A growing number of states and the federal government have set ambitious climate and clean energy goals, including achieving a carbon-free energy system, completely phasing out fossil fuels, and ensuring a just and equitable transition to sustainable energy for disadvantaged and frontline communities. This transition will require both large-scale electric generation, and smaller-scale, customer-sited resources, like solar, storage, geothermal, and energy efficiency. Large-scale resources alone can’t get us to a 100% clean, renewable, and equitable clean energy future without breaking the bank, and they might not be the most effective way to achieve major greenhouse gas emissions cuts. This episode explores how large-scale electricity and distributed energy resources can work together to help us transition to a 100% clean energy future. Because hope is not optional.

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About Our Guest

Dr. Julieta Giraldez is Director of Grid Planning at Kevala, where she focuses on solving integrated grid planning challenges and the way distributed energy resources (DERs) interact with the grid. Prior to joining Kevala, Dr. Giraldez worked for the National Renewable Energy Laboratory (NREL) where she led DER grid integration related projects. She brings a holistic view of grid integration related issues, acknowledging the importance of including multiple perspectives in the evaluation of new emerging technologies, from developers and customers to technology providers, regulators and utilities. Dr. Giraldez holds a P.h.D. in Systems Engineering from Colorado State University, an M.S. in Electrical Engineering from the Colorado School of Mines, and a B.S in Technical Mining and Energy Resources from the Polytechnic University of Madrid, Spain.

Episode Show Notes

Key Takeaways

  1. Today’s guest, Dr. Julieta Giraldez, is Director of Grid Planning at Kevala, where she focuses on solving integrated grid planning challenges and the way distributed energy resources (DERs) interact with the grid. Prior to joining Kevala, Dr. Giraldez worked for the National Renewable Energy Laboratory (NREL) where she led DER grid integration related projects. She brings a holistic view of grid integration related issues, acknowledging the importance of including multiple perspectives in the evaluation of new emerging technologies, from developers and customers to technology providers, regulators and utilities. Dr. Giraldez holds a P.h.D. in Systems Engineering from Colorado State University, an M.S. in Electrical Engineering from the Colorado School of Mines, and a B.S in Technical Mining and Energy Resources from the Polytechnic University of Madrid, Spain.
  2. The episode walks through:
    • How large-scale renewables and DERs intersect to manage the energy system;
    • What regulators and utilities need to be aware of to effectively manage large-scale and distributed resources;
    • How DERs can help shape electrical demand and make the energy system more efficient.
  3. Highlights:
    • Distributed energy resources, such as rooftop solar and battery storage, are changing the way we think about electricity demand and managing the electric grid. Historically, power has always been generated at large-scale power plants and delivered one-directionally to consumers. Now, individuals and businesses who adopt solar, for example, can export power back to the grid, and we are moving toward more complex grid management, involving more control points and the need to balance more intermittent resources. We can shape electricity demand in a way that maximizes both large-scale and distributed energy resources and allows us to tap into renewables when they are available.
    • We are making major strides in the level of granularity with which we can conduct distribution system planning (see, for example, the California Electrification Impacts Study referenced below).
    • We don’t have to make an “either-or” choice between large-scale and distributed energy resources—we need an all of the above approach to support energy sector decarbonization.

Resources and Further Readings

  1. Kevala, on behalf of the California Public Utilities Commission, completed the California Electrification Impacts Study in 2023, in order to “determine the distribution grid requirements of state transportation electrification targets. Kevala analyzed over 100 terabytes of data from Pacific Gas and Electric (PG&E), Southern California Edison (SCE), and San Diego Gas & Electric (SDG&E) to explain when, where, and how much utilities will need to invest in grid upgrades.” 
  2. A 2021 report by Vibrant Clean Energy showed that deploying optimized DERs can save $515 billion by 2050 compared to using utility-scale only resources, and that a mix of DERs and utility-scale energy (rather than utility-scale alone) can provide greater greenhouse gas reductions.

