The E+C- label for zero-carbon, positive energy buildings
Launched at the end of 2016, the E+C- (Positive Energy and Carbon Reduction Building) experimental label, which precedes the next major evolution of the RE2020 regulations, is a perfect transition towards a carbon-free building world.
Since the energy signature is an essential criterion in building design, efforts must be continued through changes in energy performance regulations. The focus must always be on "positive energy" buildings, even if this theoretical difference between the energy produced and consumed respectively does not strictly speaking reflect the actual behaviour of the building.
The thousands of square metres we design each year provide us with significant feedback to work from. As a result, we can assert that the best performances are almost always those that go beyond the strict regulatory framework and require direct discussions with the legislator, or require investments that may (mistakenly) seem unreasonable in view of the stakes. Particularly since the E3C2 objective, in dense environments such as cities, is close to the maximum achievable goal, as E4C2, which is the highest level, is currently confined to small-scale pilot operations on sites where there is an overabundance of renewable energy.
Despite these obstacles in the design of the first E3C2 buildings, we firmly believe that we are moving in the right direction, and that the paradigm shift of the RE2020 will genuinely and finally encourage low-carbon construction combined with very high energy performance.
The challenge for the building industry is clear: it must massively reduce its carbon emissions. Accounting for 70% of the global total over the past 50 years, the carbon footprint of materials is the main issue. The E+C- label perfectly addresses this issue and foreshadows RE2020, which is the tool for the new building sector to pursue the national low carbon strategy.
To calculate the carbon footprint according to the E+C- method, a life cycle analysis (LCA) must be carried out for each material, i.e., the carbon content of the manufacture, transport, use and end of life of the material in question must be calculated. This value, obtained from the INIES database, is multiplied by the quantity of material. The total footprint for a project in the past would have been well over 1,000 kg of CO2eq/m², whereas we are seeking to reduce our new projects to under 750 kg of CO2eq/m². To achieve this, all our engineers are mobilised to track down and eliminate every last kilogram, optimising both the quantity and the choice of material itself. Our expertise even allows us to go beyond the purely regulatory aspect of E+C- and take a more physical approach to LCA.