Energy Storage Technology Will Ramp Up Renewables

Published Sep 8, 2020

Dr. Elena Krieger explains how an unsung technology can increase reliable access to clean energy

In this episode
  • Colleen and Elena talk battery storage's many uses, and its economic benefits
  • The two look at upgrades to the power grid and new energy technologies
  • Elena outlines some of the potential roadbloacks of setting up at-home solar
Timing and cues

Opener (0:00-0:31)
Intro (0:31-2:42)
Interview part 1(2:42-9:47)
Break (9:47-10:47)
Interview part 2 (10:47-25:27)
Segment throw (25:27-25:32)
Poll volunteering segment (25:32-27:45)
Outro (27:45-28:46)

Related content
Show credits

Poll volunteering segment: Jiayu Liang
Editing and music: Brian Middleton
Research and writing: Jiayu Liang and Pamela Worth
Executive producer: Rich Hayes Host: Colleen MacDonald

Full transcript

The electricity grid that powers our homes is a big, complex system responsible for everything from generating electricity to transmitting it over long distances to get to us. And it’s the most efficient when supply and demand perfectly match up.

But human behavior makes that difficult. Our demand rises and falls, sometimes predictably, sometimes unpredictably. And sometimes our demand even exceeds supply. It’s not realistic to respond to these shifts by turning entire power plants on and off. In the past, this has caused unreliable service, with wasted energy and outages.

But with energy storage, the grid is a lot more flexible. By keeping some energy on standby, often in the form of batteries, we can respond more quickly when demand spikes.

And energy storage will be even more valuable as we transition to renewable energy. After all, we watch TV even when it’s not windy out. We turn the lights on after the sun goes down.

To learn more about how this works, I spoke to Dr. Elena Krieger, director of research at PSE Healthy Energy. She’s an expert on energy storage, and her research focuses on how we can more quickly transition to renewable energy and do so in a way that is healthy and equitable.

First we have a session of energy storage 101 to talk about the different types of energy storage and what advantages one kind may have over the other. Then Elena shares how energy storage creates a more equitable system—from providing backup in emergencies to how households with solar panels on their roofs can level the playing field. This is known as distributed solar and has major benefits for environmental justice, but in order to get there we need policy to create financial incentives and overcome language barriers. But for a clean, equitable electricity grid, I think it’ll be worth it.

Colleen: Elena, welcome to the podcast.

Elena: Thank you so much for having me.

Colleen: I wanna talk a little bit about energy storage. I mean, we now have the ability to store energy from wind and solar and other renewables. How exactly is it stored?

Elena: What's actually kind of fascinating is that more than 90% of the energy storage currently on the grid is in the form of pumped hydro. So what we literally do is pump water up a hill into a reservoir, leave it there until we need it, and then run it back down again through a turbine. Super simple. It's a technology we've had for a really long time.

One of the other most common forms of energy storage on the grid is actually thermal storage. So, in that case, what we do is we can make things like ice overnight and use that for cooling during the next day. So instead of storing energy in a battery or something like that, which is what we automatically think of when we think of energy storage, you're actually storing it in the form of something hot or something cold. And you can use that for heating or cooling purposes.

Colleen: Yeah, I was imagining something that seemed a lot more technologically advanced.

Elena: Exactly. So, the thing is, those are the types of technologies that have been on the grid for decades. These are things that we know how to do. What we've seen a huge growth in in the last couple of years are batteries, things like different kinds of lithium-ion batteries, for example, where you store energy in what is effectively an electrochemical reaction. And then you reverse that reaction in order to supply electricity to the grid when you need it. But these are the kinds of batteries pretty similar to what you have in your laptop or your cellphone. And those have been growing relatively explosively in the last couple of years. But in their total scale, they're still not anywhere close to what we have in the form of pumped hydro. The advantage of something like batteries is we can put them almost anywhere, whereas pumped hydro is reliant on having, let's say, a mountain or maybe in some cases, there's some novel approaches that can use things like mine shafts, but they're still limited in terms of where you can actually put that technology. And dams also have environmental impacts.

Colleen: So, what are we using energy storage for? I'm assuming it's when our demand is higher than the supply that we have, but what else?

Elena: So that is certainly one of the major applications. So let's say you have a surplus of solar energy in the middle of the day, too much wind energy generation at night, you can store that electricity and use that when demand is high, let's say, in the early evening when everyone goes home and turns on their light bulbs in their houses. However, storage can actually be used for a whole bunch of different things on the grid.

