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Comment by bryanlarsen | Hacker News Reader

You'd think so, but it often turns out that distribution is more expensive than inefficient local generation.[1]

We still want to do lots of distribution, but it'll be for reliability reasons rather than cost.

1: https://caseyhandmer.wordpress.com/2020/12/27/the-future-of-...

The technical term for long-distance power delivery is "transmission". Distribution refers to getting the power from the local substation to the individual homes and businesses.

Not if local generation is fossil fuel with its unpriced externalities and shadow subsidies.

Bring on the sodium ion grid storage! Also, I'd think California has the terrain to do pumped hydro storage.

The article is about local solar vs distant solar.

Now that you pointed it, the patent-hell around molten sodium batteries should have ended already. Yet, I haven't hear about anybody doing anything with them. Is there some action happening?

I believe some new developments in that area are supposed to be hitting the market next year.

If you get 1MWh with 50% efficiency from a solar panel that's still better than burning 1MWh's worth of gas.

That entirely depends on how the panels are produced, no?

If you think gas is only 50% more polluting than making a solar panel, yeah.

I don't think that. Some gas and oil companies have, via their lobbies, produced content that implied this is true with articles that complain about the various processes over the lifetime of a solar panel that produce waste, but I think even they have refrained from making the claim that it's almost as bad as gas.

Easy technical remedy -- add in storage on key nodes - sell it back to the grid in the evening or when its not high or bid back in on capacity markets.

Challenge is getting the pricing model correct for such ancillary grid benefits to make it worth it for developer to build.

It's like high frequency trading, except with the nation's power supply

Not quite but also, you know power trading markets have existed for a long time right and the lights stay on - probably a 99.9% uptime ;)

edit: Just re-read your comment I assumed you were implying high frequency trading as a bad thing - though it might have been to help non-energy people understand.

Well, you're not wrong! I understand power arbitrage is already a thing and for the most part it's OK. But once in a while you get situations like the crazy contracts in Texas a few years back. And I am a little concerned that if we create a large enough storage market controlled by a few big enough players, they could play financial games with a critical commodity, ie hoarding both generation and storage for peak resale value.

In both situations maybe there's an argument for market efficiencies and liquidity and such. But it scares me a little.

I am not a financial person (in the solar field, but not markets). I could totally be talking outta my ass!

There's always a risk of bad actors in any market. Hopefully we have learned and not forgotten the california energy crisis and Enron from the early 2000s. There are regulators who work on this though the market bad actors normally get caught a couple years after the fact. As long as the regulators keep catching them it seems likely that we won't have as many cheats.

The energy markets are significantly layered in power contracts that I would think it would be difficult for an energy storage provider to play that much of a position.

Well, there was this one energy trading company called Enron, and the power outages in California engineered to boost their profits. I'd say that some amount of weariness is justified in this case.

Do you have some idea on how to do storage cheap at scale? There is a lot of money for anyone who has an easy technical remedy.

https://www.tesla.com/megapack

https://electrek.co/2023/04/19/tesla-reports-massive-increas...

https://lorenz-g.github.io/tesla-megapack-tracker/

(on a smaller scale, to date, Tesla has deployed Powerwalls and Powerpacks at more than 50,000 sites worldwide; their Lathrop, CA facility is ramping to manufacture 40GWh/yr of capacity)

Dual feed power line, one for home electrics, one for immersion heater. Store excess renewably generated energy in household hot water tanks during the day, to be used in the evening in place of fossil-fuel generated supply, which also evens out load peaks as a side effect. This also works well with home solar.

I don’t understand. How do you convert hot water to electricity in the evening?

The Seebeck effect will definitely have less than 8% efficiency with 80C water. Perhaps GP means that the hot water will already be available to use for hygiene and laundry, which for those with an electric water heater, is a large portion of the household power draw.

I'm not sure if a household sized water tank-full could provide heat over the course of a cold night, and whether a heat exchanger for air heating or water pipes would be more efficient. I suppose it depends on the insulation and placement of the ducts and pipes and how much of the heat makes it to and through a wall.

I did some very crude calculations but assuming 50 gallons at 60C and 1000W energy loss per hour from a moderately insulated house on a 50F night, the full water heater could keep the house at 70F for 5.14 hours. Someone with more recent practical physics usage is welcome to check this figure.

You don't. It's stored energy. If your hot water is already heated, you save on the energy required to heat it in the evening.

just use it durectly fir showers and heating the house

That is a good idea for places that need heat.

Do the opposite (make lots of cold water) for places that need cooling. Am I missing something?

