2024 Total Solar Eclipse Grid Impact Webinar (Text Version)

This is the text version of the 2024 Total Solar Eclipse Grid Impact Webinar Video.

Opening Remarks and Introductions

[Webinar begins, host speaks]

>>BARRY MATHER: Opening remarks? Perfect. The recording has just started here. But it's my honor to ask Guohui Yuan from the Department of Energy. He's the program manager for the systems integration area within the Solar Energy Technologies office, and turn it over to him for some quick opening remarks on this event, and on this study. Go ahead, Guohui.

[New speaker takes over. Slides show speaker bio]

>>GUOHUI YUAN: Yeah. Hey, thank you very. Good afternoon, everyone. Wherever you are, welcome to this NREL solar eclipse webinar. So this may sound a little bit nerdy, but I'm really excited to be here to learn about the findings from this study.

So total solar eclipse is amazing and rare event. The last time we had it in the US was 2017, and the next one we'll see, it is the 2044, 20 years from now. So it's really a good opportunity for us to do a study like this because doesn't come here very often.

I know a lot of people are making plans to go to Texas because I heard it's the best place to see solar eclipse, and because it enters the US from in Texas. Interestingly enough, Texas also has a lot of solar in the-- it's 15 gigawatt and counting. In a typical sunny spring day, solar generation will supply about 30% of the electricity they use in Texas, so that's a very important for us to understand the impact of the eclipse to the generation and power system.

Nationally, solar has increased threefold in the last six years, from 2017 to 2023, from 60 gigawatt DC to 100 gigawatt DC and counting. So we know that there's a lot of solar on the system, and we need to understand them. So what are we studying? We are studying the impact of the eclipse in different regions, especially the ramp rates.

The drop and the backup during the eclipse time is very important for the system operators to understand those impact and to be prepared for it. So that's something that you will learn today.

Another thing that I want to mention here is that this is a very collaborative effort. We have a lot of researchers not only in the power system, but also weather modelers. I would also say that there are digital graphic designers that are part of this effort, so we will see that in the webinar today as well.

The last thing I want to say is that the models, the data, and the methodologies that developed in this project is very important for the study of [INAUDIBLE] events. Solar eclipse is easy, actually, to predict. We already know its path. We know its impact. We know the timing. We know the location.

But there are harder situations, harder events to predict and to prepare for, like extreme weather, hurricanes and wildfires and storms. So all the approaches, the methodology developed here are going to be very useful for the researchers, for the operators, and for the system planners and everybody else.

So again, I'm very excited that we're doing this, and thank you, thank the entire team for this effort. And we'll have a good learning today. Thank you very much. Back to you, Barry.

[Returns to host speaker]

>>BARRY MATHER: Yep, thank you so much, Guohui. Certainly appreciate all the comments there, and 100% agree, well, on all points, but especially the collaboration, and that really gets to our next person to offer some opening remarks, Marilyn Jayachandran from NERC. She is the manager for advanced system analytics and modeling at NERC the North American Electric Reliability Corporation, and a critical partner on this study. Go ahead, Marilyn.

[A new speaker takes over, slides show their bio]

>>MARILYN JAYACHANDRAN: Thank you, Barry, and hello, everyone. I'm really excited to be partnering in this particular study with NREL and the US Department of Energy, the Solar Technologies office. And as stated in the NERC inverter based resource strategy, the rapid interconnection of [? bulk ?] power system connected inverter based resource is the most significant driver of grid transformation and poses a significant risk to BPS reliability, as we know.

Now, the speed of this change continues to challenge grid planners and operators and protection engineers and many other facets of the electricity sector. As stated in the 2023 NERC Long Term Reliability Assessment, which projects a rapid growth of IBRs, it's mostly wind and solar, battery energy storage systems, and hybrid plants. And the projection of [INAUDIBLE] capacity of solar projects, which is an all development stages, exceeds 500 gigawatts over the next decade.

