Find out why ERCOT failed during the 2021 winter storm, sending millions into the dark.
You'll learn how the power grid works and understand why backup power is critical for severe weather.
1. You'll Learn About
US Power Grid
Disccover what makes Texas unique.
Delve into the reasons behind the blackout.
ERCOT Failure
Identify why Texas failed to keep the lights on.
Backup Power Importance
Learn how you can prevent outages with backup power.
2. Backup Power Importance
Power outages and emergency preparedness have been in the news a lot recently. In April 2025, Spain experienced a major power outage, a cascading blackout that left homes and businesses at a standstill. It happened fast. One moment, life was normal, the next, the lights were out and everything that we take for granted suddenly felt fragile. And that's the thing about emergencies. They rarely give us time to prepare. And the electrical grid is the largest machine on Earth and requires incredible precision planning and orchestration.
Now, the exact cause of the recent Spain power outage is still being investigated, but there's so much we can learn from other events. And in this course, I'm going to break down the deep freeze power outage that hit Texas in 2021. I'll be going over the events that led up to the outage, what actually caused it, and what we can learn from it going forward. The Texas outage can serve as a case study, one that we can all learn from. And it all starts now.
In February 2021, Texas faced a severe power crisis triggered by three major winter storms. Winter storm Yuri, among them, hitting between February 10th and 20th. These storms caused the state's worst enemy infrastructure failure, resulting in over 4 and 5 million homes and businesses losing power, some for days. and it even resulted in the loss of over 200 lives. Now, initial reports from state officials mistakenly blamed the outages on frozen wind turbines and solar panels. However, a full investigation revealed that the primary cause was a failure to winterize traditional power sources, especially the natural gas infrastructure, which saw a power production drop far greater than that of Texas's wind turbines. So, numerous sources of Texas's power generation went offline due to the cold.
Now, there's a lot to break down in this graph, but let's start by looking right here in the early morning of February 15th, where a massive drop in energy generation takes place. In addition to equipment problems, demand for electricity in Texas hit a record nearly 70,000 megawws for February 14th, 3,200 megawws higher than the previous record set in January 2018, and 12,329 megawatts higher than the capacity at the time. The Electric Reliability Council of Texas, URKT, initiated rotating outages at 1:25 a.m. on February 15th in response to lower energy demand and avoid a more extreme and complete blackout. We're going to spend most of the course talking about the details of exactly what happened, but first, let's talk about the environmental factors at play. Severe winter storms and extremely cold temperatures.
Cold temperatures and winter storms are common and not particularly noteworthy. But every so often, a series of events come together to create a perfect storm. The Texas winter storms of February 2021 caused a record low temperature at Dallas Fort Worth International Airport of -2° F or -19° C on February 16th, the coldest in North Texas in 72 years. This event was due to the polar jetream, a current of very cold air that circles the North and South Pole, dipping down lower in the US than usual all the way into Texas. Now, climatology and meteorology are quite complex, but let's try to make sense of the basics. The Earth's counterclockwise spin, its tilt, and the sun heating different parts of Earth at different rates play vital roles in weather here on our planet. To make this easier to understand, let's just look at the northern hemisphere. In late autumn near the North Pole, we get polar night where the sun never comes over the horizon resulting in colder temperatures. A polar vortex, a current of high-speed air in the upper atmosphere, form, separating this colder Arctic air from the warmer air near the equator. As long as a polar vortex remains strong, the colder air at the pole stays contained.
But this relies on a strong difference in temperature. If the Arctic air gets warmer or the air closer to the equator gets colder, the strong polar vortex begins to weaken. A good way to visualize this is to think of a spinning top. When the top is spinning fast, it stays stable and spins evenly. But as that top starts to slow down, it begins to wobble. This wobble results in the polar jetream going from this to something more like as cold Arctic air reaches further south into North America and Europe. Check out this amazing imaging from NASA from a sudden stratospheric warming event in early 2013.
