How can we decarbonize the building sector?

Understanding the Carbon Footprint of the Construction Sector

The building sector plays a major role in France’s energy landscape. It accounts for 43% of total annual energy consumption and contributes 23% of the country’s greenhouse gas (GHG) emissions, making it one of the leading contributors to GHG emissions in France.

It is therefore essential to address three key challenges in order to make this sector more responsible:

📉 reduce energy consumption in buildings,

⚡ control energy costs,

🚧 Reduce the carbon footprint of buildings.

🏢 What factors contribute to a building's carbon footprint?

There are many factors that contribute to a building's carbon footprint, but what are they?

🏗️ Building materials: The building materials used in a structure, as well as the production and transportation of materials such as concrete, steel, and glass, have a significant impact on its carbon footprint.

⚡ Energy consumption: Energy consumption over the life of a building is a major factor in its carbon footprint.

👷‍♂️ Transportation and logistics: The transportation of building materials, workers, and occupants also contributes to a building’s carbon footprint.

💧 Water use: Water consumption in buildings—particularly for heating and cooling—can also generate greenhouse gas emissions.

♻️ Waste management: Construction and demolition waste management is also a source of GHG emissions.

What methods can be used to assess the carbon footprint of the construction industry?

Measuring the carbon footprint is essential for assessing the environmental impact of the construction industry. It helps identify the areas with the highest emissions and guide efforts toward more sustainable and environmentally friendly solutions.

🌿 The Carbon Footprint®

The Bilan Carbone® is a tool for calculating greenhouse gas (GHG) emissions associated with a given activity.

It consists of 5 key steps:

👨‍💻 Data collection: In this first phase, companies gather information on all of their construction-related activities. This includes energy consumption (electricity, fuel, etc.), the use of construction materials, the transportation of materials and waste, as well as all other sources of greenhouse gas emissions.

🟢 Calculating emissions: Once the data has been collected, various databases (BEIS (formerly UK DEFRA), ADEME’s EMPREINTE database, etc.) provide standardized emission factors for each type of activity. Alternatively—and preferably—one can use the specific emission factors for each product or service calculated in accordance withISO 14 067, known as their Product Carbon Footprints ( PCFs ). Decarbo’Solution® offers this service online free of charge. These factors are used to convert the data into CO2-equivalent emissions. Thus, the emissions for each category are calculated individually.

📊 Analyzing the results: Once emissions have been calculated, companies can identify the areas that contribute most to the carbon footprint of their operations. This allows them to target the most effective reduction measures.

✅ Proposing solutions: The next step is to propose solutions for reducing greenhouse gas emissions. These solutions may include using materials with lower emissions, optimizing energy consumption, and adopting more environmentally friendly transportation options, among others.

🔎 Monitoring actions: Afterimplementing solutions, it is important to monitor changes in greenhouse gas emissions. This step makes it possible to assess the effectiveness of the actions taken and, if necessary, adjust reduction measures and strategies.

🌿 Life Cycle Assessment (LCA)

Life Cycle Assessment (LCA) is an essential method for evaluating the carbon footprint in the construction industry. This approach provides a comprehensive and detailed analysis of a building’s environmental impacts throughout its life cycle, from the extraction of raw materials to its demolition.

An LCA for the construction industry generally consists of four key phases:

1️⃣ Life-cycle analysis: In this first phase, all stages of the building’s life cycle are identified and divided into different phases, such as material extraction, manufacturing, transportation, construction, use, and end of life.

2️⃣ Data collection: In this step, all the data needed for the analysis is collected. This includes the quantities of materials used, energy consumption, greenhouse gas emissions, and other environmental impacts such as air and water pollution and the depletion of natural resources.

3️⃣ Impact Assessment: Once all the data has been collected, it is evaluated based on its respective contribution to environmental impacts, including the carbon footprint. This helps identify the stages of the building’s life cycle that have the greatest impact on the environment.

4️⃣ Interpreting the Results: The final phase involves interpreting the LCA results and identifying opportunities for improvement. Construction companies can then make informed decisions to reduce the carbon footprint of their projects.