That said, I just want to echo Guohui's comments that a systematic study on the impact of solar eclipse on solar generation, ramp rates, et cetera, across North America will provide valuable insights to the grid operators across the country. And it's definitely going to be very helpful to prepare for such future scenarios, and even extreme events.

And lastly, I wanted to express my appreciation to Jin and her team for their work during the past couple of months to make this study possible, and that is all I have for today. I'm going to turn it over to Barry. Thanks, everyone.

[switches back to host speaker]

>>BARRY MATHER: Thank you, Marilyn. All right, well, as Marilyn just mentioned, Jin Tan, my colleague here at NREL, is the lead, is the PI for this project, and I will turn it over to her for the main technical part of this project. Take it away, Jin.

[new speaker enters with new slide deck]

Discussion of Methods

>>JIN TAN: Thank you, Barry. Thank you, everyone, and good afternoon to everyone from the eastern time zone. And good morning to those joining us from the western time zone, and to the friends from the central time zone, I hope this presentation will serve as your lunch snack.

So thank you once again for participating in our solar eclipse webinar. My name is Jin Tan. I'm a principal engineer here, and I'm also a principal investigator for this solar eclipse study. It's my honor to share this impact of the solar eclipse on three interconnections on behalf of the entire solar eclipse study team today.

Before I officially kick it off, I really would like to thank you for participating in the Slido, and now, if you have any questions during this presentation, feel free to type your questions in the Q&A session, and we will take a look at the Q&A by the end of this presentation.

All right, so first, I will introduce some basic background about this 2024 solar eclipse. Then I will introduce the impact from three aspects, the impact on the solar generation, on load, and the grid impact with a special focus on the [INAUDIBLE].

[shows map of eclipse path across United States]

You may already know that the solar eclipse will happen on April 8, which is next Monday. Although the duration of the totality will be up to four minutes, 27 seconds, it will take more than three hours to traverse the entire country. So the path of the totality will cross 13 states in the United States, starting from Texas and ending at Maine. 32 million people already live within the totality path, and many big cities are all within the 200 miles such as Boston, New York, Philadelphia, Baltimore, and Washington DC.

So as you can see in this figure, even the solar eclipse totality path will only go across 13 states, but the entire United States will be affected by the total or partial solar eclipse. So for example, the solar obscuration in the southern end of the Florida will be at around 45%, and the California will also experience 30% to 50% of the solar obscuration.

So you may wonder-- oh, yeah, next one will be in the 2044. So you may wonder, if we recall that we already got a total solar eclipse back in 2017, and why this will be a big deal this time? So the 2024 eclipse will be different in several key ways.

So first, its path is twice as wide as in back in the 2017, and the totality will last for four minutes, lead to a longer period of the [? PV ?] power loss. Second, it will pass over more cities and with more populated area. So what does that mean?

So basically, this will affect the human behavior lead to the affecting the local patterns of the people travel to view those actual solar eclipse. Lastly, the solar installation capacity has been tripled since 2017. This is a remarkable number, so make this event is more significant.

So as [? CIA ?] data shows this remarkable increase since the 2017. So now, let's take a look at the figure on your right. The eclipse ramp actually can mirror the future PV ramp. This presents a golden opportunity for the system operator to gain some invaluable experience and rehearsal for the solar powered future.

You may wonder what will happen during this eclipse, so first, let's take a look at this animation we put in the beginning. So let's take a look at the impact on the solar generation. We have this clear sky day assumption, so Kenny, our lead visualization expert, has crafted an insight animation for data verification and visualization.

So here, those dark orange color represents the [? DTE, ?] including those behind the meter, rooftop PV, and the bright yellow one. Let me show you. So the bright yellow color actually represents a lot of utility scale PV. The larger the circle, the higher the solar generation.

So this map actually vividly show us the solar distribution across the entire United States. We can see there are a lot of solar in California region, in Texas, and in Florida, and in the east coast, especially for the New York and the [INAUDIBLE] New England. They have a rapid surge in the rooftop PV.