Now, this is a different event than the one we're talking about, but it can really shed some light here on what's happening. In mid December 2012, the polar vortex was stable, but a warming event around New Year's Day in 2013 started to disrupt the flow. By the first week of January, you can see the polar vortex is completely disrupted and little vortices of cold air are sent southward. This is different from what happened in 2021, but it's a really good illustration of how impactful the polar vortex can be on weather around the world. So whether it's cold temperatures or hurricanes, wildfires, or flooding, environmental factors will always play a role in our infrastructure and power grid.
Now that we've seen how the Texas deep freeze of 2021 was caused, let's get back to the larger question of how it impacted the grid. There are two major wide area synchronous grids. The eastern interconnection and the western interconnection. But Texas belongs to neither. They have their own, the Texas interconnection, which is one of three minor grids along with the Alaska and Quebec interconnections. Grid interconnections often span states and even countries because it can be a huge benefit to have more sources to import energy from when you don't have enough and customers to export energy to when you have too much. But Texas opted to have a more isolated power grid in some part to avoid federal oversight to have more control themselves while maintaining limited interconnections to national and even Mexican grids. They're not fully isolated, but they are much more isolated than most of the country.
The isolation has allowed Texas to deregulate their electricity market starting in the 1990s and has led to competition and better pricing for their customers. Here in California, where I am, we have monopolies and no choice.
But Texas allows users to change energy providers like cell phone providers to find plans better suited for their needs. And that can be a really good thing. Electricity prices in Texas are some of the lowest in the US. But there's always a trade-off. And in the case of Texas, two drawbacks immediately come to mind. Deregulation and isolation led to reduced investment in contingency planning since Texas got to decide for themselves where they should or shouldn't invest. And second, deregulation typically means cheaper prices, but it can also mean more volatility and higher prices when demand suddenly skyrockets. During the 2011 Groundhog Day blizzard, Texas faced similar power outages due to frozen power equipment, after which the Federal Energy Regulatory Commission reported that more winterization was necessary for the Texas grid. While some generators since then implemented new winterization practices, these limited upgrades happened on a voluntary basis.
So, Texas has seen cold events like this before, but unfortunately, the appropriate winterization investments were not made. Let's get back to the energy generation chart from that week.
If we compare Sunday, February 7th to Thursday, February 11th, you can see one of natural gas's greatest benefits. On the 7th, look at how much wind power was available. And as a result, less natural gas was needed to meet the demand. But come February 11th, not only did overall demand rise, but the available wind generation also decreased. But luckily, natural gas can be dialed up or down to make energy on demand. Solar and wind power don't have this luxury and need to be worked around as they can't be predicted or modulated. But here's what happened. In the early hours of February 15th, power generation started to fall.
Yes, it was some wind turbines, but as reports have shown, five times more natural gas generation went offline. This caused the state to issue rolling outages where certain neighborhoods or regions lost power to preserve the overall grid and reduce demand and bring it more in line with how much energy there was available. But this had a cascading effect as revolving outages also affected natural gas compression stations responsible for pressurizing and pumping natural gas to the power plants that needed it, causing even further declines in natural gas generation. Does this mean that technologies like wind and natural gas can't work in the freezing cold? Not at all. In fact, both wind and natural gas work just fine in colder parts of the world day in and day out. It comes down to expectations. Texas historically hasn't gotten extremely cold, and many Texas homes aren't as well insulated, for example, as homes in New York or Canada, where cold winter weather is expected each and every year. Many homes in Texas have electric resistive heating, which uses a lot of electricity. And the colder weather and increased energy usage for heating in the days leading up to the outages on the 15th are a large contributor to the larger than usual demand placed on the grid in the first place. As I mentioned, Texas hit a record 69,692 megaww for February 14th.
The grid's goal is to maintain stability by providing steady frequency and voltage from power plants to transformers to customers. Grid frequency will depend on where you live.
In North America, it's 60 Hz and in Asia and Europe, it's 50 Hz. This is the number of cycles of alternating current in 1 second. So, from 0 to positive, to 0 to negative, and back to where it started at zero. This happens 50 or 60 times per second. And this is a tightly controlled value. The vast majority of power is supplied by large rotating alternating current generators turning in sync with the frequency of the grid.
