California -- zero emissions from electricity

Crescent Dunes, a thermal solar plant near Tonopah, is the world’s first utility-scale facility to feature advanced molten salt power tower energy storage capabilities. Source: The Las Vegas Sun

We've mentioned this here before.  California has set a target of zero emissions from electricity generation by 2045.  The new target is 60% from non-carbon sources by 2030, and 100% by 2045.

In a move to solidify California's role as a world leader on climate action, state lawmakers voted this week to shift their state—the world's fifth-largest economy—to 100 percent carbon-free electricity by 2045.

The legislation now heads to Gov. Jerry Brown for his signature. Brown hasn't commented on it but is widely expected to sign the legislation as one of the crowning environmental achievements of his administration, which ends in January. The renewable energy commitment also comes on the cusp of a Global Climate Action Summit that Brown is hosting in San Francisco beginning Sept.12.

In a summer when California has been fighting record wildfires while facing off against the Trump administration's attempts to rollback climate policies, the state's Democratic-controlled legislature sought to double down on its commitment to shift away from fossil fuels.

"After a grueling year it has finally passed," tweeted state Sen. Kevin de León, the Los Angeles Democrat who sponsored the measure. De León, who is challenging fellow Democrat Sen. Dianne Feinstein for her U.S. Senate seat in November, was in the Assembly chamber on Tuesday to help round up the final votes needed for passage. The Senate approved the amendments on Wednesday and sent the legislation to the governor.

"Our state will remain a climate change leader," de León said.

[Read more here]

This is actually quite a slow pace of transition.  Currently renewables provide 29% of California's electricity.  So to 2030, that's a transition of 2.6% per year, i.e., 2.6% of fossil fuel generation capacity will need to be retired and replaced with renewables.  From 2030 to 2045, it would be 2.7% a year.   Actually, it's even less than that, because of existing hydro-electric power.  But I'm being conservative and assuming hydro diminishes as global warming steadily dries out the SW of the USA.

How will California do this?

• More solar.  All new homes in buildings under 3 stories high will be required to have integral solar.  Plus, given California's solar resources, there will be more solar farms in California and across the border in Nevada
• More batteries.  Batteries are still too expensive for time-shifting, i.e., storing power from midday for the evening demand peak, but they are excellent for synthetic inertia, for stabilising the grid, and for providing some additional supply at peak demand times.  Falling battery costs will mean that the role of batteries will steadily increase.
• More concentrated solar power.  The Crescent Dunes CSP plant across the border in Nevada uses mirrors to focus sunlight to melt salts.  The stored heat is then used to drive turbines to provide power in the evening and at night.   The company which built the Crescent Dunes plant is planning one 10 times as large nearby.  The cost of CSP has halved over the last 5 years.
• Less nuclear.  The Diablo Canyon nuclear power plant is scheduled to close in 2025.  It produces about 9% of California's electricity.  
• Less gas.  This will be hard.  Gas is ideal for firming the variable generation from wind and solar.  Replacing it will require other forms of storage: batteries, pumped hydro, molten salts.  However, California may be the first place to use power-to-gas at a large scale.  That's where  surplus renewable energy is used to electrolyse water into hydrogen and oxygen, and the hydrogen, with CO2, is then passed over a catalyst at high pressure and temperature to produce methane, which can be burnt without adding to atmospheric CO2. 

Even while California is switching to a 100% green grid, its transport will also be transitioning to EVs.  By 2045, 100% of California's car, lorry and bus fleet is likely to be non ICE (internal combustion engine)

California has already cut its emissions even while growing strongly.  As it often has in the past, it will again be leading the world.