What do you think of when you think of a battery? 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 in what is the defining challenge of our time and that is building a clean energy system for the future. It's quite easy for us to know what success looks like for Form Energy, and that is having the impact at scale on the decarbonization effort for the electric grid. And that is measured at no less than gigatons. So billions of tons of carbon that do not have to be released into the atmosphere any longer. It's really nice to be working on something that I think is actually going to make a difference in the world. Makes me a little more motivated to do my work to feel like it's actually going towards something I care about a lot. And as an engineer, that the problems I'm solving are problems that matter.