High ambitions are great, but even better if they lead to something good. Part of our high-ambitions-package for the first construction phase along S:t Göransgatan was the decision to be one of the pilots in Sweden Green Building Council’s new certification NollCO2 (ZeroCO2) – a guide to a more climate smart way of building. This gave us access to knowledge and a network that turned out extremely valuable. But more importantly, this is a project based on Electrolux Group core values. Sustainability is at the core of our business, including a commitment to the United Nations Global Compact – Business ambition for 1.5°C – for net zero emissions throughout our value chain by 2050, in line with the 1.5°C climate target. Work in progress.
So, where have this lead us and what have we learnt along the way? Below we share some of the insights we have gained so far. The numbers below are not final, the project is ongoing, but should be seen as an indication of where we believe we will land.
Reuse!
We realized early on that it takes a long time to neutralize CO2 if you tear down and build new. This means that we tear down as little as possible. But, since we are constructing new buildings around an existing building, it meant that we got a lot of bricks over that will be reused in the new building’s façade. (Phase 1 of the process is done, and we reused as much as 70% of the bricks we took down – roughly 200 tonnes corresponding to a saving of approx. 80 tonnes CO2 equivalents vs new brick – Thanks Rival for a well-executed demolition!) We will also reuse floor tiles (installation floors) from the existing building. Armatures, bathroom fixtures, doors and glass-walls are other materials that we will reuse locally.
Building in wood
The steel and cement industry (cement, the main raw material in concrete, is used for the foundation, floor joists and walls) are responsible for a large share of Sweden’s territorial CO2 emissions. We do use some steel and concrete – climate improved concrete – where we lack feasible alternatives (such as in the foundation work and the cellar) but our primary material is wood, namely fir trees from the woods of middle Sweden. Why? We believe that you live well in wood houses, wood has a low CO2 imprint, it is locally produced, and it is a renewable material that regenerates in a few generations. This also means that we create a carbon sink that can store CO2 in many generations to come.
What about solar panels?
The NollCO2 framework does not consider the CO2 used to manufacture the solar cell panels, from raw material to finished product, in the building imprint. Instead, we can utilize the energy created by the solar panels. The framework assumes that each kWh produced by the solar cells reduces the consumption of coal power. Coal emits 820 g CO2 / kWh, while the solar panels imprint is estimated to 40 g/kWh (IPCC 2014). This means that the calculated CO2 saving amounts to 780 g / kWh per produced solar electricity. This calculation, needless to say, is a simplification given that the solar panels’ electricity production and the building’s electricity consumption don’t go hand in hand, but in frameworks you need simplifications in order to make calculations possible at all. In our project, we are satisfied to know that our solar cell panels on the roof improves the energy mix from a European perspective, and that is enough for us!
Anyway, we were curious to find out more about the solar cell panels, which alongside wind power is one of the most common and most popular renewable energy sources. We had to work hard to obtain EPDs for the solar panels and realized that they varied very much primarily dependent on in which country they were manufactured(=the energy mix in the country). One thing that we found particularly interesting was that silicone, the semiconductor in the solar cells, represented up to 95% of the solar cells’ total CO2 imprint.
Knowledge and conscious decisions
Building carbon-low is an art that requires a lot of work. The market is not there yet. But the knowledge base is building up and the realization is here. It is possible – and wholly necessary – to make a difference with the help of knowledge and conscious decisions. As we write, the construction project that we have started along S:t Göransgatan (both the new office and apartments) has a total pre-calculated CO2 imprint of 175 kg CO2 per square meter. This translates into a total 2,500 tonnes CO2 for roughly 14,000 square meters, of which slightly more than 1,000 ton CO2 relates to brf Gourmet. For comparison, the baseline that the NollCO2 framework has calculated for us is 290 kg CO2/sqm. To meet the certification, we need to make sure that the house we build has an imprint that is at least 30% lower than that, or 200 kg CO2/sqm. This baseline takes into account the building’s specific design, if it has a basement, etcetera. If we had built “conventionally,” the imprint could have been substantially higher, more than 4,000 tonnes CO2. Even if it this is a theoretical mathematical exercise, it means that we avoided up to 1,500 tonnes of additional emissions – only by making CO2 an important part of our project. We have avoided – and now we must concentrate – 0,003% of the total CO2 that Sweden emits over a year (and yes, spent about 0,005%).
