Kent Peterson is the Chief Operating Officer at P2S Inc, a consulting engineering and commissioning firm. He has extensive experience working in the building and infrastructure industries and provides leadership, inspiration and technical direction for the firm’s engineering practices. He has served on the Office of Federal High-Performance Green Buildings Advisory Committee since 2011 and is chair of the 2022-2023 ASHRAE Building Decarbonization Task Force.
Host Vic Marinich, global marketing director for air conditioning at Danfoss, is joined by Kent Peterson, vice president and COO of P2S, to discuss the importance of recognizing embodied carbon and its role in the decarbonization of buildings.
- Operational carbon is what most people are familiar with. It’s usually generated by the fuel that’s consumed from heating and cooling or the power that goes to a building over the building’s lifetime.
- Embodied carbon is quite different. It’s basically all other carbon emissions that people don’t really think about: the emissions from manufacturing, transportation, installation, maintenance and disposal of the construction materials used in the building. It’s the greenhouse gas emissions that are released before the building or the infrastructure even starts to be used.
- There’s also a term that’s being thrown around in the industry: total carbon or whole life carbon. That’s simply the sum of the operational carbon and the embodied carbon.
- Buildings are responsible for roughly 40% of the global carbon emissions in the world. So according to the World Green Building Council, upfront carbon emissions are responsible for about half of the entire footprint. The building sector is one of the largest consumers of raw materials and products of waste in the United States and accounts for about 25% of the total energy or 75% of the raw materials consumed in the U.S. manufacturing industry
- A circular economy for building materials stands to offer significant gains for efficiency, waste reduction and decarbonization. Concrete, steel and aluminum are responsible for 23% of the total global emissions and most of those materials are used in the built environment. The emissions related to refrigerants are also considered to be embodied carbon emissions. There’s an opportunity for embodied carbon reduction in these high-impact materials through design material selection and specification of low-carbon type materials.
- Renovating an existing building vs. tearing it down and rebuilding can save somewhere between 50 and 75% of the upfront embodied carbon.
- Solutions could include optimizing concrete mixes using high-recycled steel content, selecting low-embodied carbon insulation products or low-embodied carbon glazing products or even selecting low-GWP refrigerants and minimizing the leakage of those refrigerants. There are some solutions on the method side such as reusing materials and designing for longer life as well as designing for disassembly and considering how these materials might be so disassembled so they can be reused for some future use.
- We can also reduce refrigerant emissions by making smaller refrigeration systems that go into buildings and using the low-GWP refrigerants, mitigating leakage and improving refrigerant recovery.
- Lifecycle assessments are a methodology for assessing environmental impacts associated with all the stages. A building generates these impacts over its entire lifecycle and there’s several tools that are currently out in the marketplace. These assessments are usually done in the early stages of the building design so one can make the proper selections of the types of materials used in construction, looking at the tradeoffs between body carbon and operational carbon to come up with a total carbon figure.
- Owners of existing buildings should also pay attention to embodied carbon, as buildings will be renovated and upgraded throughout their life cycle. Look at what types of solutions would have the lowest carbon impacts from an embodied carbon standpoint. Existing buildings have tremendous opportunities for reductions in operational carbon, by reducing the building energy use through energy efficient retrofits and/or electrification using heat pumps, or redesigning the buildings to optimize some of the grid flexibility and provide on-site renewable energy.
- The global building stock area is expected to double by 2060 so carbon emissions will more than double if we do not change the way that buildings are currently built and how we use energy. The building industry is going to need to achieve net zero greenhouse gas emissions across each building’s lifecycle.
- Energy efficiency is the first thing we can implement to reduce operational carbon emissions and can also reduce the embodied carbon that’s embedded in mechanical, electrical and plumbing (MEP) systems that we need to replace. If we can reduce the size of the systems that go in those buildings, we’ll be able to reduce the embodied carbon by using less resources and less refrigerants in those systems. Control systems integrated into buildings can really help coordinate the supply and demand and shift some of the energy use to times of the day when zero carbon energy is highest in the grid mix.
- The federal Buy Clean Initiative will prioritize the use of lower carbon construction materials in federal procurement and federally funded projects. California passed Buy Clean legislation three years ago that requires the collection of EPDs (Environmental Product Declarations) for building materials on construction contracts for public infrastructure projects.
- The Inflation Reduction Act funded the EPA to develop guidance on reducing in body carbon and set aside roughly $2 billion for the general service administration to reduce embodied carbon in their construction of federal facilities and several jurisdictions in the U.S. have turned their attention to building performance standards policies that require building owners to meet performance targets by actively improving the building performance over time.
For additional resources on embodied carbon, see https://carbonleadershipforum.org/clf-carbon-policy-toolkit/
To learn more about ASHRAE’s Task Force for Building Decarbonization, visit https://www.ashrae.org/about/ashrae-task-force-for-building-decarbonization
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