The climate declaration must represent the finished building; thus, it is mandatory to perform the LCA on the completed design. There are no regulations regarding calculations in earlier stages of the design, but with the introduction of limit values, calculations throughout the design process will be of importance to monitor the climate footprint (LCA-specialist-1, 2023).
Methodology
A law, ordinance and provision on climate declaration for buildings exist. Boverket is giving guidance to this regulation. The LCA calculations should be made on the finished design of the building and are most often performed by an LCA-consultant in cooperation with the design team. Since it is now a mandatory demand for new buildings, the number of LCA calculations will increase and become a common part of the building process. (LCA-specialist-1, 2023)
Organisations also perform voluntary LCA-calculations based on their internal sustainability goals and ambitions of reducing their climate impact. By setting project-specific goals for climate performance in the early stages of the design phase and then working actively with climate optimisation, they can ensure that these goals are met (LCA-specialist-2, 2023).
There are also other types of voluntary standards related to environmental certification systems such as BREEAM, LEED and the Swedish net zero carbon system NollCO2. These certification systems along with the climate declaration is the main drivers for calculating building LCA in Sweden today (LCA-specialist-1, 2023).
The most ambitious voluntary system in Sweden for calculating LCA is the certification system NollCO2. It is developed by the Swedish Green Building Council (SGBC) along with their members. To achieve the certification, a building must fulfil the demands in NollCO2 and meet a minimum grade of an environmental certification such as Miljöbyggnad (min. Silver), Svanen, BREEAM-SE (min. Very Good) or LEED (min. Gold) (Sweden Green Building Council, 2023). When registering a NollCO2 certification, the building receives a specific limit value for carbon emissions that must be met. The rest of the emissions must be compensated through selected climate compensation activities to achieve a net zero balance (Sweden Green Building Council, 2023).
NollCO2 has its roots in EU Level(s) and is based on several international standards such as SS-EN 15978:2011 regarding the system boundaries, SS-EN 15804:2012+A2:2019 regarding calculations for A1-A3 (EPD) and SS-EN ISO 14021:2017 regarding environmental labels and declarations (Sweden Green Building Council).
System boundaries
The system boundaries for the mandatory climate declaration include calculations for modules A1-A5 (Boverket, 2021). Module A5 is separated into two parts; A5 energy for climate emissions related to all use of electricity, heating, and fuels on the construction site and A5 material waste relating to the emissions (A1-A4) for materials that will go to waste during construction. The climate data that must be used is the GWP-GHG, which means that biogenic carbon in materials is not included in the calculation (Boverket, 2021). The climate declaration also states the building parts that are to be included in the calculation; all load-bearing structures, the whole building envelope, and internal walls (Boverket, 2022a).
New buildings in Sweden today need to have a climate declaration before final clearance can be given by the municipality t but there are some exempts from these rules; buildings that do not need building permit or have a temporary building permit, industrial buildings, buildings related to agriculture or forestry or similar businesses, buildings with a total area of less than 100 m2, buildings related to the armed forces and some buildings owned by the state and a developer who is a private individual and is not constructing a building in business.
(Boverket, 2023b).
In the LCA calculation for NollCO2, all modules A-C are included in the calculation (Sweden Green Building Council, 2023). The calculation period is 50 years, and most of the building parts are to be included. The GWP data that is to be used is GWP-GHG, so emissions or uptakes from biogenic carbon are not to be included in the calculation.
Operational energy use calculation
The mandatory climate declaration covers modules A1 to A5, so the operational energy is not part of the climate declaration (LCA-specialist-1, 2023).
In NollCO2, module B6 is included in the calculation. If the project has a specified contract with an energy supplier that has an EPD made according to “Product Category Rules, PCR 2007:08 version 3.0 CPC 171 & 173: Electricity, Steam, and Hot and Cold Water Generation and Distribution”, ”General Programme Instructions for Environmental Product Declarations, Ver. 2.5” ISO 14025 and ISO14044, the climate data from that EPD can be used (Sweden Green Building Council, 2023). If the electricity supplier has a “green electricity” marking from the Swedish Environmental Protection Agency, there are stated climate data values in the NollCO2 manual for solar, wind and water-powered electricity. When a project does not have a specified energy supplier, or if the supplier does not have an EPD, generic climate values for energy in the database from Boverket are to be used.
The generic climate data regarding energy presented in the database from Boverket are calculated mean values for district heating, electricity, and fuels in Sweden (Boverket, 2023d). These data are not conservative as opposed to the generic climate data for materials in the database.
