Holding on to power

30m
A mountain, a tower, a thermos full of molten salt: These are the batteries that could power our renewable future.
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Transcript

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Noam, we got some exciting news.

Meredith, what's going on?

We have a new reporter joining the Unexplainable team.

This is Neil.

I know you've met Neil.

You know Neil, this guy.

Hey, Neil.

Hello.

So Neil is a reporter who is focusing on climate change and climate science.

And together, together, we've been working for the last few weeks on this story about the grid.

What grid?

The electrical grid.

The electric grid.

Okay, what have you been thinking about?

The electric grid.

So I mostly grew up in Bangalore, in South India.

And when I was growing up, blackouts were pretty common.

Like, we'd sort of be going about our day, and randomly, without any warning, all the lights and fans would just turn off.

Blackouts are never fun, but that was before climate change was really making its impact known on the world.

Like, we've been feeling it in a very particular way in the last few years.

What we've been seeing more and more recently are these like extended blackouts that are happening because of extreme weather.

And when those happen, they can be absolutely devastating.

The first pictures now coming in from Puerto Rico after taking a direct hit.

Power out to virtually the entire island.

Hurricane Maria knocked out power for over a million people in Puerto Rico, and it still hasn't been The only noise we hear right now in San Juan is coming from generators.

That's the only lifeline these people have.

When super cold weather hit Texas in February 2021, Arctic temperatures and rolling blackouts hammering Texas.

Millions of people lost power, hundreds of people died, and it took over a week for the power to get back on.

Record low temperatures way below freezing brought the electricity grid to its knees.

And, you know, I hadn't seen that kind of impact when I was growing up.

For me, at least, blackouts were relatively minor inconveniences in the grand scheme of things.

But recently, we've been seeing these incidents from all over the world where blackouts are literally life or death situations.

Yeah.

I've been looking into this too.

Like, why is it that our grid is so precarious?

Like, even in the face of extreme weather, like,

why isn't there more power?

Why can't we just tap into some reserve to tide us over until, you know, the power plants can come back online.

And I kind of came across something that totally blew my mind, which is that

we don't have reserve power on a grid-wide level.

Like we don't have power saved up for an emergency.

We don't have like batteries?

Yeah, so like the battery technology that we have today, it doesn't really work for something as big as a city-wide or a statewide electrical grid.

So I asked Neil to help me explore this question, which was just like: how do you capture lightning in a bottle?

What would it take to make a battery so big that it could boot up our electrical system after a power outage or after some extreme weather event?

It's a pretty compelling engineering problem, science problem.

And the answer we found as we started digging into this is that it might not be about building a better battery.

We might need to build a weirder one.

Okay, Neil Denasha, Meredith Hodnott, talking about building a weird battery to hold on to power.

To start, why is it so hard to store electricity?

That seems like something that we should know how to do.

Well, a good place to start is: what is electricity?

Yeah, because electricity, it isn't a substance.

Like, it's not a thing.

It's actually a movement, like the energy of electrons.

I like to think of this as sort of like a wave in water.

Okay.

Right?

So, one water molecule bumps into the next, bumps into the next, and it transfers the energy of a wave without transferring the actual water itself.

Yeah.

So, like, you know, to extend the metaphor further, like, think about when you do the wave in a stadium, right?

You're standing up and you're waving your arms, but you're not switching seats with the person next to you.

Like, you wave your arms, and the person next to you waves their arms.

So, you know, the wave travels around the stadium, but you stay in your seats.

So, like, you're like the electron, and the wave is that movement of everyone's arms going up and down the stadium.

So, that's basically electricity.

Electricity is one big stadium wave.

So, if electricity is like a wave in a stadium or a wave in the ocean, how does that actually work?

Like how does that power,

I don't know, my lights?

So you can't hold on to movement like a stadium wave because once you hold on to it, it stops existing.

It's no longer a movement.

So our whole grid is designed to deliver that electricity.

deliver that electron stadium wave to your home just in time.

See, like you go to flip on a light switch, right?

The electricity that you're using to turn on that light, that's being generated like just then, or maybe only just a few minutes before.

That is totally not how I thought electricity worked.

