Service Request #4: How Does the Grid in Phoenix Work?

Summary

Podcast Summary: 99% Invisible, “Service Request #4: How Does the Grid in Phoenix Work?”

Host: Roman Mars
Reporter/Producer: Delaney Hall
Guests: Gretchen Bakke (Cultural Anthropologist & Author), Angie Bond Simpson (Salt River Project)
Date: April 3, 2026

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Main Theme / Purpose

This episode of 99% Invisible tackles the invisible yet essential machinery that keeps Phoenix, AZ powered and alive during extreme summer heat: the electrical grid. The show investigates not just the technical workings of the grid, but the social, political, and economic structures ensuring that, especially on the hottest days, millions have access to reliable electricity—a literal life-and-death infrastructure in Phoenix’s brutal climate.

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Key Discussion Points & Insights

1. The Stakes: Surviving Phoenix Summers

• [01:16–01:43] Reporter Delaney Hall sets the scene: Phoenix’s 2023 summer became the hottest ever recorded, with temperatures exceeding 110°F for 31 consecutive days.
  • "Everywhere you went, every building was cooled to the temperature of a refrigerator … the city cannot exist without [the grid]. If power goes out in the summertime, if all those air conditioners cannot run, people will die." — Delaney Hall [01:43]

2. Making the Grid Legible

• [03:49–05:14] Gretchen Bakke explains why the grid is complex and deliberately “illegible,” meaning most people have little idea how it truly works.
  • “It’s meant to be illegible. … It doesn’t seem to matter whatsoever what you turn on and what you turn off. … It’s illegible in every way.” — Gretchen Bakke [04:29, 04:47]

3. How Electricity Gets to Your Home

• [05:23–08:40]
  • Power is generated (coal, natural gas, nuclear, wind, solar, hydro) and sent through high-voltage transmission lines—“enough power to kill an elephant”—then stepped down at substations, and finally delivered to homes at safe voltages.
  • “All of this stepping up is to move electricity long distance, and stepping down is to keep it from being entirely lethal.” — Gretchen Bakke [08:40]

4. No Storage, No Delay: Electricity Must Be Balanced in Real Time

• [09:03–10:59]

  • The system has minimal storage; for most of history, electricity is used instantly after it’s generated, necessitating a perfect second-by-second match between supply and demand.
  • “If you flip on your light switch or turn on your air conditioner, about a minute before, that was a piece of coal or coal dust, that tends to be what we burn.” — Gretchen Bakke [09:03]

• **Balance is maintained through synchronizing frequency (60Hz in the US); any imbalance can cause cascading blackouts.

5. The Macro System: The Western Grid

• [10:59–12:53]
  • Phoenix is just one node in the vast “Western Grid”—stretching from Canada to Mexico and the Pacific to the Rockies.
  • The grid is not just wires and power plants: it’s a web of deals, regulations, and cooperation across states, companies, and even nations.
  • “There are deals at every possible level. … The fact that it works at all is just completely phenomenal.” — Gretchen Bakke [12:33, 12:56]

6. Salt River Project (SRP): Phoenix’s Electricity Maestro

• [13:00–14:17]

  • Angie Bond Simpson of SRP describes their job as “future infrastructure planning for the power system.” SRP manages electricity for over 2.2 million people in greater Phoenix.
  • On long-term planning: “We’re thinking about maybe six to thirty years out.” — Angie Bond Simpson [14:39]

• Forecasting Demand

  • Long-term: Population growth, climate trends, new technologies (like electric vehicles) inform forecasts and infrastructure planning.
  • Day-to-day: “They look at the next day and … our best prediction for what tomorrow will look like.” — Angie Bond Simpson [15:35]

7. Balancing the Stack: How SRP Keeps Phoenix Running

• [16:05–18:45]

  • Energy sources are “stacked” for each day: the cheapest (often renewables) are used first, with dispatchable sources (gas, coal, hydro) kicking in as needed.
  • “Your dispatchable resources are more like a faucet. You want to be able to go to that faucet to turn it on.” — Angie Bond Simpson [17:23]
  • Real-time teams buy and sell surplus or deficit electricity from other utilities and manage crises as they unfold.