LCA is particularly useful because it considers environmental impacts holistically and thus prevents problems from being shifted from one stage of a building’s life cycle to another. For example, using more sustainable materials can reduce CO2 emissions during the construction phase, but it is essential to take into account their extraction and manufacturing.

➡️ By using Life Cycle Assessment, construction companies can adopt a more sustainable approach by choosing materials and construction practices that are more environmentally friendly.

What environmental regulations apply to the construction industry?

⚖️ RE2020

Introduced by the 2015 Energy Transition for Green Growth Act (LTECV), the RE2020 aims to continue improving the energy efficiency and comfort of buildings while reducing their carbon footprint. It focuses on three main areas:

✅ Improved energy performance and reduced energy consumption for new buildings. The RE2020 goes beyond the requirements of the RT2012 by placing particular emphasis on insulation efficiency—regardless of the heating method used—and by strengthening the requirements regarding the bioclimatic demand indicator, Bbio.

✅ Reducing the climate impact of new buildings by taking into account all emissions associated with the building throughout its life cycle—from construction to end of life (building materials, equipment), including the operational phase (heating, domestic hot water, air conditioning, lighting, etc.)—through a life-cycle analysis.

✅ Creating living and working spaces adapted to future climate conditions while maintaining a focus on comfort during the summer. Buildings will need to be better equipped to withstand heat waves, which will become more frequent and intense due to climate change.

The implementation of RE2020 relies on a gradual transformation of construction techniques, industrial supply chains, and energy solutions in order to control construction costs and ensure that professionals in the sector continue to develop their skills.

The overall goal is to promote more sustainable and environmentally friendly construction while providing greater comfort for occupants.

⚖️ The Low-Energy Building (BBC) certification

The Low-Energy Building (BBC) label is an environmental certification that attests that a building meets strict energy consumption criteria that exceed the requirements of RT2012. Buildings with the BBC label are characterized by their low energy consumption for heating, air conditioning, domestic hot water, and lighting.

There are two types of requirements for obtaining the BBC certification, depending on the age of the home:

• For new housing: It must meet an energy consumption target of no more than 50 kilowatt-hours of oil equivalent per square meter per year (50 kWhep/m²·year).
• For existing housing: Energy consumption must be less than 50 percent of conventional consumption. The energy consumption target for these homes is set at 80 kilowatt-hours of oil equivalent per square meter per year (80 kWhep/m².year).

The BBC label is a mark of environmental quality and energy efficiency for buildings. It encourages builders and homeowners to adopt environmentally responsible construction and renovation practices, thereby helping to reduce greenhouse gas emissions and combat climate change.

Buildings with the BBC certification also offer occupants benefits in terms of comfort and lower energy bills, thereby promoting a more sustainable lifestyle.

What measures can be taken to limit the environmental impact of the construction industry?

Decarbonizing the construction industry is no easy task, but there are many measures that can be taken to make this industry more environmentally responsible. Here are a few of them:

⚒️ Energy-efficient building materials and techniques

The use of sustainable and environmentally friendly materials in construction can significantly reduce the carbon footprint of buildings. Materials such as wood, bamboo, and recycled bricks are eco-friendly alternatives. In addition, energy-efficient construction practices, such as thermal insulation and the use of natural ventilation systems, can contribute to more environmentally friendly buildings.

⚡ Integrating Renewable Energy into Buildings

The integration of renewable energy sources is essential for decarbonizing the building sector. Solar panels can be used to generate electricity, while geothermal and wind power systems can provide heating and cooling. These solutions help reduce dependence on fossil fuels and lower the environmental impact of buildings.

☀️ Energy-efficient heating, ventilation, and air conditioning systems

Heating, ventilation, and air conditioning (HVAC) systems account for a significant portion of energy consumption in buildings. Technological advances such as smart thermostats and heat recovery systems enable more efficient energy use. Improving the energy efficiency of HVAC systems is essential to decarbonizing the building sector.

🚧 Renovation of Existing Buildings

Renovating existing buildings is a key step in decarbonizing the sector. By improving the energy efficiency of existing structures, we can reduce their environmental impact. Systems such as insulation, energy-efficient windows, and solar panels can be incorporated into existing buildings.

On a related note, learn more about the carbon footprint of industries.