How electric cars and heat pumps can help Switzerland implement its Energy Strategy

Electric cars and heat pumps could play a major role when it comes to implementing the Swiss Energy Strategy. The Federal Council is aiming for Switzerland’s energy supply to be carbon-neutral by 2050. The plan is for heat pumps to replace oil and gas-fired heating systems and for electric cars to gradually replace combustion vehicles. This will result in a significant increase in demand for electricity – from around 56 terawatt-hours (TWh) a year today to around 75 TWh a year by 2050.

A new report by the Swiss “PATHFNDR” research consortium, which is funded by the Swiss Federal Office of Energy as part of the “SWEET” programme, has now shown that, alongside hydropower, heat pumps and electric cars could be key providers of flexibility for the Swiss power system in 2050. Christian Schaffner, Director of the Energy Science Center at ETH Zurich and Deputy Director of the project, explains: “The two technologies serve to better coordinate rising electricity consumption with electricity production from renewable energy sources. This relieves the burden on the power grid, reduces imports and brings down wholesale electricity prices – particularly in the winter months.”

This flexibility is apparent on an everyday basis. For example, at outdoor temperatures of 0°C, intelligently controlled heat pumps can switch off for up to ten hours in buildings meeting the Minergie standard without a noticeable drop in room temperature. This helps to avoid having too many heat pumps running at the same time and overloading the grid.

Electric cars, too, are often connected to the grid for much longer than is necessary for a full charge – for example if they are plugged in to charge in the garage at the end of the working day. This allows for an optimum charging pattern that is in line with electricity supply. The study claims that the best thing would be to charge the car at work: “During the day, when the sun is shining, many vehicles are parked anyway. Charging them there would make optimum use of photovoltaic production,” explains Siobhan Powell, an energy researcher at ETH Zurich and one of the main authors of the study.

As part of the study, a team from Empa investigated, among other things, how electric cars and heat pumps should be operated optimally in order to exploit their flexibility potential to the fullest. “Compared to heat pumps, electric cars can provide more than four times as much flexibility in residential buildings, but their availability is more difficult to predict. However, if user-specific behaviors and local conditions such as temperature are taken into account, their flexibility can be predicted much more accurately,” adds Empa researcher Federica Bellizio.

By 2050, Switzerland wants to cover 50 to 60 percent of its electricity demand (45 TWh per year) with new renewable energy sources such as photovoltaics, wind energy or biomass. The researchers’ model calculations now show that this target will be easier to reach thanks to the flexible power consumption of heat pumps and electric vehicles.

If heat pumps and electric cars are coordinated and controlled flexibly on a nationwide basis, around 4 percent more renewable electricity could be available in Switzerland in 2050. “Most of this is solar power in spring and summer, which would be utilised more efficiently so that it does not need to be curtailed,” explains Powell.

Moreover, flexible heat pumps and electric cars could reduce net electricity imports by around 20 percent across the whole year, particularly due to higher net exports in spring and summer. “These amount to some 1.8 TWh of electricity, which is equivalent to the annual consumption of around 0.5 million Swiss households,” says Powell. According to the study, Switzerland’s electricity imports would also be reduced by around 0.7 TWh in the winter months. That corresponds to a 4.4 percent reduction in net imports in winter compared to an energy system without flexibly operated heat pumps and electric cars.

According to a representative survey carried out as part of the study, around 70 percent of the Swiss population is willing to contribute to grid stability through flexible heating and charging, provided their convenience is not impacted and operation is automatic. Around 30 percent of respondents even said they would accept minor inconveniences if this would bring down their electricity costs.

In addition, the operators of electric vehicles and heat pumps should be incentivised to change their heating and charging behaviour. To this end, the study recommends measures including dynamic electricity tariffs that reward flexible charging and heating. However, significant local differences in tariffs and feed-in payments would hinder this measure’s implementation in Switzerland, states the study.

The researchers also point out that the promotional instruments in Switzerland are very heterogeneous and that there is, as yet, no national “right to charge” for tenants with electric vehicles – something they say ought to be resolved quickly.

In addition, the study shows that wholesale electricity prices could also be lower due to a more even distribution of supply and demand with the help of flexible heat pumps and electric cars. This reduction in electricity prices is greatest in the winter months of January to March, when wholesale prices could be reduced by up to 6 percent.

The researchers also estimate that an electricity system supported by flexible heat pumps and electric cars could be operated with around 4 percent lower costs than a system without these two flexibility providers.

Moreover, the use of flexibly operated heat pumps and electric cars would also mean the construction of fewer gas power stations and battery storage systems by 2050. Estimates show that the necessary investment in gas power stations and batteries would fall by around a third. “Above all, gas power stations and batteries are necessary to compensate for peaks in electricity demand. If electric vehicles and heat pumps take over this function, we’ll need fewer of them,” explains Powell.

If a large number of households are charging their cars or running their heat pumps at the same time, there is a risk of bottlenecks in the distribution grid. Many of today’s power cables and transformers are not designed for these loads and would need to be reinforced.

The researchers analysed around 50 grid areas in Switzerland and concluded that flexibly operated heat pumps and electric cars would reduce peak loads in neighbourhoods and could therefore delay and reduce the need for expensive reinforcement work on distribution grids. The actual size of these effects also depends on whether the areas in question are urban or rural.

So that electrical vehicles and heat pumps can actually act as flexibility providers by 2050, they must be equipped with the necessary control and communication technology. At present, this is not the case across the board. The authors of the study therefore recommend that further systems only be subsidised if they allow flexible and intelligent operation.

PATHFNDR is a research consortium that is funded by the Swiss Federal Office of Energy within the framework of the SWEET programme (Call 1-2020) and led by ETH Zurich. The consortium consists of eight research partners – ETH Zurich, Empa, PSI, ZHAW, HSLU, UNIGE, EPFL and TU Delft – and 25 cooperation partners and aims to develop and analyse transition pathways for renewable energy integration in Switzerland. It demonstrates feasible pathways, provides planning and operation tools, develops pilot and demonstration projects, identifies new business opportunities and innovation strategies, and analyses potential policies.