Tuesday, February 5, 2013

Who turned out the lights?

Is anyone wondering what happened to the lights in the “Mercedes-Benz” Superdome during the Super Bowl? One thing we all learned is that you don’t turn those big stadium lights back on quickly. We also learned how a long delay can shift the momentum in a crucial game like this, and the 49ers almost won the game with their play following the extended delay.

The US Department of Energy had recently praised the upgrades and improvements at the Superdome, especially the colored LED lighting on the outside of the building. I too have added colored LEDs to my home lighting scheme. Using the new Philips Hue LED lights, I’ve not only added some real energy savings to my home lighting, but the multicolored LED bulbs are controlled via my home wireless system, and I can use an app on my iPhone to control the light. It is a very impressive setup with a special attachment to my home router giving me wireless control over the lighting just like the Superdome lights.

Here's more about the Philips Hue Lighting system.


Here’s a link to the DOE article.

The DOE cited the installation of 26,000 LED lights that would illuminate the exterior of the stadium in a spectrum of rainbow colors, noting that the lights only drew 10 kW of electricity, “equivalent to the amount of energy used by a small home.”

However, along with some minor updates to the stadium electrical systems and installation of new insulation, the $336 million renovation was not necessarily an energy efficient upgrade. The main stadium lights continue to be the less efficient metal halide technology. Most of the money was spent restoring the stadium to its former glory before hurricane Katrina, putting in new seats, bathrooms, and renovating the sky boxes.

But, then, the new LED lights were not the cause of the failure either. In fact, at this point, we don’t know for certain the root cause. It may have been a failure in the power distribution infrastructure of the stadium itself (Superdome), or a failure in the external power from the local power grid (Entergy).

What we do know is that the lights went out due to a “piece of equipment sensed some abnormalities” in the electrical load and “shunted the power in the Superdome,” according Doug Thornton, Senior Vice-President for stadiums and arenas at SMG, the Superdome management company.

That “piece of equipment” was almost certainly a tripped circuit breaker. A joint SMG / Entergy press release issued Monday confirms as much. Mind you, this isn’t the simple breaker found in circuit panels in houses like yours and mine. Larger circuit breakers like those found in a modernized stadium such as the Superdome are pre-programmed with safety logic that will trip the breaker for various reasons: under or over voltage, overcurrent, frequency mismatches, or arc or ground faults are a few. Depending on the scenario, the actual cause of the trip could have come from the utility side (Entergy) or the customer (Superdome) side of the circuit.

Breakers like these will likely have a code that says exactly why they tripped. If and when officials decide to release that information, we’ll have a better sense for why the blackout happened and what we can do to prevent it from happening again.

In the meantime, we’re left to speculate as others have done. Those in favor of better energy management and “green power” are asking if a “smart grid” and other modern energy management systems would have prevented this failure.

For example, if a smart grid sensed that the Superdome was approaching an electrical load trip limit, and also had some fashion of automated demand response (such as load shedding), the stadium’s blackout probably could have been avoided. Similarly, if a problem arose from the utility side of the grid (Entergy) instead of the stadium side, and the Superdome had some level of “micro-grid intentional islanding capability” plus on-site electricity generation and storage, the stadium could have kept the lights on even as the area grid went dark.

(As it was, backup generators kicked in and restored some power while technicians scrambled to return full power to the complex.) And of course, ever on my efficiency soapbox, if the Superdome had invested in much deeper energy efficiency efforts and reduced its overall load, would it have even approached limits that theoretically tripped the breakers in the first place?

Such smart grid technology successfully prevented a blackout at the 2011 Orange Bowl, when a smart system detected that an aging transformer was close to overloading and diverted power elsewhere.

The latest news suggests that the Superdome’s breakers tripped due to a voltage surge on the Entergy side of the grid, protecting the stadium’s electrical equipment from potential damage. As for what caused the voltage surge, that may prove much harder to pinpoint. Last-minute upgrades to the stadium’s electrical system may also be partly to blame.

There are many lessons to be learned by the NFL, the Superdome management, and the local power utility. As a greenie focused on power saving and modernizing of the power grid, I would ask if reducing loads through energy efficiency and the use of smart grids and other technologies would help to make our electrical systems more flexible and resilient. We don’t want the lights going out at the next Super Bowl.

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