In May 2010, HPAC Engineering published my article ‘"The Benefits of Ice-Based Thermal Energy Storage”. Included was a sidebar that I added after one of the article’s reviewers correctly pointed out that I had not accounted for the energy required to manufacture the actual TES equipment.
It was a valid point, since the example plant I cited was designed to have four concrete tanks, each measuring approximately 106-ft-x-65-ft-x-42-ft., and just the cement used in the concrete required nearly 5 mj per kilogram (approximately 2,150 Btu per pound) to produce. That was the first time I really considered the significance of embodied energy, i.e., the total energy required to produce a product and deliver it to its point of use.
Since then, I have addressed the topic of embodied energy several times in Clark’s Remarks, because energy efficiency alone – either at the source (point of generation) or the site (point of use) – does not necessarily tell the whole story. The analog of embodied energy in the built environment is embodied carbon emissions, or the total greenhouse gas (GHG) emissions generated in the production of a built asset.
- Listen to Larry Clark in the inaugural episode of our new podcast series, HPAC On the Air.
UK-based Architects Climate Action Network (ACAN) is a group of individuals within architecture and related built environment professions taking action to address the twin crises of climate and ecological breakdown. Its recently released report, The Carbon Footprint of Construction, concluded that the regulation of embodied carbon emissions resulting from building activities is critical. ACAN specifically addresses those emissions in the UK, which it claims are nearly 50 MtCO2e. According to ACAN’s findings, approximately 49% of the UK's total carbon emissions can be attributed to buildings.
Embodied carbon emissions are presently unregulated, with regulations focused solely on operational energy consumption, which is why ACAN is advocating for legislation to regulate embodied carbon emissions in the UK. Some countries have begun to address embodied carbon. In the Netherlands, for example, they have a requirement to calculate the MPG (an environmental performance factor for buildings) for every application for an environmental permit for new office buildings larger than 100 m2 (1076 ft2). The MPG specifically indicates the environmental impact of the materials used in a building. The lower the MPG, the more sustainable the use of the building’s materials.
France also is implementing regulations that will reduce the environmental impact of new building construction by accounting for all of the building's emissions over its life cycle, beginning with construction. Here in the US, California last year passed the Buy Clean California Act (BCCA), which requires that the California Dept. of General Services establish and publish the maximum acceptable Global Warming Potential (GWP) for the production of structural steel (hot-rolled sections, hollow structural sections, and plate), concrete reinforcing steel, flat glass, and mineral wool board insulation.
Accounting for embodied energy has helped manufacturers of such products as batteries become more sustainable. Hopefully, by focusing on embodied carbon emissions in construction, the building industry will also become greener.
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A regular contributor to HPAC Engineering and a member of its editorial advisory board since 2012, Clark, LEED AP, O+M, is a principal at Sustainable Performance Solutions LLC, a south Florida-based engineering firm focusing on energy and sustainability. Email him at [email protected].