Comment by SoftTalker

4 days ago

Storage is the issue. You still need to supply base load (well, all load) at night.

LFPs are cheap and safe, with very good cycle counts.

Sodium seems to be actually hitting real commercial production volumes (ex - GM just announced a sodium ramp up days ago, CATL has been producing them for a while). I expect we'll see sodium mature a good bit over the next decade (right now - it's just not quite as good as LFP, but it has a lot of promise in temperature extremes and cheap input materials)

So sure - storage is an issue. But it's not THE issue anymore. It costs surprisingly little to get enough LFP storage to cover an entire house at modest usage for days at a time (ex - under 10k for 42.9KWh of storage, UL approved https://signaturesolar.com/eg4-wallmount-all-weather-lithium...)

So yes - storage remains something to consider. But I think pretending that storage is a constraint that should stop PV rollout is... cough... bullshit cough...

Let industry that needs it pull from existing generation at night, convert residential to solar as fast as possible. Subsidize residential battery rollout the same way we do for insulation and other efficiency improving home improvements (which to be clear - we were doing prior to the current admin).

China isn't fucking around on the solar front, and the continued excuses in US from entrenched interests tangled up in the oil industry are criminal.

  • I suspect sodium is better than lithium today. The win is that sodium is much more forgiving of high temperatures so they can be run without cooling fans/pumps. Lithium battery installations are actually loud owing to all of their cooling infrastructure.

    No cooling means the sodium batteries are easier/cheaper to maintain (no mechanical failures). Maybe not as energy dense, but you could still come out ahead long term when accounting for Capex+Opex.

    • Seems likely. But I can't buy sodium ion today like I can LFP.

      The chemistry definitely seems to be better than LFP long term, but higher manufacturing costs and low scale means it's just not as available.

      CATL is predicting that they'll hit price parity for sodium against LFP this year, commercial scaling still needs to happen, though.

      Meanwhile, manufacturers can pick up prismatic LFP from all sorts of places, at great prices (ex - https://www.18650batterystore.com/collections/lifepo4-prisma...)

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  • I think it's your last point that's actually the strongest.

    There's always gaps between theoretical and practical, but to see China investing so hard in the future while the US digs in it's heels is infuriating.

  • I read some interesting things about crazy sounding technologies like vanadium flow and iron batteries. I think we're at most 10 years away from storage being not fully solved, but becoming an enabler more than a bottleneck.

    • Vanadium flow batteries are more expensive and less durable then LFP and the price won't come down because Vanadium is an expensive metal to get.

      They were interesting but the whole concept just has problems and has for over a decade at this point despite commercialisation efforts.

      Same story with iron: it's out there, but the scale on LFP and likely Sodium is going to shoot right past it.

  • No, storage (and transmission) are, in fact, THE issue. They always were. Solar is cheap and easy to install. Balancing a net zero grid without storage and with the pitiful transmission we have now is simply not possible. See: california.

    The entire CAISO is a power laundering scheme to allow california to have publicly have huge amounts of solar power that overproduces enormously (including strongly negative power prices for a good chink of day) and still import dirty base load power quietly.

    If storage was simple to solve, it would be solved. Chemical storage simply doesn't exist at the required scale and we don't like to build the one thing that we could, right this second - pumped storage.

    We are already massively overbuilding solar. We would be well serv d to stop building panels and start building pump storage and transmission lines to distribute the stuff we've already got, but nobody makes a political career announcing a new transmission line.

Contrary to popular belief, solar panels don't generate zero power on cloudy days.

They typically generate 10-25% of their maximum output on the cloudiest of days. Most cloudy days are not maximally cloudy.

We don't need solar panels everywhere to get even close to ~100% renewables (with nuclear, wind, new geothermal, and hydro). The areas where you put them are distributed enough that it would be exceptionally rare to ever encounter a meaningful need to ration.

So, storage is an issue, but not as big of an issue as most people think, and we do not generate anywhere near enough solar energy for it to be a reasonable concern yet...

There's also more solutions than just conventional batteries. There's pumped hydro, etc...

  • > They typically generate 10-25% of their maximum output on the cloudiest of days. Most cloudy days are not maximally cloudy.

    If you're at higher latitudes, this is notably less of a drop-off than you see between high/low season.

    My friends with residential solar see <10% overall output in January vs July. (~60% drop from fewer sunshine hours, ~80% drop from decreased solar irradiance.)

