Reducing Greenhouse Gas Emissions From the ‘Operations’ Phase of the Life Cycle in Commercial Office Buildings
CitationPiano, Claudia A. 2019. Reducing Greenhouse Gas Emissions From the ‘Operations’ Phase of the Life Cycle in Commercial Office Buildings. Master's thesis, Harvard Extension School.
AbstractOffice buildings, largely occupied by the commercial sector, are not perceived as a large emitter of greenhouse gases, so the companies that occupy them and those that manage them are not required to measure, report, and reduce their greenhouse gas (GHG) emissions (WRI/WBCSD, 2017; US EPA, 2017). Yet buildings are responsible for a surprising 40% of U.S. energy use and over 40% of GHG emissions, with commercial office buildings accounting for approximately half that number (Marks, Lin, Harris, Hewitt, & Holloman, 2010; US DOE, 2014). Published life cycle analyses tend to focus on embodied energy and HVAC energy use (Scope 1 and 2 emissions), but there is little that specifically points to the operation of office buildings as a high-energy consumption service (WRI/WBCSD, 2004; Janda, 2007). What seems to be missing from our knowledge base is a fundamental understanding of the operations phase of the life cycle of an office building, not just the heating and cooling energy, but the GHG emissions generated by day-to-day operations.
More tangible guidance needs to be provided to occupants of commercial office buildings in order to make changes in their energy use and reduce GHG emissions. Building ‘green’ is not enough, because it will only affect embodied energy and possibly HVAC energy used, but not all the other operational activities engaged in by this sector. Because this industry does not manufacture, a large share of GHG emissions are generated by the Scope 3 categories: upstream purchased goods and services, employee travel, employee commuting mileage, and waste generated in operations.
This study was conducted to examine the hypothesis that in order for a green building to generate less GHG emissions than a conventional building, the operations need to be more sustainable, e.g., the occupants would have to engage in more sustainable practices. Surveys were used to examine the operational practices of ten office buildings in five cities, with four conventional and six green buildings included. The survey results were used to generate a greenhouse gas (GHG) inventory for each building and the results were compared. Representative conventional and green model buildings were created using a Life Cycle Analysis (LCA) modeling tool (GaBi), and the results were normalized using the ReCiPe method.
Green buildings outperformed conventional buildings in the area of Scope 2, purchased electricity and heat, with 17% less than conventional. However, green buildings had greater volume of GHG emissions, as well as per person GHG emissions across all buildings studied. Green buildings yielded 73% greater Scope 3 emissions, driven primarily by business travel and commuting miles. Finally, green buildings also had 10x more embodied energy then conventional.
The GHG Inventory and the LCA demonstrated which factors (square footage, building materials) were responsible for the greatest embodied energy, and which factors (business travel, commuting miles) were responsible for the greatest operational energy. This information can contribute to the knowledge base for offices in the commercial sector by providing insight into which meaningful changes should be implemented to make their operational practices more sustainable.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:42004237