Episode Transcript

Radina Valova, IREC Regulatory Vice President and podcast host: Hello, and welcome to the Energy Optimist where we start with the bad news and end with what increasingly feels like a radical idea: that there are reasons for optimism. I’m your host Radina Valova, Regulatory Vice President with the Interstate Renewable Energy Council (or IREC), an independent nonprofit that’s been building the foundation for the rapid adoption of clean energy and energy efficiency for more than 40 years. Each episode, we tackle a thorny energy policy challenge in bite-sized interviews with leading experts.

If you’re totally new to energy policy, we’ll demystify it for you. If you’re a seasoned practitioner, we’ll hopefully leave you with renewed optimism to keep doing the work to improve our energy system—because hope is the fuel for change.

You know the old saying there is nothing new under the sun? When it comes to energy, you may think our modern electric system is entirely novel. But some of today’s cutting-edge renewable energy technologies rely on methods people developed thousands of years ago.

People have harnessed the power of the sun for millennia. Some designed their buildings so that certain rooms faced the sun in order to capture its heat during winter. As far back as 2,000 years ago, others used concentrated sunlight through magnifying glasses or mirrors to light fires. Leonardo da Vinci theorized that one could also heat water using such concentrated solar power. Flash forward to today, and some of the largest solar photovoltaic generating stations use a version of this approach. These concentrating solar-thermal power stations also rely on mirrors. And while the process and scale is vastly different from the methods used 2,000 years ago, they rely on the same underlying principles.

On today’s episode, we’re going to delve into how we have traditionally produced the electricity that fuels our lives and what the future of power generation looks like.

Historically, the energy system has involved the one directional flow of electricity from a large central station power plant to end use customers. These power plants, whether they’re fueled by large-scale solar, nuclear gas, or other sources, are typically located far from the customers who rely on their electricity. The power has to flow through long-distance transmission lines that are costly to build, and that often come with their own environmental and social impacts even if the electricity itself comes from a renewable resource.

Large-scale power generators will continue to have an important role to play in the energy system, especially as we transition away from gas use in buildings and cars to electrified transportation, heating, and other energy services. At the same time, large-scale resources alone cannot get us to a 100% clean renewable and equitable clean energy future.

Recent studies show that we can save billions of dollars by combining large-scale power with distributed energy resources—not just generating resources like solar and wind, but balancing resources like battery storage. A 2021 report by Vibrant Clean Energy, for example, showed that deploying optimized DERs can save $515 billion by 2050 compared to using utility-scale-only resources. Similarly, Vibrant Clean Energy found that a mix of DERs and utility-scale energy, rather than just utility-scale energy alone, can provide us with greater greenhouse gas reductions. And DERs aren’t just an essential tool in the clean energy transition. They also provide homes and businesses important reliability, resilience, and affordability benefits.

Our guest today will take us on a deeper dive into how large-scale electricity and distributed energy resources can work together to help us transition to a 100% clean energy future.

Radina: Thank you so much for joining us for today’s episode of The Energy Optimist: Teaching an Old Grid New Tricks. We’re very excited to have as our guest for today’s episode, Julieta Giraldez with Kevala. Julieta, would you like to give a brief introduction?

Julieta Giraldez: Yes, sure. Thank you for having me. I’m Julieta Giraldez. I’m the Director of Grid Planning at Kevala. We are data and data analytics software platform, and we are really looking to change the way we interact with the grid and improve the decision-making ultimately to achieve the decarbonization goals.

Radina: Perfect. Thank you. What a great segue into our topic today which is focused on how large-scale electricity and distributed energy resources, things like smaller-scale solar and storage, can work together to help us transition to a 100% clean energy future. 

My first question to you is, how do large-scale power plants and distributed energy resources intersect in terms of managing the energy system?

Julieta: Traditionally, only large power plants far away from us, the customers, would generate the electricity that is transmitted over what we call the power grid, which is a set of high-voltage long power lines and then distributed lines in the neighborhoods, to finally bring that power to us—the customers, the homes, the businesses.

In general, since the generation has to equal the demand at all times—that’s sort of a principle of operating the power grid—meaning that when we turn on appliances at will at our house, the generators have to increase or decrease the production to keep this grid stable. So now with distributed energy resources like solar, and batteries, and even our cars now, consumers can generate their own electricity. So there can be efficiency in bypassing that large transmission and distribution system, that power grid that I just described, and also environmental benefits of reducing the emissions locally. But also, we can start shaping how the demand looks like, to meet that available generation versus just doing it the other way around, versus just the generators meeting the demand at all times.