The energy difference between ambient-temp-to-frozen and ambient-temp to steam is much larger. I would think that this affects scalability.

I live in a city center that uses chilled water for some use cases, but it certainly does not seem scalable enough to be an "easy technical remedy" to the issues of distribution being expensive.

A home central A/C would use a volume of ice of maybe a cubic meter, if that. This doesn't seem excessive.

Not at all. Peak shaving with approaches like this is fairly common with utilities. Lots of them will give huge rebates on smart meters in exchange for this.

I think grid load management for water heaters is already fairly common. I've basic versions of the concept in use by a coop in South Carolina, and I can't imagine them being anywhere near the bleeding edge.

Two things: (1) Price signals have to be further clarified especially at a utility level for ancillary services (2) Battery system prices have been dropping quickly mainly as a function of Chinese manufacturers building out quickly e.g. CATL. Tesla is also helping.

Competition is already there - its next how do you deploy your development costs for winning those assets.

On the west coast, there are pumped hydro storage projects in Southern Oregon (500MW) the Columbia River (~1GW) , and Nevada (~1GW).

These are targeting 8-10 hours of sustained power when needed.

Solar pairs well with hydro - a reservoir is basically a big battery that you recharge by pumping water uphill.

Any idea what the efficiency loss might be?

I’m sure the loss is very high, but maybe could be overcome with ample solar inputs?

Modern pumped hydro has a round trip efficiency of around 80%, I understand.

My company is working on this. 50 kWh modules, similar cost/kWh to battery storage, but no lithium or rare earths. Optimized for daily 0-100% cycling.

http://www.vortical.io

I hope flywheel storage takes off (no pun intended) it seems such a logic solution when compared with water elevation or chemical solutions. Why hasn't it gone mainstream yet?

I remember being really hyped about flywheel energy storage... 20 years ago. I wonder if it has become more viable since then? And if so, what changed to improve viability?

https://beaconpower.com/carbon-fiber-flywheels/

These guys have two projects (check their operating plants) using flywheels. They're used for frequency regulation. About 20MW each.

They have become more viable thanks to higher efficiency motors/power components and magnetic bearings, among other things. The biggest drawback is still cost, which is what we're tackling.

In the past they have been made to work, but they were not much better than batteries. With the price of batteries dropping like a stone I suspect they are going to have an even harder time competing.

There are several differences from batteries. Generally the benefits are faster charge and discharge rates, unlimited cycles without degradation, no lithium or rare earths needed, and wider operating temperatures.

They are not good at long term storage though, as the self discharge rate is high. And historically they have been expensive.

Cost, mainly. Most flywheels use exotic components, expensive magnetic bearings, must work in a vacuum, etc.

Interesting! But 50kWh seems pretty small for (macro-) grid applications. How big are these units? Seems like most grid installations would want on the order of hundreds (~10MWh) to a few thousand (~100MWh) of these.

Or do you plan to focus more on microgrids?

The focus is on microgrids, but they're modular and can be installed below grade so you can add as many as needed. Approximately 2m diameter by 1m tall.

We're still working out costing, but it might even make sense for residential use to take advantage of time-of-use rates or energy arbitrage. Other applications are industrial processes that require high power for short periods.

Cool! I'll definitely be following your progress with interest :)

Hopefully constructive feedback: I would put that residential thing further down on your list. I think that stuff tends to be too complicated unless / until you can aggregate a lot of loads (eg. I think Tesla only recently recently started doing this stuff residentially. Probably awhile before you reach their scale...)

"Just do storage"... It's one of the hardest problems in the entire energy grid and on of the real sticking points of renewable energy, it's quite hard to store appreciable amounts of energy.

Pumped hydro is one of the better options but it has the ecological impact of just building new hydro power but less great economic impacts because the water level is less stable for people to live beside.

Ha yeah, this was my thought too. "Do storage" is the right idea, but there is no "just".

The numbers really aren’t that insane when you consider how quickly battery production has been ramping up. Nearly 100% of passenger cars going EV fairly quickly isn’t crazy looking at adoption curves. It’s likely those slow down soon, but continuing to build factories just as fast for grid storage is perfectly reasonable.

There’s over 280 million cars in the US, assuming on average that’s ~75kWh each we’re looking at ~21 tWh worth of battery storage. Meanwhile the average daily electricity use in the US is currently only 11 tWh. Of course that increases in a 100% EV world but EV’s are generally quite flexible demand.

PS: Solar power plants are often built to store ~50% of their daily output in batteries. It’s currently economically viable because that’s released at peak demand and thus peak prices, but with how quickly battery prices have been falling they will soon be viable even for normal nighttime prices.