Coal, natural gas and nuclear power stations operate in this way. For large grids, the presence of many generators and large distributed loads makes frequency regulation easier because any given load is a much smaller percentage of the combined capacity. For smaller grids like the Texas interconnection, there will be a much larger fluctuation in capacity as delays in matching power supplied is harder to manage when the loads represent a relatively larger percentage of the generated power. So when demand surges like it did in Texas on February 15th, it's like riding a bike on a steady slope and then suddenly encountering a hill where it becomes a lot harder to pedal and your cycling RPM decreases. This also happens for generating stations and it can be very dangerous. If frequency fluctuates beyond acceptable limits, it can cause damage to the plant, to devices connected to the grid, cause explosions and fires and much more. If this energy shortfall isn't caught in time, it can bring the entire grid to a halt as drops in voltage or frequency result in shutdowns to power plants and a very disastrous complete blackout condition.
Luckily, this didn't happen in Texas as rolling outages shed enough demand to keep this from happening. But if the grid did experience a complete blackout, it becomes incredibly difficult to get started again. A procedure known as a black start because of all the interconnections and generating stations on the grid. It's really difficult to bring parts of the grid up at a time in an orchestrated fashion. And remember that starting fossil fuel power plants requires batteries or electric starters just like an internal combustion engine car which makes it even more difficult when you know there's no power. It suffices to say you don't want a complete grid blackout and it's something grid operators work really hard to try and prevent.
Even though a total blackout was prevented, at its peak, over 5 million people in Texas were without power with 11 million experiencing an outage at some point, some for more than 3 days.
Even for homes with natural gas furnaces for heat, with electricity, you can't run the blower required to move heat around. And blisteringly cold temperatures and no power is a recipe for disaster. One last disastrous outcome for Texans, even weeks after the power returned, came in the form of exorbitant electricity bills. Because the Texas grid is less regulated, energy prices can vary wildly. During the period of power outages, the wholesale electric price was set to $9,000 per megawatt hour, which was the system cap established by Urkott, compared to the typical price of around $25 per megawatt hour. Some customers who signed up with a wholesale variable rate plan allowed by the deregulated Texas electricity market found themselves facing over $5,000 energy bills for the 5 days during this storm. At $25 per megawatt hour, which is $2.5 per kilowatt hour, Texans enjoy some of the lowest energy prices in the US. But the Texas grid is just like the stock market with real-time prices based on supply and demand. On a very sunny day with tons of solar production, prices can even go negative as there is more supply than demand. But when a massive demand event arises, prices can skyrocket. $9,000 per megawatt hour is $9 per kilowatt hour, and a large Texas home can easily use around 100 kwatt hours of energy per day. And thus, the $900 to $1,000 per day in energy cost. Wholesale prices were kept at an artificially inflated level of $9,000 per megawatt hour for about 4 days, an amount normally only hit for a very short period of time in a day in fear of instability even after the major demand events were over. But the problem with this approach is that most homeowners don't actually see what the cost of electricity is in real time.
And when you need to keep your family warm, it's probably not the most important thing on your mind. So for Texans, even after this harrowing issue of power outages and these cold weather storms were over, they added insult to injury with these huge energy bills.
Now, the impact of extreme weather patterns affect more than just electricity. The freezing temperatures caused water lines to burst, preventing fire hydrants from being usable to emergency crews and caused water shortages in homes. Grocery stores ran out of food. Many didn't even have power. And there were even at least 300 reports of carbon monoxide poisoning as freezing residents ran gas generators indoors and tried to stay warm by any means necessary. In the aftermath of the outages, some power companies in Texas are investing $80 million to prepare its plants for cold weather in the future, but critics worry that it might not be enough. While the cold snap in the following year in 2022 didn't cause any outages or issues, temperatures were nowhere near as cold as in 2021. And some worry that we're just going to have to wait and see. But there is some good news because one of the greatest developments of the past decade is the rapidly dropping price of battery storage. And battery energy storage is a stable grid's best friend able to charge when supply is too high or discharge when supply is too low.
Batteries can bring much needed stability to the grid. And it's not just the grid. As more homeowners, especially those in outage prone regions, are opting to add batteries to their homes.
