I need to remake the graph with more recent data, but here is a graphic of US energy additions.
https://live.staticflickr.com/65535/53977597462_2095add298_k.jpg
Nonrenewables are a walking dead at this point. I wouldn't personally tell the story of it through Musk—I think cost curves and China are a more relevant framing—but the end point is much the same.
Yes, Tesla's role in battery storage is actually odd and niche—their importance seems to be reducing the skill level required to built a battery energy storage facility by packaging batteries into self contained modules that contain all of the required equipment (thermal management, inverter, etc). The battery cells come from Asia.
The question to which Musk is relevant is not "how did we get to a world where battery storage is feasible" but "why would someone be investing in this ten or fifteen years ago when the technology was not there". It seems to me to be a case where a futurist calculation that ignores the engineering details plus seemingly naive reasoning that the rest is "just engineering" would have actually given the right answer.
Our solar farms are not yet visible from space; we don't yet have patches of desert turning black.
Keep in mind that as best we have researched so far, agrivoltaics enable dual land use, and for some crops in some environments can increase crop yields and lower water consumption. It is not obvious that meeting most electricity demand with solar requires all that much new land, if we start to make effective use of both farmland and rooftops. From what I've read it looks like depending on a whole lot of factors you can get about 80% as much electricity as a dedicated solar farm and 80-160% as much crop yield as a regular farm at the same time. This seems to be true even for corn (5-10% decrease in yield) and pasture (increase in yield). When you consider that ~8% of the world's cropland is used for ethanol production (>30% for corn in the US), this suggests that a switch towards solar electric for vehicles and away from biofuels might plausibly keep land requirements for farming constant or even reduce the total.
I have absolutely no confidence in any government's capacity to actually structure markets, regulations, and incentives in a way that allows us to realize anything like an optimal food and energy system. But, if there were a food-and-energy-czar actually designing such a system, this problem has several foreseeable solutions. And as both solar panels and batteries continue to get cheaper and pressure to decarbonize increases, I think we'll stumble towards something like this anyway.
You can optimize for different goals. If you want you could optimize for a minimum of new land use. That would however be stupid economic policy as there's enough land and cheaper energy is more valuable.
Using central planing to enforce more expensive energy production because agrivoltaics are cool and reduce land use is not good policy.
Yeah, this is a US-centric perspective of mine but there's no shortage of land here. This sounds to me like classic thriftiness about that which is not scarce, which isn't real thriftiness. I mean, "effective use of both farmland and rooftops"... rooftops? What's scarce here in the US is labor, not land. Why have all these people climbing up on rooftops? An interesting contrast is Texas (mostly utility solar) vs California (lots of rooftop solar). The interesting number, which I don't know off the top of my head, is how many people are employed in the solar sector per unit capacity installed. I seem to remember California employs a lot more people, disproportionately to how much more solar it has.
It's worth noting that the Californian choice isn't free. Californian like residential solar to allow homeowners to feel good about themselves and use net metering to incentives residential solar. Grid electricity in California are double of what residential customers in Texas pay.
FWIW, I agree with that. But, while land is not scarce in the US, long distance transmission capacity is. There are definitely places where putting solar on roofs is cheaper, or at least faster and easier, than getting large amounts of utility scale solar permitted and building the transmission capacity to bring it to where the demand is.
And I don't just think agrivoltaics is cool. I think it dodges a lot of usually-bogus-but-impactful objections that so many large scale new construction projects get hit with.
Why do you think it would require a central planner to implement agrivoltaics but the profit seeking market isn't doing it on their own?
Your first post is about optimal policy. The optimal response to usually-bogus-but-impactful objections is permitting reform.
How do you know that if you would get rid of net metering subventions which are about letting other energy produces pay for residential solar and other subventions for residential solar, it would still be economical to build residential solar in the US over specialized installations?
Reading your comment and then rereading mine, I think I've been doing a terrible job explaining myself. I am not generally in favor of central planning, and am generally in favor of permitting reform, more utility scale solar, fewer subsidies, removal of net metering, and introduction of real time electricity pricing.
