The Power Grid is an amazingly reliable machine. It improves our lives with such efficiency that we don’t ever think about it… until it goes out. So if you were watching the Superdome blackout at the Super Bowl, and wondered what caused that power outage, here’s what happens when the lights go out:

Large remote power plants burn fuel, harness the elements, or split atoms to generate huge amounts of power. These huge volumes of power are distributed through a network of wires and exchange points called substations, which funnel down and distribute the power to things like the Superdome and the Flatscreen TV you watched the Superdome go dark on.

At any given instant, the amount of power being produced and the amount being consumed have to be (more or less) in balance. Which is really tricky on a small scale – like changing a wheel on a train in motion. The whole thing “sings” at exactly 60Hz, and any time that huge power demands like industrial motors or Beyonce’s lights and sounds system start up or drop off, it creates dissonance, or sometimes causes the frequency to rise or fall, which can cause wide spread and serious damage. On a large scale though, its easier because you can connect all the generation in the nation with all the load in the nation (more or less) so aggregate changes are slow enough that utilities can plan and predict the right combinations.

Early reports online seem to indicate that a piece of protective equipment (typically called a relay) in the substation that connects the Superdome to the larger Grid reacted to a condition that was potentially dangerous and destabilizing, and isolated the Superdome form the Grid to prevent damage by opening the breakers, just like a breaker in your home when you plug in one too many motors.

The power grid is getting smarter, faster, and more automated, but it’s a system that operates at the very edges of performance tolerance, and the overall design is over a century old. That aggregation and centralization that makes it possible to balance supply and demand in real time over a large area means the whole thing is interconnected. So when it fails, it fails big. People will remember the Great Super Bowl Blackout for a long while.

No matter how you felt about how or whether the blackout affected the momentum of the game, it did get you curious enough about what causes blackouts to search around for some information. And that’s good. Because the power grid is the biggest machine ever built by humankind, and it works phenomenally well almost all of the time. With increasing levels of automation and more distributed power generation and storage technologies, it can also evolve into something that not even Beyonce can bring down. It has tremendous long term potential as a platform for energy innovation and job creation. And meeting the world’s endless appetite for energy in the most effective ways is important.

Being a bit curious about how it works, what breaks it, and how it can evolve is good. Because like any piece of infrastructure, its something we as a society decide to invest in and improve, and the more people who take an interest in how energy is produced, distributed, and consumed, the better the policies and economics that shape it can become.