Grid

True or false? Checking all the myths about the grid

The seventh post in the «our grid» blog series on strategic grid planning at Swissgrid

Author: Sandra Bläuer


The grid concerns us all, but is also a complex topic – that makes it the perfect breeding ground for all kinds of myths. But which claims are true? It’s high time to examine the myths to dispel any half-truths and misconceptions. Expert Marc Vogel knows the facts and checks the accuracy of 12 common myths for us.


Interview

Myth 1: Electricity can be stored in the grid.

Unfortunately not, the grid can’t store electricity. Its sole purpose is to transport electricity. At any given time, exactly the same amount of electricity must be fed into the grid as is drawn from the grid at other locations. This is because energy consumption and production must always be balanced. Swissgrid makes sure that this is the case around the clock.

Energy consumption and production must always be balanced. Swissgrid makes sure that this is the case around the clock.

Marc Vogel

Myth 2: Electricity can flow freely in the grid at any time.

The lines in the extra-high-voltage grid are the motorways of power distribution. Just as there are traffic jams on the roads, congestion can also affect the grid. This can occur, for example, if there is insufficient transport capacity when power plant production is high. However, local fluctuations, i.e. high production or demand, can also lead to grid congestion. In the future, this type of congestion will mean that not all e-cars can recharge at the same time, for instance, or that solar systems cannot feed all of their electricity into the grid at specific times in the summer. Measures such as dynamic electricity tariffs are required to manage congestion. They incentivise the consumption or storage of electricity when it is generated locally. It is necessary to implement charging management for electric vehicles to ensure that each individual car can be charged when needed without overloading the grid.

Myth 3: A blackout will occur in the event of a power shortage.

This is not the case, because a blackout and a power shortage are two completely different things. A blackout is sudden and unplanned, for example as a result of a technical fault. A blackout is a large-scale power failure that can have far-reaching consequences for society if it lasts for an extended period. A power shortage, on the other hand, means a shortage of electrical energy. It is not unexpected and usually lasts longer than a blackout. A power shortage does not lead to a sudden interruption in supply, but can be rectified promptly by taking countermeasures, such as introducing energy-saving measures, limiting electricity consumption or, as the most drastic measure, planning short-term power cuts.

Learn more: Blog «Power shortages vs. power system failures»

A blackout and a power shortage are two completely different things.

Marc Vogel

Myth 4: Power is the same as energy.

Energy and power are related, but are different measurements. Power is measured in kilowatts, whereas energy is measured in kilowatt hours. Energy is transported via power lines. If you want to know how much energy (kilowatt hours) has flowed along a line, you have to measure the power (kilowatts) per second. The measured values must then be added together for an hour (kilowatts per hour). Power lines are designed for maximum power, which rarely occurs in practice for reasons of operational security. Typically, the power of a large Alpine pumped storage power plant of up to 1 GW can flow along an extra-high-voltage line.

Myth 5: The extra-high-voltage grid and the high-voltage grid refer to the same grid.

False, they are two separate grids that are operated at different voltages and belong to different companies. The extra-high-voltage grid transports large volumes of electricity over long distances from large power plants and from abroad to the various regions of Switzerland. This 380/220-kilovolt electricity grid is operated by the national grid company Swissgrid and is also used for the transit of electricity between countries. The high-voltage grid, on the other hand, is used for regional electricity transport and has a voltage of 36 to 150 kilovolts. The regional distribution system operators are responsible for its operation.

Grid levels
Grid levels

Learn more: Grid levels

Myth 6: Underground power lines are better for people’s health than overhead lines.

Electromagnetic radiation and its potential risks to health are often discussed in relation to power lines or electrical appliances. Both above-ground overhead lines and underground cables generate electric and magnetic fields. The public is less aware that this is the case for underground lines because, unlike overhead lines, they cannot be seen, and the ground is perceived as a protective layer against electromagnetic radiation. In fact, the magnetic field directly above an underground cable is even greater than that measured under an overhead line due to the shorter distance. However, the spread of the magnetic field is lower in underground cables. This is because the arrangement of the cables partially cancels out their fields. The installation limit value for underground cables is complied with at a lateral distance of between six and eight metres. For an overhead line, this requires 60 to 80 metres.

Spatial expansion of the magnetic field

For overhead lines, the 1 microtesla limit is observed at a distance of approx. 60-80 metres from the conductors.
1/2: For overhead lines, the 1 microtesla limit is observed at a distance of approx. 60-80 metres from the conductors.
For underground cabling, this distance is approx. 6-8 metres.
2/2: For underground cabling, this distance is approx. 6-8 metres.

Learn more: Emissions

The magnetic field directly above an underground cable is even greater than that measured under an overhead line due to the shorter distance

Marc Vogel

Myth 7: Electricity can be routed from A to B in a targeted manner via individual lines.