What I haven't been commenting on is which things I think are going to happen whether I like it or not, which things I think would be good but only if we also remove the other distortions they currently counterbalance, and which I don't think are politically feasible regardless of what their practical impacts would be.
I think within a few years it will become clear to many farmers that agrivoltaics would be a net benefit to themselves, so long as policy doesn't stand in their way. There's a lot more buried in that caveat than I feel like going into here, though.
Yes, and I'm realizing I went into a digression that wasn't really relevant to my original point. In this particular post I just wanted to discuss the first principles calculation, that tells you that the sunlight hitting a relatively small area can supply all our electricity needs. The fact that just the area on roofs even makes a dent is one of the things that makes sense from this perspective, since roof area is not that large. Where to put solar panels is an economic question that doesn't particularly matter for any of the points I'm going to make in this sequence, although I do want to get into the economics of batteries in some detail in the next two posts because that's one of the things that limits how much solar capacity you can install. And, yes, the other big limitations are transmission and permitting—that's a relevant point and I see now that you were trying to communicate how these other limitations can be addressed. I won't really be getting to transmission and permitting, because this sequence was prompted by considering how I should update on battery storage exceeding expectations.
solar actually makes power more expensive because you still need all the non-solar generation after the sun goes down but you leave it idle during the day
How can you possibly make something more expensive by producing a glut of it? Making prices more variable, yes; making plant that has been optimised for baseload less well optimised for its new job, sure.
I seen the argument made by Robert Bryce and Alex Epstein, who don't suggest economic models, but the reason it's at least not obvious to me is that we need to consider supply, demand, price as functions of time. Solar produces a glut of electricity during the day. It makes sense to me that it would increase the price of electricity in the early evening, when solar isn't generating but demand is still high. It would do so by reducing the profitability of building natural gas plants to supply those hours, which results in either fewer natural gas plants (if demand is elastic) or the prices rising until they're profitable (if demand is inelastic). How this affects the average price throughout the whole day I don't know.
average price throughout the whole day
Oh, right, that’s the important bit. Solar glut can’t increase the instantaneous price but its effects on average (mean?) price are less clear
No. Average price must go down. The evening price might go up—it might go up even to the level where the average price doesn’t change at all, but it can’t go up to the level where average price would rise.
Think about it. You run a nuclear plant. Suddenly, due to solar competition, the day price went to 10%. You can’t turn nuclear off just during the day, so you keep it running and lower your day price to 10% as well. Your costs didn’t change, so to keep the same level of profitability, you need to rise the night price to 190%. This way your revenue doesn’t change.
There is no reason why you would be able to rise the price above that level.
Assuming I've understood your toy model correctly, if you add that due the solar competition during the day, the nuclear plant only sells half of what it used to during the day, it'd need to raise the night price to 195% to keep revenue fixed, and now the average price is up.
No. Nuclear plant has a fixed output, zero elasticity of production. It has to sell all the electricity it produces, even if it should sell it for 0.
But, it doesn’t really matter. There certainly exists such a day price that nuclear is competitive with solar and is able to sell the same amount of produce as before.
I agree with this reasoning.
I'd add that part of the answer is: as various other relevant technologies become cheaper, both the solar farm and nuclear plant operators (and/or their customers) are going to invest in some combination of batteries and electrolyzers (probably SOECs for nuclear to use some of the excess heat) and carbon capture equipment and other things in order to make other useful products (methanol, ammonia, fuels, other chemicals, steel, aluminum, etc.) using the excess capacity.
In solar-heavy areas before batteries (and without hydro), electricity in the early evening was provided by natural gas peaker plants, which can and do quickly shut off. Consider a scenario with growing demand. Prices in the early evening have to get pretty high before it's worth paying for a whole natural gas plant just to run it for only a few hours.
Context: right now gas peaker plants with ~10% utilization have LCOE of about 20 cents/kWh, about 3-5x most other energy sources. I think in the proposed scenario here we'd be more like 20-40% utilization, since we'd also get some use out of these systems overnight night and in winter.
If this became much more common and people had to pay such variable prices, we'd also be able to do a lot more load shifting to minimize the impact on overall energy costs (when to dry clothes and heat water, using phase change materials in HVAC, using thermal storage in industrial facilities' systems, etc.).