To get back to your question of where they intersect is that DERs can now add what we’re referring to as “flexibility” to manage the demand. But it’s important that the rules and the controls that are still under development, they still need to be developed as we are adding pretty much as many customers to the grid now as possible control nodes and participants. And the grid still needs to meet really high-reliability standards. So we still need to design everything for when the grid goes wrong and make sure that we can still all use this system that we’ve always taken for granted as always there. It really has to meet those reliability standards.

Radina: Thank you so much. I would like to unpack that a little bit for our listeners. As I understand what you just shared, we typically operate the grid by determining how much demand, how much energy usage, is expected and then building the generation to meet that demand. And that’s typically large-scale power generation. 

You’re saying that now we’re transitioning to a different way of operating in which we’re using distributed energy resources more. Is that correct? Can you speak a little bit more about what it looks like to use distributed energy resources in this way?

Julieta: Yeah, so it means that instead of only having the large power plants to always, at all times, meet the demand of the consumers (us) requesting more or less power, or industries requesting more or less power, we are now going towards the other end of the spectrum. Those consumers [are] thinking about, well, if you install solar and battery, you can maybe start shaping when the large generators are available. And you can start shaping how you consume power to also meet maybe the large renewables may be available when sun is shining or when the wind is blowing.

Radina: Can you speak a little bit more about what that shaping means? For anyone who isn’t familiar with it, what does that mean in practical terms?

Julieta: Yeah, that shaping to me means that if you think about how we consume power on a daily basis: you wake up in the morning, you turn things on, so the demand goes up. Then in the middle of the day, typically, we all used to go work—now a lot of us work remotely—but typically, the demand in the houses, for example, may go down. Then everybody arrives home, the kids arrive home, and the demand goes back up again. 

And so that’s what I mean by a shape. There is a pattern to how we typically used to consume electricity. Now we can maybe change that pattern to meet when the generation might be available. So instead of making, for example, our demand so “peaky”—all at the same time at five or six o’clock when we’re home and we’re running the appliances and everything is connected, everybody’s charging—we can start thinking of managing that.

Radina: Thank you so much. I think that was a really helpful explanation of how energy usage or demand can vary throughout the day. Now that you’ve explained how we can shape the demand, can you talk a little bit about why it’s important to do that shaping?

Julieta: Shaping the demand is becoming more important for two reasons. The first one is one that we mentioned earlier—that to achieve 100% clean energy, we are relying more and more on solar plants and wind farms that depend on the primary resource, which is the sun and the wind. It is variable in time, but it’s also uncertain. We don’t really know when the clouds may cover the rooftop solar, or the wind may be blowing more or less. That is one of the reasons.

The second reason why we’re also looking at shaping the demand, controlling how we consume, is because the peak demand is increasing. That moment when we all get home, and we’re also now plugging in cars, and we are electrifying to achieve these decarbonization goals, we are having to make the infrastructure larger for very small moments in the day where everybody connects at the same time. And so that’s the second reason why it’s becoming more important to use more efficiently the grid and having to build less capacity overall of generation to meet that demand. It’s to be able to also shape the time where we’re all consuming at the same time.

Radina: You make a really important point there regarding the reasons for which peak demand is increasing. It’s not just us using more electricity at home like, for example, having more appliances. In fact, in general, the efficiency of appliance has increased over the years. 

Can you describe briefly what is causing that peak? You mentioned electrifying things. What exactly does that involve? What are we electrifying?

Julieta: Electrification or electrifying means that we are switching devices and appliances that used to consume another fuel like natural gas or oil towards electricity. The best example of course, the most obvious one, is the transportation sector. Now we are switching from using gas in our cars to connecting them to the grid.

The other very important one is building electrification. We are switching a lot of our thermal and cooling appliances like our air conditioning to new technologies that use electricity, such as heat pumps or other systems like that. And so that is putting a big stress in the grid in the two ways we were talking about. One is having enough generation to meet all of that new demand that is coming. But also, the wires, “the pipes,” have to be big enough to bring all of that power to the homes and businesses that are electrifying.

