OVERVIEW | An introduction to Life Cycle Assessment (LCA)
Life Cycle Assessment (LCA) is a methodology that has been developed to evaluate the environmental impact of buildings, with respect to their processes, their materials and use (energy) throughout the whole life cycle of a building. It is not to be confused with Life Cycle Costs which instead focuses on cost reduction, especially interesting when embarking in the design and construction of Nearly Zero Energy Buildings (NZEBs).
The objective of LCA is to evaluate the environmental impacts of a product from its fabrication to the end of its life, including possible recycling, as set out in the ISO14040:2006 standard. In general, three areas of protection are considered: human health, the natural environment (also named ecosystems), and natural resources. This recent article provides some examples of objectives and related indicators as shown in the table below.
Examples of objectives and related indicators for LCA
Using Life Cycle Assessment is one of the most effective ways to find out the impact on the environment resulting from construction methods, energy concepts, components and products. This involves all aspects of planning that take place in the construction of a new building and a renovation project. LCA can hence be considered a tool to both reduce the consumption of finite resources and to keep environmentally critical air, water and soil pollution to a minimum across all phases of a building's life. The DGNB (German Sustainable Building Council) has developed a set of guidelines with the primary goal to plan, operate and use the built environment in order to encourage designers and building contractors to employ life cycle assessment.
An effective and efficient real application of this methodology requires the integration of LCA databases and analysis routines in commonly used simulation tools such as energy performance simulation and Building Information Modelling (BIM). The integration of LCA tools significantly impacts the design efficacy especially in reducing environmental impacts of the construction industry.
A recent study presented the results of a full LCA applied to 24 statistically-based dwelling archetypes, representative of the EU housing stock in 2010. With the aim to quantify the average environmental impacts related to housing in Europe and to define reference values ( the baseline scenario) for policy development. Here, the environmental life cycle impact assessment was carried out using the International Reference Life Cycle Data System (ILCD) method. EU average annual environmental impact per person, per dwelling and per m2 were calculated. Results showed that the average life cycle greenhouse gas emissions related to housing per person per year were 2.62 t CO2eq, compared to a representative dwelling per year of 6.36 t CO2eq. The use phase (energy and water consumption) was the most relevant aspect, followed by the production of construction materials and maintenance. It was found that single-family houses are responsible for the highest share of impacts from housing in Europe. The same type of building has different impacts in different climatic zones, especially because of differences in the need for space heating. In general, electricity use and space heating are the activities that contribute the most to the overall impacts.
LCA in the EU
The European Commission's 2014 Communication on Resource Efficiency Opportunities in the Building Sector identified the need for a common EU approach to the assessment of the environmental performance of buildings. A study to develop this approach was taken forward during 2015-2017 by DG ENV and DG GROW, with the technical support of DG JRC-IPTS. In this context, a paper by the Joint Research Centre (JRC) was published focusing on the identification of strategic priorities (the macro-objectives) for the environmental performance of the EU building stock and was intended to provide an initial 'top down' view of what the macro-objectives should be for the building sector. Here, a shared set of macro-objectives presented in the document were split into those relating to 'life cycle environmental performance' and 'quality, performance and value creation'. The identification of these two types of macro-objectives emphasizes that the focus for the common EU framework will not only be on environmental performance, but also on other human and economic factors that may influence the service life and performance of buildings in the long term. And to support this framework, the EU shares knowledge on life cycle assessments in order to respond to business and policy needs for social and environmental assessments of supply chains and end-of-life waste management.
NZEBs have the goal to drastically reduce the energy consumption in the maintenance and use phase; this automatically leads to less environmental impact in this stage too. As reported here, the combination of LCA with optimization methods facilitates decisions to minimize environmental impacts of nZEBs, while keeping the costs as low as possible. The same study found that the overall environmental impacts of nZEBs are substantially lower than conventional buildings. On this basis, the report recommends using LCA from the early design phases, when decisions have the largest influence on the environmental performance of the building.
In terms of tools to perform LCA, we would like to mention EduFootprint app tool which has been created in the context of the Interreg Mediterranean and in the context of the EduFootprint Project. The latter is aimed at better managing, planning and monitoring the energy consumption in public buildings in the Mediterranean area. Specifically, EduFootprint aims to reach this aim by focusing work in public school buildings with an innovative LCA approach, considering not just direct energy impacts of buildings (consumption), but also indirect ones (public procurement or general human awareness and behaviour). Schools tend to use energy in a different way than other buildings, therefore, instead of focusing on energy conservation measures by infrastructural choices (insulation, refurbishments, etc.) and renewable energy sources (photovoltaic, thermal solar, biogas, etc.), the tool promotes and raises awareness of energy efficiency and conservation in the schools. Including a methodology for the calculation of the Environmental Footprint of schools.
Earlier this year, the Royal Institution of Chartered Surveyors (RICS) hosted a topical seminar on embodied carbon in buildings, to showcase the updated version of the ICE (Inventory of Carbon and Energy) Database. The ICE (Inventory of Carbon and Energy) Database is a leading embodied energy and carbon database for building materials. This free-to-use database has been downloaded by over 20,000 professionals from around the world and has appeared in countless reports, journals, books, lectures, embodied energy and carbon footprint calculators. The first version was released in 2005 following an extensive literature review and has been updated at periodic intervals. The database has been significantly updated in recent months.
In addition one may find the use of One Click LCA interesting, this is software to be integrated in BREEAM and other certification schemes, including LEED, DGNB, Energie Carbone, HQE, and many more. This tool also provides modules for Life-Cycle Costing, Infrastructure, and Ecodesign.
The HYBUILD project is aimed at developing a framework for both cost-effective and environmentally-friendly solutions, while ensuring comfort conditions in residential buildings located in two different climates are met, specifically in the Mediterranean climate where cooling is critical, and the Continental climate where a stronger focus is on heating demand. In this project, Key Performance Indicators (KPI) are being defined in order to ensure a proper assessment of the impact of the solutions, as a function of the various cases of application.
With a focus on renewable energy aggregator business models the BestRES project aims to Improve the current business models considering market designs with a focus on competitiveness and Life Cycle Analysis (LCA). These improved business models were then implemented with real data and monitored case studies in different countries.
With a specific focus on geothermal projects, the GEOENVI project aims at answering environmental concerns in terms of both impacts and risks, by assessing the environmental impacts and risks of geothermal projects operational or in development in Europe. The project is working towards proposing recommendations on harmonised European environmental regulations to the decision-makers and elaborate simplified LCA models to assess environmental impacts. This is pursued by engaging decision-makers and market actors to adopt recommendations on regulations and to see the LCA methodology implemented by geothermal stakeholders.
Finally, we would like to mention two projects that employ LCA as a main research tool. The CINDERELA project aims to develop a new Circular Economy Business Model (CEBM) for use of secondary raw materials (SRM) in urban areas and focuses on different streams of waste (i.e. construction and demolition waste, industrial wastes, heavy fraction from municipal solid waste and sewage sludge, mostly currently landfilled or incinerated). The project will contribute to 20% reduction of environmental impacts along the value and supply chain, reducing virgin material exploitation and converting wastes to products. Here, LCA is one of the main methods to prove the environmental, economic and social assessment. In a similar vein, the REEEM project uses LCA as part of their ambitious project to gain an understanding of the system-wide implications of energy strategies in support of transitions to a competitive low-carbon EU energy society. In support of this overall aim, this project will define pathways towards a low-carbon society and assess their potential implications.
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