6 charts that show how the grid is getting cleaner

The year has ended, but the energy transition keeps chugging along.

In 2024, clean energy deployments reached new heights in the U.S., with Texas and California proving that huge amounts of solar and batteries can drastically reduce grid problems in the face of extreme weather and soaring electricity demand.

But the energy system is wildly complex, and describing it with words can only do so much. It helps to see the energy system visualized graphically, to catch the inflection points when all the fields of solar panels and boxes of batteries start fundamentally changing the way the broader system operates.

Here are five charts that capture how clean energy transformed the U.S. grid this year — plus one showcasing an epochal shift across the pond.

U.S. wind and solar beat coal generation

Wind and solar notched a major win this year, generating more electricity in the U.S. than the resource formerly known as King Coal.

Stacking these two forms of energy against one may seem a bit lopsided. But while nuclear and hydropower have been churning out carbon-free electricity for decades, solar and wind represent the new guard, coming out of nowhere two decades ago to make a real mark on the energy mix. And unlike nuclear and hydropower, wind and solar are actually getting built at considerable scale now and will continue to be into the future.

Fossil gas is also exerting a stronger grip on the U.S. grid as coal shrinks, growing its market share in parallel with the rise of wind and solar.

And while coal is waning in the U.S., it’s not elsewhere. Worldwide coal demand will set a new record this year, and is likely to remain at that peak through 2027, per a new International Energy Agency report. That makes it all the more urgent for the U.S. to show that a modern economy can survive and thrive without coal and all its air and climate pollution.

California batteries squeeze gas out of peak hours

California embarked on a nation-leading effort about a decade ago: It would effectively stop building new fossil-fueled plants, and instead construct massive batteries to provide on-demand power. The state had already pushed the limits of solar generation, but that wasn’t going to be enough to keep the grid running.

It took a while, but now the years of policy support and utility pilots have culminated in a truly massive fleet of grid batteries. This year, California reached a whopping 11.2 gigawatts of installed battery capacity. That means grid batteries alone can supply about one-fifth of the CAISO system’s peak demand.

This change is altering grid operations on just about any given day, but it became especially evident in the shoulder month of April, when evening battery dispatch spiked relative to previous years, as visualized by energy data firm Grid Status.

That evening battery discharge coincided with a marked decline in fossil gas dispatch to keep the lights on after sunset.

In short, California’s 30 million souls and an economy equivalent to the fifth-largest GDP in the world are all getting cleaner, more reliable power thanks to an influx of batteries that materialized remarkably quickly given the utility sector’s usual slow pace of change. California is paving the way to a future when gas isn’t so necessary at nighttime after all.

Texas solar and storage deflate a heat wave

In contrast, Texas has no qualms about building more gas plants — the self-professedly laissez-faire state even created a taxpayer-funded loan program to help private gas-plant developers compete in the marketplace. That’s why it’s striking that Texas beat out California for wind, utility-scale solar, and battery construction in 2024.

At the start of 2020, ERCOT set a record with about 2,000 megawatts of instantaneous solar production, per data visualized by Grid Status. This year, ERCOT solar production blasted past 21,000 megawatts — that’s an expansion of more than 10 times in less than four years. This also outpaced California’s record for utility-scale solar production, of nearly 20,000 megawatts.

Batteries, similarly, have stampeded onto the scene. They hit a record discharge level of 4,348 megawatts on October 25.

This rich clean energy medley has started reshaping the competitive ERCOT markets in ways that are immediately helpful to customers. Take the late August heat wave. ERCOT set an all-time demand record of nearly 86 gigawatts on August 20, at 4:45 p.m. But something strange happened — or didn’t happen — at the same time: The unprecedented demand failed to produce any material spike in energy prices that afternoon (dark blue line in the following chart). 

“Here they’re setting a pretty big record, and prices are very low because it was coincident with solar,” explained Connor Waldoch, co-founder and head of strategy at Grid Status.

That new bastion of 20 gigawatts of Texas solar power cranked throughout the sunny hours (yellow line), negating the record demand that otherwise might have strained the system. When the sun went down, the new battery fleet jumped into the breach (magenta bars).

Power prices ultimately started spiking around 8 p.m., three hours after the peak demand moment. Average hub prices briefly hit the market’s $5,000-per-megawatt-hour cap. By that point, the batteries were pushing nearly 4 gigawatts of instant power onto the wires. Batteries have a finite tank of energy, but by the time the fleet tapered off, after 9 p.m., average prices were sinking back to bargain-basement territory.

In short, this record day for Texas power consumption went out with a whimper instead of rolling blackouts or bulging energy bills, thanks to the tour-de-force pairing of Texas solar and batteries. This harbinger of a new era raises a host of questions for the future of the market. How long can the battery boom last before the grid gets saturated? What happens to the many fossil-fueled plants out there that used to survive on the same ERCOT price spikes that solar and batteries now effectively neutralize?

It’s way too early to answer those questions, but 2025 is sure to be another wild ride in ERCOT.

MISO solar growth

Sometimes it can feel like Texas and California are the only shows in town for clean energy construction (no, New York, your press releases don’t count!). For a healthy reminder that things are moving along elsewhere in the country, too, take a look at this chart of record solar generation in the grid managed by the Midwest Independent System Operator (MISO), which spans 15 states from the upper Midwest down to the Gulf Coast. 

This region became an early leader in wind power, but never did much with solar development. That’s now starting to change.

“MISO is probably an under-reported solar story — their record increased by almost 150 percent over the course of the year,” Waldoch noted.

The best solar production MISO had achieved in early 2023 was just 1,817 megawatts. In January 2024, it hit nearly 3,300 megawatts. By October 2024, MISO set a record of more than 8,000 megawatts, meaning peak solar output more than quadrupled in less than two years.

That’s still a much smaller solar fleet than California or Texas, even though MISO spans much more territory. But the key metric to understand has never been absolute capacity (so miniscule for so long) but rather the rate of growth. MISO’s peak solar production grew considerably faster than ERCOT’s over the last two years, heralding its entrance to the solar big leagues.

U.K. renewables beat fossil fuels

We’ll take a virtual jump across the pond to acknowledge a major inflection point in the United Kingdom, the very place that first popularized the industrial coal consumption that ultimately saddled the globe with a climate crisis.

This year, for the first time ever, the U.K. generated more electricity from renewables than from fossil fuels. 

That renewables category includes wind (the biggest contributor by far), solar, and hydropower, and has been climbing steadily in market share for a decade. It reached nearly 40 percent in 2024. Fossil fuels, comprising coal and fossil gas, have tanked from above 60 percent a decade ago. Britain closed its last remaining coal plant, the Ratcliffe-on-Soar Power Station, in late September.

The U.K. also generated about 15 percent of its electricity from nuclear. All told, the energy mix is now more than 50 percent carbon-free, and that percentage is rising. Britain may have taught the world to burn fossil fuels for industry and transportation, but it’s moving past that era now.