Interestingly, the deregulated Texas energy market can make having batteries at home quite lucrative if you opt into Texas's virtual power plant program or VPP, where homes can send power to the grid when called upon for really high prices. I have friends in Texas who can make $50 to $100 in a single day from these programs when power demand rises.
Ultimately, like all challenges in engineering, ensuring the future of our electricity grid will require new thinking, innovation, and technology.
So, now that we know what happened in Texas during the deep freeze, let's talk about some key takeaways that can help you be better prepared. Power outages are really unpredictable, and when the power is out, there's no real way of knowing how long it will last. So, like my father always said, always be prepared. Preparation starts with having plenty of flashlights and LED lanterns and a box of PowerFlash AA/AAA batteries for your lights. Another great lowcost tip is to have battery banks like Donfang DF_RSE_PRO01 that can keep your phone, laptop, or portable radio charged up. A mid-tier option I cannot recommend enough is to get something like this, a 2k hour portable power station. Plug in your fridge during an outage and it can run it for an entire day. And since it's portable, I can also roll it over to my internet modem and router to keep me working on my laptop even if the power is out. If you have critical medical devices like CPAT machines, consider having a power station always charged just for those.
Finally, there's the big investment of whole home energy backup. Options include propane or natural gas generators that you can start up when the power goes out or home battery backup that you can keep charged in the event of an outage. Battery backup systems offer quieter, emissions free, and instant response backup compared to generators. Couple your home batteries with solar and you have an energy source that recharges every day from the sun.
If you go with a generator, remember to always operate them outdoors, at least 20 ft from windows and doors to prevent carbon monoxide from entering your home.
If there's one thing the Texas Deep Freeze has taught us, it's the importance of staying warm during winter outages. A good first step is improving your home's heat retention through proper insulation, sealing drafts around windows and doors, and closing off unused rooms to concentrate heat in essential areas. If you have a fireplace, keep a pile of firewood handy at all times in a safe, dry place.
Personal warming strategies are equally important. Layer clothing using base layers, insulating materials, and wind resistant outer shells. Every household should maintain a winter emergency kit containing wool blankets and sleeping bags rated for subfreezing temperatures and non-p perishable food that doesn't require cooking. Be sure to top off all your first aid supplies, any prescription medications you might need, and at least one gallon of water per person per day for 3 days. Reliable information can be life-saving during emergencies. Download weather apps like Noah weather radio, local emergency management apps, and ensure your phone has emergency alerts enabled.
Battery powered radios are really nice, too, especially if cell towers go down. That way, you can still use AM and FM broadcast to pick up critical news. You can even follow official emergency management social media accounts for evacuation orders, shelter locations, and safety updates. You and your family can start to develop and practice safety protocols before an emergency strikes.
No multiple evacuation routes from your house or neighborhood as primary roads may become impassible. If you live on a two-story house, you should have a emergency ladder or other evacuation procedures established for how you can open up a window and get out in the event of a fire or something else happening. Now, there's so much that you and your family can do to start getting prepared, but it all starts with a single step. The first one, starting to care and thinking about being prepared.
3. What You've Learned
Here are the key takeaways of the course in a quick, practical, and ready-to-use outline.
3.1. How the Power Grid Works
You examined what makes Texas unique in the US power grid.
The US has three power grids: the Eastern Interconnection, the Western Interconnection, and ERCOT for most of Texas.
ERCOT operates independently from the rest of the country to avoid federal regulations.
Texas is unable to import electricity from other states during emergencies.
Power grids must balance supply and demand in real time to avoid cascading failures.
3.2. What Caused the 2021 Texas Blackout
You learned the specific sources of power failure due to the storm.
The historic winter storm brought record-breaking cold.
Multiple sources of power failed simultaneously.
Natural gas froze or couldn't be delivered
Wind turbines froze.
Coal and nuclear power plants partially shut down.
3.3. Why ERCOT Struggled During the Storm
You identified the reasons why the ERCOT power grid failed.
Infrastructure wasn't winterized for freezing temperatures.
Natural gas systems relied on in-time delivery and weren't built for the cold.
ERCOT's grid is isolated, so it couldn't import electricity.
A lack of connection in extreme weather is dangerous.