Here, this small figure actually illustrates the total US solar generation already surpassing 100 gigawatts with a slightly dip actually indicating the aggregated impact of the solar eclipse on the entire United States. So now, let's visit this animation again. [INAUDIBLE]

So as the solar eclipse totality is approaching and moving, the totality is approaching the solar first effect that those southern regions, as you can see here, so we can see the clearly shrink of those circles. And then when the totality passed to move towards to the northern region, we also can see gradually those solar recovered.

So in a summary, actually, this solar eclipse influence on the solar generation is very evident, and we also can see a dynamic response observed across the different regions at the different locations. So how do we make it happen? So conducting a comprehensive study on the impact of the weather event request, like Barry said, the experts from the different multiple fields to collaborate closely. So we need the sophisticated model that can integrate data, weather modeling, solar modeling, and the power grid modeling into one framework.

We highlighted the need for diverse data source, including the weather data, GIS data, the PV capacity for the accurate solar modeling. Similarly, those historical data on load [? when the ?] grid infrastructure are also important for the grid impact analysis. So at the end, we used a powerful visualization tool to verify the data accuracy and uncover the crucial relationships.

So next, let's delve into our temporal and the spatial solar modeling analysis approach as outlined in the four steps as shown in the left figure, and also the workflow and the data flow on the right. So first, we have to model the utility scale PV and the distributed PV separately. Using the reliable open source data, such as the EIA data, the [INAUDIBLE] PV is modeled at a plant level, and the [INAUDIBLE] PV is modeled at the zip code level.

And meanwhile, when we start this project, actually, we only have the data by the end of the December, but how do we know that the PV capacity by the April 8? So we also notice a very big increase in the pipeline of those solar projects, so that's why we also did a projection there. So next step is process the metadata to prepare the inputs for the eclipse meteorology modeling.

[Shows software modeling process]

So the [INAUDIBLE] SAMPA team integrating their SAMPA model with the NASA data and calculate the solar irradiance based on the solar and the moon's position. So this information is then passed to NREL's SAM team led by [INAUDIBLE] accurately to estimate the solar generation by considering different types of the PV technologies.

Importantly, we achieved this one minute temporal resolution for the UPV and DPV thanks to those high resolution modeling and data, so that we can analyze those solars at a very geospatial and temporal time scales-- [INAUDIBLE] scales. With this approach, so actually, we can analyze the impact of a solar eclipse from the interconnection level down to the [INAUDIBLE] level and the rebalancing area level, even the plant level as needed, so let's take the [INAUDIBLE] as one example.

Visualization of Results

So the key parameters that we are extracting from this study are summarized in the figure here and also in a table here. We can see that the duration of the whole impact on ERCOT approximately three hours, and during which ERCOT is projected to lose 33% of the solar generation, accounting for roughly 20% of its electricity supply.

Now, many of you may curious about how solar eclipse different from the regular sunrise and sunset. Well, this lower figure here, the left figure showing you, paints a clear pictures why this is different. During the solar eclipse, actually the generation ramp down and up can be two to four times faster than during the regular sunrise and sunset, so this requires a lot of great operator to be prepared for handling those rapid change effectively.

So we are associated very similar analysis for the west interconnection, east interconnection. As we can see here, the eclipse impact occurs at a different time, a different location, and we have a different impact in terms of the duration and the magnitude. And we compare those three interconnections quantitatively by using those key matrix, finding that [INAUDIBLE] will experience the largest duration of the eclipse.

But the comparing the percentage of the PV reduction is clearly see that ERCOT will suffer the largest drop as the totality path right cuts through its region directly. Similarly, when we look at the ramp rate here, the ERCOT remains the most severe one.

Here's another panel just to show you the diverse impact of a solar eclipse for each ISO. They actually generate all the detailed information for all the ISOs. Due to the limited time, I won't be able to go over it one by one today, but if you need any further information, please contact us. We are very happy to chat more with you.

