Story Telling behind the EAACA Roadmap

• The construction sector is responsible for almost 40% of all CO₂ emissions. What is the share of AAC’s CO₂ emissions in regard to the total construction sector in Europe?

It is difficult to give a figure here, as the emissions figures of the building sector refer to the use of the buildings and not to the embedded emissions that occur in so-called upstream chains. In almost all countries, these are still assigned to industry according to the polluter-pays principle and not to buildings. With a share of approx. 0.09 % (Scope 1-3) of total emissions within the EU (as of 2020), the aerated concrete manufacturers organized in the EAACA have a rather small share of CO₂ emissions. If the share of Scope 3 emissions, i.e. the indirect emissions of the supply chain, is excluded, the share of our industry is about 0.02%. Despite this small share, we take our responsibility for the decarbonization of the economy very seriously, which is ultimately also reflected in the EAACA roadmap just published.

• Which developments and innovations in building materials or systems do you regard as competition for AAC? And why are they a better or worse alternative?

Although AAC has been used for almost 100 years, the material has never lost its innovative power. Whether in fire protection (non-combustible), in sound insulation or in summer and winter thermal insulation: With AAC you will find an economical and sustainable solution. It is understandable that, especially recently, with regard to CO₂ emissions as so-called grey energy, more attention has been paid to lightweight constructions with wood as a possible alternative. But even here, the available studies and calculations show that AAC is not inferior to other innovative solutions when considering the entire life cycle fairly. On the contrary: AAC is far ahead of other solutions in terms of recycling up to a closed material cycle. And we are working in research and development to achieve CO₂ neutrality by incorporating many of our customers' ideas.

Across some of our markets we are seeing an increase demand for more ‘off site manufacture’, sometimes driven by regulatory or local requirements, rather than by customers choice. As a result, the industry has faced the challenge and developed its own system of larger format AAC (usually lightly reinforced) to compete head on with these systems. We already compete with different formats of masonry materials, and we use are benefits to compete in the following way:

•          AAC is the best performing structural thermal material providing the thinnest overall wall solution.

•          It is versatile and easy to work with and cut into shape.

•          It is lightweight and easy for the bricklayer to lay.

•          The design junctions with other parts of the construction provide a significant reduction in energy and heat loss at junctions (linear thermal bridging).

•          Highest performance against fire.

Against other forms of construction (steel and timber frames) AAC provide a solution which is fire and rot proof. 

Within high rise, framed construction, AAC infill walls are ideal as they reduce the dead weight load on the supporting frame and foundations, allowing less material to be used in the frame.

•What drove the EAACA to develop this roadmap? Is it merely out of compliance to the Paris Agreement? Or does it serve a higher purpose or interest? The Paris Agreement was in 2015, why did it take until 2022 to set up this roadmap?

In looking to answer this question, we have to look to where the EC has been focusing its thoughts. Up until recently, there has been a focus on how energy (and therefore carbon emissions) has been used. There has been a long history of tackling operational energy in buildings, which is the biggest area of energy use and carbon emissions, for example, via the EPBD. As new buildings have become more energy efficient, the focus moved to existing buildings. AAC constructions have been used extensively to achieve this goal.

However, AAC manufacturers were, and still are, in a continuous process of reducing their own energy and carbon footprint. Much of this is obvious. Lower energy costs mean lower fuel bills. With energy prices set to get even higher, manufacturers will continue to strive for the lowest energy demand with capital investments into their plants. But, this was being down way before the publication of the current AAC Roadmap. The Roadmap is driven by customer demand and commitment from the AAC Industry to improve further its environmental credentials.  

• The ‘Fit for 55’ program strives for 55% reduction of emissions by 2030. Will the EAACA comply with this as well?

Much will depend on the cement and lime industries to achieve this. However, it depends on the baseline for this target. The cement industry has already made a significant reduction over the last decade and is striving, via research and development, to achieve the lowest target possible. We would anticipate that the EAACA Members own footprint for Scope 1 and 2 is likely to meet the 55% reduction target.

• What will be focused upon to achieve this and what will be the quick wins?

This is likely to be the transfer from fossil fuels in the manufacturing process to renewable energy sources or hydrogen where possible.  Changing the electricity supply is an easy win; more challenging will be the conversion of boilers to other fuel types.  However, all of this is practically achievable. 

• Do you think that changing the AAC products by making them more sustainable could harm their position in regard to competing building materials in terms of pricing, performance, reliability, reputation etc?

No, it should make the material more competitive for the reasons given elsewhere in this paper.

