Measuring and reducing embodied carbon in buildings: 5 hospitality case studies in Bologna, Italy
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European CommissionThe research from architectural & engineering Open Project aims to contribute to the definition of a benchmark for the CO2 emissions at construction stages for “hospitality” buildings, taking into account four hotel or student dormitory buildings (three of which are completed and occupied, the fourth one still to be built), located in Bologna, Italy.
The effects of the climate change already have a great impact, and the IPCC projections for the XXI century show potentially devastating impacts. The objectives of limiting the global warming subscribed in the Paris conference do require a drastic reduction of the CO2 emissions in all of the productive sectors. The construction sector is responsible for approximately 39% of the warming gases emissions, thus it requires attention and priority of intervention.
Being aware of the importance of the CO2 emissions associated to the whole life cycle of the buildings, since 2022 Open Project carries on Embodied Carbon and Whole Life Carbon analysis on all of the projects.
A detailed calculation of the CO2 emissions related to the construction stage has been undertaken and the results can be compared with the figures from standards and international best practices, such as RICS and LETI in UK, AIA and CLF in the U.S. A BIM model of a theoretical typical room was also developed, in order to double check the results obtained for the 4 case studies with reference to the most standardized categories (façade, horizontal and vertical internal partitions, finishes), and MEP systems.
The study confirmed that structures are the largest contributor in the CO2 emissions of buildings, and the building height, number of lower ground floors and deep foundations systems, are between the most significant driver for the CO2 emissions related to the structures.
(Note: opinions in the articles are of the authors only and do not necessarily reflect the opinion of the EU).
Authors
Marco Capelli (a), Andrea Botti (b), Remo Fabrizi (c), Simone Marino (d), Francesco Conserva (e) (abcde are superscript)
a Marco Capelli, Facade Engineer, BECxA, LEED AP BD+C, Open Project
b Andrea Botti, Head of Sustainability, Open Project
c Remo Fabrizi, LEED GA, Open Project
d Simone Marino, BIM and Sustainability Specialist, Open Project
e Francesco Conserva, Vice President, Open Project
Author contributions
Marco Capelli developed the research concept and scope, supervised the LCA model development, discussed the results and wrote the conclusions of the article.
Andrea Botti helped organising the structure of the article, produced the graphics, wrote the introduction and contributed to conclusions and limitations.
Remo Fabrizi and Simone Marino built the LCA models using the OneClickLCA software package.
Francesco Conserva authorized the use of confidential documentation for the purpose of the research.
Introduction
The importance of addressing embodied and whole-life carbon
The built environment is responsible for approximately 39% of the global Greenhouse Gas Emissions (GHG) : 28% from operational emissions (i.e. those resulting from energy consumption needed to heat, cool and power buildings), and 11% from embodied carbon emissions, that is those associated with the extraction, production, transportation, and assembly of building materials, as well as their end-of-life disposal [2].
In the face of escalating climate change concerns, associated both with the impacts currently observed globally and the alarming IPCC projections for the medium and long-term future, the construction sector has been increasingly recognising the fundamental importance of addressing embodied carbon emissions with urgency. As a matter of fact, while operational energy and carbon have been received attention over the last two decades, the substantial role of embodied carbon has been recognised in the recent years.
At a European level, this is reflected in the EU Taxonomy regulation [3], a classification system aimed at promoting sustainable activities and transforming investment practices and reporting related to sustainability. The EU Taxonomy, enforced through the legally binding EU Regulation 2020/852 since 2021, plays a vital role in supporting the EU’s ambitious target of achieving climate neutrality by 2050.
In accordance with the regulation, any building larger than 5,000m2 is required to undergo a Life Cycle Assessment (LCA) analysis following the methodology outlined in EN 15978:2011. This analysis examines the Global Warming Potential (GWP) resulting from all stages of the building’s life cycle, including construction, usage, and end-of-life. The LCA report should be readily available to investors and clients upon request, facilitating informed decision-making. However, it is worth noting that the regulation does not specify any quantitative goals, leaving room for industry stakeholders to proactively strive for carbon reduction targets.