Here is a key figure that we compare all the ISOs from different aspects quantitatively. So using the ERCOT as a base case, note that, for [INAUDIBLE], even it's not under the totality path, percentage of the PV reduction is only 43%, but considering those significant PV capacity, we still can observe very significant PV generation reduction, and the ramp rate is as high as 300 megawatt minutes. So the severity is a compound result of their location in stored PV capacity as well as the size of the system. So later, we will have another one to emphasize these findings.

Now, let's take a look at this panel to show you that the varied impact of the solar eclipse at the BA level, balancing area level. This figure actually [INAUDIBLE] show you that the solar eclipse impact can be different from one location to the other. Now, we already understand how solar eclipse affects the solar generation. Let's consider its impact on load.

[Shows graphs of eclipse impact on power system generation]

So this is a very crucial. Note it's crucial for two reasons. First, with a significant amount of rooftop PV embedded in the load, estimating their impact becomes more challenging, especially during those special weather events. Secondly, it's important for the grid operator to forecast their lag load as shown in those curves. It's very important to focus them accurately, so we can determine the required generation capacity.

The left figure is showing this [INAUDIBLE] stack curve actually generated back in 2008. So this shows that, as the PV penetration increase, the dark will have a heavier and heavier [? valley, ?] indicating a greater need for the ramping capabilities here, if you can see my mouse.

So in California region, so the right figure is actually, this is the current status of the California. So we can see, in the upper figure here, the current light load curve has transformed from the duck curve to the canyon curve already, thus exacerbating the ramping issues.

[? It's ?] the solar eclipse here, and this curve will be transitioned again into a [? funnel ?] curve presenting [INAUDIBLE] operator with the challenges of managing the rapid ramping twice within several hours. So in this figure, let's take a deep dive into the CAISO case. So we can fully understand those impacts.

So in this figure, those dashed line represent the light load. The solid line actually represents the typical demand with the distributed PV embedded. The red color represent the solar eclipse case, so in this case, we can see the solar energy in California region appears to be able to meet 100% of the load despite maximum solar reduction of only 43%, but this is still caused a very significant increase in the light load during the eclipse.

The change in CPV also visibly can impact this part, the load shape, so underscoring the importance of accurate DPV estimation. We needed a similar study for the different ISOs. Here's a panel to illustrate the different impact of the solar eclipse on the load profiles. And later on to find some interesting findings for those three ISOs, CAISO, ERCOT and ISO New England.

Let's take a closer look at all the ISOs comparison. So here is all the ISOs, and here is the key parameters. Here, we propose using the percentage value to value-- to better understand the significance of those changes relative to the normal load level, as shown in the column two and the column four.

The percentage of the light load actually can indicate how much ramp the operator will actually handle comparing to normal operation, and also the percentage of the load change indicated the DPV impact on the load. So in this way, it reveals some interesting findings. So first, California experienced the largest percentage change in light load, even it's not in the totality test.

Surprisingly, actually, ISO New England follows closely behind with 0.5-- 5.5 gigawatts total net load [INAUDIBLE], translating to a 50% percentage change of light load due to the small load base. Distributed PV impact also called for attention for the ISO New England, as we are showing here.

Interestingly for ERCOT, which is in the totalities, also ranking the highest in terms of both percentage of the solar reduction and the absolute value. But the impact on load appears relatively smaller due to the substantial load base, so this echoes our previous point again. The impact of severity is a [INAUDIBLE] result of their location [INAUDIBLE] and the size of the system.

So next, we wonder how this solar eclipse will affect the grid. We use the 2031 EI case and conduct a two day simulations with and without the solar eclipse. On this map, you can clearly see the different generation type with different colors, and we can see the different generation mix for each ISOs in the red bar. And let's play the animations here.