• Inside the Control Room

  • “It’s a large room with screens … pretty quiet … a very calm environment and you want it to be calm.” — Angie Bond Simpson [19:20]

8. The Challenge of Summer and Grid Reliability

• [24:23–25:29]

  • All planning focuses on the “hottest hour of the hottest day,” building in reserves for contingencies.
  • Summer preparation is a year-round task, with reliability hanging on careful, conservative planning.

• Nightmare Scenarios and Everyday Outages

  • Cascading blackouts (like in Spain/Portugal) are rare, but most outages stem from mundane issues: car crashes, Mylar balloons, or “gender reveal parties that popped confetti into the distribution lines” [27:10].
  • “You can't always know when someone's gonna shoot confetti into a transformer or something like that.” — Delaney Hall [28:02]

• Heatwaves: Special Threats

  • Infrastructure (as at airports) is rated for certain temperatures; intense heat degrades wires, transformers, and can push the grid to its limits.
  • “The power grid is not necessarily designed to run full tilt at those extreme temperatures without having the ability to cool off.” — Angie Bond Simpson [28:42]

9. Close Calls and the Stress of Success

• [29:13–31:42]
  • Even without rolling blackouts, the pressure is immense—especially during 31 days over 110°F in 2023.
  • “Everybody is holding their breath and waiting for it to cool off.” — Angie Bond Simpson [31:35]

10. Growth Compounds the Challenge

• [31:42–33:05]
  • Phoenix’s rapid growth—including new data centers and factories—adds enormous, unpredictable load. Infrastructure can take up to a decade to build.
  • “That pace is, to use a very technical term, bonkers … Making sure that we have the equipment … is going to be really challenging.” — Angie Bond Simpson [32:11]

11. The Invisible Miracle: Why the Grid Matters

• [33:05–34:02]
  • The “boring” reliability of the grid is an engineering and social marvel, with thousands working behind the scenes to keep it invisible and functional.
  • “There are about 5,500 employees at SRP that think about it all the time.” — Angie Bond Simpson [33:48]
  • “So that we don’t have to.” — Gretchen Bakke [33:56]
  • “All so that when the temperatures outside hit 115 degrees, you can flip a switch on your air conditioner and know that the power will be there.” — Delaney Hall [34:02]

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Notable Quotes & Memorable Moments

• “It's meant to be illegible ... It’s illegible in every way.” — Gretchen Bakke [04:29, 04:47]
• “Those electrons are not moving steadily in one direction like water flowing downhill. … They're jiggling back and forth, back and forth, 60 times a second ... That back and forth motion is what's traveling through the wire.” — Delaney Hall [06:51]
• “Electricity is always very, very fresh.” — Gretchen Bakke [09:03]
• “The fact that it works at all is just completely phenomenal.” — Gretchen Bakke [12:56]
• “Your dispatchable resources are more like a faucet.” — Angie Bond Simpson [17:23]
• “It is a very calm environment, and you want it to be calm.” — Angie Bond Simpson (on the control room) [19:20]
• “There is so much that goes into actually planning and executing to make that [a working grid] come to fruition at all times.” — Angie Bond Simpson [25:42]
• “That pace is, to use a very technical term, bonkers.” — Angie Bond Simpson (on demand growth) [32:11]
• “We started with a question: how does the grid in Phoenix actually work? ... Phoenix sits inside the Western grid, an enormous piece of infrastructure that coordinates the delivery of power to the western states. Every summer, thousands ... focus on keeping electricity flowing even on the hottest days ... consider your service request resolved.” — Delaney Hall [34:02]

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Timestamps for Important Segments

• [01:16] – Scene setting: Phoenix’s deadly dependence on AC and the grid
• [03:49] – Gretchen Bakke introduces “the largest machine in the world”
• [04:29–05:14] – Why electricity and the grid are “illegible”
• [06:03–08:40] – How electricity is generated and delivered
• [09:03–10:59] – The need for second-by-second supply-demand balance
• [12:33] – The web of deals and regulations behind the grid
• [13:42] – Introduction to Salt River Project (SRP)
• [14:39, 15:35] – Long-term vs. day-to-day demand forecasting
• [16:05–17:23] – The “stacking” of energy sources
• [19:20] – A calm control room
• [24:23] – Planning for the “hottest hour of the hottest day”
• [27:10] – The mundane roots of most outages (“gender reveal parties”)
• [28:42] – How extreme heat threatens grid components
• [32:11] – Phoenix’s explosive energy demand
• [33:48] – The invisible but ever-present workforce behind the grid
• [34:02] – Summary and resolution

