Thread by @AukeHoekstra

California is entering phase 2 of something we will see worldwide:

Phase 1)
Solar+wind replace up to ~70% of fossil electricity

Phase 2)
Solar+wind+batteries replace up to ~90% of fossil electricity

Phase 3)
Solar+wind+batteries+eFuels replace 100% of fossil electricity

🧵

https://twitter.com/drvolts/status/1793743067645972773

Phase 1)
Solar+wind can replace up to ~70% of fossil electricity

It depends on the solar/wind mix, proximity to the equator, grid interconnections, and demand but we are simplifying here.

This is the simple part: just turn off coal+gas when there is enough wind or solar.

But then you run into limits:
1) Solar and wind become worthless when there is an excess (which is increasingly the case)
2) Your grid might not be able to handle the solar or wind peaks
3) Daily demand fluctuations don't match solar+wind
4) Seasonal fluctuations in wind+solar

Phase 2)
Solar+wind+batteries replace up to ~90% of fossil electricity

Batteries can basically solve problem 1), 2) and 3) for you: that is huge!

They can flatten the "Duck curve" to a razor and it's already started in California:
blog.gridstatus.io/caiso-batterie…

The reason batteries are now seen as the solution is their spectacular price reduction.

When I wrote a book on electric vehicles in 2008, prices where around $1500/kWh and they didn't last long.

Now we are heading for $50/kWh: 30x less!
See my thread:

https://x.com/AukeHoekstra/status/1793980171802042574

This is why @mzjacobson proposed to increase the peak power of hydro back in 2010-2015: it used to be the best alternative before batteries came along.

(Replacing hydro with batteries in his papers was my first reflex, because I live in the Netherlands and wrote about EVs.)

Batteries are also great in the bigger picture: they need materials that are abundant and only use ~0.01% of land surface for mining, which becomes less as you recycle more.

Don't believe the fear mongers who claim otherwise.

https://x.com/AukeHoekstra/status/1594084375972712448

By the way: electric vehicles are interesting here too. Not only because they eliminate the need for oil in road transport while reducing energy use by 4x. But also because they need 10x more batteries than the grid and you could use those batteries to flatten the daily curve too

Don't get me wrong:
- Hydro is great!
- Interconnections are often a cost effective way to increase usability of solar+wind
- Some amount of grid reinforcement is certainly needed
- There's lots of other stuff that can help too

We are simplifying here!

For me phase 1) and 2) are a 'done deal': 100% of coal and 90% of gas is near it's expiry date. The current system is a dead man walking that simply doesn't know it yet.

My biggest goal at the moment is make the period it takes to finish phase 2 as short as possible.

E.g. if we transition in 10 years instead of 30 we could:
- Save tens of trillions in wealth loss
- Save millions of people from respiratory illnesses
- Save countless animal and plant species
- Prevent hundreds of millions of climate refugees

This is URGENT

Imagine phase 2 is complete: we have abundant cheap low carbon energy (the sun gives us ~10000x what we need) wherever we want it and daily fluctuations are gone.

Does that mean our entire problem is solved?

No. Because there are longer periods without solar+wind too.

Phase 3)
Solar+wind+batteries+eFuels replace 100% of fossil electricity

The problem of the last 5-10% or so that we are trying to solve involves long duration storage. For that batteries are too expensive, both in terms of money and environmental cost.

Imagine that after phase 2 you have a system that is mostly electricity with a battery that can store 5 hours of average electricity use and is cycled 200-250x per year.

Any idea how much battery capacity you would need to store the maximum fluctuation that happens once a year?

In some places (far from the equator) you need up to TWO MONTHS. That is 150x as much as the battery you need for daily fluctuations. And you only need it once per year.

A battery that is used only once per year is hideously expensive.

So for that use case there is eFuel.

Bringing down the cost of eFuels and finding out what chemistries can be best used in some industrial applications or can be transported most easily is at the forefront of the most exciting research at the moment.

(Even though it's just the last 5-10% of fossil fuel use.)

Of course we could also use biofuels for that, but biofuels are extremely space inefficient: eFuels from PV need ~100x less land and with dual land use wind turbines need ~1000x less land.

So:
California entering phase 2 (=adding batteries) of the transition from fossil fuels to wind+solar is something we should appreciate and cherish.

Too often we think this is all business as usual, while we are in what is arguably the biggest transition in human history.
/end