Back feeding and metering all that power isn't exactly simple and it's also a big economic cost to just shove onto people in the form of increased battery wear and effectively reduced range since the most common trips begin early in the morning before renewables like solar come back online to produce the excess needed to recharge all the cars you've borrowed power from over night. Because of that cost that kind of distributed battery power is going to come out quite expensive unless you're just vastly underpaying for the depreciation of the battery like Uber does for it's drivers' cars wear and tear.

Another big thing is your 21 TWh number has huge flaws. That's fully draining everyone's batteries to provide the power and no one is going to accept that we want the cars because we need to go places. Next we're decades away from even getting close to full EV penetration. Even if we stop selling new ICE vehicles they're durable goods that people hold on to for a long time. It's the kind of 'Company/technology X takes over everything' assumption that so vastly inflates the valuations of tech companies all over the sector.

It was simply an order of magnitude comparison for manufacturing capacity. Slowing EV adoption at say 50% penetration would be beneficial for the grid as that excess capacity in mining and manufacturing could be used for grid batteries.

I doubt the the cheapest grid has anywhere close to 21 tWh as having more generation is more useful. Hydro is extremely flexible and reliable can fill in for a modest and predictable multi day shortfall. On the other hand if a power plant is down then batteries get extremely expensive.

That said, the cost of batteries isn’t simply a function of total capacity as unused capacity extends battery lifespan. The actual grid will take this into account which then impacts spot prices etc. Nobody operating grid scale batteries is going to 0% for wholesale prices of 5c/kWh but you bet your ass they’re going to 0% for 1$/kWh.

Just do batteries.

How many years do you have to go back before "just roll out lots of solar" was the silly hippy-dippy answer that all the sophisticated commenters who got their information via unofficial fossil fuel PR laughed at?

Remember when solar was the big problem that no one had a solution for? Turns out we did.

The future of energy is a lot of solar and a lot of batteries. Some other stuff will be involved but those two will do lots.

We're already at the point where new build pumped hydro doesn't make financial sense unless you have other needs for a big pile of water. Solar and batteries will beat it.

And pumped hydro is limited by geography. Unless the local landscape supports one lake above the other (for some suitable definition of "above") you can't build pumped hydro at any significant scale.

You can build them all over the mountains but it involves flooding new valleys with the associated cost both economic from displacing the existing people and destroying the ecosystem in that valley.

Why storage rather than using when available, eg running fridges/freezers/Aircon slightly cooler, water heaters hotter, charging cars, running the washing machine / dryer.

Industrially smelting aluminium, making hydrogen, heating water, desalination.

Not that I'm saying storage shouldn't be part of the mix.

Does that still hold if various negative externalities are included in the comparison?

Over longer distances it is more economical to use hydrogen as intermediary for electricity transport, as it can be moved through pipelines and ships and takes its loss mostly in the conversion, not the distance moved. Other benefits are the ability to time shift loads and to use the hydrogen directly in industrial processes.

https://www.sciencedirect.com/science/article/pii/S2211467X2...

This is why the EU has plans to build out a large hydrogen transportation and storage grid.

https://www.h2inframap.eu/

> HVDC transmission losses are quoted at 3.5% per 1,000 km (620 mi)

https://en.wikipedia.org/wiki/High-voltage_direct_curren

> The Changji-Guquan ultra-high-voltage direct current (UHVDC) transmission line in China is the world’s first transmission line operating at 1,100kV voltage. The transmission line traverses for a total distance of 3,324km and is capable of transmitting up to 12GW of electricity.

https://www.nsenergybusiness.com/projects/changji-guquan-uhv...

https://en.wikipedia.org/wiki/Ultra-high-voltage_electricity...

Losses can be compensated for with...more renewable generation.

(note that the above distance is roughly the distance across Europe east-west, distance across the US is a bit more, but you don't need to pull east coast generation all the way to west coast load centers or vice versa)

This is interesting. I guess I would've have expected more and more localized generation and coordination rather than long distance transmission and storage, but maybe it will be more of a combination of things.

Thanks for the insights, its not something I really thought of before.

Also, if you pay the cost of making the hydrogen, you can use it not only for transmission, but also for storage at both ends of the pipeline. This allows the pipeline to be operated at constant high load, allows smoothing of the production fluctuations, and smooths demand fluctuations too. Multiple bites from one apple.

The cost of a hydrogen pipeline is only slightly larger than that of a methane pipeline of the same BTU capacity, even though the energy value of a hydrogen molecule is considerably less than a methane molecule. That's because hydrogen has considerably lower viscosity, which reduces pumping costs.

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