Nordic Harmonisation of Building LCA – Constraints and Enablers

Denmark has already set normative limits for the carbon footprint of buildings, while other Nordic countries aim in the same direction. Harmonisation of the processes and calculation methods behind these carbon footprint requirements between the Nordic countries has several benefits. Although regional differences exist, the Nordic construction market is connected, and a more aligned methodology would be preferable. Common methodologies would help to create a common market for low-carbon buildings and products and thus help to boost decarbonisation efforts in the whole area

Roadmap: Harmonising Nordic Building Regulations concerning Climate Emissions, 2023, Nordic Sustainable Construction programme, https://pub.norden.org/us2023-450/

. Harmonised methods would also enable comparisons between countries and facilitate follow-up on decarbonisation efforts of the building stock in the Nordic countries.  Even more wide-ranging harmonisation is needed to understand the role of buildings and the building sector’s responsibility in relation to the European climate targets and to create a basis for the limit-value regulation of carbon emissions of buildings. The green funding based on the EU taxonomy creates challenges for the Nordic funding organisations if each country has its own calculation methods in the building sector. The harmonisation work between Nordic countries has been ongoing for several years, but there remains work to be done.

Total harmonisation of the methodology might not be possible, but a process for unified labelling of the building parts, handling of the BIM material inventory lists and tracking of assumptions could streamline life cycle analyses. The status of the legislation in the Nordic countries varies; some countries already have mandatory LCA calculations for new buildings and large renovations, while others are currently developing the guidelines and preparing the legislation. This creates possibilities and challenges for harmonisation. Those still developing their methods can learn from those with experience. The process of getting new legislation into force is slow, and many parties are involved. Therefore, the countries already applying the national LCA calculation methods will not likely change their methods or guidelines in the near future. These challenges could be partly tackled with smooth communication between the authorities in the Nordic countries. Also, the possibly forthcoming Energy Performance of Buildings Directive (EPBD)

Revision of the Energy Performance of Buildings Directive: Fit for 55 package, https://www.europarl.europa.eu/thinktank/en/document/EPRS_BRI(2022)698901

might provide a harmonised LCA rule or a mandate to make a delegated act for it.

Issues of methodological harmonisation include which life cycle phases are included, which building parts are included, how the replacements of building parts and service life are calculated, how process-related (like transportation, construction and deconstruction) emissions are dealt with, the choice of units of the GWP indicators, the treatment of biogenic carbon, and the acceptability of different data sources (including generic and specific sources) and the need for conservative values. In addition, the consideration of decarbonisation of energy should be consistent, and common principles should be defined.

Finland and Sweden already have national databases for building products and energy, providing typical values for the LCA. When using the typical values for normative calculation, a conservative factor must be used for building products, which in Finland is 1,2 and in Sweden and Norway 1,25. A similar database exists in Estonia, following the Finnish system, but this database is not yet validated and will get an update with the BuildEST

https://kliimaministeerium.ee/en/research-and-development-program-life-ip-buildest-starter-building-renovation-marathon

project. Denmark uses generic data in BR18's table 7

https://bygningsreglementet.dk/Bilag/B2/Bilag_2/Tabel_7#787e83a6-b7d9-4a83-a4be-37574156daef

and if the generic data does not cover the needs, then ôkobaudat can be used or any EPD. Iceland does not have a national database, and the country has little national production of building products. The differences in the data used for emission factors are a constraint for harmonising building LCA. Still, once the products have been chosen, the already existing standards for EPDs ensure that climate data for products that have an EPD, are comparable and verified. With the introduction of digital EPDs, this climate data will be even more accessible.

The differences in the indicators result from the treatment of biogenic content in the products. The use of biogenic content in the calculation creates differences between calculations. For example, the values for glued laminated timber in the databases used in the Nordic countries can result in remarkable differences in the calculations (Table 3).

Table 3. Values for the emissions of glued laminated timber for the nominal calculations in Denmark, Finland, and Sweden.

 

The Finnish legislation requires using the GWP-total values and recommends using the national emission database CO2data.fi, which currently provides values for the GWP-fossil, but national harmonisation is still expected

Based on the calculation methodology and the true energy sources the assessed difference between GWP-total and GWP-fossil is minor as explained in Reports of the Finnish Environment Institute 48 | 2022 Section 4.1.2 page 15.

. Sweden and Norway use GWP-GHG, which is calculated by subtracting the amount of biogenic content from the GWP-total. Denmark is using GWP-total, and Estonia will use GWP-fossil or GWP-GHG. If the national assessment method does not include module C, using GWP-total would be problematic as the biogenic carbon content would not be subtracted from the calculations.

The operational energy use creates a large share of emissions, strongly affecting the LCA calculation result. Although the basic principles have been agreed upon

The set of Energy Performance of Buildings standards, developed by CEN under mandate M/480, provides a methodology to calculate overall energy performance of buildings supporting the EPBD.

, there are differences in calculating the building energy consumption. An important issue is also that there are differences in energy scenarios: how the energy sector will develop and how the emissions decrease during the calculation period is assessed. In addition, there are large differences in the energy sectors between the Nordic countries and Estonia, which mandates different emission factors and scenarios.

The building parts included in the scope of LCA are defined differently in each country. Comparison is difficult because the naming is not always directly comparable or at the same level and also the level of detail in defining the included parts differs. For example, Denmark leaves most plumbing-related parts out from the calculations, Sweden and Norway leave out all technical equipment, and Finland includes most major parts of HVAC systems but excludes building automation and smoke extraction structures. Groundwork and foundations, especially pile foundations, can have a major impact on the results of the carbon footprint calculation (up to 50% of A1-A3)

Values from actual building LCA calculations done by Asplan Viak

and will generally increase emissions by 10% per 10-meter length of pile foundations for A1-A3 calculations. All countries include foundations in the LCA methodology, but there might be differences in how much of the site preparations are included in the scope and whether site structures are included in the limit values.

When considering BIM-based LCA calculation, the availability of models must be taken into account. Though, it must be noted that some LCA tools can be used to complement partially missing inventory data from the BIM quantity take-off. Table 4 presents the stage where mandatory LCA calculation is performed in different countries. The accepted emission sources and conservative emission factors are also presented.

Table 4. The stage of normative LCA reporting and accepted data sources.