Emerging embodied and whole-life carbon benchmarks: RICS and LETI (UK), AIA and CLF (US)
The definition of appropriate benchmarks is a necessary step towards the creation of a consistent and transparent method to measure building performance, most importantly with the goal to minimise resource use, decarbonise and reduce the overall environmental impact of the Architecture, Engineering and Construction (AEC) sector. This is now well-established when it comes to energy efficiency and operational energy (and carbon) where following the introduction of the EPBD, the introduction of Energy Performance Certificates (EPCs), now mandatory for any building to be sold or rented out, has been a crucial step towards achieving the goal. Leading global initiatives within the AEC sector are aiming at somehow similar goals, that is to reach the definition of robust benchmarks that allow to rate buildings’ performance based on their embodied carbon.
The Royal Institute of Chartered Surveyors (RICS) in the UK launched an Embodied Carbon Database designed to help built environment professionals identify where carbon reductions can be made throughout the construction process of buildings. The database indicates the typical embodied carbon footprint of different building typologies and for each phase of construction.
The London Energy Transformation Initiative (LETI) has been working on aligning definitions, scopes, measurement methodologies, and targets for embodied and whole life carbon following the release of the Embodied Carbon Primer in 2020. LETI has developed an embodied carbon rating system to track the necessary performance improvements from now until 2030. They also provide a self-certifying Embodied Carbon Reporting Template, where project owners can place their projects against the LETI benchmarks for an indicative rating.
In the U.S., the American Institute of Architects (AIA) and the Carbon Leadership Forum (CLF) have placed great focus on reducing embodied carbon associated with buildings. The AIA-CLF Embodied Carbon Toolkit for Architects provides an understanding of measuring embodied carbon through the methodology of a life cycle assessment and equips designers with strategies to reduce embodied carbon in their projects.
Being aware of the contribution from buildings to global carbon emissions throughout their lifecycle, at Open Project we have been carrying out Embodied and Whole Life Carbon analysis on all our projects.
The research examined four buildings, three of which have been built, whereas the fourth one is undergoing technical design stage. A detailed calculation of the CO2 emissions related to the construction stage has been undertaken and the results can be compared with the figures from standards and international best practices, such as RICS and LETI in UK, AIA and Carbon Leadership Forum (CLF) in the U.S.
By providing representative case studies, the research here presented seeks to contribute to the definition of a benchmark for the CO2 emissions related to the construction of student housing and hospitality buildings, in a similar way to what has been done as part of best-practice initiatives such as LETI in the UK.
Research objectives
Being aware of the contribution from buildings to global carbon emissions throughout their lifecycle, at Open Project we have been carrying out Embodied and Whole Life Carbon analysis on all our projects.
The research examined four buildings, three of which have been built, whereas the fourth one is undergoing technical design stage. A detailed calculation of the CO2 emissions related to the construction stage has been undertaken and the results can be compared with the figures from standards and international best practices, such as RICS and LETI in UK, AIA and Carbon Leadership Forum (CLF) in the U.S.
By providing representative case studies, the research here presented seeks to contribute to the definition of a benchmark for the CO2 emissions related to the construction of student housing and hospitality buildings, in a similar way to what has been done as part of best-practice initiatives such as LETI in the UK.
Case studies
The Hotel Bologna Fiera project comprises an extension an existing building, with a new 6-storey wing hosting 60 rooms. The intervention also included, for the existing wing: structural work to achieve a seismic improvement of the existing concrete frame structure; a strip out and replacement of the entire building envelope; a substitution of the internal partitions and finishes and a complete replacement of MEP components.
The Social Hub project comprised a complete strip-out of an existing office building, with the demolition of MEP systems, the seismic improvement of the existing concrete structures and the addition of a top floor (steel structure).
Beyoo Laude Living Student Accomodation is a new construction in an infill site situated north of Bologna train station.
Hotel Porta Mascarella is a new building, located in an infill site between existing building to the west, a public road to the south and east, and the railway on the north side.