So you can put it on, let's say, your distribution and transmission lines, when you might have otherwise needed to upgrade them. And you can defer your grid upgrades by putting storage at the end of those lines. You can use it to provide what's called power quality on the grid. So to stabilize fluctuations in your voltage or in frequency to make sure that you have consistent power. You can use energy storage for backup. So, let's say that there's a grid outage of some kind, distributed storage, particularly at people's houses, at medical clinics, can provide backup power in the case of an emergency.

Colleen: So this is what batteries can do that the other storage methods can't?

Elena: Can't. Which something like pumped hydro can’t. So pumped hydro can help balance out your loads but is not going to be able to provide backup to a medical clinic if there's an outage or to a nursing facility.

Colleen: So now that we have better and better battery storage, that's really helping us get to a renewable energy future.

Elena: Yeah. So, batteries are going to play a critical role as we move forward in integrating wind, solar, and other variable and intermittent renewable energy sources. What they do is they also enhance the grid flexibility. The way that our grid is structured right now is that we typically have an electric supply, your power plant, an electric demand, your household, and you flip on a switch or whatever. And when you turn on your switch, that power plant effectively has to go up a little bit in order to supply that electricity.

As we start to have variable and non-dispatchable sources of electricity on the grid, like wind and solar, it is very useful to have a flexible load on the other end. So that means that we can do things like shift around when you run your dishwasher. And that means that we can do things like store energy and help create this flexible demand on the opposite end to match that variable generation.

Colleen: So if I have solar panels on my house, can I store my own surplus energy?

Elena: You certainly can if you have a battery.

Colleen: What kind of battery do I need?

Elena: You need a rechargeable battery.

Colleen: A rechargeable battery.

Elena: Typically, the batteries that we're seeing installed in households right now are different kinds of lithium-ion batteries. Lithium-ion batteries are not all one thing. You're gonna get a slightly different set of materials in a battery that's in your computer, as opposed to one that is going to be used in a car or at your house for backup, based on how it's gonna be operated. Are you discharging it 100%? How long does it need to last? How frequently is it used and it will be calibrated so that it lasts longer in a given use condition.

Colleen: So currently, if I hook up my solar panels, my excess energy is going back into the grid. But I could actually store that in a battery if I have a battery.

Elena: You could actually store it in a battery. You wouldn't...

Colleen: Are people doing that?

Elena: So you can. But from a broad grid standpoint, it's not necessarily that valuable because the grid is sort of acting as your battery and balancing it out. It's useful to have that storage to manage your bills, and to reduce your demand charges, and to provide backup. But if there is excess electricity of some other kind on the grid at any moment or it can be used directly, that's more efficient because there's always efficiency losses associated with energy storage. When you charge it and then discharge it, you're gonna lose a little bit of that energy. And so, if there's any way that you can match your generation and your use at the same time, that is gonna be more efficient, overall than it gets stored.

Colleen: That's the best scenario.

Elena: And so, storage comes in when you can't match it anymore.


Colleen: So, I wanna talk a little bit about a study that you published last year on distributed solar and environmental justice. Tell me a little bit about that. What is distributed solar?

Elena: So distributed solar is solar that is sited at people's homes, at residences, at commercial facilities. Basically, it's sort of distributed throughout the community as opposed to located in a giant utility-scale solar project. It is typically located behind your electric meter, which means that whatever solar is generated on your rooftop, if you use that directly in your house, the grid never sees it and the utility never knows it happens. Your excess is often then supplied back to the grid through a process called net metering. Let's say you have an excess of solar that you can't use directly, you supply that back into the grid. And at nighttime, you pull electricity from the grid and through the net metering process, the utility calculates the total amount that you either oversupplied or pulled from the grid.

So, in California, we have a set of policies, which dedicate clean energy funding towards what we designate as disadvantaged communities. So these are communities that have a cumulative burden of numerous environmental health and socioeconomic stressors. California has created a score through a tool called CalEnviroScreen, which integrates environmental exposures, like air pollution, and traffic proximity, and Superfund sites with socioeconomic indicators such as income levels, and educational attainment, and health indicators, like asthma rates. And ranks every census tract in California against the others on an integrated index, that pulls together all of these different metrics. And the 25% of communities that rank as the most overburdened or potentially vulnerable due to these stressors on this index are considered disadvantaged. And we have funding from our cap and trade funds, which is specifically set aside for clean energy investments in these communities.