I kind of figured it was like,

I don't know, I figured it was sort of like a well or something that stored up a lot of electricity.

And then we were kind of like tapping into it.

Yeah, I know.

It's wild.

Yeah, our power grid kind of works in this precarious balance where like supply and demand need to be perfectly balanced all the time.

Like there's very little room for mistakes.

Something as innocuous as a single power plant going down or there being a problem on a transmission line, there's going to be an imbalance.

I talked to Eric Fournier, who's a research scientist at UCLA.

He spends a lot of time thinking about the grid.

An imbalance and the grid's going to encounter a period of real difficulty.

Especially if the grid's already stressed under extreme weather and people are turning on their ACs or heaters more, the grid could be in big trouble and there could be a blackout.

But we have like Duracell batteries, right?

If electricity is a movement, like a wave in a stadium, how does a battery like that hold on to electricity?

So you can't hold on to a wave, but you can hold on to other things.

So you can transform electricity into heat and hold on to heat.

Or you can transform electricity and use it to interact with chemicals and hold on to that energy like in the chemical bonds okay so we can't hold on to electricity itself but you can transform it into another shape

so for batteries like the batteries you would plug into the back of your remote they use these special metals that can hold on to the charge of electricity but you're not like actually like containing the electricity itself you're you're transforming it to look like something else and holding on to that.

Okay, so that seems great.

It seems like we have a way to store electricity, right?

Why can't we just do that on the grid?

Yeah, I mean, so the best kind of like battery is lithium-ion batteries, right?

Like they're great.

We use them for all kinds of stuff.

They're in our phones and our laptops and our electric cars.

But the problem is scaling them.

Like chemical batteries like lithium-ion batteries use all these special metals that can be charged up with electrons.

But those metals are expensive to mine and they're limited.

They're like a limited resource.

Lithium, nickel, cobalt, et cetera.

Do you have enough of that stuff on the Earth's crust?

And we're having a lot of trouble making enough batteries for electric vehicles as it is.

So, you know, it's not exactly easy to make a bunch of batteries in general, but making a bunch of batteries at the level we need to store energy to power millions of homes, that's a big ask.

We're also starting to hit a bit of a plateau in what we can can expect from chemical battery technologies like lithium-ion batteries.

What do you mean?

They're not good enough.

It's just that we would need like a big jump in innovation to use them at the scale that we're talking about here.

Battery tech has been advancing very quickly, and that's why you see batteries almost everywhere, right?

But we're now in this kind of period of slower stagnation where each generation they're going to get a little bit better, but at a slower rate.

The question is whether that's happening fast enough.

So, Eric's question is basically: like, do we have enough time to invent a better chemical battery at the scale that we need in order to save the grid and prevent these blackouts?

And so, like, chemical batteries like lithium-ion batteries, they absolutely have their place in storing electricity.

They're lightweight, they're portable, they're powerful, but you know, we don't need lightweight, we don't need portable for the grid because the grid is not going anywhere.

It's

pretty stuck in place.

So it might be better to use these lithium-ion batteries since they are a limited resource in the places where it makes the most sense to use them.

Right.

You know, we should probably be putting the lithium-ion batteries that we can in electric cars.

And that means that we got to start thinking more creatively about what we can do to store electricity for the grid.

So what do we do here?

We can't just make like a mountain of AA batteries.

Yes, but we can use mountains like real mountains.

Okay.

Or we could look at things like towers or underground caverns.

Okay.

There's all kinds of things.

I like towers and caverns and mountains.

Yeah, so we got to get weird.

That's after the break.

I was going to ask if you could tell me right now.

No, you got to wait.

It's the break.

We'll listen to some ads and then we'll come back with a little

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Okay, we're back.

Meredith.

Hey, hey.

Neil.

Hi.

We're trying to think through how to solve sort of this like

fundamental flaw at the core of our power grid, which is that like we're creating all the power that we need right when we're making it, and we don't really have a way to store this power long term you know for a rainy day or a snowy day or a very hot day all the days right okay so so is this where the the the mountains and the towers come in they do okay so last month i drove to western massachusetts a town called northfield it was a beautiful fall day great road trip and i pulled into what looked like a state park this this mountain and this mountain is like storing energy somehow?