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Conclusion

This episode demystifies the careful orchestration, constant vigilance, and immense behind-the-scenes effort required to keep Phoenix powered—especially as heat waves become commonplace and the city grows. A “miracle of modern life,” the grid is a system so ubiquitous and vital that its very invisibility is a sign of success. But, as the show makes clear with stories and voices from those who manage it, that success is fragile—requiring daily diligence, long-term planning, and constant adaptation to a hotter, more electrified world.

Transcript

[Narrator/Host]

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[Delaney Hall]

A couple years ago, in the summer of 2023, I was in Phoenix doing some reporting and that summer turned out to be the hottest on record. Not just for Phoenix, but for the entire planet.

[Narrator/Host]

September greeted millions of Americans with some of the hottest weather of the summer.

[Angie Bond Simpson]

Here in Phoenix, we are def used to this extreme heat. We are not used to experiencing 110 plus degree days this many days in a row.

[Delaney Hall]

For 31 days from the end of June until the end of July, temperatures exceeded 110 degrees. Saguaros were dropping dead from heat exposure. People were spending days and then weeks inside. Playgrounds were empty because the playground equipment would burn a kid's skin. The unrelenting sun high above Phoenix seems to be taking its toll on all living. And what struck me walking around the city during that time was how totally dependent Phoenix is on air conditioning. Everywhere you went, every building was cooled to the temperature of a refrigerator, and it was an enormous relief to walk into one of those crisp buildings after struggling through the hot air outside. No matter where you live, the electrical grid is essential infrastructure. But in Phoenix, it's not an overstatement to say that the city cannot exist without it. If power goes out in the summertime, if all those air conditioners cannot run, people will die. Which made me wonder, how does the city know how much energy they'll need to provide on the hottest summer days foreign. I'm Delaney hall and this is Service Request, a show from 99% Invisible and Campside Media. Each episode we investigate a question about infrastructure, the vast and hidden machinery of modern life. We're looking at the pipes, the wires, the systems beneath your feet that you never really think about until they stop working. Today I'm submitting a service request. How does the grid in Phoenix actually work? What an excellent question. And the answer takes us into the enormous and complex machine that sends us our power.

[Gretchen Bakke]

So it's weirdly local, even though it's also incredibly immense. It's often called the largest machine in the world.

[Delaney Hall]

This is Gretchen Bakke. She wrote a book called the Grid. She's a cultural anthropologist who's studied the work of electrical engineers, regulators, utility operators, and energy traders trying to understand what they do. And I'll be honest, right here at the start of this episode, the grid is not easy to describe. Electricity itself is not easy to describe. The system that delivers it to our homes is not something that we really see.

[Gretchen Bakke]

And it's meant to be illegible. I mean, it's really, it's this. You don't have any access to a power plant. Like, you cannot, like just go wander into a nuclear power plant or to a coal burning power plant or even a hydroelectric dam instead.

[Delaney Hall]

The way most of us interact with electricity is when we get our monthly utility bill.

[Gretchen Bakke]

So you just get this thing in the mail and it doesn't seem to relate to anything. It's in some sort of unit that you have no idea what it actually means. It doesn't seem to matter whatsoever what you turn on and what you turn off. It's like going to the grocery store for the whole month and then just getting the bill at the end of the month. Did you buy pomegranates? And were they really expensive? You don't even know, right? You don't know why your electricity bill goes up and down. So it's illegible in every way.

[Delaney Hall]

But we're going to do our best to make this whole system that generates and transmits our power more legible, starting with where electricity comes from.

[Gretchen Bakke]

No matter how big of an electricity system you're talking about, there's always this more or less the same set of components. But let's talk big.

[Delaney Hall]

Big is power plants.

[Gretchen Bakke]

Power plants were originally mostly coal burning. With time, the transition in the 2000s was toward natural gas. But wind is a power plant. Solar panels are a power plant. They're just scattered everywhere.