So, we were curious to see how much solar actually is in disadvantaged communities in California. Is this changing and can we set a baseline as these investments continue moving forward? And so, what we did is we looked at rooftop solar adoption in households across the state of California on a census track basis and looked at these CalEnviroScreen scores, these environmental justice scores, both the cumulative score and individual indicators within each score to see what solar adoption rates look like, and whether specific characteristics seem more correlated or less correlated with solar adoption.

What we found was that what California designates as the most disadvantaged communities have an eighth of the solar adoption rate as the least disadvantaged communities. And so that means that you have a lack of access to clean energy among your most disadvantaged communities. We looked at specific indicators in CalEnviroScreen as well and we saw things like communities that had higher rates of linguistic isolation, had higher housing burdens, and lower median income levels, and lower educational attainment levels, were also highly correlated with lack of access to solar.

Colleen: So, what are some of the solutions to even out the playing field?

Elena: Yeah. So, I think that there's a whole suite of potential approaches. Some of them will have to do with financing and making sure that finance is available even to those with low credit or with low-income levels. Some of it has to do with trying to overcome the split incentive problem for renters and landlords. So, unfortunately, what happens right now, is you often have a landlord who owns the building and has control over whether or not you have solar on the rooftop and you have renters who are paying the electric bill. So how do you incentivize the landlord to put in solar to help reduce the bills for their renters?

Some of that could be solved with things like community solar so that people could subscribe to local community solar installations instead. Some I think is simply as we said, education and outreach, and trying to reach people from different communities, and building that trust. Some is dedicated funding. So we have funding going towards disadvantaged communities.

We have funding for low-income customers in single-family and multifamily homes, dedicated funding. And so some of it is increasing with those levels, but we also have some challenges. So they set aside funding right now for low-income customers to have access to energy storage. And almost none of that funding is being used. And so, we have to figure out why. Is this a lack of providers coming in? Is this a lack of understanding of what storage is and what it does? We have to figure out why that's not being used.

Colleen: One thing that I found interesting when you were talking is that language is a barrier in some way.

Elena: So solar can save money on your bills, for example. And you can either buy your solar panels outright or you can often have companies who will lease them to you and ensure that your bill is lower by a fixed amount every month. But understanding that that's possible and what those benefits are all going to be, require to some extent that you have, you know, materials, and understanding, and trust.

Colleen: Well you know that’s a really good point, because when you think about it I get confused about how I can get solar panels on my house, and I’m a native English speaker so it’s complex, it’s complicated.

Elena: So, if somebody says that we can come in and we will lease this to you for 20 years and you'll own it at the end of it, like, that ends up being complicated. And we're gonna save you $10 per bill or $20 per bill or whatever it happens to be. That is something that is complicated, right? I think your average person probably doesn't really understand how that works anyway. You're hooked up to net metering as we said. And so how do you explain that your solar is generated on the top of your house? You pump it into the grid when you're not using it, you pull from the grid, and that they subtract one from the other, and charge you for the difference. I have trouble explaining that in English.

And then, of course, I think as you're working with people across languages and across cultures, there certainly are trust issues. And there have been cases, certainly in California and others, of companies taking advantage of people who don't fully understand their bills.

Colleen: What are the new technologies on the horizon that you're really excited about?

Elena: I'm excited about some technologies and some sort of shifts in how we operate the electric grid as a whole. So, right now, we are seeing a lot of lithium-ion batteries come onto the grid. They matured in laptops and electric vehicles, and they commercialized quickly, prices have plummeted. They dropped by, I think, a factor of 90% over the course of 9 or 10 years. Like, it's been crazy. And so we're seeing lithium-ion batteries everywhere on the grid. However, as we move forward, we're gonna need more long-duration storage batteries that are cost-effective to operate over a longer period of time, over a day, over multiple days.

So things like flow batteries, where all of the battery materials are made out of liquids instead out of the solids. These technically exist, but they haven't really been manufactured at scale, so they're not cost-competitive yet. The other thing that is sort of cool to watch in general is grid modernization as a whole.

The standard grid has, you know, your electric supply on one end and your electric demand on another. And what we're trying to do is overhaul the grid entirely so that everything is flexible and responsive. So that when you use your electricity it's responsive to when you have a change in your supply of electricity. And so that's gonna require a lot of smart technology. That means responsive, you know, electric water heaters in your house. That means electric vehicles. That means that your energy storage systems and everything else.

