(C03) How building design & operation changes when we know grid carbon emissions vary hour-by-hour—and how buildings can accelerate grid decarbonization

While the annual average carbon emissions of utility-generated electric power are dropping, they vary significantly over the course of the day, seasonally, city-by-city, and state-by-state. This means that projects that generate or purchase clean electricity equal to annual consumption may be Net Zero Energy, but they are usually far from Net Zero Carbon. And as we move to electrify both buildings and transportation, the alignment, or misalignment, between demand and clean energy availability means that buildings can either trigger the use of more dirty power or allow utilities to deploy more clean generation than they otherwise would.

This session provides designers the software tools, datasets, design guidance resources, and conceptual framework they need to lower the operating carbon footprint of their project by designing for their project's local grid today and in the future. It starts with the basics of how grid carbon intensity varies across hours, seasons, and regions today and shows the different trajectories these are anticipated to follow based on historical trends and recent legislation such as the Inflation Reduction Act. It then shows how to calculate predicted lifecycle carbon emissions for buildings using these hourly profiles and explores how shifts in design and operating strategies can substantially reduce emissions. This framework can enable designers to consider the carbon impacts of their designs across various scales, including embodied carbon, onsite direct emissions, and upstream grid carbon emissions. Presenters will emphasize key design and operating strategies, customized for various building types and regions, that minimize future risk for owners and operators while positioning buildings to contribute to the transformation of the grid. These strategies include everything from passive strategies (building envelope and thermal mass) to building systems incorporating thermal and electrical storage to smart automated controls to operational strategies.

Next, we look at the impact these strategies could have if implemented at scale if the US were to deploy them across three broad categories: New construction, major renovation, and altering the operational strategies for existing buildings. We then explore how clean energy deployment might change if a substantial fraction of the built stock were grid-responsive.

Then we look at how rating systems are currently taking this into account and how this might shift in the future. We start from a review of the LEED v4 BD+C and O+M "Demand Response" credit and v4.1 BD+C and O+M "Grid Harmonization" credit (including the Grid Optimal Alternative Compliance Path) to how hourly carbon awareness might be taken into account in the general energy performance credits of LEED, ASHRAE 189.1 / IgCC, and other codes and standards.

Our vision for buildings that are "efficient, electric, and able to shape their load" moves us from buildings that respond to where utilities are today to buildings that help accelerate decarbonization of the grid itself.