[Delaney Hall]

And the Electricity that flows to your house has to come from one of these sources. It could be a natural gas plant or a nuclear plant, a wind turbine, a solar array, a hydroelectric dam. Someone had to generate that electric capacity. Let's say you're on a coal system.

[Gretchen Bakke]

So there's a coal burning factory somewhere not too far away, within a couple hundred miles, probably. And it's flash combusting coal powder, coal dust. So it's doing that. And there's a magnet stuck on the piece of a rotating piece of metal. The coal dust is producing heat that's producing steam. That steam is causing this thing to rotate. And there's tiny little brushes on the outside. And those brushes touch those magnets and they produce what we call an alternating current. And that alternating current is sort of going, you can't see me, but it's sort of like forward, back, forward, back, forward, back, forward, back, forward, back. So it's not a constant stream. It's this motion forward, back, forward, back, forward, back, forward, back of electrons that are jumping from atom to atom. Is this too much detail?

[Delaney Hall]

No. I mean, honestly, this is like poetry. I'm loving this. Those electrons are not moving steadily in one direction like water flowing downhill. Instead, as Gretchen said, they're jiggling back and forth, back and forth, 60 times a second. And that back and forth motion is what's traveling through the wire.

[Gretchen Bakke]

What we have now are transmission lines, which are the really, really big lines that children watch happily through the window on cross country driving trips.

[Delaney Hall]

I have been that kid.

[Gretchen Bakke]

Exactly. They're beautiful in their way. They really are. They're striking in how they sort of hold their wires up. They're a decorative piece of the grid in some ways, or the piece we're most likely to notice.

[Delaney Hall]

Those big transmission lines carry high voltage electricity over long distances. It's way more power than anyone would need to run their household appliances. It's enough power to kill an elephant, actually. And so the transmission lines eventually run into substations, which is the piece we're

[Gretchen Bakke]

least likely to notice, which is essentially a kind of gray, industrial looking, kind of Lego built box. Sometimes in a box, but it's often just a square of land with a fence around it. And what happens at the substation is that the electricity is stepped down in voltage and it goes on to a totally different system, which is called the distribution network. And that's what goes into the house.

[Delaney Hall]

Before it goes into the house, it's stepped down once again by a transformer, which is often located on top of a utility pole outside your home. Again, this is for safety, so that an elephant killing dose of electricity isn't flowing into your house.

[Gretchen Bakke]

So all of this stepping up is to move electricity long distance, and stepping down is to keep it from being entirely lethal. You can still kill yourself with it, but it's harder to do.

[Delaney Hall]

Okay. The amazing thing about this system, the generation of power and then the movement of electricity through power lines to the home, is that it happens incredibly fast.

[Gretchen Bakke]

Electricity is always very, very fresh. If you flip on your light switch or turn on your air conditioner, about a minute before, that was a piece of coal or cold dust, that tends to be what we burn.

[Angie Bond Simpson]

Wow.

[Gretchen Bakke]

Or a drop of water or a gust of wind. Right. It's a very fast system, and it will go simultaneously anywhere it's called, and we call that a sink. So if you turn on your air conditioner, all of the electricity in the system will say, ooh, a pathway. And it will all come to you.

[Delaney Hall]

Wow.

[Gretchen Bakke]

And then it comes poof. And your air conditioner goes on.

[Delaney Hall]

And here's another amazing thing about this system. Historically, the grid has not had much storage capacity. This is changing quickly. Grid scale battery storage is a very hot field right now, and it's important for renewables. But for most of the grid's history, electricity has typically been consumed almost the instant that it's produced. As Gretchen says, it's fresh, and it makes sense to do it that way. If you can deliver electricity on demand, it doesn't really make sense to spend billions of dollars building giant batteries to store it. It would be like running a restaurant and deciding to build a massive warehouse to stash the meals when you could just cook them to order instead. This metaphor doesn't totally work, because electricity doesn't go bad like food. But you. But when you're delivering electricity on demand, the grid has to stay in perfect balance. Meaning the amount of power being generated has to match the amount being used pretty much exactly every second of every day. Because what's really being maintained is that Precise frequency of 60 back and forth cycles per second.

[Gretchen Bakke]

Forward, back, forward, back, forward, back.

