It is estimated that the building sector accounts for 36% of global final energy use and generates 39% of global carbon dioxide (CO₂) emissions. Of that 39%, almost a third (11% of total emissions) is attributable to the impact of the materials used in construction. The remainder is attributable to energy consumption over the lifetime of a building (28% of the total).
The importance of the Zero Impact Building or Zero Environmental Impact Construction
Constructing zero or nearly zero energy buildings is a reality nowadays. The environmental sustainability certifications (LEED, BREEAM o Passivhaus), as well as the technical codes of developed countries (the DB HE section of the Technical Building Code, in the case of Spain), already include this requirement, which is gradually becoming standard practice in the building sector. This means that the 28% of emissions attributable to the energy consumption of buildings will gradually be reduced to zero. The key – as many are aware – lies in creating buildings with low energy demand, met by low-consumption systems which, in turn, are powered by renewable energy.
While the problem of emissions corresponding to the use phase of buildings seems to be on the way to being resolved, we cannot say the same for emissions corresponding to the construction of buildings
Whilst the problem of emissions corresponding to the use phase of buildings seems to be on the way to being resolved, we cannot say the same for emissions corresponding to the construction of buildings. To this day, the environmental impact of the life cycle (extraction, manufacturing, transport, installation and disposal/recycling – cradle-to-grave analysis) of the different materials and systems used in the construction sector remains an issue not addressed by the various government regulations.and barely touched tangentially by the main international environmental certifications. Only Level(s) and the European Taxonomy, more advanced in this regard, seem to address it.
As a result of this, Zero Impact Building emerges, an initiative developed by Evalore to create buildings with zero environmental impact over the building's lifespan (50 years according to the Technical Building Code – CTE).. Through the use of the building and the surplus production of clean energy (resulting from minimal consumption and a surplus of energy production from renewable sources), the impacts generated by the materials and the construction process are mitigated until they are neutralised, achieving a zero impact within 50 years.
¿How is a Zero Impact Building achieved?
The first thing to consider is that the key lies in the building's conception and design phase. This is where Evalore comes in as a sustainability consultancy, advising developers, as well as architectural and engineering teams, to achieve environmentally optimised projects. This stage is of the utmost importance since the decisions made directly impact the building's environmental footprint.
The strategies to be implemented would be as follows:
1. Optimisation of energy consumption
The first step towards achieving a Zero Impact Building is to optimise the building's energy consumption so that a positive energy balance can be achieved. Improving the characteristics of the envelope or properly selecting and sizing the building services are key actions. For this task, optimisation tools such as solar radiation calculation software, parametric optimisation software or dynamic energy simulation software are used.
2. Calculate and minimise the building's lifecycle impact
Equally important is calculating the environmental life-cycle impact of each material making up the building. The analysis will allow the selection of those materials and systems that minimise the carbon footprint derived from the construction of the building.
Account is also taken of the end of the building's useful life, or part of it. This follows the lines of “design for disassembly”. This is a design conceived to facilitate the recovery of systems, components and materials used for construction. The strategy is based on the recognition that every building represents a “material bank” which, at the end of its useful life or when undergoing renovation, rather than ending up in a landfill can be reused or at least recycled.
3. Specify a renewable energy system that exceeds consumption
Lastly, an on-site renewable energy system will be designed to not only exceed the annual consumption, but also to gradually offset the carbon emissions generated by the construction of the building. To this end, it is essential that local legislation and infrastructure allow surplus energy to be sold back to the grid or, at least, used in the immediate urban surroundings. Photovoltaic and wind energy are currently the most suitable options for this type of project.
It is important that a management system is installed in the building that allows the performance of the renewable energy installations to be controlled and optimised, as well as the appropriate time to feed energy back into the grid or for it to be used in the building's various subsystems.
How much does it cost to implement the Zero Impact Building?
A Zero Impact building does not necessarily entail significant additional costs. Initial studies indicate additional costs of between 3 and 5% on top of the Construction Implementation Budget (PEC). The main additional cost lies in the installation of the renewable energy system. In some cases where there are restrictions on the installation of renewable energy, the main strategy for reducing the environmental impact of the building’s construction may entail higher costs. In such cases, materials such as timber can become indispensable allies.
In any case, the alignment of Zero Impact Building with the European Taxonomy means that this type of project has tremendous potential to secure unbeatable financing conditions from financial institutions. The Zero Impact Building process itself, based on KPI measurement and reporting, helps to facilitate the process of demonstrating alignment with the European Taxonomy.
This initiative is 100% aligned with LEED or BREEAM certifications
What is the relationship with certifications such as LEED or BREEAM?
This initiative is 100% aligned with LEED or BREEAM certifications. In fact, A Zero Impact Building project will achieve the maximum score in the categories related to energy efficiency, renewable energy and building materialisation.. Given that these categories are also usually the ones with the highest impact on scoring, a Zero Impact Building will qualify for the highest certification categories under the various environmental standards.
What is Evalore's role?
En Evaluate we are pioneers in Spain in the development of environmental consultancy processes for the real estate sector. Our projects are often framed within the context of international environmental certifications such as LEED, BREEAM, WELL or Passivhaus. The result is an optimised project, in terms of both environmental performance and cost
Pablo Muñoz, CPHD, LEED GA, BPI MFBA
Co-founder and CEO of Espacios Evalore SLP