So as the solar eclipse-- yeah, so as the solar eclipse pass over, the solar gradually reduce from SPP to MISO, [INAUDIBLE] New York ISO, and ISO New England. Where the solar reduce, we also can see the support from the gas and the pump hydro storage. So in this study, the first good news is there is no observed load on the solar eclipse day. So this also imply that the existing resource in the EI can handle the faster ramp caused by this 2024 solar eclipse.

To understand what mitigate those eclipse impact, so we plot generation dispatch with and without the eclipse on one slide. So as you can see here, the dashed line is with the solar eclipse-- sorry, the line is without solar eclipse.

So if you take a look at-- a closer look, you can find out this system actually primarily rely on the pump hydro, gas, hydro, and battery for the faster ramping support during the solar eclipse. The bar chart on the right actually showing that the pump hydro is the top contributor by providing 42% supporting followed by the gas, and other hydro sources.

Next Steps for the Study

Now, this comes to the end-- almost to the end of the presentation, but also important one. So what's the next step for this study? So for the next step, we will summarizing the mitigation methods to mitigate the impact on the grid operation.

So in 2017, we have outlined five key aspects for handling the solar eclipse, increasing the reserves, strategically use of the pump storage hydro, optimizing the market role for generation flexibility, reducing the power interchange among the [? TSOs ?] so you have enough room to support the [? neighboring ?] regions, and enhancing the management and coordination.

I also want to emphasize the accurate solar forecasting and extending the power reserve will be crucial. So this is about the mitigation methods we learned in the past, and we are going to have some deeper investigation in the future.

In parallel, NREL will also have a team. We are implementing a real time monitoring platform at NREL to capture this national wide potential impact of the solar eclipse for the entire US in real time. And so for the post event analysis part, we will use the data provided by the [? ETK ?] team to analyze the actual solar eclipse impact on the grid reliability in terms of the frequency.

Here, I also want to call for the collaboration on the post event data analysis real world countermeasure interviews, and also the systematic studies on those countermeasures. So we are here. We would like to collaborate with you and to investigate, study more insights into those weather related events.

Acknowledgements

So in summary, our framework is not only for analyzing the solar eclipse. It can be easily expanded to those thunderstorms or other weather related events and fully understand and study the impact on the grid operation, reliability, and resilience.

So at last, I would like to introduce our fantastic team to all of you, so, team, please turn on your camera. So recall that we started this project last December. We are facing the challenges of only having these 3 and 1/2 months to conduct this pre-event analysis since this solar eclipse never wait for people. So I would like to thank you [? Cong, ?] Manajit, and the SAMPA team led by [? Rita ?] and the [? STEM ?] team led by Travis for prioritizing this task.

I was amazed by your professionalism and the efficiency in generating our solar data just within one month. That's amazing. So thank you, thank you.

And also, all the credits for these fantastic animations should go to Kenny, and I believe he brought our project to a very high new level by utilizing those visualization techniques. Also, I would like to see my-- show my great appreciation to the NERC team lead by Marilyn because without you-- you team is fantastic to provide those data promptly.

And also thanks to the grid impact analysis team, [INAUDIBLE] for their efforts in developing those EI plexus model. Special thanks to Seong and his team who have been working so hard on the real time visualization platform, and they are super self-motivated and passionate about it.

So this will be our next important activity on April 8, 2024, under this project, so please stay tuned for that activity. I also want to thank Guohui for providing valuable visions and insights into this project, and thanks to all the communication team for their support, dissemination efforts to make this happen. I probably won't be able to read all your names one by one.

So here, there are too many appreciations. I won't be able to go over them, but without your support, assistance, and help, I believe we won't be able to generate so many results by today, by April 2nd. Just want to show my sincere appreciation to our external industry advisors, lab collaborators, and NREL colleagues.

Last, but not least, I want to thank to our sponsor SETO. Without your support we won't be able to work on this important project. Thank you all. Then let's go to the Q&A session.

[Switches back to original host]

>>BARRY MATHER: All right, thank you so much, Jin. And we're getting really good participation in the Q&A area in slido.com. The link is.