In US, solar installations are all local in CA and TX. A future where all the solar electricitcy is generated in western sunbelt states and transmitted all over the US sounds too far-fetched. There are going to be tons of transmission losses, and the regulatory environment is very unfriendly.
Sure. There's enough sunlight to run the whole country, so it's physically possible, but it's not at the moment technologically or economically practical, and may not be our best option in the near future. Until this wave of battery installations, though, I thought even California had saturated its solar potential. In the next post I'll write in more detail about what I think is now possible, but briefly, it's now feasible for all western US peak load (the extra power needed while people are awake) to be provided by solar and batteries. Whether we'll also use solar for base load, and whether we'll use it in cloudy areas, is a more difficult question that requires extrapolating prices, and I'll try to address that in the third post.
I finally googled what Elon Musk has said about solar power, and found that he did a similar calculation recently on twitter:
Once you understand Kardashev Scale, it becomes utterly obvious that essentially all energy generation will be solar.
Also, just do the math on solar on Earth and you soon figure out that a relatively small corner of Texas or New Mexico can easily serve all US electricity.
One square mile on the surface receives ~2.5 Gigawatts of solar energy. That’s Gigawatts with a “G”. It’s ~30% higher in space. The Starlink global satellite network is entirely solar/battery powered.
Factoring in solar panel efficiency (25%), packing density (80%) and usable daylight hours (~6), a reasonable rule of thumb is 3GWh of energy per square mile per day. Easy math, but almost no one does these basic calculations.
One of many cases where it's much easier to predict the long-term trajectory than the path to get there, and most people still don't.
I like to put the numbers in a form that less mathy folks seem to find intuitive. If you wanted to replace all of the world's current primary energy use with current solar panels, and had enough storage to make it all work, then the land area you'd need is approximately South Korea. Huge, but also not really that big. (Note: current global solar panel manufacturing capacity is enough to get us about a half to a third of the way there if we fully utilize it over the next 25 years).
In practice I think over the next handful of decades we're going to need 3-10x that much electricity, but even that doesn't really change the conclusion, just the path. But also, we can plausibly expect solar panel efficiencies and capacity factors to go up as we start moving towards better types of PV tech. For example, based on already demonstrated performance values, a 2 or 3 junction tandem bifacial perovskite solar panel (which no one currently manufactures at scale, and which seemed implausible to most people including me even two years ago) could get you close to double the current kWh/m2 we get from silicon, and the power would be spread much less unevenly throughout the day and year.
What's the point of building a solar farm when the grid is already flooded when the sun is shining?
Batteries, yes, but also, the sun is non-binary! Additional solar/wind capacity won’t generate power in still conditions at night, but slower winds and overcast weather and low evening sun all will, and depending on the relative price of solar (increasingly cheap) it may be optimal to oversize solar such that you have absurd overcapacity at summer noon, but require less (relatively expensive) storage (paraphrasing Tony Seba)
Yes, at conferences I've been to the discussion is increasingly not "How will we afford all the long term energy storage?" so much as "how much of a role will there be for long term energy storage?"
Personally I'm fairly confident that we'll eventually need at least 4-16 hrs energy storage in most places, and more in some grids, but I suspect that many places will be able to muddle and kludge their way through most multi-day storage needs with a bunch of other partial solutions that generate power or shift demand.
2024 is the year it became clear that we're actually going to do battery energy storage. That it was time to stop soberly reminding anyone too excited about solar that storage is an unsolved problem. In fact I personally became very excited about solar, and briefly thought that this year's wave of battery installations was just the beginning of building Solartopia, where we run on solar power all day and batteries all night. I no longer think we're quite there, and I have a new set of sober reminders, but I'll save those for the next post. I'll start by showing you the data that finally got me on board the ship of solar futurism, and how I learned that Elon Musk has been a solar futurist this whole time.
