In Japan, where power outages are relatively common, electric car batteries are often used as a backup power source when the grid goes down temporarily. In this case, the car's battery feeds back the energy it stored when it was last charged.

Value for consumers

In Sweden, we do not have the same problem. In fact, power outages are becoming less frequent. However, even here, more and more households are looking into ways of securing their electricity supply in the event of a temporary outage, particularly in light of recent social developments such as the Coronavirus pandemic and the current unstable security situation in Europe. This can also help other motorists whose cars have run out of power and enable households to balance energy usage during the day when prices are highest.

– But whether it is economically viable for end users remains an open question in Sweden, says Mattias Persson, a researcher in electrical power systems at RISE. Stefan Pettersson, a professor and the head of the electromobility unit at RISE, agrees.

– Something of value must be created before consumers will buy this. You could get paid for the electricity you feed back into the grid, become more self-sufficient in combination with solar cells, or contribute to a green transition, which some people find valuable.

Future network benefits

In a future where this technology is commonplace, electric cars could contribute to increased grid stability. Smart charging ensures that cars are charged when there is plenty of electricity in the grid. At critical energy consumption peaks, it sends energy back to the grid instead.

– The individual car doesn't make much difference here, says Stefan Pettersson, but collectively, many vehicles can create opportunities.

If you collect a large number of rechargeable vehicles, the potential energy they generate can be fed back into the grid. This also presents a potential business opportunity for grid owners.

Due to increased electrification and greater energy needs, it is possible that we in Sweden may find ourselves in a situation where the infrastructure is unable to deliver the desired output at certain times.

– Even if the network is stable, problems can still arise due to highly fluctuating usage. In such cases, this can be a way of stabilising the frequency from a more local perspective, says Stefan Pettersson.

– In Gothenburg, for example, local flexibility markets have been set up to counteract transmission constraints. This means that smaller, more local grids can benefit from this too, as well as the large electricity grid, says Mattias Persson.

Legislative changes are required

When it comes to technology and infrastructure, there are few technical obstacles. According to Stefan Pettersson, charging points need to be designed so that they can also receive energy, but this technology is not difficult to implement.

Instead, a few other elements are required, such as standards, laws and policies. Today's electricity law was not written with mobile consumers, such as electric cars, in mind and it may limit what players in the system can do to find profitability.

– It is the laws, not the technology, that are getting in the way. There are grey areas and white areas in the legislation. On the one hand, existing legislation can hinder the technology, and on the other, the concept of feeding energy back into the grid is not even defined. Is it permitted at all?

Interdisciplinary collaboration is required

RISE has the capacity to be a valuable partner in many areas where questions remain unresolved, whether that involves developing and reviewing standards, or drafting legislation and policies.

– We have test sites for battery wear and IT security, which will be very important issues, says Mattias Persson.

– For a vehicle-to-grid solution to be widely implemented, many different areas of expertise need to collaborate to gain an understanding of the bigger picture. Stefan Pettersson says that these areas of expertise are available at RISE.

This is where electricity, vehicles and telecommunications converge. We can work across disciplines and conduct research into the remaining obstacles. At RISE, our expertise ranges from technology and behaviour to business models, laws and policies. By working together with partners in the field, we can get closer to finding a solution.

All electricity that we produce must be converted before it can be used. And this requires power electronics in the shape of, for example, diodes, transistors and transformers – large components for the substations where electricity is converted ready to be routed nationwide via power lines, and small components for our mobile phone chargers to ensure the right current and voltage. The problem here is that some of the energy is lost each time it is converted, such as in the form of heat.

– “Power electronics will be extremely important to society in the future as everything is becoming increasingly electrified. Whether you use, say, solar power or hydropower as the initial energy source, you still benefit from transferring this energy as efficiently as possible. If, for example, we consider an electric car, a combination of battery size and efficient power electronics can enable it to cover another couple of dozen kilometres,” says Klas Brinkfeldt, Unit Manager System Integration at RISE.

Better components mean lower losses

To minimise energy losses, we need to improve the actual components, including by means of new materials. Using silicon carbide rather than silicon in transistors and diodes, for example, greatly reduces energy losses. However, it is also a matter of more intelligent control components to enable power electronics to be used as efficiently as possible.

– “To remain competitive in the future, it’s extremely important to keep abreast of developments. Many Swedish companies are way ahead when it comes to intelligent control, and they have great potential to excel at power electronics systems,” says Klas Brinkfeldt.

Researching and testing the power electronics of the future

Autumn 2021 saw the beginnings of an extensive research project at RISE, the goals of which are to produce power electronics with lower energy losses, smaller, lighter and more efficient hardware and intelligent systems for control and preventive maintenance.

– “A large share of the budget will be used to purchase equipment to test the power electronics of the future. Since the trend is for higher currents and more power, we need equipment that can test this type of power electronics. So that the industry can use us as a test partner, and so that we’re able to develop new systems ourselves,” says Klas Brinkfeldt.

In addition to this, RISE is involved in three major EU projects and a number of national projects centred on power electronics – with more in the pipeline. Most of them concern vehicles, but there are also projects involving trains and household appliances.

– “Any companies that are interested in the field are welcome to get in touch. We can help with everything from power electronics system design and testing through simulations and literature studies to putting together Swedish consortia and applying for funding for different projects. Since we have a large European network, we can also help companies by mediating contacts with whom to develop project ideas,” says Klas Brinkfeldt.