[Delaney Hall]

That frequency of 60 Hz synchronizes every power plant, every transformer, and every home on the grid. If demand suddenly exceeds supply, the frequency drops and the whole system gets out of whack. Cascading failures can knock out the grid entirely. That's why the supply of electricity must always meet the demand. Not too much, not too little. But here's what makes this whole system even more complicated. The grid isn't just One power plant serving one city. It's a massive group project, an interconnected system that stretches across huge distances. Many power plants and many utilities, all trying to balance supply and demand in real time. In the US There are actually three grids. The eastern grid, the Texas grid. And this is the grid that matters most for Phoenix, the western grid.

[Gretchen Bakke]

It's my favorite grid.

[Delaney Hall]

Oh, good. The western grid is huge. It stretches from western Canada down to Mexico and from the Pacific coast to the Rocky Mountains and beyond. The western grid includes coal plants and solar farms and hydroelectric dams. And it ties together dozens and dozens of utilities across multiple states. Some are for profit, some are municipal, and some are co ops. The thing to understand is that the grid is not just physical infrastructure. It's an immense web of social, political, and economic relationships.

[Gretchen Bakke]

There are deals at every possible level. There's state governance, there's companies that are making deals for electricity across that space. So you have different business models, you have different utilities, you have different states, and you have a set of federal regulations, and you have two countries.

[Delaney Hall]

What could go wrong?

[Gretchen Bakke]

The fact that it works at all is just completely phenomenal.

[Delaney Hall]

Within the western grid is Phoenix, Arizona. And a central piece of Phoenix's relationship with the larger grid is a utility called the Salt River Project, or srp. When you flip on your air conditioner in Phoenix, that electricity might come from a hydroelectric dam in Oregon or a solar farm in the Arizona desert, or a natural gas plant somewhere in between. SRP's job is to coordinate all of that. Taking power from neighboring utilities when Phoenix needs it and managing the moment to moment balance between what the city demands and what the grid can supply.

[Angie Bond Simpson]

SRP is one of the nation's largest public power utilities. We serve power and water to over 2.2 million people in the greater Phoenix metropolitan area.

[Delaney Hall]

This is Angie Bond Simpson. She works for srp, and her job, in essence, is to make sure that Phoenix never runs out of electricity, especially in the summer.

[Angie Bond Simpson]

My job is to do future infrastructure planning for the power system. I am the senior director of Resource management.

[Delaney Hall]

As we've learned, the grid has to stay in balance. And Angie has a view on how that actually works. I'm curious, how do you know, kind of minute by minute how much electricity Phoenix needs? And then how do you make sure you're generating exactly that amount? How does that balancing happen?

[Angie Bond Simpson]

Yeah, that occurs with really good planning and different planning horizons. So when we're talking about big infrastructure planning, that takes years. So when my group looks at planning for what's needed in the Future, future. We're thinking about maybe six to 30 years out.

[Delaney Hall]

For the long term, Angie's team looks at stuff like population growth and climate data and new technologies like electric vehicles. All of that information gets plugged into a long term forecast that helps SRP make decisions about building new power lines and substations and finding new sources of power. But there's another planning horizon that is much shorter. I'm curious on a more day to day basis how you anticipate the energy needs of Phoenix at any given moment.

[Angie Bond Simpson]

Sure. So they'll look at the next day and they'll say, based on the weather, based on how customers have used electricity over years of data, here is our best prediction for what tomorrow will look like.

[Delaney Hall]

Based on that prediction, the Day Ahead team will make an energy plan for the next day. They look at what power plants are available and what the forecast says about wind and solar, and they consider how much each source will cost to use.

[Angie Bond Simpson]

What they do is they essentially stack the generation in a way to meet reliability and to do the best economics for the system. So they're trying to solve for both reliability and economics.

[Delaney Hall]

But. And when you say stack the generation, you know they're handing them a plan that says, you're going to get this much energy from this power plant, you're going to get this much energy from this wind farm. Do I have that right?

[Angie Bond Simpson]

That's correct.

