Screen shot 2013-07-22 at 6.30.59 PMWe’ve heard about it and vaguely know it’s responsible for ensuring that our DVRs record our favorite shows, our laptops and mobile phones can be recharged, and our air-conditioners continue humming to stave off the summer heat. (Plus it powers our lights, refrigerators and other such minor things.)

But where is the energy grid? It sounds obscure, but it’s actually in plain sight all around us.

“It’s not a grid in a sense of square grid,” says Bill Muston, manager of research and development for Oncor, which delivers electricity to Dallas homes. He instead describes it as “radial.”

Those giant high-voltage transmission lines around the city, the kind that run along the Tollway, for example? Power generated by gas, coal, wind and other sources at 550 plants throughout the state travels through lines like those and into Dallas.

The high-voltage transmission lines carry up to 345,000 volts and can transmit anywhere between 50 and 500 megawatts of energy at a time, which power between 10,000 and 100,000 homes at peak demand. That power then “goes through transformers to step it down to 12,500 volts, and those are called substations,” Muston says. Neither Oncor nor other electrical entities publish maps of the grid flow or substations for security reasons, but “there’s no secret,” Muston says. A large grouping of metal poles and wires in a gated area is hard to miss.

The substations then transmit the power to various “districts” around the city and deliver it to the transformers and utility lines near our homes. One transformer — what looks like a cylindrical tube attached to a utility line — serves between four and eight homes, Muston says. The transformers convert the electricity into either 240 volts, powering electric stoves or dryers, or 120 volts, powering just about everything else in a home.

The high voltage transmission grid is networked across the state, so “if you lose one segment of it, it just keeps going,” Muston says.

“The outages occur more at the district level where you have trees fall onto lines or drivers hit poles.”