A team of Aalto University students has won accolades from their instructors for their idea to decarbonise Helsinki’s heating supply. They did so as part of a Thermal Energy Storage course this spring that asked its participants to come up with a solution for the Helsinki Energy Challenge.

“I first heard about the Helsinki Energy Challenge when the mayor announced the competition on Twitter last year. It was a cool idea; true out-of-the-box thinking to solve a serious problem,” says Risto Sonni, one of the future energy engineers in the top-scoring group.

Launched in February 2020, the Helsinki Energy Challenge invites entrants from around the globe to come up with a long-term sustainable solution that will phase out the use of coal to heat the city, without resorting to the use of biomass as a substitute. Helsinki has pledged to be completely carbon-neutral by the year 2035.

Sam Cross, manager of the Aalto Energy Platform and responsible teacher for the Thermal Energy Storage course, explains what elements propelled Team 7 to success.  

“The students were asked to investigate two kinds of thermal energy storage methods to meet the course requirement, as well as meet the criteria set out by the Helsinki Energy Challenge. This team did an excellent comparison of the different options and presented a very feasible solution,” says Cross.

A winning combination of carbon-free technologies

Teemu Lehtonen, Mihail Merkurjev, Risto Sonni, Aaro Piirainen and Joni Palin’s winning solution was a clever synthesis of several existing technologies.

“Helsinki has to come up with a hybrid solution, as no single idea will be able to fill the gap that coal leaves. These kinds of competitions encourage the kind of multidisciplinary know-how that is necessary for this kind of teamwork to take place,” says Merkurjev.

The Aalto University Energy Platform managed by Cross is a strategic initiative that promotes interdisciplinary research and education in the field of sustainable energy. The Aalto School of Engineering’s new MSc course in Thermal Energy Storage, led by Professor Annukka Santasalo-Aarnio, integrated the Helsinki Energy Challenge into the syllabus to provide students with a real-life case study and further Aalto’s push towards a more “challenge-based education”.

“A competition like this gets people together from different disciplines. This, plus collaboration between academia and companies, produces ideas that you wouldn’t get if you just put out a tender to different contractors. It’s a great way to generate a new approach and add new voices,” Cross says.

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Students happy to tackle a pressing world problem

The five students found it highly motivating to have a specific, real-life challenge they could address.

“Knowing that we were working on something real gave our project an extra boost. These kinds of projects are always more interesting than coursework that is strictly theoretical,” says team member Joni Palin.

The Aalto University students agree that the Helsinki Energy Challenge is an effective way to foster innovation.

 “It will generate very outside-of-the-box thinking and new ideas will be born. This was true in the student groups, at least. Although some of the solutions may not be possible to execute, the challenge will result in a lot of ground-breaking research,” says Aaro Piirainen.

“I don’t think one solution will be the key, but a combination of several ideas that work together will be feasible. We don’t want the city’s energy to come from a single source anyway, so the goal should be to disperse it out among several methods,” adds Teemu Lehtonen, the final member of the team.

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Helsinki as an example to the world

The students are proud of their nation’s capital for showing a bold example in the search for energy solutions that are not based on coal or biomass.

“Helsinki may be a small city on a global scale, but I’m a firm believer in the idea that everyone needs to do their part. It is very important for Helsinki – and for all of Finland – to become as carbon neutral, and eventually carbon negative, as possible. Energy production is a great place to start when trying to mitigate emissions, not just in production, but in every phase of the energy system’s life cycle,” says Merkurjev.

The team of students hopes that Helsinki will become a ground zero from which attitudes about and awareness of alternative urban heating solutions can radiate out to other players. The shared sentiment is that with four clear seasons, if a carbon-free heating solution can work in Finland, it can work anywhere.

 “The CO2 reduction in Helsinki may not have much of an impact on a global scale, but as an example, the Helsinki Energy Challenge has great value. The proposed solutions could also prove valuable for other countries and cities,” Sonni says.

The first-round deadline for the Helsinki Energy Challenge – and its one-million-euro prize – is on 30 September, so there is still plenty of time for all interested parties to finesse a competition entry.
“Someone has to do the research and show the way. Hopefully, the others will follow,” says Piirainen.


Text: Pamela Kaskinen
Photos: Susa Junnola