To conclude, and as a reference, it may be interesting here to mention that one cubic meter of wood holds 772 kg CO2 (according to our wood supplier Setra). This means that the first phase of the residential project, brf Gourmet, once completed, will have a carbon sink that holds somewhat more than 2,000 kg CO2 for many generations to come – CO2 that the Swedish forest has absorbed from the atmosphere through photosynthesis. This can be compared with the roughly 1,000 ton CO2 used to make and build brf Gourmet.
Isn’t that fantastic!
If you have questions, let us know at greenhousesthlm@electrolux.com.
Ulrika Kågström, AB Electrolux, overall responsible for the Greenhouse Sthlm property development.
Rasmus Olsen Falk, Hedström & Taube, Consultant, in charge of environmental certification and carbon dioxide calculations in the project.
Note: This text was edited August 30, 2023 (correction of numbers)
Sources
https://www.naturvardsverket.se/amnesomraden/klimatfakta/darfor-blir-det-varmare/kolets-kretslopp-rubbas/
https://www.ipcc.ch/
https://climate.nasa.gov/
https://www.svd.se/a/lE4w2A/hapnadsvackande-ras-men-manga-tolkar-det-fel
https://www.carbonindependent.org/54.html
https://sv.wikipedia.org/wiki/Kolcykeln
If you are interested in learning more – this is for you!
In a construction project, it is not enough to analyze how much energy the new buildings will consume once ready, it is also very important to understand how much CO2 that is consumed during construction of the building – how much of the total CO2 budget will our building use up? We must also evaluate different scenarios – CO2 emissions now or CO2 emissions in 10 to 20 years? To arrive at a decision, information is needed. An established system used to describe a product’s total CO2 emission from a life-cycle perspective are so called EPDs (Environmental Product Declaration).
When we started our project, few companies actually calculated EPDs. More are doing so today, but we are still at the very beginning of a necessary development and adjustment. The three main reasons companies don’t produce this information is 1) that it is expensive, 2) the company has deemed that it not important or 3) customers don’t ask for it. There is quite a lot of work involved to prepare an EPD, not the least because it requires a good grasp of where all material and components come from. For small companies, it can be very difficult to collect this information, if it is at all doable.
For products where the main part of the carbon imprint comes when operating them (perhaps someone here thinks household appliances?) EPDs are not always wholly relevant since the product’s total imprint depends on where in the world it is used (and also when during the day or night it is used – read more about this in the blog post Theme: Energy). But, since appliances usually account for the largest part of the total CO2 imprint of an apartment’s fixed furnishings, it is of course interesting to understand how much CO2 that was used to manufacture the machine – from raw material to finished product. Next time you buy an appliance, ask for information about the product’s estimated imprint from scratch to finished product and compare different brands. If the salesperson can’t answer – contact the sustainability officer at the sales company – they know. Manufacturers who take these questions seriously have estimated their imprint.
CO2 in a bigger context
The concentration of greenhouse gases in the atmosphere affects the average temperature on earth. Greenhouse gases is a collective name for a number of so called climate gases, including carbon dioxide and methane for example. These gases contribute – to a greater or lesser extent – to the warming of the earth. The greater impact, the higher GWP (Global Warming Potential) has the gas. By multiplying the weight of the emission with the gas’ specific GWP value, the total emissions of these climate gases can be expressed in one unit – so called CO2 equivalents.
The concentration of CO2 in the atmosphere has historically fluctuated, but when mankind started to burn fossil fuels on earth the concentration increased markedly to an average of about 420 ppm today (the figure varies over the year and also geographically), compared with around 280 ppm before the industrial revolution. Reports, based on the probability that the average temperature on earth does not rise more than 1,5 degrees (67% probability), shows that the “CO2 budget” we have left to spend is around 400 gigaton CO2 (year 2020). Given global emissions right now, that means this budget will be spent by around year 2030.
When we talk about CO2 emissions in a country, we usually refer to either territorial emissions, which includes all emissions from a country (but not land and transports to and from the country) or consumption-based emissions – the emissions the inhabitants in a country causes irrespective of where the goods or services has been produced. As a reference, if the total remaining CO2 budget is expressed per capita, it lands at around 50 tonnes per person based on all inhabitants in the world. Looking at the consumption-based emissions we have in Sweden (around 8 ton per capita) we only have six years of the budget left.
Sweden’s total territorial emissions are about 50 million tonnes per year.