Electricity always seeks the path of least resistance. When it flows from point A to point B, it therefore does not necessarily travel there directly, but is divided between the various lines connecting A and B. This is relevant for cross-border trade, for instance: under certain circumstances, only part of the traded electricity flows directly across the national border – and part of it flows through the grid of a neighbouring country that is not involved in the trade. For example, let’s say that Germany is supplying electricity to France. Only part of the electricity flows directly across the Franco-German border, while another part flows from Germany to France via Switzerland. Unplanned flows of this kind lead to a basic load on the electricity grid of uninvolved countries, in our example Switzerland, which can reduce their import and export possibilities.

Learn more: Blog «Unplanned flows in the grid – a risk for Switzerland»

Myth 8: The Swiss transmission grid operates independently of neighbouring countries.

That’s not true. This is because the Swiss transmission grid is part of the European transmission grid, which stretches from Portugal to Latvia and from Denmark to Greece. It works like one large machine that is operated jointly by all European grid operators according to the same rules. As the coordinator for Southern Europe, Swissgrid works alongside the German transmission system operator Amprion, which is responsible for Northern Europe, to complete an important task for ensuring secure grid operation throughout Europe. An electricity agreement between Switzerland and the European Union is needed to ensure that the grid can continue to be operated safely and efficiently in the future. Without an electricity agreement, economic costs will rise, and grid stability and security of supply will be jeopardised. An electricity agreement is therefore not only in the interests of Swissgrid, but also in the interests of all Swiss end consumers.

Learn more: European internal electricity market

An electricity agreement between Switzerland and the European Union is needed to ensure that the grid can continue to be operated safely and efficiently in the future.

Marc Vogel

Myth 9: The transmission grid is becoming less important as higher volumes of renewable electricity are being generated locally and only need to be transported via the distribution grid.

The expansion of solar installations and wind farms places demand primarily on the low-voltage distribution grids. However, large installations such as Alpine solar plants and large wind farms off the coasts of Europe, as planned by the EU, also require the domestic and cross-border transmission grids to transport the electricity generated. What is more, when local electricity production from solar and wind power plants is low, electricity has to be transported to consumers from more distant power plants or storage facilities. This is another reason why the transmission grid remains important.

Learn more: Blog «The grid must always be taken into account when installing a solar plant»

Myth 10: New transmission lines can be built or existing lines reinforced rapidly if necessary.

That would be ideal, but is not actually true. Projects of this kind currently take around 15 years from the start of the project to the commissioning of a new line. However, objections and court judgements always lead to significant delays in projects, so they can take up to 30 years. The aim is to reduce this period as much as possible in the future so that the development of the grid can keep pace with the transformation of the energy system and the requirements of grid operators and users. This is the only way to ensure that electricity can be transported from the generation site to the consumer centres and to continue to guarantee the supply of electricity in the future.

Learn more: Approval process

Myth 11: The grid will collapse if large numbers of additional electric cars are put into operation.

A smart charging management system must be implemented to avoid peak loads when charging multiple electric cars at the same time. Smart management will ensure that electric cars even have the potential to reduce the load on the grid by acting as storage units. This requires conventional charging stations at people’s workplaces and bidirectional charging stations in their homes. This would allow electric vehicles to be charged during the day and discharged at night. Vehicle-to-grid and bidirectional charging are currently still expensive in Europe, and there are regulatory obstacles to overcome.

Myth 12: Every time the tariffs for the transmission grid are modified, there is a major impact on household electricity costs.

The electricity tariff for households is made up of various components. Consumers pay not only for the electricity supplied, but also for its transport, among other things. As the national grid company, Swissgrid is responsible for part of the path followed by electricity. Swissgrid uses the tariffs for the transmission grid to finance the secure and stable operation, expansion and modernisation of the transmission grid. This component only accounts for around seven percent of a household customer’s annual electricity costs. Therefore, a tariff increase or decrease by Swissgrid is of little relevance to individual electricity consumers. Swissgrid currently invoices the costs associated with the power reserve on behalf of the federal government. The power reserve is an insurance policy to protect against a power shortage in the winter. The costs of retaining water in reservoirs and maintaining gas reserve power plants account for around four percent of annual electricity costs.

Learn more: The electricity price in focus

Swissgrid uses the tariffs for the transmission grid to finance the secure and stable operation, expansion and modernisation of the transmission grid.

Marc Vogel

Author

Sandra Bläuer
Sandra Bläuer

Communication Manager


More Blog posts

Contact

Title

Please select a title.

Please enter your first name.

Please enter your last name.

Please enter a valid e-mail address.

Please enter your message.

Please click the checkbox.