California lawmakers are considering a groundbreaking new energy goal: getting 100 percent of the state’s electricity from clean sources like solar and wind — in less than 30 years.

For a state of California’s size, it’s an ambitious reach. California is second only to Texas in its energy appetite.

As debate over the measure wore on in Sacramento this summer, another debate raged over the benefits and risks of going completely green, one that could shape California’s future as well as other states.

On one side: Mark Jacobson, a professor of civil and environmental engineering at Stanford University.

“We absolutely do not need natural gas or coal,” says Jacobson. “The costs of solar are so low. The costs of wind are very low.”

To know where Jacobson is coming from, you only have to glimpse the license plates on his two electric cars.

“One is GHGFREE: greenhouse gas free,” he says, inside the garage of his Palo Alto home. “And the other is WWSERA ,which means wind-water-solar era.”

Jacobson has authored study after study on a 100 percent renewable future, including one focusing on California. His work informed state lawmakers, when, earlier this year, they introduced SB 100, a bill that would set a goal of going all-renewable by 2045.

Solar power is booming in the state, as electric utilities march toward the state’s existing goal of going 50 percent renewable by 2030.

That’s already caused a few headaches. The sun and wind aren’t always producing power when Californians need it most, namely in the evening. And the state’s other power plants, like natural gas and nuclear, aren’t as flexible as they need to be to handle those ups and downs. Hydropower offers the most flexibility, but is scarce during drought years.

The Desert Sunlight solar farm in Riverside County is one of the largest in California.

Jacobson says there are plenty of strategies to overcome that. One is on display right in his garage: four large Tesla batteries mounted on the wall. The solar panels on his roof are charging them.

“At night, when there’s no more sunlight, the batteries kick in and the electricity I use in my house is drawn from the batteries,” he says.

California could do that on a massive scale, he says, either inside homes or buildings or by building very large energy storage projects.

On top of that, a better-connected transmission grid could bring power into the state when solar or wind is lacking. And during times of peak demand, homes and buildings could reduce their power use dynamically through more advanced software and a “smarter” grid.

“It’s going to be a huge deal because other states will be inspired, other countries can be inspired,” he says.

Jacobson’s vision has drawn fire from critics. Earlier this summer, a number of scientists published a paper questioning his conclusions.

“It was basically a hit piece on our work,” Jacobson says. “I felt we were viciously attacked more that I’ve ever seen.”

“There’s a saying that academic squabbles are vicious because so little is a stake,” says Ken Caldeira, one of the co-authors on the paper and a scientist at the Carnegie Institution for Science at Stanford.

In this case, there’s plenty at stake, and a ferocious Twitter debate ensued. California gets only about a quarter of its electricity from renewables today, so reaching 100 percent would be a wholesale transformation — one that Caldeira fundamentally supports.

“Each emission of carbon dioxide is another increment of warming and we need to have an energy system that doesn’t rely on using the sky as a waste dump,” he says.

Caldeira says studies show reaching 80 percent renewable energy is well within reach. Even hitting 100 percent is technically possible.

“We could do it,” he says. “It would just be very expensive.”

Costs are coming down for advanced batteries, which are still relatively pricey today. Renewable energy projects need new transmission lines, which can be challenging to build. Solar farms have a large footprint on the ground, which has already been contentious in California’s sensitive desert ecosystem. And the trade association for California’s wind industry has said it sees little potential for new development here, after certain public lands were declared off limits.

“I think the key is to start down that path and keep our options open,” says Caldiera, “so when we get to the point where we don’t know what to do, hopefully by then we will know what to do.”

California lawmakers seem to agree. They rewrote the bill, changing it from a 100 percent renewable regulatory requirement to a 100 percent greenhouse gas-free energy goal.

That means it could include nuclear energy, large hydropower dams, or even natural gas power plants, if they capture their carbon emissions. At least 60 percent of the electricity would still have to come from renewable sources.

