The environmental impact of the building sector has always been a concern in all parts of the world. To lower the environmental impact by buildings, the NYC came up with Local Law 97 (LL97) which puts emission limits for buildings over 25,000 sq. ft. The law will be applicable from 2024.
When it comes to building emissions, there are mainly 2 types –
- Operational carbon, which is the amount of carbon emitted during the operational phase of the building.
- Embodied carbon, which is the amount of carbon emitted during manufacturing, production, and transportation of the building materials that are required to make a building.
Even when operational carbon is reduced, the challenge of reducing the embodied carbon still remains. A study by Architecture 2030 estimated that three materials, steel, concrete, and aluminium, account for 23% of the global emissions. If targeted actions are not taken, embodied carbon could very likely surpass operational emissions in the near future.
Reduction Strategies for Building Operational Carbon
There are several measures that effectively reduce the building carbon emissions. All the measures are generally based on the 2 main strategies:
- Direct energy consumption reduction – This strategy includes measures like using less kWh, cubic feet of natural gas, gallons of fuel, etc.
- Switching to cleaner energy sources – This strategy includes replacing the grid electricity with onsite renewable energy.
While both the strategies have the same goal of reducing the building emissions, direct energy consumption reduction reduces the units of energy utilised by the building, and switching to cleaner energy source reduces the carbon footprint of every energy unit.
Building energy bills and emissions go hand-in-hand. Building carbon reduction measures not only protects the environment, but also come with attractive ROI for building owners. One such option is the PACE loans which offers repayment period of up to 30 years. They can also be transferred to different building owners in case the building is sold.
Every building is unique, which means the carbon emission reduction measures will also vary for every building. To achieve the best possible result, the recommended course of action is to consult to an energy professional.
Reduction Strategies for Embodied Carbon
Unlike operational carbon, which can be reduced by improving the building energy consumption profile, embodied carbon is already released into the atmosphere by the time a construction project is finished.
To deal with embodied carbon, there are 3 main strategies –
- Reuse of construction materials when buildings reach their service life end.
- Lowering the initial carbon footprint of materials to be used during new construction.
- Isolating the carbon that is already released into the atmosphere.
Even though there are not many innovations available to deal with embodied carbon, there are many excellent concepts that apply to the building sector. Some of these concepts are – design for deconstruction, carbon sequestering materials, carbon sequestering sites, low-carbon and zero-carbon materials, etc.
An excellent way to minimize the use of construction materials during design stage is BIM modelling. Using BIM, the layout of the building systems can be optimized even before the materials are bought. Also, using prefabrication and modular construction methods, material waste can be further reduced.
There will be a considerable growth in the building sector within the next few decades. According to the United Nations, 68% of the global population will be living in cities by 2050. Considering the sheer volume of construction that is likely to happen, quick and effective actions are needed to mitigate the impact of embodied carbon.
Michael Tobias, PE, is the principal and founder of NY Engineers. He leads a team of over 50 MEP/FP engineers. Although New York Engineers main headquarters are in NYC, the business has led over 1,000 engineering projects in New York, New Jersey, Connecticut, Pennsylvania, Florida, Maryland, and California, as well as Malaysia and Singapore. Michael is an advocate for green technology and energy efficiency, and approaches engineering as a vehicle to raise the quality of life.