Experts urge rethink of energy metrics to fully decarbonise buildings

The EU wants to rely on primary energy use in its revamp of the EPBD, a measure most consider flawed, prompting calls for changes. [Shutterstock/Kaspars Grinvalds]

Primary energy consumption is a metric that is commonly used worldwide, including by the European Commission. Most experts agree though that the metric is not fit for purpose when it comes to measuring energy use in buildings.

Energy accounting is a challenge. The dominant method until now is the input-reliant system of “primary energy,” which measures the energy content of coal, oil, gas, solar or wind before their conversion into electricity or thermal energy.

For fossil fuels, much of the energy is lost in the conversion process, while renewables have little to no conversion losses.

This reference to primary energy can be found in all EU climate and energy legislation, including the ‘Fit for 55’ package of laws currently under discussion in Brussels, which aims for a 55% reduction in carbon emissions by 2030.

However, some are questioning the relevance of using primary energy use as a metric when it comes to buildings, which can be both producers and consumers of energy. In fact, most experts consider the current energy labelling system for buildings to be inaccurate and even unhelpful when it comes to measuring climate performance.

“Fundamentally, primary energy use is the wrong metric to focus on. Not a single consumer knows what it refers to, or cares about it,” says Sam Hamels, an energy economics researcher at the university of Gent in Belgium.

The reliance on the primary energy metric becomes especially problematic when looking at the assessment of “zero-emission buildings” under the EU’s Energy Performance of Buildings Directive (EPBD), which is currently up for review.

“The use of only one requirement is misleading,” warns the International Energy Agency’s Energy in Buildings and Communities (EBC) initiative, referring to the global best-in class zero-emission building standard EN ISO 52000-1.

Similarly, the construction industry has voiced concerns about the metric in the proposed revision of the EPBD, which was tabled last year as part of the European Commission’s ‘Fit for 55’ package of energy and climate legislation.

Accurately measuring the energy performance of a building’s envelope is crucial because “it will be around for a long time,” explained Katarzyna Wardal, public affairs manager at Knauf insulation.

Taking primary energy use as the sole indicator of whether a building is “zero-emissions”, as laid out in the EPBD, “risked missing out energy savings crucial for building users’ thermal comfort and their energy bills,” she explained.

'Inaccurate' EU energy labels for buildings up for review

Energy performance certificates (EPCs) for buildings are sometimes so inaccurate that they can even become a hindrance to the EU’s climate goals, industry says. The upcoming revision of the EU’s Energy Performance of Buildings Directive could offer a way out.

Alternatives

Alternative metrics do exist, however.

For a “coherent assessment” of (near) zero-emissions buildings, the European Builders Confederation proposes a combination of several measurements:

  • Indoor environmental conditions
  • The thermal characteristics of the building
  • An accounting of heating, air conditioning and ventilation installed as well as a broader optimisation of the energy use of technical systems in the building
  • Active renewable systems, and
  • District or block heating and cooling systems

For Hamels though, a more straightforward approach is to measure the associated CO2 emissions of buildings. “They are what we should care about,” the researcher said.

Others, meanwhile, are pushing for the introduction of a complementary metric. Knauf Insulation, for instance, proposes measuring a building’s energy needs for heating and cooling, and use this as an upper limit for it to qualify as “zero-emissions.”

Better data needed to manage our buildings

Energy Performance Certificates (EPCs) have immense, as-yet untapped potential to help Europe decarbonise. But the methodology that underpins them must be revamped first, argues Adrian Joyce, who is calling for a reform as part of the upcoming revision of the Energy Performance of Buildings Directive (EPBD).

Taking a second look at comfort

Related to the notion of primary energy use is also consumer’s understanding of comfort. As European leaders call on citizens to reduce their thermostat settings to reduce the EU’s reliance on Russian gas, comfort may be getting a second look.

Whether a building’s target temperature in winter is 21°C, 20°C or 18°C can make a huge impact on energy consumption, the IEA recently stated in a joint plan with the Commission to “save money, reduce reliance on Russian energy, support Ukraine and help the planet.”

So the time may be just right for policymakers to ask: “What is comfort?” says Italian researcher Lorenzo Pagliano.

How people perceive comfort translates into choices that can have a big impact on energy use, Pagliano says. For instance, the choice between air conditioning to keep indoor rooms at 25°C in summer and a fan that keeps air moving could result in similar levels of comfort, but different levels of energy use, as fans use much less energy.

“By increasing the use of fans, which were long considered a second class option, we can significantly increase comfort levels with lower energy needs for cooling,” the researcher explains.

However, this concept of comfort is currently largely absent from the EPBD. “The notion of better energy performance through measures that maintain comfort at lower energy use are not very present in the EPBD,” he concluded.

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[Edited by Frédéric Simon]

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Knauf Insulation


We manufacture sustainable insulation solutions For A Better World. Our products contribute to saving energy and cutting emissions. They are designed to make sure buildings are good for the environment and safe and comfortable for everyone who uses them.






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