Energy for eternity: the KU Leuven sonoor podcast featuring prof Lieve Helsen


Lieve Helsen (EnergyVille / KU Leuven) talks about how to heat efficiently and sustainably, the fairness of energy prices and how to achieve carbon neutral by 2050.

A heating system produces hot air or hot water. This can be done in several ways. Through natural gas, such as with condensing boilers. Or by solar energy, with a solar collector. However, you can also use heat which is freely available in the environment and contained in the ambient air, soil or groundwater. However, you still need to continue heating these, with a relatively small amount of electricity, to get them to the desired temperature. That’s what a heat pump does. – Professor in engineering science Lieve Helsen, expert in ‘thermal systems’

Some systems are more sustainable than others already. “Sustainability is crucial,” she says. “Our natural resources are limited, so we have to be very careful with them.”

“There are disadvantages to fossil fuels. Burning gas or heating oil leads to CO2 emissions, but it also releases other pollutants. Nitrogen oxide, for example, which contributes to ozone formation and acidification. If a gas boiler is poorly tuned, you also run the risk of carbon monoxide formation, which can lead to CO poisoning. Poorly tuned heating oil boilers add soot particles, fine particles that find their way into our respiratory system. A heat pump, on the other hand, uses electricity. And that will eventually be produced exclusively from renewable energy sources or with carbon-neutral technologies.”

Collective thinking

To maximize the sustainability of a heating system, you have to make sure you limit heat demand in a house. “By insulating well, improving airtightness and double glazing,” Helsen says. “You don’t have to overdo this. At some point, extra insulation is going to provide very little additional benefit. You have to look for a balance between the quality of the building envelope and your energy system. You can’t separate the two.”

According to Helsen, we shouldn’t provide every house with solar panels or a heat pump separately. “We should think collectively. For example, you could install one heat pump that provides energy to three houses. On extremely cold days, a gas boiler – which is still present in one of the houses – can help out. When that gas boiler reaches the end of its lifespan, it can be replaced by an air-source heat pump. This saves us both in investment and operational costs, and we also pay attention to the value of materials. By thinking collectively, you create synergy, which is the way to make these sustainable technologies feasible and affordable.

Energy crisis

How does she view the current energy crisis? “Energy was undervalued in the past. The current price is a fairer price. Nowadays people are more conscious of their energy use and make more sustainable choices. Of course, social corrections are needed for those who cannot afford their energy bills. We want to bring that group along with us towards more sustainability.”

“In the future, we will need to rely more on local, renewable energy sources and residual heat or cold, and ensure that we can use and store them flexibly. This will allow us to better provide for our energy supply, stabilize prices, and create jobs. And we’ll do something for the climate and the environment. But all of this requires a long-term vision, a system approach, and courage from our policymakers.”

Helsen concludes with a call for more “STEMpathy“. “STEM is an acronym for ‘science, technology, engineering, and mathematics’,” she says. “Besides our technical skills, as engineers,  we also need to use our human skills. We need to rely more on our instincts and gauge what is happening in society. We need to interact with each other, rather than compete. By 2050, our society must be carbon-neutral. This will only be possible if we join forces across disciplines and sectors, with our noses pointing in the right direction.”

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