Optimizing the whole life carbon of buildings

Miisa Tähkänen
Leading Specialist
Green Building Council Finland
Finland

miisa.tahkanen@figbc.fi

Sustainability has been a hot topic in the construction and real estate industry for several years. The industry has joint investors, constructors, and legislators in working towards a lower carbon construction and real estate market. Most major market players have net-zero carbon targets but are lacking a definition for what this means on a building project level.

Traditionally the environmental impact of construction projects has been seen to largely be a result of the energy consumption of buildings. Though energy consumption does create a massive amount of greenhouse gases, we have come to notice that more and more attention should be placed on the embodied carbon of construction products. In modern energy efficient buildings over half of life lifecycle emissions might be produced before the building is even taken into use. That’s why it is key to also focus on the emissions resulting from the production of construction materials and of the construction sites themselves. These are called embodied emissions.

Building emissions should always be evaluated as a lifecycle assessment. The calculation of emissions should begin with the sourcing of natural materials, run through the construction product industry and construction sites into the energy consumption of buildings and finally the recycling of demolition waste. There are generally accepted systems for analyzing such lifecycle emissions such as the EN Standard EN15978 and the EU Commission’s Levels framework. Whole life carbon analysis has also been included in most of the major environmental certifications used in real estate projects. The certifications are voluntary but are more of a rule than an exception in the commercial real estate investment market.

A trend can be seen throughout the Nordic countries, and more recently also in the Baltics, to regulate the life cycle emissions of construction. Life cycle emissions would be regulated as a part of the building permit process similarly as energy efficiency has been done for several years. Legislation is in place already the Netherlands, France, Sweden and Denmark and is being developed also in Finland, Norway and Estonia in the near future. But what is the impact of such legislation?

Current legislative framework

The more carbon intensive construction materials are included in carbon trading schemes such as the European Emission Trading Scheme (ETS). This includes cement, which is the main source of emissions in concrete, steel, aluminum and the like. As the price of the trading scheme has increased the industry has focused on energy efficiency and removing fossil-based energy from the value chain. However, many materials are fossil-based themselves and by focusing on energy consumption alone only so much can be done to decrease emissions. As a result, the industry has been working towards creating low cement concrete, recycling steel and aluminum, and more recently low carbon steel production. These materials are still in piloting phase and can be expensive for regular construction projects.

The energy efficiency of buildings is also widely regulated in Europe through EU legislation as well as national guidance. There are specific energy consumption limits for building types as well as energy certificate type guidance which works towards ensuring the selection of sustainable energy sources. In addition, energy production is included in the ETS, making fossil-based energy less attractive.

With such measures in place, why is whole life carbon legislation still relevant? Firstly, current legislation does not cover for all emissions of a construction project: certain materials and processes are omitted from the ETS. It is also important to note that it is not enough just to lower the emissions of energy or material production, it is also important to focus on energy and material efficiency in the project. A significant amount of emissions could be decreased if material usage in building projects was optimized. This is where whole life carbon legislation steps in.

How to ensure sustainable construction moving on?

As mentioned, several countries around the Baltic Sea are in the process of creating or have applied whole life carbon legislation. However, the legislative scope differs from country to another as does the level of impact. It is paramount that the results be comparable independently of the expert producing the evaluation: evaluations should be done by certified experts, a specific direction for the scope of evaluations and assumptions must be implemented and a thorough investigation of usable data must be executed. Industry professionals should be taken in to provide data on their products and to make sure assumptions made are an indication of industry practice.

A recent study found that while undertaking the process of creating new whole life carbon legislation one should focus on four aspects: early involvement, a wide scope including entire value chain, setting limit values that push innovation as well as allowing markets to produce additional third party verified data on better preforming building products. It is not enough for developers to optimize the mass of structures; product manufacturers must also be able to compete in the race towards net-zero.

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