Yeah.

Okay.

So

in the 60s and the 70s, there is a new fleet of nuclear power plants in New England.

And the problem with nuclear power is that it's not designed to ramp up or ramp down.

Like once it gets going, it is generating the same amount of electricity day and night.

It just...

keeps going.

Okay.

But demand for electricity, that fluctuates all the time.

So like in the the dead of night, when everyone's asleep, there isn't a huge demand for power.

Sure.

So these plants, these power plants, they needed somewhere to store all the extra energy that they were generating.

And so they hollowed out a mountain and put these four ginormous pumps in there.

Sorry, wait, I just need to.

They hollowed out a mountain?

I just like let that pass.

Like, what's happening?

They hollowed out a mountain.

Okay.

Northfield Mountain.

It's right next to the Connecticut River, and they hollowed it out and put in four enormous water pumps.

And when they needed to store electricity, they pump water up from the river and fill up a giant reservoir on the top of this mountain.

And how is filling up a reservoir storing electricity?

So Northfield Mountain uses this pumped hydro to store electricity by transforming it into potential energy.

Okay.

That is by like holding this water at the top of the mountain.

So when they need that electricity back out again, Northfield Mountain, they release the water from the reservoir.

It flows downhill.

The pumps that originally pumped it up to the reservoir in the first place, those pumps become generators and create electricity by spinning a turbine, just like a dam would at a hydroelectric station.

So this reservoir is basically like a 5 billion gallon battery.

And you actually got to see this in action?

Yeah, I drove a quarter mile down a road into

the heart of this mountain.

Okay.

We're underneath a mountain.

Are we below the river?

We are below the river.

Right now?

Oh, yeah.

Like on top of us.

Maybe I should have told him.

No.

We had cleaning personnel that we had to,

they came down underground for the first time and we had to get them out of the, they started to hyperventilate.

They didn't like it.

It's too claustrophobic.

Did you see any

pumping going on?

Any pumping up or flowing down?

Inside the pump.

What?

What?

What you're looking at

is unit 4321.

And this is Neil Slocum.

He's the operations manager for the facility.

So it sounds like stuff is on.

Does that mean water's being pumped, or does that mean water's going down in generating power?

Let me find out from the control room.

Until I get down there.

It all sounds the same.

It was so loud.

It was so loud.

It's unit one.

It's unit one?

Unit one.

We found it.

There's this just giant housing.

Then you get to go inside the housing and like see the thing spinning.

It was pumping water up.

So right now, just to be clear, we're walking into the pump.

We're walking into number one pump.

Let's do it.

Let's go into the pump.

They were pumping water up the mountain and into the reservoir that day.

So so they were storing electricity and charging up this giant mountain battery.

You look at the unit, you can see it's kind of spinning this way, which is counterclockwise when you look down.

You know it's bumping.

So Northfield Mountain has been storing electricity for the grid of New England for decades now.

It was built for this constant flow of electricity from nuclear power plants in the 60s, but today it also stores electricity from an entirely different kind of power plant.

The grid's changing a lot.

This is Alicia Barton.

She's the president and CEO of First Light, the company that runs Northfield Mountain.

And she was telling me that renewable energy from wind farms and solar panels, that has the opposite problem from nuclear energy.

Okay.

It fluctuates all the time.

We can't control how much electricity they make because we can't control when the wind is blowing or when the sun is shining.

What we're able to do is to effectively grab that solar energy while the sun's shining and then hold on to it until usually we then generate it back in the evening.

And most importantly, Northfield Mountain can actually store electricity at a huge scale.

We're as large or even larger in some cases than a nuclear power plant.

292 megawatts per unit at full output, and that will provide electricity for a quarter of a million at homes.

That's so much power!

It's so much power.

And they are an essential system for the grid in New England.

When the grid operator is worried and knows that we're going to see strain on the system, we're going to have record heat or something like that,

they'll actually ask Northfield to just be on standby and not run until they're called as the last backstop to keep the grid going.

Lights will flash.

