Masdar: The importance of cutting embodied carbon
The brains behind Abu Dhabi’s Masdar City explain why the Gulf’s construction sector must work to reduce carbon embodied within buildings
It’s easy to see how operational buildings release greenhouse gases into the atmosphere.
What’s less obvious is that the extraction of raw materials, processing, transportation, construction, wastage, maintenance, and the demolition or recycling of buildings, also add to global warming. Yet all these processes – known collectively as the ‘cradle-to-grave’ lifecycle – contribute to the build-up of greenhouse gases that trap heat within our atmosphere.
Embodied carbon has been largely neglected by the construction industry in its efforts to reduce whole-lifecycle carbon emissions of buildings. Historically, it has been deemed insignificant when compared to buildings’ operational carbon emissions.
In the UAE, there are relatively few people – even amongst those involved in infrastructure – who understand the connection between embodied carbon and global warming. Whilst architects and developers take pains to limit carbon emissions from operational buildings, few account for the lifetime sustainability of their projects.
Yet an increasing proportion of the total carbon emissions for high-performance buildings come from the materials and products used. As a result, developers are looking for building materials with less embodied carbon. With no immediate financial payback, the incentive to plan for net carbon emissions during the construction phase does not extend much beyond social responsibility.
Based in Abu Dhabi, UAE, Masdar, part of Mubadala Development Company, understands the importance of embodied carbon. The organisation’s mission is to change the way the world designs, constructs, uses, and disposes of buildings. To this end, Abu Dhabi’s under-construction Masdar City is set to become one of the world’s most sustainable communities upon completion. But completion aside, for the team tasked with turning the Abu Dhabi leadership’s vision into a reality, low-energy buildings must also have low levels of embodied carbon.
Dr Nawal Al-Hosany, director of sustainability at Masdar, explains: “As buildings become more energy efficient, embodied carbon emissions assume greater importance. These emissions can account for up to 25% of total carbon emissions for a concrete-framed building over its 60-year lifecycle, and up to 35% of total carbon emissions for a steel-framed building [during the same period].”
Dr Al-Hosnay points out that for structures with shorter lifecycles, embodied carbon can account for more than half of the buildings’ total lifecycle emissions.
He adds: “These carbon emissions are released during the first few years of construction, and this [is] a large [quantity] of embodied carbon emissions in a relatively short span of time.”
The brains behind Masdar City are acutely aware that much of the development’s environmental impact resides in the supply chain, and that the actions of suppliers are important factors in its sustainable performance. However, Masdar says that suppliers’ lack of awareness about their environmental impacts – and their inability to accurately measure embodied carbon across global supply chains – represent significant challenges to the implementation of carbon-reduction measures.
Addressing these issues, according to the company, has necessitated not only the education of suppliers, but also the provision of relevant, inspiring, and practical solutions for their senior management teams.
With this in mind, Masdar has developed a ‘Sustainability Action Plan’ to benchmark its development, and to provide a minimum standard for the UAE. One of the plan’s core principles is to source “local and sustainable materials”, which in turn, encourages the use of construction materials that are locally available, reclaimed, renewable, recycled, and that have the smallest-possible environmental impact.
With its aim to become a low-carbon community, Masdar City has adopted a holistic approach to addressing embodied carbon through the establishment of a carbon-reduction programme to mitigate the environmental impact of its construction activities. Its developer has focused on a small number of high-mass, or highly-manufactured, components of buildings so that the most readily achievable sources of reductions are targeted.
As part of this holistic approach, Masdar considers the respective environmental impacts of the materials it uses, and when preferable options are not readily available, it engages with the supply chain to create the infrastructure necessary to deliver such materials. For example, the firm has encouraged its suppliers to use recycled materials in their products, conserve natural resources, and minimise embodied carbon of building materials used in the construction of Masdar City.
The overall aim is to reduce the embodied CO2 of building materials by 30% (compared to ‘business-as-usual’ practices) so that the embodied CO2 of construction of buildings is reduced to 550kgCO2/m2, which will then become a baseline in the UAE for sustainable development. Encouragingly, for the recently completed Siemens Building, Masdar achieved 530kgCO2/m2.
To this end, the company has used green aluminium in the façade panels and windows of Masdar City. Working with suppliers, the team developed a 90%-recycled aluminium sheet, which lowered embodied carbon from 10.44kgCO2/kg to 0.98kgCO2/kg. Masdar also developed 34%-recycled aluminium extrusions, which lowered the embodied carbon to 2.7kgCO2/kg.
In collaboration with the supply chain, a similar exercise was conducted for concrete, steel, and building blocks. By focusing on these materials, Masdar has been able to address around 80% of the total embodied carbon in its construction activities.
Using the experience and knowledge gained from this approach, the company has established the Middle East’s first database of green building suppliers and products. ‘The Future Build’ is an online, subscription-based, supply-chain management tool that provides a range of services to support the emerging green construction sector.
The Future Build database consists of independently-assessed green building products and materials, and provides information on innovative products and trends within the market. It also boasts features such as xD Sustainability Manager, a proprietary green building certification tool.
Faisal Saleem, business development manager of The Future Build, explains: “The vision for The Future Build is twofold. Firstly, it is consistent with Masdar’s holistic, full value-chain approach to the development of sustainability and the renewable energy industry. Secondly, The Future Build has been developed as a solution to a very practical problem.
“One of the biggest challenges we have faced in the development of Masdar City has been the lack of awareness surrounding the availability of credible, truly sustainable, local suppliers. Although this is a hurdle we have been able to overcome, it represents another potential barrier to the adoption of similar developments elsewhere. So, The Future Build is our way of clearing the way to the adoption of sustainable development.”
Saleem continues: “It is also important to remember that the UAE’s economy is growing fast, and that growth will add pressure to our national energy demands, which will in turn strain both our hydrocarbon supplies and our most valuable resource – potable water. Through more sustainable building practices, which result in energy-efficient, low-impact, and resource-smart construction, the region will be able to reduce its carbon footprint and save both costs and resources.”
Masdar says that it will continue to seek out, innovate, and implement leading environmental management practices to proactively understand, manage, and mitigate negative environmental impacts, with close attention to greenhouse gas emissions from construction activities. In keeping with this strategy, Masdar City is working with suppliers and strategic partners to analyse the entire product lifecycle, and to work out where carbon savings can be made – whether through more efficient production processes, procurement, or local production. Moreover, the company encourages the introduction of more recycled materials and renewable energy into the production process.
But a dearth financial incentives means that it can be difficult to persuade the construction industry to switch from high-embodied carbon materials to their low-embodied counterparts. Without immediate cost benefits, low-embodied carbon emissions are likely to remain the poor relations in the debate over greenhouse gases and their impact on the climate.
Nevertheless, Masdar’s Dr Al-Hosany contends that accounting for embodied carbon – and switching to low-embodied carbon products – makes both economic and environmental sense in the fight against climate change.
He concludes: “Energy efficiency initiatives have made the contribution of embodied carbon more significant over a building’s lifecycle. Reductions in the carbon emissions of materials have an immediate effect, while the carbon reductions through operations accrue over many years. To minimise the impact of climate change, we need to reduce the total quantity of greenhouse gases getting into the atmosphere as quickly as possible. So it is important we reduce the embodied carbon of building materials.”