We are in desperate need of a green energy future.

I mean to be honest, at this point, we really need a green energy present, but at this  point, I’ll take what I can get. And a green energy future is  going to need a lot of things, but one of them is batteries.

But batteries… kind of suck.. They need lots of rare resources to make, they don’t last for all that long,  and it’s just too hard to make enough of them to store all the juice wel need. But it turns out that one of  the most promising solutions to this battery problem is both  incredibly simple and extremely cool.

We’re going to make batteries… with skyscrapers. [♫ INTRO] Now, before we get into how a  skyscraper can be a battery, let’s talk about why batteries are so vital. The gist is that pretty much every  kind of green energy solution we’ve come up with has the same  major drawback, which is that the amount of energy you can make  at any given time fluctuates. You’re gonna make a lot more  solar power on a sunny day than a cloudy one, and a lot more wind power  on a windy day than a still one.

But we need that power all the time,  not just when it’s windy or sunny. And peak demand doesn’t always  match up with peak output. So we need ways to store up that  extra energy on the good days and release it on demand for the less good days.

We could use the batteries we have  now, but like I said… They suck. Most common batteries right  now are lithium-ion batteries, which require a whole bunch  of non-renewable resources that can be environmentally destructive  and exploitative to acquire... On top of that, they’re also expensive and they get less efficient with age...

Anyone who’s had a phone longer than a year knows just how much worse  the battery gets at holding a charge after a while of charge, drain, repeat. So, if the goal is both to be  green and to make the world better for everyone in the process,  lithium isn’t the way to go. We need to find an alternative.

And to find one, we’re going to have to look somewhere completely different. Allow me to introduce you to the gravity battery. Gravity battery.

Gravity battery. And the way they work is right there in the name. It’s a battery that uses gravity to store energy.

More specifically, gravity batteries work by harnessing potential energy. Which you might remember from your physics class. When I lift up my phone I am  storing its potential energy because gravity is pulling  it down, but it can’t go down because I’m holding it up.

But that potential energy gets  released when I drop the thing. So gravity batteries work by  lifting something super heavy to create as much potential energy as possible. Then when you need to use  that stored power, bombs away!

Now, obviously it’s not that simple. Like, I can’t just keep dropping my phone over and over to charge my phone. We need to get a little creative  with our engineering to be able to harness the energy  released when the thing drops.

This solution is also really simple. We can use one device as both a motor and a generator at the same time. A motor and a generator are actually, like, the same thing, but in reverse of each other.

Motors turn electrical  energy into mechanical energy to make a thing spin, and generators turn movement into electrical energy. So with some clever engineering,  you can use one device to do both. During times of excess energy generation, like when you’re in California  and all the solar panels are just throwing out free electrons, motor mode would push the heavy stuff up high, where it has more potential energy.

And then when they need it, they can switch to generator mode and release all that stored potential energy as kinetic  energy to make the generator go. The coolest part is that  we’re actually already using gravity batteries and have  been for quite some time in the form of pumped storage hydropower. All you do is connect two reservoirs, where one is higher up than the other.

Water gets pumped up to the higher one while lots of energy is being produced,  and then released to turn the generator when not as much energy is flowing. Most gravity batteries are still  squarely in the development phase, but pumped storage hydropower is  already flowing here in the US. There are some downsides to  pumped storage hydropower.

It can have environmental impacts,  like disrupting migratory paths and removing access to or even  destroying certain habitats… So there’s good reason to think about other designs for gravity battery systems. Thanks to Policygenius for  supporting this SciShow video! They help you make life insurance  decisions that work for you, answer all of your questions about the process, and even handle your paperwork!

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That’s policygenius.com/SCISHOW. Experts are playing around with all kinds of ways to make use of these potential energy machines. Turns out, there are a whole  lot of ways you can design a system that just needs to lift  and drop stuff over and over.

Options include using abandoned mine shafts, the sides of mountains, or even in the ocean. And then there are the delightfully weird ones, like an octopus-style crane that  builds and unbuilds a tower, which never got made, maybe  because of how the wind was going to affect those giant blocks  of concrete on the end of tethers Or there’s one that just drives  little trains up a hill.. I like that one.

They all have their ups and downs. Get it. But when used at scale, they  usually blow lithium ion batteries out of the water in terms of cost,  durability, and overall impact...

Which finally brings us to skyscraper-batteries. The architects that built the  Burj Khalifa are teaming up with the people who designed the  octopus-crane battery to design a skyscraper that basically  wraps around a gravity battery… The core of the building  will contain something called a large-scale pumped hydro energy  storage system. Concise, I know. .

Basically, they incorporated the  existing tech for pumped storage hydropower into the walls  and core of their building. It will store water up in the higher floors and then release it to turn  generators when energy is needed. Then, when there’s plenty  of energy they can pump it back to the top and start the cycle over again.

These battery-skyscrapers would  fit right in in urban environments, which also means that you can  generate electricity exactly where you need it, no electricity  transportation required. There’s no need for big  holes, bulky dams, or cliffs. The battery is just in the building.

Plus, because it’s in the middle of the city there’s no habitat disruption needed! I’m sure the fish will be thrilled. We’re going to need a whole lot of solutions to solve the climate crisis that  we’ve gotten ourselves into.

And some of those solutions are going to be complicated, confusing, and difficult. So it’s great that one of the  biggest advances in energy storage is as easy as lifting something  up and then dropping it. We definitely know how to do that. [♫ OUTRO]