Level of detail in calculating and reporting building LCA
Since the climate declaration is to be made on the finished design of a building, information regarding most of the materials is often available at the stage of calculation (LCA-specialist-1, 2023). However, there are usually some materials not specified or quantified, or there might be a lack of accurate climate data. Therefore, it is mandatory within the climate declaration to calculate a coverage rate (Boverket, 2022c). This coverage rate is calculated based on either the cost of materials or their weight. By adding the cost/weight of all materials included in the LCA and dividing it by the total cost/weight of all mandatory materials, the coverage rate (%) is found. This rate is then multiplied by the total climate performance from the LCA-calculation to receive a final result. All documentation regarding the climate declaration must be stored by the developer for five years (Boverket, 2022b).
Accepted data sources
In the climate declaration, it is acceptable to use either specific climate data or generic conservative data from a database provided by Boverket (LCA-specialist-1, 2023). The specific climate data must be from a third party verified environmental product declaration (EPD) that has been calculated using the international standard EN 15084 or equivalent (Boverket, 2022b).
The database with generic data has been developed by Boverket in cooperation with the Swedish Transport Administration, the Swedish Environmental Protection Agency, and the Finnish Ministry of Environment (Boverket, 2023d). It is provided for free online and can also be accessed using an open API. It is possible to retrieve data files in the form of Excel, JSON, and XML. The generic data for a material has been calculated by the Swedish Environmental Research Institute using a mean value of the climate data in EPDs used in Sweden corresponding to that material. 25% is then added to the mean value to ensure the generic data is conservative. This is done to promote the use of materials with low carbon emissions ensuring that it is better to use specific climate data for a material with high carbon emissions.
If there is no available data in the accepted databases that matches a specific material or product, and there are no similar materials either, this can be left out but noted as a missing data point and then included in the coverage rate calculation (LCA-specialist-2, 2023).
In the NollCO2 system, there are priority rules when choosing what climate data should be included in the calculation (Sweden Green Building Council, 2023). A project must choose data from the highest available priority. The highest priority is given to product-specific EPDs followed in order by the database from Boverket, the Finnish database co2data.fi, and the German database Ökobaudat. The two lowest priorities are given to data calculated using so called LCEs (life cycle emission calculations) and proxy EPDs that have been calculated using EN 15804+A2 or EN 15804+A1.
Building LCA tools
There are several different tools used for LCA calculations in Sweden, but some of the most common ones are OneClick LCA and the Swedish system BM (Byggsektorns Miljöberäkningsverktyg) (LCA-specialist-1, 2023).
BM is a climate calculation tool for buildings created by the Swedish Environmental Research Institute (IVL) based on the methods of the international standards EN 15804 and EN 15978 (IVL, 2023a). Users can input material quantities manually or import them from cost calculations or adjusted digital formats. IVL is currently investigating techniques for importing data to BM from BIM-models in a cooperative project between property owners, architects, contractors, and suppliers (IVL, 2023b).
In OneClick LCA, there is a function allowing the user to make climate calculations in conjunction with the BIM model throughout the different stages of the design phase (OneClick LCA, n.d.)
Both mentioned tools are open for all users, however they both require a subscription. There are also tools used in Sweden that are developed and used internally, for example, by environmental consultants and architects (LCA-specialist-2, 2023). One start-up company that has developed a BIM-based LCA tool is called Plant An Idea and they are growing rapidly on the market as one of the most digital solutions available so far (LCA-specialist-1, 2023).
BIM practices in Sweden
Interviewees’ background
The BIM specialist interviewed (BIM specialist) has a long experience working with BIM, with the overall responsibility for coordinating the modelling work in construction projects. The interviewee also teaches courses at the university level for various of the most used BIM-tools and have been participating in national research projects regarding BIM practices in Sweden.
The use of BIM
Using BIM is a common practice in construction projects in Sweden today (BIM-specialist, 2023). In the schematic design phase of a project, the model usually consists of input data from the architect outlining the shape and the envelope of the building. As the design development continues, information from the other disciplines is added to the model.
The most used BIM tools in Sweden today are Solibri, Navisworks, Revit, Archicad, Tekla, MagiCad for Revit, and AutoCad. The use varies between different design disciplines. (BIM-specialist, 2023)
In Sweden, the main forum for discussing and developing BIM-related practices is BIM Alliance Sweden (BIM-specialist, 2023). This non-profit organisation’s overall aim is to facilitate the flow of digital information within the building process, and it consists of members from different organisations and companies within the Swedish building sector (BIM Alliance, n.d. -c)
There have also been several research projects regarding BIM with funding from SBUF (Svenska Byggbranschens Utvecklingsfond). One such ongoing project is investigating methods on how to use the information that already exists in the BIM model to make LCA calculations for the different design stages of a construction project (SBUF, 2021). These methods will be based on a combination of using AI with a rule-based definition of materials.