They don't even normally call us,

but we'll get an emergency startup.

So they'll know what's important.

They know exactly what it means and what to do when they get that signal.

Northfield Mountain responds in less than 10 minutes.

So we're counted on when things don't go so well or as planned.

This is one of the few lifelines that they have built into the system in order to avoid a blackout.

And then it's like let the water flow down the mountain and power all the houses in Western Mass.

Yeah.

All right.

I think I'm sold on mountain batteries.

Humped hydro.

Yeah, so chill.

Let's go hollow out the rest of the mountains, right?

Like,

what's stopping us?

Well, I guess, I guess, hollowing out the rest of the mountains is expensive.

And also,

but you need specific landscapes.

It is very dependent on the geography.

I talked to Darik Malapragata.

He's the principal research scientist at the MIT Energy Initiative.

So you need to have that geography where you're essentially moving water up and down a hill.

Like mountains aren't everywhere, right?

Especially mountains that are next to water that can be used for pumped hydro.

Right.

But there is something kind of similar to pumped hydro that you can build anywhere.

You don't need a mountain for it.

A system that looks like pumped hydro, operates very much like pumped hydro, but can be deployed anywhere, right?

And is not geographically constrained and does not have to have access to water.

What's that?

So this is an idea called gravity storage, which can look like a lot of cool things.

But the most famous people doing this essentially is a company called Energy Vault.

Energy Vault.

Yeah, right?

It's a great name.

Sounds like a power ranger.

Yes.

And like, you know, and like for good reason, it kind of looks like out of this world in a way.

They build this massive crane with lots of arms and it's surrounded by these huge concrete blocks.

Okay, so you weren't lying about power ranger?

No, not at all.

It's like, just like, imagine this giant, like super tall tower with these cranes sticking out of it at the top, like pointing in every direction.

The The crane is surrounded by these huge concrete blocks.

And so, when there's lots of renewable energy available, the crane, like, it picks up these blocks and it builds an enormous tower of concrete blocks around itself.

And then, to get the electricity back out, when they need power, like when there's not as much renewable energy coming from solar or wind, what they do is they essentially drop the blocks.

They let the blocks fall, and they use that falling block to spin a generator and make electricity.

You know, basically moving blocks of concrete up and down can generate electricity when you need to.

How does taking the blocks down transfer energy?

Is it just gravity?

Yeah, so it operates on the same idea as pumped hydro.

So it's trying to take the idea of doing pumped hydro storage and trying to make it modular such that

you can do this anywhere.

So this is the kind of battery too, right?

Because you have power coming from renewable sources like solar power or wind power, and that's powering the crane.

And then it lifts up the blocks with that power.

And when you let the blocks fall, you're releasing the potential energy in the block.

So that seems like portable and easy.

Is there a reason that big block towers are not a,

I don't know, replicable solution here?

Yeah.

The biggest problem with building concrete blocks is that you need to make concrete blocks.

And that requires, like, you know, that itself is energy intensive.

Yeah.

You know, making concrete comes with its own set of challenges.

You have to produce the concrete, right?

There's a lot of steps involved in handling all that material.

Whereas with pumped hydro, the water was already there.

And so like, you know, just like the long-term math of like building a tower of concrete blocks and putting all the energy into building the cranes and the making the blocks and everything might not pan out when you, when you look at how much energy you can store and release.

Yeah, that sounds like a lot of work.

Yeah, so both pumped hydro and gravity storage would require building up like a bunch of new infrastructure.

But there are other kinds of batteries that could plug directly into the power plants and infrastructure that we already have.

What kinds of batteries can do that?

So one thing that we talked to Darik about is thermal storage, which is essentially saving heat.

The simple concept is, you know, very much much similar to the way we heat our homes.

The same concept can essentially be extended to heating materials.

The idea behind thermal storage is that we use renewable energy to heat up something like rocks or salt, and then we hold onto that heat.

You surround that rocks or salt or whatever else you're using to store that heat with insulation.

Sort of like putting hot coffee into a really good thermos.

And that stops the heat from leaking out.

And then you release the energy when you need it.