[Delaney Hall]

The stack looks like a stacked bar chart showing the cheapest energy on the bottom, with the more expensive sources layered on top, ready to be used if needed. And within that stack, different types of power plants play different roles. There are the weather based sources like wind and solar, and if those are available, you want to use them, but

[Angie Bond Simpson]

they're not always there. Sometimes things happen, right? Sometimes the wind doesn't blow, sometimes there are clouds.

[Delaney Hall]

When that happens, you want to turn to the sources that are called dispatchable, the ones that grid operators can turn on and off and ramp up or down on command. That's stuff like natural gas, coal and hydroelectric. As Angie says, you can think of the weather based resources as rain. When it's there, you can capture it

[Angie Bond Simpson]

and use it, and you want to do that as much as possible. But your dispatchable resources are more like a faucet. You want to be able to go to that faucet to turn it on. And sometimes you need a large flow of water and sometimes you need just a trickle.

[Delaney Hall]

So the Day Ahead team takes all of these resources, the rain and the faucets, and then proposes a stack for the following day. But of course things happen. The weather might not cooperate or a power plant might go offline. And so the stack gets handed off to another team called the Real Time team, which watches how the actual day unfolds and makes adjustments on the fly. There are two groups within the Real Time team. The first are the real time operators and they're working on something called the supply and trading floor. They're actually buying and selling electricity with other neighboring utilities.

[Angie Bond Simpson]

So they are working with other utilities in the west and looking at what our demand is and what our generating portfolio and capability is. And if there's a surplus, that team is able to potentially sell into a market. And if there is a deficit, that team may have to purchase from another utility in the market.

[Delaney Hall]

And then there's yes, another team, they're called the grid operations Team that is

[Angie Bond Simpson]

solely looking at the reliability of the system. So should something occur, they're the sort of ones that go in and can emergency respond. But that's sort of the last line of defense of you really want to have boring operations.

[Delaney Hall]

So I'm curious, is there an actual control room where all of this balancing happens?

[Angie Bond Simpson]

There absolutely is.

[Delaney Hall]

So take us inside. What does the control room look like?

[Angie Bond Simpson]

Each power plant actually has its own control room that then can communicate with a central control room at srp. And what that control room actually looks like is a large room with screens, pretty much screens for as long as you can see. And then there are different pods of operators that are looking at different components of the system. One thing that was sort of shocking to me is it's pretty quiet in the control room. And I think that's by nature because you have a lot of people that are studying what is happening in real time and in some instance making calls and doing checks and making sure that the right procedures are being followed. But in essence it is a very calm environment and you want it to be calm.

[Delaney Hall]

It's funny because I think I'm imagining something much more chaotic, almost like an open trading floor, you know, where it's like bring up the solar call, Utah, you know, just like a, like a more out loud kind of situation. But what you're describing is something much quieter and much more focused.

[Angie Bond Simpson]

Yeah. And you know, if you think about that, that's the way that you actually want it to be. Right. Because as you were planning the grid, you were planning proactively for a number of conditions. None of us can predict the future. So we're trying to make sure that the right amount of infrastructure with a little bit of wiggle room for things that could go wrong is built.

[Delaney Hall]

So that was the basic overview of how SRP works day to day and year to year. It's complicated. The whole grid is complicated. It's full of organizations and agreements that go by acronyms like FERC and NERC and ISOs and RTOs and IRPs and PPAs, and it's kind of a nightmare to describe. But I've also come to feel that the sheer density of acronyms involved is weirdly comforting because each one represents a layer of oversight, a whole team of people who are there to keep the lights on and the AC running Now in Phoenix. All of this planning the long term, forecasting the day ahead, stacking the real time operators. It all gets put to the test during one season in particular, summer and specifically the hottest day of the hottest week at the hottest hour. That's when we come back.

[Narrator/Host]

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[Delaney Hall]

So to move to reliability, grid reliability, it's obviously a huge issue and I guess how do you prepare for the energy needs of Phoenix on what you know is going to be a really, really hot day?

[Angie Bond Simpson]

Yeah, the hot day again starts pretty far in advance with that forecasting very far out. So the planners will actually look at the projection for the hottest day of the hottest time of the year and the hottest hour and we'll essentially build the system for that time, that extreme time. And if we can meet that peak and have a little bit of reserves for contingency purposes, then the assumption is that the remainder of the year can be covered and that you use those times where it's not hot to do your proactive and preventative maintenance.

