Who Cut The Lights?

Power consumption during the biggest event in the United States sports calendar has caused lively debate for several years now. On the one hand, electricity consumed by all those large-screen TVs rises dramatically during the Big Game; on the other, analysts suggest the collective experience of watching the game may actually reduce demand because we don’t engage in other activities that normally require electricity.

All of which is a bit ironic, given that Sunday’s event was interrupted during a 35-minute power outage at the Superdome, attributed by officials to a problem with the electrical load coming into the venue; this triggered a safety feature and partially cut power to the New Orleans stadium.

Matching supply to demand has been a traditional problem for power generators to wrestle with. This becomes even more relevant with renewable energy sources, many of which suffer from being inherently intermittent in their capacity to generate electricity – like tidal energy.  Some sources, such as solar and wind power, are also more unpredictable because they depend on local weather conditions.

So, what can be done to iron out such peaks and troughs? There are various technological solutions and demand-management strategies that need to be considered.

In 2010, two Californian academics, Mark A. Delucchi and Mark Z. Jacobson published a paper setting out ways to design and operate renewable energy systems that will satisfy electricity demand reliably.* Forecasting and managing demand were seen as important factors, as was the greater resilience offered by a wide grid; the authors also highlighted the issue of storing electric power, at the generation site or nearby, using a variety of methods such as batteries, hydrogen gas, compressed air, pumped hydroelectric power, and flywheel technology.

Examples of such storage solutions are starting to come online this year as several pilot projects take shape.  In western Texas, a giant battery was switched on in January; it’s mission to smooth out the supply from the nearby 153 megawatt (MW) Notrees wind farm.

Built for the largest electric power holding company in the US, Duke Energy, by local start-up Xtreme Power, the array is the biggest and fastest in the world and is at the heart of a new 36 MW energy storage and power management system. As a result of the initiative, the whole electricity grid also becomes more resilient to spikes in demand, because such batteries can respond almost instantaneously; in contrast, traditional power plants may take 15 minutes to boost their output.

Elsewhere, further joint initiatives between the US Department of Energy and the power companies are due to switch on during 2013. Different battery technology will see a Modesto wind farm use a system based around zinc-chloride flow to provide a 25 MW back-up. Meanwhile, a California power company is planning to use compressed air as an energy storage medium and will shortly begin filling depleted gas wells near Bakersfield. This system will be capable of delivering 300MW of power.  

In their paper, Delucchi and Jacobson also discussed using ‘smart’ demand-response management to shift flexible loads to a time when more renewable energy is available. Clearly, that’s never going to be an option for the Big Game!

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*Delucchi, Mark A. and Mark Z. Jacobson (2010). ‘Providing all Global Energy with Wind, Water, and Solar Power, Part II: Reliability, System andTransmission Costs, and Policies’. Energy policy.