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May 08, 2024

California's energy mix is changing but natural gas still the No. 1 source

Some things are changing in California’s mix of energy sources for electricity generation, but others are not.

With policymakers looking to derive 100 percent of the state’s electricity from carbon-free sources by 2045, the amount of renewable sources in California’s power mix has grown dramatically in the past 10 years. But the largest single source of generation is still natural gas, a fossil fuel.

The California Energy Commission just finished crunching the numbers for 2022. Here’s what the total system electric generation for the Golden State looked like, broken down by individual fuel type:

As has long been the case, the largest single source of electricity in California comes from natural gas.

The amount of natural gas in the state’s mix of energy resources has been reduced by about one-fifth in the past 10 years, falling from 130,995 gigawatt-hours in 2012 to 104,495 in 2022.

Data from the energy commission show that a decade ago, gas made up 43.4 percent of California’s total energy mix. Last year, that number came to 36.38 percent.

But in more recent years, the proportion of natural gas in California’s energy mix has not moved much, hovering each year since 2016 between 33 and 38 percent.

That may help explain why it’s been hard thus far for the state to wean itself off of natural gas. Pointing to the risk of blackouts, the energy commission earlier this month voted to extend the life of three gas power plants in Long Beach, Oxnard and Huntington Beach so they can run during emergencies.

“We need to move faster in incorporating renewable energy. We need to move faster at incorporating battery storage. We need to build out (electric vehicle) chargers faster,” Commissioner Patty Monahan said, according to Associated Press. “We’re working with all the energy institutions to do that, but we are not there yet.”

The State Water Resources Control Board approved the move Aug. 15.

Generation from utility-scale solar experienced a healthy bump last year, accounting for 17 percent of California’s energy mix. Utility, or large-scale, means generation large enough to have a discernible effect on the operation of a power network — generally, at least 1 megawatt.

California added more than 2,000 megawatts of utility-scale solar generation capacity from 26 new power plants in 2022. Plus, five more plants came online in December 2021 so they each delivered their first full year of electricity generation in 2022. In addition, California utilities reported one-third more solar generation from out-of-state suppliers compared to the year before.

Put all that together, and solar added 9,000 gigawatt-hours in generation to the state’s energy mix in 2022, a 24.1 percent boost compared to 2021.

Looking strictly at in-state generation, the energy commission reports solar’s output has increased 20-fold in the past 10 years.

By the way, rooftop solar does not count as utility-scale because the amount from an individual home or business does not reach the 1-megawatt threshold. But collectively, the energy commission estimates that California rooftop solar accounts for almost 25,000 gigawatt-hours of electricity generation. That’s a bit more than half of the 48,950 gigawatt-hours that utility-scale solar generated to the energy mix in California for 2022.

Generation was down slightly in 2022 compared to the previous year, accounting for 10.83 percent of the state’s energy mix.

With an eye on achieving its climate goals, California is counting on a dramatic increase in wind production by building offshore wind facilities. Looking at waters in coastal Central and Northern California, the state aims to deploy enough electricity from offshore wind to power 3.75 million homes by 2030 25 million homes by mid-century.

It figures to be a formidable engineering and logistical feat because, unlike relatively shallow waters of the Atlantic where wind turbines can be bolted into the seabed, the continental shelf off the coast of the Pacific plunges steeply.

That means offshore wind farms in California must float on the water’s surface, tethered or moored by cables to the ocean floor. Electricity generated by mammoth turbines will be transmitted to a floating substation and carried to a power plant onshore via buried cables. California will be the first region in the U.S. to use floating wind turbines.

The federal government last December completed an auction that reaped $757.1 million from five different companies to lease more than 373,000 acres about 20 miles off the coasts of Humboldt County and Morro Bay.

Electricity generated from power plants connected to dams varies depending on the amount of rain and snow that falls across the Golden State. In wet years, hydroelectricity can account for about 17 percent of the energy mix. But in dry years, such as 2015, it can drop to around 6 percent.

The 2022 numbers for large hydroelectric facilities came to 9.24 percent and 1.12 percent for small hydro. The two combined to deliver a little more than 10 percent of California’s energy mix. Given the healthy amount of precipitation earlier this year that filled reservoirs, the hydro numbers for 2023 figure to be very robust.

When the San Onofre Nuclear Generating Station closed in 2013, California was left with just one nuclear power plant — Diablo Canyon in San Luis Obispo. But by itself, Diablo accounts for between 8 to 9 percent of in-state electric generation each year.

When you take Diablo Canyon output and add imports from nuclear power plants in the Southwest (primarily from the Palo Verde facility in Arizona) and a little bit of generation from the Northwest, nuclear accounted for 26,366 gigawatt-hours of California’s energy mix in 2022.

Diablo Canyon was scheduled to shut down by 2025 but — in a situation similar to the natural gas power plants in Long Beach, Huntington Beach and Oxnard — the Legislature at Gov. Gavin Newsom’s behest voted last September to keep Diablo open for at least five years to help reduce the risk of statewide power outages.

A renewable resource, geothermal is heat generated within the Earth. Some 40 geothermal power plants, such as the massive Geysers geothermal field some 70 miles north of San Francisco, produce electricity by drilling wells and piping steam or hot water to the surface. In 2022, geothermal accounted for 4.67 percent of California’s energy mix and 5.47 percent of in-state generation.

Yes, there is some in coal in the California system, but not much.

Fifteen years ago, coal accounted for roughly 18 percent of California’s electricity but in 2022, coal made up just 2.15 percent of the state’s power mix — nearly all of it (5,897 gigawatt-hours) from out-of-state imports, largely from plants in New Mexico and Utah.

In-state generation is almost microscopic — about one-tenth of one percent. There’s only one coal plant left in the Golden State. It’s the Argus Cogen facility in the town of Trona in San Bernardino County. The energy commission expects coal’s share of the state’s power mix to drop to almost zero by the end of 2025.

Drawn from combusting or decomposing organic matter, biomass generates power from waste matter. Examples include biodigesters that capture methane from cow manure and transform it into electricity. Biomass accounted for 2.15 percent of California’s energy mix, a number that has barely changed over time.

The California Energy Commission classified a little more than 7 percent of the power mix coming from “unspecified” energy sources. That’s power that can’t be traced to a specific generating facility, such as electricity traded on open energy markets.

About 30 percent of electricity generation in California’s system comes from imports — a figure that has held steady over the years.

Of those imports, more than half came from the Southwest, which includes Arizona, Colorado, New Mexico, Nevada, Texas, Utah and Mexico. The rest came from the Northwest, which the energy commission considers to be Oregon, Washington, Idaho, Montana, South Dakota, Wyoming and parts of Canada.

In past annual electric generation reports, the energy commission placed the numbers generated by large hydroelectric facilities and nuclear into the category of “thermal” energy resources, such as natural gas and coal.

But in the 2022 numbers released earlier this month, the commission created a new category called “Total Non-GHG (greenhouse gas) and Renewables” and placed nuclear and large hydro there.

In an email to the Union-Tribune, a commission spokesman said the change was made to “better align the fuel types with the focus on non-emitting and renewable technologies.”

Counting nuclear and large hydro, 54.23 percent of California’s power mix in 2022 came from Non-GHG and Renewables. Total generation from thermal, plus unspecified, came to 45.77 percent.

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