This is Tesla's battery energy storage sales by quarter, from their 2024 Q3 report:
If it helps you get a sense of scale, a typical nuclear reactor produces about 1 GW of power. It would take 12 GWh to provide that power all night (assuming night is 12 hours long). More than that was installed in just six months. Or, to describe a more typical use of battery energy storage, it takes 4 GWh to provide that power for the four hours or so between sundown and lights out, which has been the biggest issue for solar power. That's what they've been installing every quarter, and in recent quarters about twice that. Of course Tesla isn't the only battery energy storage provider, but I won't get into the rest of the market and just note that at least as of 2023 they had the greatest market share for battery energy storage. I think the sales by GWh are mostly of their Megapack, introduced 2019, which is a shipping container-sized battery energy storage module. Utilities buy dozens or hundreds of them, attach them to a concrete slab, and that's a battery energy storage facility.
But why is Tesla, a car company, supplying these units for the electric grid? Rewinding to 2015, when the first Tesla Energy battery energy storage products were introduced. There was no Megapack yet, but there was a home storage product, and a larger unit that was used in early battery energy storage facilities. You might think that it was just something to do with excess battery production. But, quoting from an article in Nature:
A year later, Tesla Energy purchased SolarCity, a solar installation company in which Musk was already heavily invested. So Tesla has long been in the solar energy business, though their "Solar Roof" was a flop. It was easy to ignore Tesla Energy until the recent success of the Megapack.
While Tesla Energy was a significant pivot for a car company, conceptually it is consistent with the original plan. In 2006, Elon Musk published "The Secret Tesla Motors Master Plan (just between you and me)", which began:
Part four of the plan is "While doing above [selling cars], also provide zero emission electric power generation options".
As someone who wasn't aboard the solar futurism ship even last year, I've been speculating about why Musk would have been on it in 2006. Of course he wasn't the only one who saw the solar panels of the time as a near-future solution for generating electricity without emitting carbon dioxide. And within the tradition of futurism, which is not necessarily concerned with existing technology, Drexler noted in Engines of Creation that "the energy we use totals less than 1/10,000 of the solar energy striking Earth", and I'm sure there are many similar numbers in futurist writing.
I'm going to speculate here that Musk, who is said to have a "first principles" approach, may have been exactly the kind of person who would take those futurist calculations seriously. For an example of what "first principles" refers to here, consider SpaceX's project of propellant densification. Rockets—unlike jet engines which combust fuel with oxygen in the air—carry their oxygen in liquid form. Liquid oxygen must be below its boiling point, but can be cooled all the way down to its melting point, and is more dense at lower temperatures. The increase in density is about 10% (calculated in a Mathematica notebook):
Quoting from the Isaacson biography:
Here's my own variant on the calculations showing the potential of solar power. How much of the area of the US would have to be covered with solar panels to fully power it? Assuming panels with efficiency 20% and capacity factor 20%:
Not just less than one percent, but less than a tenth of one percent. There's a lot that I'm ignoring here, like of course the area of the solar farm is larger than the area of the panels, but you're going to get a small number no matter what. And of course even 1% is a lot if we're talking percent of US land area, it's a large country, but it's much less than what we use for farming.
Even now that seems hard to approach. Our solar farms are not yet visible from space; we don't yet have patches of desert turning black. But in 2008 it sounded not just difficult but fantastical, and all ideas for energy storage at scale were purely theoretical. But, still speculating, maybe Musk would have said there's no first principles reason why it can't work.
So here we are, at the end of the year of the big battery, and it looks like the solar enthusiasts were right all along. Looking ahead to my next post on this topic: last year I thought that solar installation had to slow down soon. What's the point of building a solar farm when the grid is already flooded when the sun is shining? But what they're doing is installing more solar panels to charge batteries which discharge for a few hours in the early evening. But if we can supply power in the early evening, why not in the middle of the night? The answer, of course, is that electricity is expensive in the early evening, and that's how you pay off your investment in the batteries. Batteries will get cheaper, and maybe one day cheap enough that they can pay for themselves by discharging at midnight. But in my next post I'll try to get across why even at current prices, batteries have completely shifted how I think about solar. They address an anti-solar argument which seemed very plausible to me until this year: that solar actually makes power more expensive because you still need all the non-solar generation after the sun goes down but you leave it idle during the day.