• The success of your roadmap is very dependent on the success of the cement and lime industry. Do you cooperate with them or influence them in some way? Are their ways to be less dependent on them, for example by doing R&D on cement, lime and binders yourself?

We have been in contact with many manufacturers for years. I can assure you that there are good and economically feasible solutions to produce both cement and lime with a much lower CO₂ footprint. Since we stand for quality with our brands, it goes without saying that these developments can be carried out without compromising the quality and durability of our products. A certain dependence on the successes of the cement and lime industry is certainly present, but the decarbonization of society is always a development dependent on many individual factors. If, for example, the electricity does not come from renewable sources, other industries will not be able to meet the targets either. On the positive side, the AAC's ability to absorb CO₂ itself during lifetime helps us to significantly reduce this dependence.

The success of the Roadmap does depend to large degree on the cement and lime industry. We are talking with these industries at both a National and International level.  AAC manufacturers have a strong relationship with their raw material suppliers and these suppliers are aware of the AAC industry needs. There is cooperation at a much higher level and we work in collaboration with them on subjects such as the recent project looking at ‘Carbon Accounting for Building Materials’. (www.CA4BM.org). As an industry to are constantly on the look out for new binders and formulations, but these are carefully balanced with the final product characteristics such as product performance and longevity of the constructions that they are used in.

• How will results be monitored? How do you measure CO2 emissions?

The emissions are determined by means of real and continuously recorded energy consumption values. Based on the politically prescribed CO₂ factors for the individual energies, the CO₂ emissions can be calculated. Thus, both a significant energy saving and a reduction in the CO₂ factor can contribute to a reduction in emissions.

• Will reducing the emission to zero change the position of AAC in regard to competitive building materials or building solutions?

Over the last few years, we have found that are customers are getting more and more concerned about sustainability in its widest sense. Part of that is the growing interest around embodied carbon and Company carbon footprint. This is driven (in the UK) by larger companies having to declare their footprint. In addition, under ESG rules, EAACA member companies are having to make their emission publicly available.

We are seeing that more and more, competitive building materials and systems are highlighting that bio based (timber) systems are deemed to be more ‘eco friendly’. In addition, European and some National policy makers are promoting and suggesting the greater use of timber in construction, based on perception rather than any scientific basis. As a result, reducing the emissions of AAC will benefit and protect our industry going forward. As we decarbonise, the temptation to move to other building systems reduces. In most countries that we operate in, AAC is the most cost effective solution. This is because in one material, we provide the building with a energy efficient, fire proof, rot proof, acoustically sound and weather proof shell.

Within the targets for our future product production and in use values, there is opportunity to become not only carbon neutral, but carbon negative owing to the materials natural recarbonation in use. This will improve the position of AAC in the marketplace.

• If, in 2050, all building products are sustainable, will that change the playing field? And in what way?

If all building products become ‘sustainable’, AAC solutions will continue to be sold on their key attributes. These have been mentioned about, but AAC is already the material of choice in most of the operating markets. Take the UK for example.  We have a market share of the inner leaf of the cavity external wall of over 60%. The reasons are generally about its lightweight properties and the fact that it provides the most cost effective overall solution. Because the solutions are the thinnest available in the marketplace, customers opt for the external shell that takes up the least amount of footprint space.

We have to recognise that energy regulations for buildings will change in the future to require lower ‘U’ Values. AAC is set up to meet these challenges and even if additional insulation is required with the wall structure, using AAC will reduce the amount of needed. Thus overall, it will lead to even lower carbon emissions if the insulation industry cannot reduce to zero.

Timber will no longer be seen as the carbon neutral material. At the end of life, all timber will eventually disappear, and release is carbon back into the atmosphere. Any carbon used to manufacture or transport the material may have a negative value placed against it.

• Given the material characteristics how does AAC contribute to future oriented building?

AAC constructions are well placed to meet the future oriented buildings. Why? The constructions that are achievable with AAC allow for quick, high performance buildings. We are seeing that some of the proposals with the amendments to the EPBD will help AAC as they are made from locally sourced raw materials. The constructions are highly thermally insulating using all of the characteristics that have been mentioned previously (and also given within the AAC Roadmap). The future building stock will have to consider climate change and the effect on indoor air quality. AAC does not give off harmful substances and does not have any negative effects on the indoor air quality. It does perform a useful feature in the maintaining a stable temperature requirement using the materials beneficial thermal mass that smooths the internal temperature during the heating and cooling period both in the winter and summer seasons.