Submeters Put Team on the Offensive

It took the promise of a new football stadium to lure the NFL back to Baltimore after the city's beloved Colts defected to Indianapolis in the eighties. So when the Ravens moved to Maryland in 1996, the Maryland Stadium Authority started construction on a 69,000-seat downtown arena next to Oriole Park at Camden Yards.


It took the promise of a new football stadium to lure the NFL back to Baltimore after the city's beloved Colts defected to Indianapolis in the eighties. So when the Ravens moved to Maryland in 1996, the Maryland Stadium Authority started construction on a 69,000-seat downtown arena next to Oriole Park at Camden Yards.

But amenities such as heated benches and sideline cooling fans came at a high price—so high, in fact, that it quickly became apparent that a winning game plan for energy conservation would be needed to tackle skyrocketing power bills.

Facility managers chose an automatic meter reading (AMR) system that continues to score major points with the franchise. That's because in exchange for free rent, no lease terms, and all concession, parking and suite revenues, the team picks up the stadium's $5 million annual operating and maintenance bill. And while huge crowds bring big revenues, it also means big-time operating expenses, especially power usage.

So where does all the power go? It goes to 62 oversized bathrooms, 245 food and beverage concessionaires, sports lighting equipment, scoreboards, 108 private suites, air handlers, parking lot lighting, security systems, kitchen power and more. Plus, the stadium shares its power plant with Oriole Park. Between the two, energy usage represents roughly 20% of overall budget.

"It became very obvious that we had more power usage in the stadium than we first anticipated," says Sherman Kerbel, director of facilities management. "Yet, when we did simple things like turning the lights off, it didn't make a difference. So we figured, 'a-ha, something else is happening here that we're not seeing.' So we put some meters on things to find out what's going on where."

Kerbel's efforts in reducing power usage wherever possible to quickly lower energy costs led him to evaluate the strategy already in use at neighboring Oriole Park at Camden Yards. Because energy meters had already proven their reliability in metering the baseball stadium, Kerbel decided to install them at Ravens Stadium as well. Over 40 meters were soon installed throughout the 1.6-million-sq.-ft. arena to measure energy in all its forms, whether gas, water or electric. These individual meters were strategically placed to track specific energy usage at various locations in the stadium, including the sports lighting, upper and lower suite power, suite kitchen power, decorative lighting, kitchen power, air handlers, scoreboard, press level power, hospitality village, and the parking lot lighting. Phase II of the project, to be initiated in the near future, will involve tenant metering to accurately allocate and bill energy costs to individual users.

Advanced submetering equipment and software is increasingly used in all types of facilities to monitor energy via comprehensive energy profiling-information needed to determine a building's energy demand and usage levels. The information garnered from precise tracking of electrical demand (kW) and usage (kWh) is used for peak shaving, load shedding, aggregation and other measures, that lead to lowered energy bills. The measured data is collected by the submeter, which may be located up to 2,000 feet from the current sensor. The data is accumulated and digitized by an interface device that relays it via modem to a centralized computer for analysis.

By measuring energy usage at different points—and at different times—the submeters installed in the Ravens' stadium were able to track how the facility's energy was specifically distributed and consumed.

At Ravens Stadium and Oriole Park at Camden Yards, most of the energy savings—estimated to be around 10% to 15%, or $500,000 to $750,000 per year—have been the result of peak shaving, load shedding, aggregation and other benefits accruing from having a 3.6-MW power plant on site. Massive diesel electric generators powering both the football stadium and neighboring Oriole Park relieve much stress on the city's electric grid during events at either park. And it's the automatic meter reading system that gives energy managers at the Maryland Stadium Authority the tool they need to make the critical energy management decisions they need to make.

Kerbel is pleased with the meters and software, adding, "We're not as finely metered yet as we want to be. Some of the meters are reading gross numbers, and we need to go back in and add more meters to read particular areas better. But we knew that from the start, because you don't know where you need more meters until you put in the basics. Probably next year, we'll be adding more."

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