[Delaney Hall]

So it sounds like planning for summer is sort of a year round project.

[Angie Bond Simpson]

Absolutely, absolutely.

[Delaney Hall]

What happens when something goes wrong? And I'm curious if there are any nightmare scenarios that keep you up at night when it comes to grid reliability.

[Angie Bond Simpson]

Well, sure, there are plenty of nightmare scenarios, but just to be clear, my job is to prevent those situations for actually coming to fruition or to at least give our real time operations as many tools in their toolkit to manage those times. So having good planning, good standards, good training, making sure that if there is a small outage, that there's a response, that there's good relationships across the west so that if we need to purchase power, we have a good handle on who is selling and what's available. And so there's just this, this constant hum in the background for preparedness. And I think that's what most people probably don't appreciate, is that when you go home and you flip on the air conditioner or the light, you have an expectation of it being there. And there is so much that goes into actually planning and executing to make that come to fruition at all times.

[Delaney Hall]

Angie mentioned the recent blackout in Spain and Portugal when the entire Iberian Peninsula went dark after a small electrical disturbance turned into a massive cascading failure. That's the Kind of nightmare scenario they are always trying to prevent. But she said the more likely risks are smaller and less dramatic and happen on a much more local scale.

[Angie Bond Simpson]

Because it's actually pretty mundane things that cause power outages. Oftentimes when a customer is without power, it's more something that has happened on that distribution or that neighborhood grid. And those are things like a car accident that runs into a power pole or there was a gender reveal party that popped confetti into the distribution lines or Mylar balloons. And so it's, you know, it's things that everyday people are doing and they accidentally get into the distribution system. At srp, we're very fortunate to have a lot of different redundancy to where we can try to minimize those outages and have fast response times. But it's almost impossible to prevent every outage and every Mylar balloon from getting

[Delaney Hall]

in the power line. Those unpredictable gender reveal parties. You can't always know when someone's gonna shoot confetti into a transformer or something like that.

[Angie Bond Simpson]

Exactly. Try to forecast that.

[Delaney Hall]

So why might the power go out when there's a heat wave? Why are heat waves a particular concern?

[Angie Bond Simpson]

Every piece of infrastructure for every, I'd say, major critical function, whether that's the airport or whether that's the power grid, has a temperature rating to it. So you may have heard there are temperatures where sky harbor airplanes, they can't land at sky harbor because the tarmac's not rated for that.

[Delaney Hall]

Right.

[Angie Bond Simpson]

And you know, that's the analogy I would use for the power grid is the power grid is not necessarily designed to run full tilt at those extreme temperatures without having the ability to cool off. So things like transformers and anything that has rubber or plastic components will degrade faster in the heat.

[Delaney Hall]

In the time you've been with srp, have there been any close calls where, you know, for example, Phoenix almost had rolling blackouts?

[Angie Bond Simpson]

You know, I can't think of any times that we got that close. You know, my awareness in this position, what I will say is you don't have to have the nightmare scenario happen for large amounts of stress within the operators to occur. So, you know, think about in 2023. It was the hottest summer on record for Phoenix. We had over a month that temperatures were over 110 degrees. You know, consecutive days where our customers and our community had high heat. 110 degrees.

[Delaney Hall]

Right.

[Angie Bond Simpson]

And if you think about what that's like. Right. You can't open a window at 110 degrees, even when it's nighttime. And it cools to 87 degrees. You can't open a window then. And if the power goes out, you're not just going to ride it out. You're trying to think about, where am I going to go? So that's always in the back of mind in the summer, but when you have these consecutive days, you start recognizing the system I've been planning for, for the hottest hour of the hottest day of the hottest year. Those days are occurring back to back to back. And you're always thinking about, is something going to happen? Not a total system collapse, just is there a minor component that I'm going to have to repair quickly at night to get it back up and running for the next day? Do I have good communication with the region? Is the region also experiencing a heat wave? Is the, is there not enough capacity on the market? And you know, what I can say is in 2023 and even in 2024, where we had over 100 days, over 100 degrees, the system behaved very well. But it was stressful. It was continued stress of making sure of double checking, of communicating with cities and making sure they knew what our plans were. And I have no other way of describing it other than stressful. And that's on a successful year. Right. That's when all the plans are put into place and they worked and everybody did their job. And still it was hard.

