European buildings account for 40% of final energy consumption and 36% of energy-related greenhouse gas (GHG) emissions, making them a key priority for decarbonization efforts, as stated in the « Fit for 55 » plan. Consequently, several programs targeting GHG emission reductions in the EU will place significant emphasis on the real estate sector. To address these challenges, the Energy Performance Building Directive (EPBD) serves as a crucial regulatory tool for the EU. This directive mandates that all new buildings constructed by the end of 2020 must adhere to Nearly Zero Energy Building (NZEB) standards.
NZEB, a brief history
Initiated in 2010, by the Energy Performance Building Directive (EPBD), the NZEB standards stands for Nearly Zero Energy Building. This standard was defined in the directive as an impulse for new construction to enhance energy performance (1) and develop local renewable energy sources (2). The EPBD expected Members States to implement those ambitions in their national building regulations before January 2019 for all public buildings, and January 2021 for all buildings.
The ambition was to make of NZEB a collective standard which would transcend borders to align energy performance ambitions on the EU level. Therefore, some European frameworks and ambitions have decided to rely on this standard: the EU Taxonomy establishes the NZEB-10% efficiency level as one of the substantial contribution criteria for the mitigation objective under activities of construction and ownership of buildings (although solely for buildings constructed after 2020)[1].
NZEB, ZEB and NZEB – 10%
As the standard evolved into the cornerstone of other regulations, and the ambition of the European Union grew up, new targets emerged. It is important to be able to understand what each of them means, what they are linked to:
- NZEB, for Nearly Zero Energy Building, is the existing target, requiring high energy efficiency and the use of renewable energy,
- ZEB, for Zero Emission Building, is the target highlighted in the latest update of the EPBD,
- NZEB-10% is a level of energy efficiency, relative to the NZEB standards implemented in each Member States, used to measure alignment with the EU Taxonomy, to achieve climate change mitigation.
Common ambition, national objectives
Along the way, the European Commission came up with guidelines, and ranges of energy performance to maintain a certain cohesion at the EU scale. Yet, the approach of the NZEB standards differs from one member state to another, and this generalized divergence constitutes a challenge in the context of the emergence of the Taxonomy, and other European ambitions relying on a such standard.
To illustrate this challenge, ESREI has published a study that covers the challenges and digs into the application of the NZEB standard in 10 European countries.
Fig. 1 Countries studies in the ESREI publication.
The ambition shown by the NZEB standard did work as an impulse for national regulations to implement new and demanding standards when it comes to energy performance and renewable energy. Moreover, the following graph shows that most countries decided to get ahead of the European Commission prescription, and implemented lower energy consumption limits than expected, illustrating a will to anticipate upcoming challenges linked to energy and climate problematics.
Fig. 2 Compared PEC max regarding NZEB regulation in the studied countries. Source: OID, 2023.
Yet this also shows a vast amplitude between the different national objectives. This quantitative divergence is reinforced by numerous variations in methodology, and a detailed picture of the different national regulations turns out to be more complex than it seems at first sight. Several countries have in fact established changing thresholds, based on either:
- geographic variations at national scale, like in Spain,
- similar environmental characteristics, such as the RT2012 in France, whose requirements vary, for example, according to the noise emitted by the site,
- technical criteria related to the building itself, such as in the Danish and Spanish regulations.
As a result, instead of a reference value, the primary energy consumption thresholds adopt a variety of values that make international comparison impossible. The same goes for renewables energy, where not only the values but also the method can change a lot from one country to another. Indeed, some countries made it compulsory for new buildings to produce a certain proportion of their energy consumption, through local renewable energy. Others decided to only rely on incentive method.
Harmonization, the next challenge
Although the NZEB did work as an impulse for the building sector across the EU, the divergence still remains a challenge as Members States show different levels of ambitions.
Fig. 3 Ambitions of NZEB regulations for each country regarding renewable energy source policy and PEC max. Source: OID, 2023.
The next objective of the European process regarding energy performance of buildings must now be to align these standards, especially in regard of transnational legislation being implemented because of these specific standards. Actors therefore need to be able to count on clear, standardized rules as much as possible.
The EU is still working of next version of the EPBD. It is now necessary that, while it keeps pushing towards higher expectations regarding energy performance, the European institutions now also focus on encouraging a convergence of values within a specific range considering the climate and technical features of the different countries.
[1] More information: fact sheets on the technical criteria of the EU Taxonomy (FR).
