RMF's Jared Markle Featured in District Energy Magazine on Urban Electric Microgrid

Reimagining, and rewiring, an urban electricity delivery system

The University of Maryland, Baltimore has a new state-of-the-art microgrid

By Jared Markle, PE

Years of planning and collaboration informed the decade-long development of a campus electrical distribution upgrade for the University of Maryland, Baltimore that would support projected future growth while ensuring system reliability.

Centered in downtown Baltimore, UMB is a medical research school and the original campus of the University System of Maryland, covering 61 acres and 23 city blocks. It provides professional education, research, health care and social services for 7,000 students and has a daily population – staff included – of over 20,000. UMB students work toward degrees and research in dentistry, law, medicine, nursing, pharmaceuticals and social work.

The campus electricity modernization plan that was ultimately adopted required miles of new duct banks and underground concrete vaults routed beneath the busy streets of Baltimore and thousands of feet of campus sidewalks. It called for mirrored switching stations on the north and south sides of campus with a complete replacement of the underground distribution system, and it required each switching station be
configured into a ring bus with four separate utility feeders, totaling eight utility services to the campus at two- separate locations.

The campus had been served by an electrical system that was well maintained over the years but was last substantially upgraded in the 1960s and was approaching the limits of its capacity. UMB had grown substantially and needed a system that could both accommodate continued expansion and enable the use of new technologies across its programs. UMB is evaluating renewable energy- systems that could include solar PV and battery energy storage as well as electrified heating systems such as water source heat pumps, air-source heat pumps and electric boilers. Its research focus requires a constantly evolving academic program that relies on high-end electrical service.

UMB brought on RMF Engineering Inc. in 2016 to design, plan and install a new campuswide electrical system to meet projections for future expansion while ensuring continuous electrical reliability, redundancy and resilience. In addition to vastly improving electrical support for the important work being done, RMF laid groundwork for UMB’s broader campuswide sustainability goal of achieving carbon neutrality.

BRAINSTORMING A PLAN TO MANAGE PROJECT COMPLEXITY

The new master plan came together after an in-depth assessment of UMB’s existing electrical distribution system, including an investigation into associated duct-bank routing, sizing and ownership, as well as a survey of available real estate on campus to determine potential locations and sizes for new switching stations. At the time, the university was served via a master switching station fed by a single substation operated by
Baltimore Gas & Electric. To meet growing campus load and future demands, RMF recommended a substantial, multiphase, multiyear overhaul that would require roughly $60 million to $80 million in new construction to meet the university’s needs over 40 to 50 years.

The plan re-anchored UMB’s central system with two new mirrored switching stations, positioned north and south on opposite ends of the campus. Both were to be supplied with power from four dedicated incoming BGE service feeds. Because campus development space is at a
premium, the switching station location options were evaluated according to cost and in the interest of maintaining valuable space. 

This approach required a high level of coordination with BGE, as two separate utility substations were to be tapped to access 60 MW of capacity through the eight utility feeders. Numerous meetings were conducted years in advance of construction to coordinate utility requirements, provide upgrades on the underground pathway to campus, and to ensure that the various utility departments (protection, control,
metering, etc.) were satisfied. The plan included a complete replacement of the underground distribution system, taking advantage of both existing university owned duct bank and new duct bank within the proposed infrastructure for new feeder pairs running between the two switching stations. Every campus building could be fed from either end, enabling the load to be balanced between the two stations.

BRINGING POWER TO THE NEW NORTH SUBSTATION

RMF worked closely with BGE through design and construction to establish the campus load profile, verify distribution pathways and ensure conformance with the primary customer substation equipment requirements. The findings were essential to informing the geography of the feeder routing to the campus, the intertie protection scheme, and the new system fault current versus the existing campus equipment ratings. The dedicated utility feeders allow for a high-speed protection scheme, further increasing the reliability of the campus electrical supply.

Construction of the North Switching Station began in October 2020, co-locating within a new 15,000-square-foot building UMB’s new recycling center and the 13.2kV switchgear required to provide redundant electric service to the campus grid. In keeping with UMB’s sustainability
goals, the building features a bio-retention within a new 15,000-square-foot building UMB’s new recycling center and the 13.2kV switchgear required to provide redundant electric service to the campus grid. In keeping with UMB’s sustainability goals, the building features a bio-retention vault for stormwater management, skylights in the second-floor corridor for natural lighting, and an outdoor planter wall and screen at the loading dock.

