard procedure for us and was easy to manage. However, we need to reinforce more connection lines to individual properties. This ties up resources that are then no longer free for other projects.
Large numbers of solar plants will be installed in the coming years. What would it mean for your distribution grid if, for example, solar power production increased tenfold in the long term?
Roland Schindler: We are not currently anticipating a tenfold increase. But there will certainly be a massive rise. The extent of the challenges we face will depend on the volume and speed of expansion.
The load on the grid will continue to grow due to the electrification of the heating sector and mobility. How are you preparing your grid to deal with this?
Roland Schindler: With target grid planning. That involves updating the current grid for the future – taking into account all the influencing factors known to us, i.e. technological, social, political and regulatory aspects. We outline the most likely scenario of how electricity consumption and local generation will develop, and work out the target grid on the basis of this data. For example, if we expand the district heating network and gradually dismantle the gas network in one of the districts of Thun, many homeowners will switch from gas heating to district heating, but some people will opt for heat pumps. We take this additional electricity demand into account in our target grid planning. It is the most important strategic and operational tool for getting our grid ready for the future. The latest target grid planning is concentrating on the focus years 2035 and 2050. Based on this, we decide which priorities to set for the further development of the grid and how to invest our funds most effectively – also with regard to the climate goals of our owner, the City of Thun.
Is target grid planning a new tool?
Roland Schindler: No, we have already prepared target grids several times. But the tool is becoming increasingly dynamic. We used to carry out target grid planning with a five-year focus. We are now shifting towards an annual process, which partly determines our investment planning for the following year.
To avoid expensive grid expansion, we need the support of our customers.
Christoph Woodtli, Energie Thun AG
When it comes to investments, how can expensive expansion of the distribution grid be prevented?
Roland Schindler: As far as grid expansions and enhancements are concerned, there is a risk that grid operators will make allowance for unnecessarily high power in order to be prepared for all eventualities. For example, they could consider that all the future solar plants in a neighbourhood will feed the total volume of electricity produced into the grid. However, this is not very realistic and makes grid projects more expensive. We choose the following approach: we only carry out as much grid enhancement as necessary, and then monitor it, i.e. we observe the load on the grid. The distribution grid is in a better situation than Swissgrid’s transmission system: it can be developed more rapidly and isn’t slowed down by planning and approval processes that take ten years or longer.
Christoph Woodtli: However, to avoid expensive grid expansion, we also need the support of our customers. In the best-case scenario, they will adapt their electricity consumption more and more to the current load on the grid.
How is that supposed to work?
Christoph Woodtli: By offering financial incentives and not patronising customers. Dynamic electricity tariffs are a promising tool. For example, drivers of electric cars can decide for themselves whether they want to charge their vehicle immediately and at a higher tariff – or do so later, when the grid is less congested and the tariff is lower. Grid operators should have the courage to try out solutions like this with a few voluntary customers, and gather practical experience. Digitalisation helps us to do this: if the various installations that make up the energy system increasingly communicate and coordinate with each other, decisions such as how to optimise the charging of an electric car can be automated. Drivers then no longer need to actively concern themselves with the question.
This is moving towards the idea of a smart grid. How realistic do you think this is?
Roland Schindler: A smart grid can help us to overcome the challenges of the future. Most of the high-voltage and medium-voltage grids are already smart grids, which means that the various systems communicate with each other. This is not yet possible across the board in the low-voltage grid. For example, every domestic junction box would have to be smart and communicate with the large consumers in the building. That is still a long way off. We need to think carefully about which initial steps we should be taking in this direction. After all, digitalisation should never be an end in itself. Sometimes, a conventional solution is simply cheaper and makes more sense. For example, a 400-volt cable line replacement without extensive civil engineering work may turn out to be more economical overall than a local voltage controller with higher investment and operating costs.
Christoph Woodtli: I see things the same way. In my opinion, the idea of «intelligence instead of copper», which is often associated with the smart grid, is the wrong approach. The electricity supply of the future needs both copper and intelligence.
And it requires more storage systems. Will it mainly be electric cars that take on this role in the distribution grid?
Christoph Woodtli: Electric cars are useful for us as flexible loads. In the best-case scenario, we can choose to postpone charging processes if necessary, or reduce the charging power to ease the load on the grid. It is still unclear whether and how quickly bidirectional charging will become established, allowing the electricity from a battery to flow back into the grid. On the one hand, the charging stations required for this are still very expensive at the moment. And on the other hand, the financial incentive must be high enough for owners to make their electric car batteries available for storage in the first place. As great as the potential of bidirectional charging may be, there are still many practical questions to be answered.
Reservoirs and pumped storage power plants in particular remain a particularly efficient storage solution.
Roland Schindler, Energie Thun AG
What other storage technologies do you see for the distribution grid?
Christoph Woodtli: The idea of neighbourhood storage systems has been around for some time. These could receive a boost from the consolidation legislation – the new Federal Act on a Secure Electricity Supply from Renewable Energies. This is because the law provides for Local Energy Communities, or LECs. These are made up of electricity consumers from an entire neighbourhood, who join forces with producers of renewable electricity and storage operators to freely supply each other with electricity. Neighbourhood storage systems become financially attractive because no grid utilisation fees are charged for the electricity stored and released.
Roland Schindler: Reservoirs and pumped storage power plants in particular remain a particularly efficient storage solution. Even if the supply of electricity is becoming increasingly decentralised, centralised storage systems of this kind continue to make a lot of sense due to their size and high efficiency.
Are specific projects for neighbourhood storage facilities in Thun already being planned – by housing cooperatives or by your company, for example?
Christoph Woodtli: No, I am not currently aware of any projects. However, they will certainly come about as a result of the changes brought in by the consolidation legislation.
All grid levels are affected by the new challenges associated with supplying electricity. How do you liaise with the operator of the upstream grid – in your case BKW?
Roland Schindler: We have always had a contractual agreement with BKW regarding the maximum power we can take from the upstream grid during normal operation. I am now looking forward to analysing our latest target grid planning, which focuses on the period up to 2050. It will show whether we will have to adjust this power in the future due to the additional loads on the grid. But I don’t expect that to be the case: the power will probably remain sufficient for the next 20 years or so.
In a few years’ time, it is conceivable that, for example, on a sunny Sunday lunchtime, the volume of solar energy fed in to the grid will be greater than the current consumption peak. Have you already taken measures to be able to regulate solar plants if necessary?
Roland Schindler: In the future, producers will have to make the necessary arrangements for standard control after submitting their technical connection application (TAG). On the grid side, we now have the conventional ripple control system and the smart meter system. However, more innovative systems and applications will be needed to flexibly and dynamically influence energy recovery in the future.
Due to the growing complexity of the energy sector, we are offering fewer and fewer run-of-the-mill jobs, but instead, there are all the more extremely interesting expert jobs available.
Roland Schindler, Energie Thun AG
What role does the shortage of skilled labour play in the further development of distribution grids?
Roland Schindler: There are two aspects that play a role: firstly, sufficient skilled workers such as grid technicians and electricians must be trained. However, higher numbers of specialists currently seem to be retiring than arriving. Secondly, job profiles are changing. Grid technicians increasingly need to have an understanding of IT and be capable of managing technical applications, for instance. They require a networked way of thinking that goes beyond departmental boundaries. For the grid of the future, it is therefore not only the number of specialists that is crucial, but also the fact that we need people with broad, constantly updated expertise. Due to the growing complexity of the energy sector, we are offering fewer and fewer run-of-the-mill jobs, but instead, there are all the more extremely interesting expert jobs available.
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