C04 -- Energy and Operational Carbon Savings in Community Scale Low-Carbon Retrofit with Dual Source Cold Climate Heat Pumps

Community-scale electrification is critical to transforming the US (and other nations with similar goals) into a carbon-neutral country. However, reducing energy and operational carbon emissions through electrification is a process that requires careful design and analysis to execute properly. This process often includes retrofitting heating systems with cold-climate heat pumps. Still, it requires special consideration in very cold climates, especially for community-scale retrofit scenarios where the local power distribution network might not handle the additional load from electrical backup resistors. This motivates a need for dual-source heat pumps. Our analysis focuses on a community located in Lake County, CO, USA at about 10,000ft (~3,000m) above sea level, in a heating-dominated climate that is in the process of being retrofitted and partially electrified. The community consists of approximately 30 manufactured homes which range in age from 1960s to 2000s. In this project, academia, state government, non-profits, and local utility collaborate to demonstrate whole community benefits for community-scale electrification in low-income communities. This particular paper focuses on the community-scale using URBANopt to allow for community simulation and distributed energy resource optimization which provides critical information before actual community retrofit is performed. Our study simulates actual homes based on publicly available information and compares different carbon emissions sources/calculators: NREL Cambium, WattTime, and EIA data and the impact on low-carbon retrofit under partial (dual source heat pump) electrification. The additional retrofits include upgraded crawlspace and attic insulation, windows, air sealing, and lighting. Our analysis shows that 1) there are differences up to 38% in annual emissions between carbon emissions tools and 2) the average reduction after electrification and retrofit is 20% when averaged between the three emissions-evaluating methods. We also note a large bias error between the three emissions calculation methods, and more consistency in standard deviation.