In Q2 2025, the City of Madison will begin using the first-ever grid-interactive building management system powered by open-source software. Deployed in six municipal facilities, the innovative system enables the City of Madison’s Department of Facilities to manage load profiles for better utilization of grid assets, lower the city’s energy bills and reduce carbon emissions. Over a typical year, the City of Madison estimates that the new system will enable it to save 1.4 GWh of energy, shed 250 kW of load and shift 432 kWh of load—without negatively impacting occupant comfort.
The new system is the result of a collaborative partnership between the City of Madison, Madison Gas and Electric (MGE) and Slipstream. Later in the project, MGE plans to use the learnings from the project to deploy automated demand management in up to 10 additional commercial, industrial and multifamily buildings in its service territory. For MGE, strategies like this aim to help manage long-term costs and ensure reliability. Other potential customer benefits include lower emissions and energy costs after deploying the new system in their buildings.
The project team made three notable decisions related to the development, testing and deployment of the grid-interactive building management system deployed in Madison, Wisconsin.
- Occupant comfort must be a key component of a successful system
- The system’s design must reflect metrics for evaluating the system’s benefits for both building owners (e.g., City of Madison) and power companies (e.g., MGE)
- The software engine for the system must be transparent so that potential users and their technical advisors can see how the system works
In this post, we explore how each decision helped make the system more replicable, scalable and cost-effective.
Designing and Deploying a Grid-Interactive Building Management Solution in Madison
Background: Through a grant from the U.S. Department of Energy (DOE) Connected Communities initiative, the City of Madison, in partnership with Slipstream and MGE, has deployed an Energy Management Information System (EMIS) and a grid-interactive building optimization solution in six municipal buildings. For the City of Madison, the EMIS solution provides greater visibility into the operations of its municipal buildings. The grid-edge solution also reduces energy use, utility demand charges and greenhouse gas emissions.
The system enables the following energy efficiency and demand flexibility strategies:
Technical Overview: The City of Madison selected a project team including ACE IoT Solutions LLC (“ACE IoT”) and Hammel, Green and Abrahamson, Inc. (“HGA”) to build and deploy an integration and automation platform for the project. HGA designed and tested a series of algorithms/sequences that maximizes onsite renewable generation, improves resiliency, and optimizes load management in tandem with other systems (HVAC, solar) in the city building(s) where batteries and/or EV chargers are deployed. HGA’s strategies adhere to the control theory principles of ASHRAE Guideline 36 and deliver state-of-the-art operational efficiency of the HVAC systems in the City of Madison’s facilities. ACE IoT encoded HGA’s algorithms/sequences in software. To run the HGA sequences in the City of Madison buildings, ACE IoT implemented a system that is integrated with—but not developed within—a building’s existing building automation systems. The integration occurs using the open source VOLTTRON technology. Developed at Pacific Northwest National Laboratory with U.S. Department of Energy funding, the VOLTTRON technology includes support for critical building system protocols including BACNet, Modbus and OBIX.
Three Decisions Central to the System’s Replicability and Scalability
To ensure that the solution that HGA and ACE IoT developed can be readily deployed at sites beyond the initial City of Madison buildings, Slipstream, the City of Madison and MGE made three key decisions.
- Prioritize occupant comfort. The City of Madison Facilities Department takes pride in operating Madison’s municipal building effectively and efficiently. The main priority is that the employees and visitors who occupy the City’s buildings must be comfortable. Manual demand response (DR) initiatives involve more effort from facility operators and run the risk of prioritizing demand reduction over occupant comfort. The City of Madison has designed and deployed a system that provides the facilities team with new capabilities to shift and shed load intelligently as well as increased visibility into the energy use and occupant comfort of buildings in their portfolio.
- The system must have proven results. Slipstream, a nonprofit research organization with a mission to accelerate climate solutions for all, is responsible for assessing, quantifying and documenting the impact of the new system. In collaboration with the City of Madison and MGE, Slipstream has implemented a robust evaluation framework that will confirm the system’s return-on-investment. Slipstream expects to release case studies documenting the system’s cost and benefits for building owners, utilities and Independent System Operators (e.g., MISO).
- The system’s technological engine cannot be a black box. The sequences and optimizations as well as the code operationalizing the optimizations will be released as open-source projects. The opportunity to see under the hood and evaluate how the system implements the load shift and load-shed strategies, for example, should provide other municipalities and/or utilities with more confidence to explore how best to use and deploy the solution. Additionally, release of the optimizations and the code required to implement the strategies means that any organization with an interest in the system can select their trusted technology vendor to deploy and support the system. In addition to reducing project risk, vendor choice should result in lower costs and enhance the replicability of the GEB solution in Madison and beyond.
The City of Madison has Created a Blueprint for Grid-Interactive Building Management
A May 2021 U.S. Department of Energy study of Grid-Interactive Efficient Buildings outlines the problem statement that crystalizes the challenge—no, opportunity—that drives interest in the deployment of grid-edge solutions in buildings.
“Buildings consume power indifferent to grid conditions, blind to the high costs and threats to reliability posed by high peak demand and grid stress; inflexible to opportunities offered by variable, renewable power sources; and senselessly missing the smart and connected technology revolution.”
To address this problem statement, the City of Madison is using smart technologies to advance energy efficiency, demand management and comfort in its municipal buildings. With a new grid-interactive building management system, the City of Madison, Slipstream, MGE and other project partners have the potential to remake buildings into assets that support a more flexible power grid for the region and its residents. The City of Madison has made at least three decisions that have transformed a smart technology demonstration into a viable blueprint for a replicable, scalable grid-interactive building management solution.