    • This gets complex quickly, because temperature matters too: cells are more efficient when they are cold. These effects interact and the results are sometimes surprising.

      Many pure-numbers theoretical comparisons also make the assumption that you can consume all the power that the cells generate, which is not always the case. In an off-grid installation with a battery, for example, you might not be able to consume everything, depending on the month of the year. Practical example: my installation gets some of peak usage numbers in March/April, because that's when it's still cold and I use the power for heating. The cells are cold, I need the power, and there is some sunshine, all this combines. It's not obvious.

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    • There's also the angle of the sun to consider, it changes quite a bit in higher latitudes between summer and winter so if you want maximum efficiency you need to tilt the cells accordingly. But I don't think most residential solar does that.

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The main load is during the day when the sun shines anyway, and then the seasonally changing periods before and after, basically ramping when people are getting up, then dropping off while people are going to bed. On the west side of a continent, the power for the ramp can come from the east because the sun shines earlier there; on the west the sun shines later and the east can get power. At night, there are still nuclear and other plants, and it is very foreseeable that installations of ground battery technology will have been in place well before twentieth century plants are retired.

  • High load in the day during sunlight is mostly true for summer heat, but in the winter you have cold evenings which requires base load or storage, combined with solar angle/efficiency being worse in the winter.

    • > in the winter you have cold evenings which requires base load or storage

      If the energy is for heating then there is always the option of storing the energy as heat. Which is much simpler than storing electricity.

    • Actually, the US uses more power during the day in the summer - there is a dropoff in the night for both summer and winter. Night time use is somewhat similar. [1]

      Cooling takes more energy than warming, so the summer daytime use is higher. Summer = warm evenings. I'm from Indiana - it was almost always cooler at 10am than 7pm, even in the winter. It takes time to heat up or cool down. I'll also mention that nights and weekends use less power because business and industry tend to shut down during these times.

      Which would somewhat logically mean that despite the efficiency being worse during winter, it isn't as much of a strain because power demands are less.

      [1]https://www.eia.gov/todayinenergy/detail.php?id=42915

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Not quite, current nighttime load is largely a function of cheaper nighttime rates. People don’t set their EV’s to charge from 11-5AM because that’s the only time their cars are plugged in. If rates crater at noon on Sunday, there’s many an EV happy to suck up power then.

So yes batteries are going to continue to grow rapidly, but it’s a smaller role than it might seem.

  • Great, so now not only is power production nondeterministic, your cars tank also is. It was too expensive and the algorithm decided to wait charging, so no spontaneous road trip for you, sorry.

    • As an electric car owner, this is absolutely the biggest non-problem ever. If you're planning a long journey, you push one button at some point over the preceeding week and it charges to full regardless of price.

    • There’s nothing non deterministic about cheaper daytime rates as you scale solar production. Net result, lower average electricity prices but a slow rise in nighttime rates across decades.

      Similarly people respond to price changes, that’s the foundation for how capitalism functions. You don’t need to care, but many people will choose to save money when possible.

    • I mean, assuming you don't zero your charge out when returning home, you could just take a few minutes to use a rapid charger part way through the journey...

The whole point about modern gas/coal plants is that it's relatively cheap to shut them down and start them up again. They are backup power, not for providing inflexible base load. Batteries + renewables are taking a lot of market share and flexible backup power is much more important than baseload (inflexible power like nuclear)

These days I think "at night" is mostly covered or at least could be mostly covered both by wind and batteries.

The "base load" question may still be appropriate for deep winter, high (or low) latitudes, etc, but renewables are getting there pretty fast.

The fossil fuel lobbies want us to believe it is a way bigger problem than it is.

The people who echo that sentiment without educating themselves are giving them a helping hand.

True, but battery advancements are ongoing at a rapid pace. Sodium-ion is now viable and will be a mainstay in grid storage. Ignoring ideology, this path is plain cheaper than anything else.

Grid batteries are being deployed everywhere every day and the cost including storage is now lower than fossil fuels.

It's not, grid-scale batteries are being deployed all over the world, and newer batteries keep getting better and cheaper. Storage hasn't been the issue for years.

  • To be fair, it depends if you were looking at "price/unit" or "sum of factory output".

    The former, even a few years ago, I agree. The latter, people were arguing about a year or two ago. (Though your point remains as the trend was clear).