The new, fully automated switching system coordinates operations with the later-phase South Switching Station and backup standby power to the campus –designed with ring-bus connected switchgear, redundant battery systems and medium voltage power factor correction capacitors. It was important to the team to leverage existing assets to the extent possible when considering upgrades. A central generation hub within the campus medical school buildings was installed to connect 7 MW of existing generation to a new 2 MW natural-gasfired generator, with the ability for future expansion. This central generation hub is integrated into the campuswide control system via dedicated and redundant fiber-optic communication loops that interconnect the three main switchgear control hubs, which allow operators to safely and securely run the control system at the north station, the generation hub and the future south station.

The addition of the gas generator allows UMB to continue leveraging its existing systems while bringing them under the control of the new central program. This was a key piece of RMF’s master plan because it enabled the project team to begin testing functionality and optimizing capabilities before the microgrid was complete. By prioritizing the electrical distribution replacement – as opposed to the buildout of the second, south station – UMB will benefit from its new grid sooner. But the amount of excavation required for a comprehensive, interconnected underground network of duct banks and vaults beneath a densely built urban campus was a significant challenge nonetheless.

COLLABORATION IS ESSENTIAL IN DISTRIBUTION PLACEMENT DECISIONS

RMF’s design for the new power distribution system included 9,600 feet of four-way, six-way, eight-way, 12-way and 24-way concrete-encased duct bank; more than 200,000 feet of 15kV cabling and underground concrete vaults; and 7,500 feet of campus sidewalk and city street restoration. Construction coordination required heavy involvement with the city of Baltimore.

Through the city’s developer’s agreement process, RMF and its design subconsultant, Carroll Engineering Inc., were ultimately granted approval to build out electrical infrastructure in city rights-of-way. Special approvals – in addition to standard right-of-way, building and excavation permits – required many face-to-face presentations, extensive correspondence and design drawing submissions for each phase of construction.

UMB’s electrical distribution network now includes feeder connections that link the two switching stations to one another, as well as to every building on campus. Dual radial feeders, in particular, provide resilience. The interconnected system allows for load balancing and energy
use optimization while providing total redundancy in the event of an outage at either station. The system today is a self-healing, highly reliable network that ensures no part of campus ever goes offline. Close work with UMB Operations and Maintenance led to maintenance plans and strategies that allow for no interruption to campus operations during equipment maintenance.

TAKING A LAYERED APPROACH TO DIVERSIFYING CAMPUS SYSTEMS

After nearly a decade of planning and building, UMB has a new microgrid in place, equipped with state-of-the-art switchgear and a generator control system designed for reliability and ease of maintenance. In the event of an outage of either station, load can be transferred to the other one, a highly reliable arrangement with capacity for future growth. The upgraded system also enables UMB to incorporate distributed generation down the road. Generation can be distributed to both switching stations, resulting in a fully redundant and expandable system that will serve a world-class medical research campus for years to come.

Further, the new microgrid allows the university to leverage existing generator peak shaving for economic and environmental returns. With its
increased capacity, the new system is set up to allow for both electric vehicle charging and carbon reduction technologies for campus heating in line with UMB’s vision of a sustainable future. Anticipated peak electric load this year, the end of the 10-year capital plan, is approximately 34,000 kW. The upgrade also provides UMB with the flexibility to consider all options for building out sustainable heating systems, both centralized and decentralized, across the campus. The upshot is that the university is closer to meeting its goal of a 60% reduction in on-campus greenhouse gas emissions by 2031 and achieving carbon neutrality by 2045.

As colleges and universities around the world seek to meet both institutionally and legislatively driven decarbonization goals, electrification
of heating systems, in particular, is one of the most viable ways to get there. Regardless of the technology chosen – air source heat pumps, electric boilers, geoexchange – the result is load growth on the electrical system that campuses with older or lower capacity systems won’t be
able to accommodate easily.

UMB’s upgrades serve as a powerful example of how to diversify systems through a layered approach that supports sustainable growth initiatives while ensuring resilience and reliability.

Jared Markle, PE, is an RMF principal and leads the company's Baltimore electrical infrastructure team, where he manages electrical
modernization projects and specializes in medium voltage planning and design in the mid-Atlantic and the Northeast. He joined the firm in 2011 and holds a Bachelor of Science degree in electrical engineering from Penn State University.