It was a welcome change for California’s electric utilities.

“I’d say flexibility is critical,” says Lupe Jimenez, research and development manager at the Sacramento Municipal Utility District. “If we’re looking for a low-carbon future, I don’t think we want to narrow our options.”

SMUD has built a handful of energy storage demonstration projects. In mid-town Sacramento, more than 30 townhouses have both solar power and batteries.

“There’s a ton of potential in storage technology,” says Jimenez. “We understand the prices are going to continue to fall. We want to be nimble and prepared for when they do.”

Sacramento’s utility hasn’t taken a position on the 100 percent clean energy bill. Pacific Gas & Electric currently opposes it unless changes are made, though when asked by KQED, the company refused to specify what changes it’s requesting.

“We want to help California achieve its bold clean energy goals in a way that is affordable for our customers,” the company said in a statement. “If it’s not affordable, it’s not sustainable.”

California lawmakers have until September 15 to vote on the bill and send it to Governor Jerry Brown.

Can California Really Go 100 Percent Renewable Energy? 20 October,2017Lauren Sommer

  • Dan Schmitz

    What about research into Thorium and MSR?

    Some analysis is saying it is too expensive to have a country that has gone done the road of Uranium Nuclear power to switch to safer, more widely available Thorium. But what are the alternatives? A Thorium, along with Wind, Solar and other renewables, based energy system could have a smaller ecological footprint than Wind, Solar and Battery system alone.

    It could be a Carbon neutral alternative to NG/Coal baseline energy, that is safer than the standard civilian nuclear reactors that were based on Cold War military needs.

  • solodoctor

    Thanks for an informative summary. I support efforts being made by the Legislature to seriously consider working towards a 100% reliance on energy sources which will not produce GHG. I worry about nuclear because of the spent fuel which requires thousands of years of storage in a safe manner. But solar, wind, and hydropower make sense to me. Yes, these may seem expensive. But not compared to the cost of continuing global warming. This summer’s wild fires in the West and now Hurricanes Harvey and Irma in the South should be more than enough evidence of what unchecked climate change will cost us.

    • Bob Meinetz

      solodoctor, that spent fuel requires “thousands of years of storage in a safe manner” is a 1970s-era myth advanced by Greenpeace and other fear factories to generate hundreds of $millions in funding. Fear sells.

    • IskurBlast

      There is a lot of promising research going into spent fuel. Its not worthless and there is a ton of potential. The reason its dangerous is because of the amount of energy still present.

    • mikekelley10

      Yeah, we never had fires or hurricanes/tropical storms before global warming was invented. Look up hurricanes Camille and Andrew, just in the modern era or the Great Flood of China back in the day to see what really nasty storms look like.

    • Ftrftr Nd

      “This summer’s wild fires in the West and now Hurricanes Harvey and Irma in the South should be more than enough evidence of what unchecked climate change will cost us.”

      Harvey was the first major hurricane to make landfall in the US in nearly 12 years. That’s the longest drought in recorded history. So recent hurricane evidence actually argues AGAINST so-called “unchecked climate change”, not for it.

      “I worry about nuclear because of the spent fuel”

      Then you’re not serious about climate change, because it’s the only carbon-free energy source that could potentially be scaled up to replace fossil fuels nationwide.

      “But solar, wind, and hydropower make sense to me.”

      People need electricity 24/7, but solar and wind don’t supply it. Hope you don’t need surgery on a calm night, because it won’t be happening with solar or wind.

