For most, it's what we use to power devices

for both work and play and maybe even your car.

Over the past few decades,

they've gotten way more powerful,

long lasting and affordable.

But all of this is just a prologue

to what the next batteries are going to do.

As we drive to increasingly renewable power driven grid,

we also need to be able to store energy and release it later

to cover those periods of weather intermittencies

that are driving this new grid that we're in.

It's a multi-trillion dollar opportunity

and it's imperative that we figure out the solution here.

How we store energy on a massive scale

is in many ways the central challenge

of the fight to stop climate change.

And the solutions we're coming up with

might not be what you think.

The need for massive batteries

stems from an aspect of electricity

that we don't often think about.

So when we make electricity,

we produce it and we use it almost instantaneously

because of this inability to store.

When we turn on a button or switch on a light,

at that very moment somebody somewhere has generated

electricity for you to be able to do that.

That exact electricity that's making that light

just had to be produced somewhere within about a minute.

It's very, very new, the power that we use.

If there's not enough electricity being produced,

we get what we all know

actually, which is called a brownout.

Which means there's not quite enough electricity coming in

to power stuff.

And if you have too much electricity,

that will also bring down the system.

So you can't produce a lot more than you're using

and you can't produce a lot less than you're using.

For most of the grid's history,

this hasn't been much of a problem.

We've got our power from steady, reliable sources

like coal plants and hydroelectric dams.

But now of course, that's all changing.

We can adjust the coal fire power plant,

how much electricity it's making,

but we can't adjust how much wind a wind turbine is making.

Wind and solar power

can't always give us the juice right when we need it.

But if we could save up energy from renewables

and release it when it's needed,

clean energy could be as reliable as coal.

The amount of energy storage we need is going to grow

because we are going to have to rely on solar and wind

which are more intermittent, but it's also going to grow

because the pure amount of electricity

that we are going to use going forward is going to grow.

So dozens of companies are working on gigantic batteries

hoping to store enough energy to kick our fossil fuel habit.

And one of the biggest batteries is this mountain.

FirstLight Power, we are today,

the largest portfolio of operating renewable energy

and energy storage in the New England region.

We are using a mountain as a giant battery

and that's what we do here.

Being here, inside Northfield Mountain,

it's an incredibly unique facility.

We are carved out of the inside of a mountain,

it is a facility that dates back 50 years

and yet at the same time is ideally situated

to drive the energy transition of the future.

So pump storage is the oldest form of energy storage.

It's essentially transferring water

from an upper reservoir to a lower reservoir

and back and forth throughout the day.

Our lower reservoir is the Connecticut River

which is flowing by about a mile from where we're standing.

And then our upper reservoir is a man-made dam, essentially,

on top of a mountain.

Water is pumped up to the upper reservoir

and stored for whenever it's needed later.

And then it flows down through turbine generators

to generate electricity.

If that sounds like a giant battery charging

and discharging, well, exactly.

So what we're looking at here

is one of the four units at Northfield in pump mode.

So right now we are pumping water from the Connecticut River

to the upper reservoir.

Later on, we'll use that same water

spin the machine the other direction

and generate electricity.

When we're standing at Northfield Mountain,

we're talking about 1,200 megawatts of instantaneous power.

We can provide enough power

to support roughly a million New England homes

on any given day.

Pumped hydro storage is more than a century year old.

It was initially used to be able to just generate hydropower

when you wanted it and then in the '70s

when you had the creation of nuclear power

where power plants had to be run all the time

even when there wasn't demand for electricity,

pumped hydro storage became

the stores of excess electricity.

Atomic energy, the reality for homes and factories

and schools all over the world.

But today with the nuclear industry in decline,

the mountain has had to find a new niche to fill.

So rather than pairing with nuclear power,

we're a great pair to solar or wind

or other intermittent renewables.

Offshore wind has been a long time coming in New England.

It's been on the drawing books for a number of years,

but we are now seeing the first very large projects

come to fruition.

So the opportunity for a facility like Northfield Mountain

is to provide that balance to large scale offshore wind

and store it for times when that electricity is needed.

Unfortunately, mountain-sized batteries

do have some unique limitations.

