Energy efficiency research supports grid-interactive townhome development

Neighborhoods in the Southeast continue to become more energy efficient with the support of ORNL. Under a collaborative research and development agreement with Southern Company, ORNL researchers have developed a home energy optimization platform for 46 townhomes in Atlanta’s first Smart Neighborhood. The platform optimizes each home’s heating, ventilation, and air conditioning and water heating systems, in coordination with rooftop solar and batteries, to minimize costs and maintain comfort.

This is the second Smart Neighborhood project ORNL has provided research and development support for. The first, with Alabama Power and Southern Company, was completed in 2018 and features 62 state-of-the-art homes connected to a residential microgrid that houses battery and solar energy capabilities.

The Georgia neighborhood, which completed construction in late 2020, differs from the Alabama neighborhood in that each townhome is equipped with solar panels and a battery pack, rather than having those components located at a centralized microgrid. The Georgia homes are equipped with automatic transfer switches that allow essential loads in the homes (refrigerator, lighting, HVAC) to continue operating with battery and solar power in the event of a grid outage. The townhomes are also equipped with electric vehicle charging stations.

ORNL has leveraged DOE’s VOLTTRON platform as the framework supporting the ORNL code to optimize the home loads. ORNL’s system interacts specifically with the home’s HVAC and water heating systems.  Using the algorithms developed by ORNL researchers, the system can forecast and optimize the townhomes’ energy use in response to signals from the utility.

“The process of data gathering, optimization and control happens seamlessly for the homeowner,” said ORNL’s Heather Buckberry, project manager for both the Georgia and Alabama neighborhoods. “All the homeowner has to do is set the appliances to their comfort level and the system takes care of the rest, providing an efficient, economical and reliable energy source.”

Battery storage systems within each townhome provide resilience as a backup power source available for critical loads. The battery systems also maximize the value of the rooftop solar panels by allowing storage of excess power generated during the daytime for use in the evening. Georgia Power anticipates the panels will produce approximately one-third of the homeowner’s annual energy usage.

“We’re comparing two approaches with the two neighborhoods to test how appliances within homes can be connected to each other and a microgrid and how that interaction can reduce energy usage, while maintaining comfort and affordability,” Buckberry said.

Recently published research results on the Alabama Neighborhood showed that the homes consumed 44 percent less energy than all-electric homes, and the peak winter heating electric demand was about 34 percent less than that for a similar all-electric community.

“This is a significant result, especially in the national context, where residential and commercial buildings consume nearly           75 percent of the nation’s electricity use and account for 40 percent of its total energy,” Buckberry said.

Both projects provide data on what connected neighborhoods of the future could look like and how future buildings need to communicate with each other and with the grid for shared comfort, efficiency and value.

ORNL’s connected neighborhood research is supported by the Department of Energy’s Building Technologies Office.