Sensortechnology leads to savings on green power for residents of bornholm

Bornholm’s energy utility company BEOF in Rønne

More intelligent electricity consumption is an important element of working with the energy islands. Research from DTU has helped residents at Bornholm to use electricity when it is cheap and supports security of supply.

Tekst: Miriam Meister

Most Danes do not think about what time of day they start the dishwasher or tumble dryer. But as an increasingly large share of the power supply comes from renewable energy, partly via the planned energy islands, it will be useful to begin doing this if you want to save money on the green power while also reducing strain on the energy system.

New sensor technology can help consumers use electricity when it is cheapest, according to research from DTU. In an extensive research study conducted by DTU, jointly with IBM and other partners, the technology was installed in 800 Bornholm households to help change habits.

“The project has looked at how consumption can be made more flexible, so that power is used when it is windy and postponed as long as possible when it is not,” explains Professor Jacob Østergaard, who has been researching smart energy solutions using Bornholm as a test case since the 2000s.

In the project, researchers fitted heat pumps and electric radiators on Bornholm with control boxes and sensors that could give price signals. The local heating units responded to these by delaying electricity consumption—as long as the homes maintained the required temperature set by each household.

This reduced the households’ electricity consumption by at least 30 percent in the winter season during the hours when the electricity grid was under the most pressure. The project thus succeeded in moving electricity consumption from hours with the most significant demand and therefore the highest price to hours when the electricity was cheapest and greenest.

Ecogrid, Anders Beier
The family pictured here was part of the study, where DTU’s researchers helped them manage their electricity consumption using sensor technology, so the grid came under less strain and the price of electricity was cheaper. (Photo: Ecogrid, Anders Beier)

Laboratory monitors electricity consumption

The majority of the study, which ran from 2016-2019, actually took place at DTU’s Lyngby Campus—about 160 kilometres from Rønne in a straight line. This is where PowerLabDK is based—a living energy laboratory where researchers from DTU can monitor the Bornholm electricity system in real time via a control centre.

The screens in the control centre show how much electricity the island is producing, what proportions are coming from various sources (wind, solar, and biomass), whether Bornholm is supplementing supply with imported electricity from Sweden, and the island’s total electricity consumption.

In the study involving 800 Bornholm households, researchers were able to collect data about Bornholm’s consumption, and whether the sensor technology and control boxes changed this.

According to Jacob Østergaard, Bornholm is ideal for this kind of energy research because the consumption pattern is a miniature version of the total Danish electricity consumption.

“In reality, we are dealing with a ‘laboratory’ that will end up matching the energy system of the future. We can develop and test technologies here to support the energy system and then disseminate these technologies out in the world.”

Apps can guide consumption

The research in PowerLab aims to help ensure there is sufficient power at all times of the day, even when an increasing share of this power comes from renewable sources such as wind and solar energy, which do not necessarily produce energy around the clock.

With the establishment of the energy islands, the future energy supply will largely be based on wind, and this will require that consumers use electricity—quite literally—as the wind blows, to a greater extent.

“Integrating a lot of wind energy will require creating a power grid that is flexible and intelligent, so we can postpone consumption when it is less windy and store surplus energy when there is high wind,” explains Professor Jacob Østergaard.

The experiment with sensor technology has helped towards achieving this. Based on the results of the project, standard models have been developed for how flexible electricity consumption is incorporated into the energy system, and they have been used, for example by the company True Energy.

True Energy has created an app for everyday consumers that ensures that their electric car is charged or the household’s energy-consuming devices kick in at times that benefit the budget and the environment the most.

IBM has also developed a flexible platform that can be used by players operating between the electricity market and consumers. Using the platform, these players can ensure that consumers’ unnecessary consumption drops out when the price is high or there is a shortage of green power, and reconnects when the price falls and the power is greener.

Finally, researchers at DTU are using what they have learned from the project in their ongoing work to develop models that can control the electricity grid in an intelligent way using artificial intelligence and digitalization.

In DTU's Powerlab in Lyngby researchers can follow the energy consumption of the residents of Bornholm on large screens. (Foto: Torben Nielsen) 
• The monitoring in Lyngby takes place in real-time, and one thing it shows is that all electricity and district heating production on Bornholm is based 100 percent on renewable energy.

• It also shows that the island exports green power to the Nordic energy system for long periods at a time through the cable that connects Bornholm to Sweden.

• Of the total energy generated by the island’s energy systems in 2020, 43 per cent came from wind turbines and 13 percent from solar cells.

• Anyone interested can look into the numbers in real time on the website.


Jacob Østergaard

Jacob Østergaard Professor, Head of Division Department of Wind and Energy Systems Phone: +45 45253501 Mobile: +45 25130501