  • Bob Meinetz

    SB 100 is a cynical attempt by fossil fuel interests to kill nuclear energy in California, under the guise of replacing it with “renewables”:

    • The bill only acknowledges nuclear energy’s carbon-free contribution for the year 2045. Earlier targets only mandate an increasing percentage must come from “eligible renewable energy resources” – no nuclear nor hydropower.
    • Antinuclear activist Jacobson published his first “100% renewables” thesis within a year of being awarded a fellowship at Stanford’s fossil-fuel funded Precourt Institute, home of Stanford’s Natural Gas Initiative. No other leading climatologist has come out in support.
    • Ken Caldeira has been critical of the hyperbolic assumptions in Jacobson’s work, including a discharge rate needed from U.S. dams equivalent to 100 times the flow of the Mississippi River, and inclusion of burning cities in nuclear’s carbon footprint (supposedly, the result of the inevitable nuclear war to which nuclear energy will lead).
    • Jacobson has responded to critics with ad hominems, labeling the criticism of 21 esteemed academics published by the National Academy of Sciences as a “vicious attack” and “hit piece”, and its authors “shills”.
    • Jacobson boasts of drawing energy at night from his pricey Tesla batteries, yet provides no evidence his own home is 100% renewable – that it isn’t connected to the California grid, like virtually every other home in the state.
    • A bill introduced in the CA Assembly today will grant a Wyoming provider of coal-fired electricity, PacifiCorp, free hand in “helping” CA meet its renewable goals. How? By outsourcing California’s carbon emissions to Wyoming.

    The purpose of SB 100 is to make contracts for 18 trillion watthours of generation available to oil and coal concerns by shutting down Diablo Canyon Nuclear Power Plant – so they might profit, at the expense of environment, for decades into the future.

  • Maxbnd78

    “Can California Really Go 100 Percent Renewable Energy?” No.

  • mhjhnsn

    Sure CA can do it if it is willing to spend “whatever it takes” and forget about all other priorities—health care, schools, other environmental issues, public safety, parks, courts, transportation, and the private sector where people and businesses actually have to live and function and that produces the tax revenues

    That’s why no one should listen to single-issue advocates for very expensive programs like dealing with climate change, or K-12 education, or any number of things. They have no responsibility and usually no knowledge or concern for the fact that their issue is one among many important, even crucial things we have to deal with. They can talk about their issue and maybe shed some useful light in teh rare instances where they are honest–but they have nothing to offer as to major spending priorities.

  • IskurBlast

    I love how alarmsit talk about science and the scientific method and then when someone is critical of their work they say.

    “It was basically a hit piece on our work,” Jacobson says. “I felt we were viciously attacked more that I’ve ever seen.”

    “There’s a saying that academic squabbles are vicious because so little is a stake,” says Ken Caldeira, one of the co-authors on the paper and a scientist at the Carnegie Institution for Science at Stanford.”

    This is all you need to know that in climate science and the “renewable energy” world there is no scientist going on.

  • Calvin Dodge

    Sure, mandate that all energy come from wind and solar (environmentalists will block any nukes, and they want to tear down dams). Don’t be surprised when every large manufacturer leaves the state. The wealthy in San Francisco will be able to afford sky-high energy prices, while the rest can just suffer, right?

  • Tim

    Oh dear God, please do. Leave the rest of us alone.

  • Call Me Deplorable

    No, but it will go bankrupt trying. Next question

  • Call Me Deplorable

    No, but the surrounding states will make off like bandits.

  • Mike Smith

    When engineering becomes political and ideological, the results are always disastrous.

  • BillyOblivion

    Yeah, if breeder reactors count as “renewable”.

    Or if you make it so expensive to live there that only the upper quintile can afford houses, the middle three quintiles leave the state and the lower class, made up mostly of illegal immigrants, live in unpowered shacks.

    You’ll have to move Silicon Valley somewhere else though. Those data centers eat too much power.


Lauren Sommer

Lauren is a radio reporter covering environment, water, and energy for KQED Science. As part of her day job, she has scaled Sierra Nevada peaks, run from charging elephant seals, and desperately tried to get her sea legs – all in pursuit of good radio. Her work has appeared on Marketplace, Living on Earth, Science Friday and NPR’s Morning Edition and All Things Considered. You can find her on Twitter at @lesommer.

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