Radina: That gets us to our next big question. It seems like there are two things going on here simultaneously. Number one, we want to electrify more services or more energy uses, like you said, like transportation, like heating in buildings, in order to move away from fossil fuels. That requires electricity. 

At the same time, we’re trying to get to 100% renewable energy, which a lot of states now have these goals. We also have broad, ambitious federal goals as well. So if we’re trying to electrify everything and we’re trying to get to 100% renewable energy, it seems like if we try to do that purely through large-scale power plants that require these huge long-distance transmission lines, that would probably be quite expensive. 

How can we use distributed energy resources to make that transition to renewables and electrification more cost efficient?

Julieta: I think there’s cost efficiency, but there’s also the time component. The transmission system in the U.S. more than in other countries is already playing catch-up. Even if we’re not transitioning to 100% clean energy, it is very hard to build long power lines that cross multiple states and regulatory environments. They take a long time to build, and it hasn’t been a good business for utilities and companies to invest in this for different reasons.

There’s now a consensus that the transmission system is underbuilt—those large power lines that bring the generation to the cities and customers. Which means that, even today, if we were able to solve this challenge and design all of the long-distance power lines to bring that generation of the large-scale renewables to the loads, it would take 10 to 20 years to build these projects.

And so if to that we add the goal of 100% clean energy in which the plants can only be built where the renewable energy resources are, the catch-up we need to play is even larger. And if to this we add the electrification to meet the decarbonization goals—the fact that we’re not going to be using electric cars and heat pumps—then it sort of becomes unfeasible to think that only large power plants would be built and would be able to put their generation into a power grid that can transmit it to the consumers.

That’s where DERs are very important. Because they can truly help manage that transition by adding generation locally and increasing the flexibility to control that demand, as we talked [about] before, that is imposed to the grid.

Radina: Can you define what is included in the term “distributed energy resources?” We’ve already mentioned solar, but I know that there are others as well. Can you provide a few more examples?

Julieta: Yeah, actually, in my mind, distributed energy resources is anything that is installed at the customer level, so at a house or at a business, that can increase or decrease the demand that is affecting the traditional way we used to consume energy.

There’s solar and batteries as we talked about. There’s energy efficiency. It is a form of a DER. Building electrification is also a form of DER. Of course, electric vehicle is a new device that we’re now adding to homes and that is increasing and decreasing our consumption.

Radina: Because with electric vehicles in particular, they’re not just a transportation resource, but they’re also mobile batteries that you can plug in in different locations and charge or discharge from the grid.

Julieta: They are. That DER has really changed the way we think [about] the demand. Because solar and batteries in our homes started to disrupt a little bit the way we thought about our predictable usage patterns with just one-way power flow. It’s what we called it, right? The power always came from the large centralized grid, from the large-scale power plants, and was consumed in one direction.

Solar suddenly in businesses and in homes meant that you can put power back to the grid. But it’s at least in one location. It doesn’t move. And so electric cars now is a demand on the grid that can be imposed pretty much anywhere, and it’s becoming harder and harder to manage. So it’s not just that it’s unpredictable. It’s also that it can be connected anywhere.

Radina: That leads nicely into a follow-up question which is, given these capabilities of distributed energy resources to both serve as demand—meaning to draw from the grid—but also to export back to the grid, how can we use DERs to more cost effectively get to that clean energy future? 

If I can restate the question: are there any tools or methods that you might recommend to regulators to optimize the usefulness and the benefits of distributed energy resources?

Julieta: Yes, one of the challenges is that, I think we talked a little bit about this at the beginning, it was a lot easier to manage and control the grid on a daily basis and for planning when we only had to count on a few large generation plants and transmission lines to bring this power to the customers. But now having to rely on as many control nodes as there’s customers, so millions of control nodes, to make decisions in the market and on the daily basis to control the grid and the stability of the grid, that is a challenge.

And so we do need to understand the grid modernization, is what we call it, initiatives. It is very important to support those so that utilities can modernize the way they are able to understand what’s happening in every home and in the distribution system so that they can effectively participate in the control of the grid and in meeting the generation that is available.

Radina: A related question to that is, can large-scale renewables and storage assist with increasing those benefits or that optimization of distributed energy resources?

