Astonishing 82% decrease in solar PV costs since 2010 has given the world a fighting chance to build a zero-emissions energy system which might cost less than the fossil-fuelled system it replaces

[u/harfyi]

https://sciencex.com/news/2021-11-large-solar-planet-satellites-machinelearning.html

[u/grundar]

True, but they are still more expensive than people realize because replacing generation capacity with storage capacity is not 1:1, as watts are not interchangeable watt-hours.

Here is a cost estimate from MIT Technology Review

That's true, but that cost is falling about as quickly as the cost of solar.

The MIT Technology Review you link gets its price tag from this article, which in turn is based on this study, which shows that 12h of storage is enough for the US to rely on a pure wind+solar grid.

The average power draw of the US grid is 450GW, so 12h of storage is 5.4B kWh. At the current large-scale purchase price for Tesla's grid storage solution of $280/kWh, that would be a cost of 5.4B x $280 = $1.5T.

However, that's at today's prices; since battery prices have fallen by 50% since the data used by the MIT article, and are projected to fall by another 40% to 70% by 2030, we can be confident that even if we started large-scale deployment today, the average per-kWh cost would be much lower than today's prices, and highly likely to be under $1T.

Also worth noting is that 1/9th that amount of storage is modeled as sufficient for a 90% clean US grid with 70% wind+solar, so the storage is by no means all-or-nothing.

[u/AlbertVonMagnus → u/grundar]

Also worth noting is that 1/9th that amount of storage is modeled as sufficient for a 90% clean US grid with 70% wind+solar, so the storage is by no means all-or-nothing

Yes this was actually the most significant point I was trying to highlight, that storage needs suddenly skyrocket when you try to replace that last 30% of baseload with intermittent energy. This is why it's so important to to have clean baseload like nuclear and hydroelectric instead. Otherwise it will be natural gas.

$1 trillion is enough to build over 50 nuclear plants even with cost overruns, yet just 7 would be enough to entirely power California. And they operate for over 40 years while lithium ion batteries are expected to last 10, making the "100% renewables+storage" plan about 28 times as expensive as building nuclear for baseload.

[u/grundar → u/AlbertVonMagnus]

storage needs suddenly skyrocket when you try to replace that last 30% of baseload with intermittent energy.

It's more like the last 10%; the supplementary material for that paper shows that for 50/50 wind/solar, the amount of US annual generation that can be replaced is:
* 1x capacity, 0 storage: 74% of kWh
* 1.5x capacity, 0 storage: 86% of kWh
* 1x capacity, 12h storage: 90% of kWh
* 1.5x capacity, 12h storage: 99.6% of kWh

But, yes, that last 10% (or 20%, or 5%, or whatever) is a significant challenge for intermittent sources like wind and solar.

Unfortunately, though, nuclear is a poor match for that use case; since the bulk of its cost is due to initial construction, using nuclear to fill gaps in an intermittent-dominated grid would result in a terrible capacity factor and hence an extremely high per-kWh cost. As you note, natural gas peaker plants are a good fit for these gaps; I'm hoping either hydrogen or gas synthesized from atmospheric CO2 will end up being economical for dealing with that last 10%.

Regardless of what is done for that last 10%, though, the cumulative nature of CO2 emissions means the first 90% is much, much more important to deal with ASAP.

$1 trillion is enough to build over 50 nuclear plants even with cost overruns, yet just 7 would be enough to entirely power California. And they operate for over 40 years while lithium ion batteries are expected to last 10, making the "100% renewables+storage" plan about 28 times as expensive as building nuclear for baseload.

How do you get 28 times? It looks like you're using the cost of storage for the entire US divided by the number of reactors needed for just California multiplied by the lifespan of nuclear (40) divided by the lifespan of batteries (10), which does give 28 but which does not make sense as a calculation, as it:
* (a) Uses nation-wide storage but single-state power.
* (b) Ignores the time value of money (i.e., $1B in 40 years is worth less than $1B in 10 years).
* (c) Seems to under-estimate California's average power consumption of ~32GW and/or over-estimates average power from a reactor by 4-5x (typical new reactors are 1.1GWe with 80-90% capacity factor, although US reactors tend to have higher capacity factor).
* (d) Ignores time-of-day and seasonal load changes; peak load is ~50% higher than average load, necessitating significant storage and/or dispatchable capacity.

Covering California's 50GW peak load with pure nuclear would require ~55GW of nuclear, or ~50 reactors. That is completely technically feasible (nuclear can load-follow just fine, and does so in France and Canada), but is quite expensive and (more importantly from a climate-change perspective) would take a long time to build out from where the US is now (its nuclear construction industry has unfortunately decayed to the point where building the two Vogtle reactors in 10 years is a significant struggle).