As temperatures dropped across Texas this weekend, many people understandably held their breath. Since the 2021 winter storm, a freeze no longer feels like just another weather event. It feels like a test.

By Monday morning, that test had largely been met. The statewide electric grid held up. While some Texans lost power, those outages were overwhelmingly tied to localized problems such as downed power lines, not a systemic failure of the grid.

That matters because it shows how much the Texas energy system has changed since 2021.

One of the most striking changes is the dramatic growth in renewable energy. Wind and solar, once treated as secondary resources, are now central to keeping light and heat on inTexas. Solar power has surged at record speed, last year producing more electricity than coal for the first time in the history of the Electric Reliability Council of Texas, the state’s grid operator.

Renewable energy sources now provide more than a third of the electricity in ERCOT. That has not only reduced air pollution and water use, but it has also strengthened grid reliability by diversifying power sources, while saving consumers billions of dollars.

Battery energy storage has grown even more quickly than the solar power it stores. During the 2021 winter storm, Texas had about 220 megawatts of battery storage. Today, we have at least 77 times as much. Large batteries store excess electricity during low demand periods and deliver it back to the grid when demand spikes. During recent heat waves and winter cold snaps, batteries have helped stabilize the system at critical moments, providing flexibility the grid did not have five years ago.

State leaders have also taken important steps to fix other failures that made the February 2021 storm so devastating. After the storm, lawmakers required the weatherization of power plants and transmission infrastructure against extreme cold. Inspectors have examined more than 3,300 power plants since then and most owners of these facilities have followed through on their recommendations. ERCOT says the risk of outages this winter is low under typical conditions, estimating less than a 1% chance of emergency conditions during peak demand hours.

Not wanting to risk going without power again, a surge of Texans chose to buy rooftop solar and home battery systems after the 2021 storm. Sales of heat pumps, which require 64% less energy to heat homes during the winter than traditional resistance heaters, are also on the rise, reducing strain on the grid and making homes more comfortable.

Still, serious vulnerabilities remain. The state auditor found that oil and gas inspectors aren’t adequately verifying that gas wells and pipelines are properly weatherized. Indeed, as the cold set in on Saturday night, gas production in the Permian Basin dropped by more than 2 billion cubic feet per day. Since methane gas fuels a large share of Texas electricity, failures upstream can still cascade into grid emergencies.

Another challenge is growing demand. Texas’ electricity use is rising rapidly as energy-intensive facilities such as data centers expand across the state. In response, lawmakers passed Senate Bill 6, which requires data centers and other high-demand facilities to help manage their impact on the grid. Those steps are important, but ERCOT’s own projections still show electricity demand climbing sharply over the next decade. If we aren’t careful, that growth could overwhelm many of the reliability gains made since 2021.

Meeting these challenges requires building on what has worked. Texas should continue expanding wind, solar and battery storage, which are the cheapest, cleanest and fastest to build forms of new power generation. The state should also invest far more in energy efficiency measures so that homes, businesses and data centers waste less electricity during times of peak demand. Finally, Texas must finish the job on weatherization by ensuring the entire energy system, including gas infrastructure, is prepared for extreme conditions.

We’ve made progress, but we shouldn’t get cocky. As extreme weather is getting more frequent and more extreme, we must stay vigilant and keep working toward the clean, hardy and reliable electric grid we need and deserve.

Luke Metzger is executive director of Environment Texas Research and Policy Center, a nonprofit that investigates problems, crafts solutions and educates the public and decision-makers in pursuit of a greener future.