[Delaney Hall]

Right? Right. Yeah. What I hear you saying is in a summer like that, the margin for error is small.

[Angie Bond Simpson]

Exactly. Everybody is holding their breath and waiting for it to cool off.

[Delaney Hall]

And summers in Phoenix are only getting harder, not just because the heat is getting more intense, but because of the growing demand on the whole system. Phoenix is one of the fastest growing cities in the US Even as it gets hotter and hotter. And major industrial customers like data centers and factories, they're moving to Arizona too. Angie told me that a single big customer can use as much as electricity as 55,000 homes.

[Angie Bond Simpson]

That pace is, to use a very technical term, bonkers because. Because just to site transmission lines can, you know, sometimes take three to five years, in some cases a decade to site generation and go through processes for public input and environmental compliance and working with a community and hiring a firm to go out and construct, that can take six years. And so you've got this just growing year over year over year demand and a lag in being able to site and construct infrastructure in that same time frame. So to me, you know, making sure that we have the equipment, the generators, the transmission lines, the transformers and all of that in place when Customers need it is going to be really challenging.

[Delaney Hall]

The system Angie describes is resilience. It's been built and rebuilt and adapted over more than a century. But right now, it feels like the grid is facing its biggest challenge yet. Summers are getting hotter, and the infrastructure needed to keep the city cool can take a decade to build. This is such a classic infrastructure thing where, like, people don't think about it. You know, it's quite boring when it works because it just exists in the background and we take it all for granted. And it's really only when something goes. Goes terribly wrong that, you know, we. We wake up and pay attention to how very important something like the grid is.

[Angie Bond Simpson]

Absolutely. Well, I do know that there are about 5,500 employees at SRP that think about it all the time.

[Delaney Hall]

Right?

[Gretchen Bakke]

Yeah.

[Delaney Hall]

So that we don't have to.

[Angie Bond Simpson]

Exactly.

[Delaney Hall]

We started with a question, how does the grid in Phoenix actually work? And we have an answer. Phoenix sits inside the Western grid, an enormous piece of infrastructure that coordinates the delivery of power to the western states. Every summer, thousands of people who work within the system focus on keeping electricity flowing even on the hottest days. To do that, they plan 365 days a year. They maintain the infrastructure. They stack energy sources the day before and then watch screens in a quiet control room to make sure that nothing goes wrong. All so that when the temperatures outside hit 115 degrees, you can flip a switch on your air conditioner and know that the power will be there. With that, consider your service request resolved. Today on the show, you heard Gretchen Bakke, author of the Grid the Fraying Wires between Americans and Our Energy. You also heard Angie Bond Simpson, the senior director of resource management at the Salt River Project. What infrastructure mystery keeps you up at night? It could be something you use every day but don't actually understand. The switch. You flip the wire above your head. If you're curious how it works, we want to know. Submit your service request by recording a voice memo with your question and emailing it to servicerequestnine PI.org Remember, if you're having a gender reveal party, please don't shoot confetti into the power lines. I'm Delaney Hall. Infrastructure is everywhere, and we're here to help you decode it. Service request is a production of 99% Invisible and Campside Media. The show is produced and fact checked by Julia Case Levine and edited by Shoshi Shmulovitz. Mix by Ewan Lai Trimuin. Theme song and music by Swan Raal. Additional editing by Emmett Fitzgerald and Vivian Le show art by Aaron Nestor. Roman Mars is our boss at 99pi. Cathy Tu is 99pi's executive producer. Matt Sher is the executive producer at Campside. We are part of the SiriusXM podcast family. You can find us on all the usual social media sites, as well as our Discord server. There's a link to that as well as every past episode of [e-mail]. Hey, everyone, it's Kelly Ripa, and we're celebrating three years of my podcast. Let's talk off camera. No hair, no makeup. Just three great years of the most honest conversations, real stories and unfiltered talk. And we're joined every week by celebrity guests like Nikki Glaser, Kate Hudson, Oprah, and more. Three years in, and we're not not done yet. Listen to let's Talk off camera. Wherever you get your podcasts.