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City of Madison's Grid-Interactive Pilot Started With Patching Unexpected OT Gaps: Network, Data-Path, and Point-Level Validation
The City of Madison set out to turn up to seven municipal buildings into grid-interactive assets that could shed and shift load on command. The plan assumed those buildings were already connected, already BACnet, already writable. After surveys, the OT reality was quite different.
The project runs under a 2021 Department of Energy Connected Communities award, with ACE IoT Solutions handling the data layer and HGA Architects and Engineers designing the load-flexibility strategies. The target was 1.46 gigawatt-hours saved a year, 250 kilowatts of real-time shed, and 432 kilowatt-hours shifted in usage time across the portfolio.
When the team dove into the networks, they found a much messier situation than the "BACnet writable" architecture they were expecting. Buildings sat on different subnets. One of the main sites turned out to be a stack of LON controllers bridged through a BACnet system, which left many points read-only. The city believed its building automation system could do everything the project needed, since it had bought one sold on exactly that promise. "They'd never been able to test it," said Bill Maguire, co-founder of ACE IoT Solutions. The first real test came midway through the project.
Where points were writable, it was still a challenge to determine which HVAC and lighting points needed to be adjusted to effectively reduce load. "An HVAC system doesn't have a single point that says reduce load," said Andrew Vavoulis of HGA. "You have to get clever and manipulate other points." Setpoints meant different things on different equipment, submeters were missing or stranded on the wrong networks, and the team had to stand on site to confirm that changing a point actually had the anticipated load-shed result.
The team found solutions to load shed by mapping which meter reads which load, confirming write access, and standardizing what a control command means across equipment. Buying integrated systems had made the buildings look ready for grid interaction; however, getting writable control of all building systems proved to be one of the most challenging aspects of the project.
ACE IoT and the City of Madison are open-sourcing the project, so the next city inherits Madison's network, meter, and semantics fixes instead of paying the same learning tax.
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The City of Madison set out to turn up to seven municipal buildings into grid-interactive assets that could shed and shift load on command. The plan assumed those buildings were already connected, already BACnet, already writable. After surveys, the OT reality was quite different.
The project runs under a 2021 Department of Energy Connected Communities award, with ACE IoT Solutions handling the data layer and HGA Architects and Engineers designing the load-flexibility strategies. The target was 1.46 gigawatt-hours saved a year, 250 kilowatts of real-time shed, and 432 kilowatt-hours shifted in usage time across the portfolio.
When the team dove into the networks, they found a much messier situation than the "BACnet writable" architecture they were expecting. Buildings sat on different subnets. One of the main sites turned out to be a stack of LON controllers bridged through a BACnet system, which left many points read-only. The city believed its building automation system could do everything the project needed, since it had bought one sold on exactly that promise. "They'd never been able to test it," said Bill Maguire, co-founder of ACE IoT Solutions. The first real test came midway through the project.
Where points were writable, it was still a challenge to determine which HVAC and lighting points needed to be adjusted to effectively reduce load. "An HVAC system doesn't have a single point that says reduce load," said Andrew Vavoulis of HGA. "You have to get clever and manipulate other points." Setpoints meant different things on different equipment, submeters were missing or stranded on the wrong networks, and the team had to stand on site to confirm that changing a point actually had the anticipated load-shed result.
The team found solutions to load shed by mapping which meter reads which load, confirming write access, and standardizing what a control command means across equipment. Buying integrated systems had made the buildings look ready for grid interaction; however, getting writable control of all building systems proved to be one of the most challenging aspects of the project.
ACE IoT and the City of Madison are open-sourcing the project, so the next city inherits Madison's network, meter, and semantics fixes instead of paying the same learning tax.
Register for the next Nexus Labs event.
Sign up for the newsletter to get 5 stories like this per week:
This is a great piece!
I agree.