Modeling the Implications of Fugitive Gas Emissions on Building Heat Upgrade Decisions

The majority of US buildings use natural gas for heating even though it is a potent greenhouse gas that relies on a leaking infrastructure with significant life cycle fugitive emissions. Recent developments in all-electric heating alternatives or ‘certified’ or ‘renewable’ gas alternatives have made decision making about operating building heating systems more complex given quickly evolving emissions and economic profiles. Here, a novel modeling tool was developed to help provide engineers with full cost-accounting of both the economic and greenhouse gas emissions associated with different heating options. The tool is based on the University of Virginia's model for estimating costs and emissions associated with capital expenditures and it was updated with location-specific fugitive emissions and cost estimates. Users can input various different common options for heating systems to understand how much of an impact each will have on economic factors such as return on investment, estimated lifetime cost as well as full-cost life cycle impacts including carbon dioxide-equivalents avoided per year, and life cycle greenhouse gas emissions. The analysis suggests that in most cases it is economically and environmentally preferable to replace gas infrastructure with a heat pump once fugitive emissions are considered. In support of the University of Virginia's net-zero emissions targets, the tool was used to assess several hypothetical heating upgrade projects on grounds including one for Carr's Hill. The tool contains fugitive emissions data for all the major metropolitan areas in the United States and can be easily adopted for use in other locations to provide first-of-its kind information for building managers.