Julieta: Absolutely. I really don’t think it’s an either-or question, whether it’s distributed resources versus large scale. It is definitely an “and.” We need all of the tools in the toolbox to address the decarbonization goals and the decarbonization of the energy sector.

Large-scale renewable energy and storage are becoming very cost-competitive, winning bids against traditional thermal power plants, and will be key for many reasons. One very important one that we started to talk about is keeping the grid stable.

So again, as we transition to a clean energy future, there are more and more control points being involved in keeping this system balanced—as we were saying, generation equals demand—so that the grid works. New ways of performing that control with non-traditional generators are still being developed, designed, and understood. Large-scale renewables are going to be key to maintaining and participating in making that grid stable and reliable.

Radina: I’d like to turn now to a question submitted by one of our listeners. This question was submitted by Cambria Janshen. Cambria asks: what would happen if the world did not have solar energy?

Julieta: Oh, well, I would personally be very sad. I’m from Spain. And as my dad says, we need photosynthesis to survive. But without—setting that aside, my selfish solar energy needs, I guess we would have to depend even more on wind and geothermal maybe and, of course, battery storage.

The other big one would be, maybe we would be giving even more importance than we are already doing to hydrogen, which is still expected to make big breakthroughs, I think, in the upcoming years and will be key to the future, I think, of the clean energy transition.

Radina: I absolutely love that you found the positive in that otherwise very sad question.

Julieta: Definitely. I really cannot relate. Nature, I mean, can you imagine? I just learned that my chickens depend on the sun to lay eggs. So no, I think the ecosystem in my house would be very, very sad without sun.

Radina: Yes, we would not want sad chickens. I did not know that.

Julieta: Things you learn when you become a chicken owner.

Radina: That’s right.

Thank you, Cambria, for submitting your question. We look forward to being able to answer future listener questions as well. 

Now on to our final question, and this is a big one. What gives you hope?

Julieta: That is a great question.

I think my hope is that we are innovating and achieving really great technological breakthroughs, from battery technology to our ability to solve very complex models and scenarios of what the future may look like.

For example, at my company, at Kevala, we just modeled every single house in the state of California, so 13 million customers, to start thinking about how they will respond to the climate, different climates, how their demand will go up and down, and how they may or may not adapt DERs—all of these technologies that we were talking about—to understand the impact to the grid for the next 15 years. 

This is something that would have been impossible to think about maybe 5 or 10 years ago: the idea of modeling every single house, every single control node, as we were talking before, in the grid for planning. It is becoming real, I think, to be able to take into account now in the models all of these nodes that can become part of the clean energy transition.

I think another big thing that gives me hope is that the climate crisis has also helped arise, I think, injustices and equity concerns over how we do this transition. An equitable and more just clean energy transition is a hugely important challenge for regulators and for utilities. It is a conversation that is happening, and I’m very excited to contribute to that. I think it is an opportunity also to fix maybe issues of the past. So it really does give me hope.

Radina: That is wonderful to hear. 

First, I’m so excited by the research you described that Kevala is doing. I imagine that also relates to the equity element, because if you’re talking about whether or not people’s homes will be livable in a climate changed future where you’ve got increased heat waves, for example, if they don’t have efficient homes, or if they’re not able to invest in distributed energy resources, that can significantly impact their well-being. Thank you so much for the work that you’re doing.

Julieta: Yes, we have been very happy to be able to be a part of that.

Radina: All right. Well, thank you again so much for joining us today, Julieta. It was wonderful speaking with you, and I look forward to seeing all the great work you’ll continue to do.

Julieta: Thank you so much. Thank you for having me. It was great to be an energy optimist with you.

Radina: And that’s it for today’s episode. A huge thank you to you for tuning in. Yours truly, with optimism, Radina.

This episode of The Energy Optimist was produced and recorded by Radina Valova, edited by Mari Hernandez, Gwen Brown, and the team at Podcast Engineers. And graphic design was provided by Nicole Wilson. If you enjoyed this episode of The Energy Optimist, subscribe to our email announcements about new episodes by visiting IRECusa.org/TheEnergyOptimist. Or you can find us on your favorite podcast streaming service.