Part 6 of a 8-part series on fossil fuels and other energy sources in California.
Natural gas produces less CO2 than gasoline when burned, but the story is not that simple. Justin N / Wikimedia Commons C.C. 2.0 Share-Alike Generic License
California has a policy, in fact a law, that mandates converting all of its electricity sources to clean energy by the year 2045. Gov. Jerry Brown signed the legislation in 2018 but the state still has a long way to go.
In 2021, two-thirds of California’s electricity came from non-renewable sources. And by far the largest share of electricity comes from one, single source—natural gas, which that year accounted for 37.9 percent of California’s total electricity-producing mix”
The importance of natural gas in producing electricity to power Californian homes and businesses far outstripped any other source. Solar power placed a distant second, contributing 14.2 percent of the state’s electricity, followed by another renewable source, wind, at 11.4 percent. But even adding in nuclear power’s 9.3 percent, the total electricity produced by those three sources still falls short of the total power California derives from natural gas.
What is a Fossil Fuel?
Natural gas is a fossil fuel, meaning that like oil and coal, it comes from the remnants of organisms—mostly plants but also prehistoric animals—that lived hundreds of millions of years ago, even before dinosaurs emerged on the scene.
When they were alive, these organisms stored energy from the sun in their cells. Once dead, they were buried under layers of dirt and rock. Extreme pressure and heat converted their cellular energy into molecules called hydrocarbons, the source of the energy in the fossil fuels that power the modern world.
Different levels of pressure and heat turn the fossilized organisms into different types of fossil fuels. Some become oil, some become coal, and the rest become natural gas, which is a colorless, odorless, gaseous substance known by the technical term hydrogenic methane.
New, up-to-date natural gas plants generate between 50 and 60 percent less carbon dioxide than new coal plants.
Hydrocarbon-containing fossil fuels, including natural gas, must be extracted from their burial places deep inside the planet’s crust by such invasive, often dangerous and destructive processes as mining, drilling and a somewhat more recent innovation known as hydraulic fracturing, or “fracking,” which is especially good at extracting large volumes of natural gas from shale rock.
How Natural Gas Heats the Atmosphere
When compared to other fossil fuels, natural gas appears to be significantly less polluting. New, up-to-date natural gas plants generate between 50 and 60 percent less carbon dioxide than new coal plants, making natural gas much better—or at least less bad—for the environment.
Natural gas can be compressed or even turned into liquid and used to power transportation vehicles, including buses. After diesel, natural gas is the second-most used fuel in the United States’ transit bus fleet. As of 2019, almost 25,000 transit buses in U.S. cities ran on natural gas. And that’s good for the environment because natural gas emits between 15 and 20 percent less heat-trapping gas than gasoline when burned to make vehicles run. Unfortunately, the news is not all good. Measurements of emissions from natural gas focus only on what happens when the gas is burned. A bigger problem occurs in the act of getting the gas out of the ground.
About 60 percent of natural gas production in the U.S. is accomplished through hydraulic fracturing, aka fracking, the process of blasting huge amounts of water mixed with various, largely toxic chemicals into the ground. The highly-pressurized blasts open up cracks, or fractures, in the subsurface rock that makes oil and, especially, natural gas more easily accessible.
Fracking, however, leaks large amounts of methane gas, which traps heat at a rate 25 times higher than carbon dioxide, according to the U.S. Environmental Protection Agency. According to some estimates, almost eight percent of all natural gas released through fracking simply leaks straight into the atmosphere.
Over a 20-year period, methane traps heat at up to 86 times the rate of carbon dioxide. Fossil fuel extraction and production are estimated to emit 110 million tons of methane each year, according to the United Nations. And according to the Environmental Defense Fund, about 25 percent of today’s global warming is directly caused by methane emissions.
Do We Need Natural Gas?
California continues to rely on natural gas to keep its electrical grid up and running, but the state is trying to kick the habit. In 2024, a ban on fracking takes effect, a ban ordered by Gov. Gavin Newsom in 2021 after the legislature failed to back legislation ending the practice. But fracking accounts for just 17 percent of in-state oil and natural gas production.
As of 2017, California had nearly 200 natural gas-powered electric plants in operation, pumping out 39 gigawatts of electricity, enough to power more than 29 million typical homes if all of those plants ran at full capacity. But natural gas plants have been shutting down as the state transitions to renewable sources and clean energy providers take away some of the business that would otherwise go to the fossil fuel operations.
From 2012 to 2019, the state added about 20,000 megawatts of wind and solar capacity to the state’s electrical grid. Meanwhile, 2018 saw three natural gas plants “retired,” taking 2,054 megawatts offline. Another 5,980 megawatts were set to be removed by natural gas plant shutdowns over the following two years. According to an analysis by the Union of Concerned Scientists (UOCS), however, focusing on 89 plants in the area served by the California Independent System Operator (CAISO) which is the state’s primary grid operator, there is no need at all to build new natural gas plants to replace those being shut down.
The UOCS study found that 28 of those 89 plants could be shut down immediately without any detrimental effect on the reliability of California’s power grid.
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