The trouble is that pumped hydro storage

requires a specific kind of geography.

Typically, hills with either a river

or lots of access to water

in a form of rainfall that is consistent

to be able to make it an economical project

that you can build and then operate for decades to come.

And that's not always feasible

because of the lack of mountains or lack of water.

Some of the obstacles facing large scale build out

of new pumped storage projects; one is cost.

These projects are billion dollar projects now.

They require ongoing significant capital investment

to make sure that they can continue to run reliably.

And eventually we will run out

of how much pumped hydro storage can do.

So we are going to have to need other solutions as well

to fill those gaps.

Form Energy is developing the kind of energy storage

you need to enable the complete decarbonization

of the electric system.

It's a battery that's dramatically cheaper

than anything else that's out there today

and is also made of materials

that scale to the size of the challenge.

Co-founded by former Tesla VP, Mateo Jaramillo,

Form Energy is making a new kind of battery.

They hope can store energy on a massive scale.

An iron-air battery.

When we talk about batteries

we kind of think of these black boxes,

but really what goes inside that black box

can be very different chemistries and different metals

that enable those batteries to do different things.

Take the example of lithium-ion batteries.

These are what go inside electric cars.

In a car, you want it to go fast

so you want it to draw electricity at very high rates

from the battery into the car and then drive it forward.

Lithium-ion batteries are super powerful

but relatively expensive.

Batteries that store massive amounts of energy on the grid

are going to have to be way cheaper

in order to build them at scale.

To be able to build a battery that is really cheap,

one of the things that you're going to require

is using materials that are very cheap.

Iron is really, really cheap,

and it's really really abundant in the earth's crust.

And if anybody's familiar with iron it's that it rusts.

So we are rusting and unrusting iron. That's the battery.

When iron takes on oxygen,

that means it's giving off an electron.

That process which is really a chemical reaction,

a nuisance for most of us

is also a process that generates energy

which could be converted into electricity.

And then when you want to store electricity

into that battery, you convert that rust back into iron.

And that's really how simple that battery is.

It's never been commercialized before

but it has been understood for about 50 years.

So this is the iron material,

which is in these pellets.

There will be many, many kilograms in each repeat unit

of the cell.

So I set this cell to charge, I'm putting energy into it.

And when we do that charge process, we unrust the iron.

The big things that you can see on the outside

of this battery are iron electrodes.

And then we generate oxygen.

So the oxygen comes off in tiny, tiny little bubbles

and they flow around on the inside.

We're standing in front of an incubator

full of subscale cells that we are testing.

So these are miniature versions of the big cell

that we use to test out different material combinations,

different designs,

different conditions that we cycle the batteries under.

And we have 2,000 of these all over this lab.

It is still the scrappy problem solving atmosphere

of a startup even though we're getting bigger

and constantly problem solving on your feet

trying things that have never been tried before.

Form Energy has been going strong

in the last couple of years,

raising more than $350 million to date.

But an entirely new battery chemistry like this

still has a long road ahead to prove itself.

It took about 30 years

from when the first lithium-ion battery

was put in a camcorder

to it becoming a mainstream battery that powers

all electric cars in the world.

Iron-air batteries are going to have to do that

but in a much more compressed period.

Form Energy has only been around for about five years

and it's going to have to show its commercial applications

within the next five years.

That's shrinking the development time down to a third

and that's no easy challenge.

So as we're commercializing this iron-air chemistry

for the first time,

the challenge is to demonstrate unequivocally with data

that it is a reliable durable piece of infrastructure

that scales to the existing infrastructure that's out there.

So we are already building at the intended production scale.

So this is a meter cubed device that we have

and we're already producing those devices today.

The idea of the energy transition can seem daunting.

The current energy system just works

aside from the whole melting the planet thing.

But the gigantic battery industry is growing fast

and other solutions are gaining steam as well

like storing energy with compressed air

or using hydrogen as a clean fuel.

A total carbon free grid is getting easier and easier

to imagine.

It's just a question of whether we can get there in time.

We are going to, I think as a society,

really have to embrace our ability to do big things,

to build a large energy infrastructure

if we're going to succeed