They all have to be optimized across all of these different technology types. And they all have to communicate with each other. So it's this massive big data problem that you have to solve. And we're starting to test out and try to figure out how to solve. It's complicated. You have to change all of your electricity markets. You have certain electric markets right now that will compensate a power plant to come on. And what you want them to be able to do is compensate a hundred energy storage systems, five cars, and six electric water heaters to come on and do the same thing. So, creating that aggregated system that can all play within the existing network is going to be a hard problem but it's a fascinating one that we're trying to sort out as we go.

Colleen: I love the fact that you're so excited about this.

Elena: Also, I'm a nerd.

Colleen: That's what's gonna make it possible. There's people that are excited about this and see the possibilities.

Elena: So, you know, I think what is also cool and what's so crazy is how fast the prices have been dropping for solar, for wind, for offshore wind, for energy storage. So there's all these technologies that we thought were gonna be mature in, like, 2030 or 2040 and they're competitive now. So, we are at the point where energy storage is becoming cost-competitive in certain places with power plants. So, we're starting to see a number of cases where instead of what are typically called peaker power plants is power plants that come on and operate on the grid to meet peak demand, hot summer days, when everyone turns on their air conditioning. They use maybe 5% of the time, usually 0 to 10%-ish. We are now starting to see energy storage step in and fill that role. So in California, we have power plants that are being built, but they're not power plants, they're batteries. We're having 100-megawatt batteries being built to take the place of what used to be gas-fired power plants. They're being built in California, even actually in Florida. Florida Power & Light is building a 400-megawatt energy storage system. That's huge. It's gonna be the biggest in the country, I think.

Colleen: In terms of physically, like, how big is it?

Elena: The utility-scale energy storage so these big systems will often sit on the footprint of a fat power plant. You can also meet that same demand with a bunch of distributed systems. So you can aggregate energy storage at houses, and commercial and industrial sites across the city and aggregate all of those to also displace a power plant.

Colleen: Which is pretty cool. I mean, that's a lot more flexible than having to have everything in one spot.

Elena: It makes it more flexible and it means that you can also do other things with that energy storage, like provide backup in the case of emergencies. So, in California, we have had rolling blackouts, public safety power shutoffs when there are wildfire conditions across California because transmission lines, electric transmission lines have been responsible for some of the largest and deadliest fires in California in the last couple of years. So, the utility, in response, has been shutting down the transmission lines whenever we have hot dry conditions with high winds. The result is that we've had communities that have been left without electricity for days and days. And this is particularly a problem for folks like medical baseline customers, people who rely on electricity for oxygen, for other kinds of, you know, life-supporting machines, as well as just, let's say, the elderly who are, like, more susceptible to heatstroke and might need access to things like air conditioning.

So, distributed energy storage has the potential to provide backup when we have outages. Whether it's a public safety power shutoff or an actual wildfire or an earthquake or some other kind of emergency, that energy storage can provide backup, particularly for those most vulnerable populations. And then simultaneously, you can add up all those batteries and provide grid services. You can also put batteries at, let's say, community centers, or schools, or cooling centers so that people have somewhere to go.

Colleen: Are there examples of this happening already? Because I think the power is in people seeing these possibilities in action.

Elena: Yes, actually, we are starting to see energy storage and solar as part of microgrids that can do what we call island from the grid. They can separate from the grid and operate on their own when the grid goes down. So, we frequently see these actually in military facilities. One, they have the funding and two, they understand the importance of resilience. In the case of disasters, they need to make sure they have access to electricity. But we're also starting to see this at certain kinds of critical facilities. There is a tribe in Northern California, for example, that built its own microgrid a number of years ago, I believe. That was the only place that had electricity during the public safety power shutoffs this fall. And everyone from all the surrounding communities came to that tribe because they still had power for, you know, their local store and so on.

Colleen: Yeah, it's really exciting.

Elena: It's super exciting.

Colleen: I'm glad we're talking about this because now people listening to the podcast will know that this is happening.

Elena: It's happening everywhere from schools in New Jersey that are putting in solar and storage systems, to critical facilities in California. So, you can do this at fire departments or medical clinics anywhere that you think that people may be able to go and gather.

Colleen: Well, Elena, thanks for joining me on the podcast. It's been really fun talking to you.

Elena: Thanks for having me.

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