You can heat up the material when electricity is cheap and then when you need to produce electricity you can basically produce steam and that steam can then be used to drive a turbine that produces electricity.

Yeah, so most power plants today, they make electricity by using heat to boil water.

And then that steam turns a turbine and that makes electricity.

So with this technology, you can just go to a coal power plant, you can take out the coal burner, plug in this like thermal storage battery, and most of the rest of the infrastructure pretty much remains the same.

It's a heat battery, basically.

I'm just making sure I understand.

You're sort of like reversing, instead of like the power going from the coal power plant, you're having all these wires that were going from it and capturing the heat and then sending that back to the coal power plant.

Yeah, so it'd be, it'd be, yeah, sort of like two ways.

So instead of like electricity just going out of the coal power plant, you would have like electricity coming into the power plant, heating up this heat storage device, right?

And then when you need it, you release the heat

and then send electricity back out.

You know, we have these coal power plants, we have these natural gas power plants that also have a steam cycle there.

And we are looking to basically repurpose this facility into something like a storage system that can continue to operate until the end of its useful life.

I mean, these all seem like creative solutions, but it doesn't seem like any of them is all that close to future-proofing our power grid, right?

Yes, like there is no one perfect solution.

Like, that's sort of like true of climate change in general, too.

Like, we can't just like expect there to be one thing that solves all of our problems for us.

Like, we're going to need this sort of like mixture of technologies, like pumped hydro and solar power, and maybe these towers, or this, like, thermal heat stuff and like all of these other ideas that exist out there.

And we had to use what's right in the moment at the right place, at the right time.

We want to sort of think about all of these options and the right answer will look very different for California as it might look for, you know, the Northeast or you know other parts of the country or even other parts of the world.

What I love about like tackling these questions and reimagining energy in these ways is that it's very dependent on the landscape.

Like it depends depends on if there's a mountain by you, if there's a river by you, if there's underground caverns that you can pump full of air and then pressurize and get that energy back out through a flywheel.

Like all of these solutions give us a more in-depth relationship with the landscapes that we live in.

I may not sound like this all the time, but I'm quite optimistic that we can solve this problem, right?

Because we have all of these different options.

But I think no single technology is going to make this happen.

We really have to think about the jigsaw puzzle, right?

Where each piece plays its role in a way that is, you know, fitting with the rest of the pieces in the system.

If we were able to build a better battery for the grid, just like build in more energy storage in general, then that could really change our whole relationship to electricity.

So researchers like Darique, they know an important part of fighting climate change is to electrify absolutely everything that we can electrify.

But this this push to electrify everything will essentially double our electricity consumption compared to what we use today.

So not having good storage in the grid is one of the things that's standing in the way of our electric future.

We need a lot of electricity to electrify everything, right?

And so if you want to make it compelling for people to use electricity, it has to be cheap, it has to be abundant, and it has to be reliable.

Power isn't just a luxury, you know?

Like extreme weather is going to keep getting more extreme.

As the cold gets colder and as heat waves get hotter, we're going to need more air conditioning and more heating.

And so we can't afford to keep on powering those air conditioners and heaters with sources that are just going to keep making the problem even worse.

You know,

if you keep relying on these fossil fuels, that need is going to get stronger and stronger.

And we also can't afford to keep on having blackouts because that's what all this extra energy demand is going to lead to.

So figuring out a way to store electricity is going to be key to both fighting and living with climate change.

This episode was reported and produced by Meredith Hadinott and Neil Denasha.

It was edited by Catherine Wells, Brian Resnick, and Noam Hasenfeld, who wrote the music.

Mixing a sound design from Christian Ayala and fact-checking from myself, Zoe Mullick.

Bert Pinkerton is getting ready to hit us in the gut, and Mandy Nguyen is making us weep for joy.

Special thanks to Northfield Mountain and Claire Bellinger.

If you want to learn more about climate change and the future of electricity, check out Neil's reporting at vox.com slash unexplainable.

If you have thoughts about this episode or ideas for the show, please email us.

We're at unexplainable at vox.com.

We'd also love it if you left us a review or a rating.

Unexplainable is part of the Vox Media Podcast Network, and we'll be back next week.

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