How Denmark leads the way in decarbonising the construction industry

A reduction of 70% of greenhouse gas emissions by 2030, compared to emission levels of 1990: this is the ambitious target Denmark wants to achieve across all industries. To reduce the environmental impact of construction, the Danish Ministry of Interior and Housing has introduced a national strategy.

Currently, Denmark’s strategy for sustainable construction is based around a voluntary standard, but it enters a new phase in 2023. From then on, voluntary regulations become mandatory and a strict, maximum value of greenhouse gas (CO2 equivalent) emissions for new buildings will be in place. We spoke to Peter Konnerup, Associate Structural Engineer in our Copenhagen office about the implications of the new requirements for the construction industry.

Peter, can you describe the Danish sustainability strategy for construction and its holistic approach?

With this strategy, Denmark is the first country to introduce embodied carbon limits into building regulations. Taking into account that approximately 11% of global CO2 emissions result from manufacturing building materials, this is a crucial step for decarbonising the built environment.

Overall, it is a holistic approach, comprising three dimensions of sustainable construction. It aims at reducing the environmental impact of buildings by minimising the consumption of energy and resources, while considering social (human health and wellbeing) and financial value (balance between Life Cycle Cost and building quality). By including potential reuse and recycling, the regulations cover the entire environmental life cycle of a building.

Prior to the role out of the new regulations, a voluntary sustainability standard was launched in May 2020 with the intention to test new requirements for construction, foster the development of Life Cycle Assessment (LCA) tools, promote recycling and fossil free construction sites.

With this strategy, Denmark is the first country to introduce embodied carbon limits into building regulations.

Peter Konnerup

What will happen with the start of a new phase in 2023?

New requirements will be phased into the building code. With regards to the environmental impact of new buildings bigger than 1,000m2, a threshold limit value of 12kg CO2-eq/m2/year is coming into force. This threshold value comprises all building related greenhouse gas emissions. New constructions smaller than 1,000m2 are required to conduct a Life Cycle Assessment (but without a threshold limit value).

Over time, at two-year intervals, this limit will be lowered, meaning the environmental impact of construction in Denmark will decrease dramatically over the next decade – constantly improving itself.

Step-by-step phasing in and scaling up of CO2 requirements (adapted from “National Strategy for Sustainable Construction” by the Danish Ministry for Interior and Housing, April 2021)

What will be the challenge for our clients?

The new regulations will guide everyone towards common targets with common denominators and thus help the wider industry to transform into more sustainable practice. This has been a challenge because clear guidance on embodied and operational carbon values and limitations has been previously missing. Now that data is more available and we know what threshold values we must meet, the challenge is to analyse and understand the effects of design decisions from all disciplines as early in the design process as possible.

As a result, the greatest challenge for clients and developers will be to understand that the environmental performance of a project will have a much greater weighting than before when considered in relation to functionality and cost. A building project that conforms to environmental requirements is now essential to receive a building permit. Form, function, cost, the environmental impact of materials and operational efficiency need to be considered much more equally. It is important for clients to better understand the environmental impact of the many decisions that are made throughout a construction project.

The new regulations will guide everyone towards common targets with common denominators and thus help the wider industry to transform into more sustainable practice.

Peter Konnerup

How can we help our clients to comply with these regulations?

A creative, innovative design approach becomes even more important to achieve a sustainable outcome. At Buro Happold, we consider how our engineering disciplines can complement each other to improve the performance of a building, both technically and sustainably. We are privileged to work together with architects who appreciate our approach and see the consideration of architecture and engineering together as the best way to achieve low-impact buildings.

In our daily work we consider practical aspects of sustainability alongside buildability and cost. Our integrated design approach considers passive design measures, energy efficiency, informed choices on structural layouts and materials, together with the re-use of existing building elements.

From guiding the orientation of a building so that it receives beneficial daylight and heating during winter, avoids overheating from direct sunlight as well as heat loss, through to the column grid of the structure – we will inform and guide our clients through the environmental impact of the decisions taken.

We have been gathering carbon data on our projects, internationally, for several years, so are aware of the types of structures and building systems that meet the new targets, or in some cases – should now be avoided. This database of knowledge will help guide our clients in the right direction from the very start. 

Through certification schemes like DGNB and BREEAM, Buro Happold has a lot of experience working with LCA. To facilitate this, we developed a real-time LCA toolkit that is part of our Buildings and Habitats Object Model Framework. The toolkit pulls together the data from BIM models of various disciplines and helps us visualise the effects of design decisions in real time. The example below shows how our BIM models for various disciplines are actively used in the LCA process, ensuring consistency and accuracy.

BHoM LCA Toolkit

We are currently developing our Structural Scheme Carbon Calculator which allows us to quickly assess the environmental impact of different framing systems in real time. Now used for timber frame assessments, we are in the process of adopting it to different structural materials, such as hybrid timber, steel and concrete. With its simple interface, the main purpose of this tool is to be used in a live environment with our clients and collaborators, engaging all parties in the decision-making process, comparing options to evaluate the best overall solution for the project.  As part of our consultancy work on design competitions, we can advise on the best options for meeting sustainability targets from the outset.

Structural Scheme Carbon Calculator 

What building types or construction methods will make the regulations achievable?

There is no doubt, the most sustainable building is the one that is not built. Refurbishment of existing buildings, adaptive re-use and the re-use of existing building elements are something I see playing an important role in our industry’s need to reduce its environmental impact.

I believe that design as much as technical solutions will lead the way for better buildings.  Designing a building using materials where they are most appropriate, together with a strong passive design approach maximising the use of natural and energy-efficient sources is where my focus lies. For me, as a structural engineer, we should look to employ timber structures in our designs, but sometimes this is just not technically appropriate – if we need to use steel and concrete, we must use it the right way: designed as efficient as possible, using recycled steel and lower carbon concrete.

A good example of this is EDGE Suedkreuz Berlin. This timber concrete composite structure used material in the right way. The LCA carried out for the DGNB rating resulted in 4,2 [kg CO2 eq./m² (NRF)*a] embodied carbon (stages A1 to A3, B4, C3-4 and D).