Old salt mine is the first emission-free compressed air energy facility (2019) | Hacker News Reader

Old salt mine is the first emission-free compressed air energy facility (2019)

cbc.ca

80 pointsluu122 comments

Sometimes I hate the quality of science reporting due to obvious mistakes.

> The Hydrostor facility can keep up to 10 megawatts of power, enough to keep the lights on in about 2,000 homes, or approximately half the town of Goderich for about five hours.

Megawatts instantaneous power, but the sentence wording makes it sound like capacity. That's how much energy it can supply at any moment vs how big the battery is.

And they talk about X number of homes for Y hours. Did they mean 10 megawatt-hours? Or did they mean 10 megawatts for 4 hours? That's 40 megawatt-hours or MWh.

Judging from this other site, it is 1.75 MW max and a capacity of 10 MWh. Which means someone messed up units in the article. Possibly even they read "MWh" from a technical summary and just guessed it meant megawatts. Because they spelled it out in the article.

http://www.energystoragejournal.com/hydrostor-and-nrstor-ann...

I would have parsed the article as saying that the facility could provide 10MW power for about five hours, so with a total capacity of 50MWh... this is terrible reporting.

Hydrostor own website confirms your figures: https://www.hydrostor.ca/goderich-a-caes-facility/

It's such a common error, someone should travel the country giving lectures to every journalism school about the diffences between W and Wh.

It's such a common error that perhaps the terms are too close and confusing and could've used a better nomenclature.

Do you have a suggestion for better nomenclature? Watt hours are fairly straightforward IMO.

I agree, that's why in scientific contexts the unit of energy is the Joule.

It seems to be very common to not understand, or misunderstand, the difference between power (watts) and energy (watt-hours). Even amongst technically-minded people who should know better.

A respected UK newspaper once printed a dramatic article claiming "20 new nuclear power plants" would be needed to power electric vehicles in the UK. This was nonsense and all based on confusing the estimated energy use of an EV fleet (in GWh) for instantaneous power (in GW).

They did publish a tiny sheepish apology several days later[1], and changed the online version of the article, but the damage was done and the claim still gets repeated today.

[1] https://twitter.com/dpeilow/status/831717762259099648

I don't even know why we need Watt-hours? Joule work just fine, don't they?

They're measuring the same thing. Except a joule is one watt-second, which is an inconveniently small unit when talking about large energy storage like an EV battery.

It would be like road signs measuring distances between cities in inches.

Besides, energy has long been accounted for in hour-based units. Your power bill, for example. It's just easier to use those same units when thinking about storage, rather than rebasing everything around seconds.

I know that they are both measuring energy. It's just that Watt is usually defined as Joule / second, so Joule seems more fundamental.

> They're measuring the same thing. Except a joule is one watt-second, which is an inconveniently small unit when talking about large energy storage like an EV battery.

That's what we have SI-prefixes for.

A Watt-Hour is also pretty small. We usually use Megawatt-hours or so. Using Giga-Joule instead wouldn't be too much of a difference.

> Besides, energy has long been accounted for in hour-based units. Your power bill, for example. It's just easier to use those same units when thinking about storage, rather than rebasing everything around seconds.

Yes, tradition seems to be the real reason.

Unfortunately seconds & minutes & hours aren't metric

Exactly! There wouldn't be a problem here if there were 1000 seconds in an hour.

True scientists use natural units anyway. https://en.wikipedia.org/wiki/Natural_units ;)

Electrical goods are labelled with kW ratings, and W is just V * A. (Although not many non-STEM people know that.)

kWh makes sense as an intuitive unit because it makes it easy to work out how much your heater costs to run for an hour.

You can do the same calc in Joules but it's far less intuitive to convert a rating in J/s into J/hr into $/kJ (or worse $/MJ)

Mostly agreed.

It's not so much that W : = V * A, it's that V is defined as V := W / A.

Or to be more precise and pedantic, V := J / C, Joule per Coulomb. In any case, Volt is the derived unit, and Joule is more fundamental.

Let this be a lesson: assume that journalists muddle everything else as badly as this.

Treat the news as an indicator that "something happened"... maybe.

This type of storage, whether it be water reservoirs or compressed air, is especially important in Ontario. We have a very strong base supply from our three large nuclear facilities and hydroelectric dams, but the rest is largely made up of wind, solar, and gas.

Because the peak supply from solar is midday and the peak load is often in the evening [1], you're left running the 'peakers' (gas plants) for most of the night to make up the difference. If we were able to store more energy short term, we could conceivably remove natural gas energy production and be 100% green/renewable. As of 2018 we were 96% renewable [2] so it's really not some pipe dream.

[1] https://en.wikipedia.org/wiki/Duck_curve

[2] https://www.cer-rec.gc.ca/nrg/ntgrtd/mrkt/nrgsstmprfls/on-en...

And honestly, I'm okay with paying a little more on my energy bill for the next couple years knowing that my province has made the decision to be part of the solution.

It's important or will be everywhere. Source: California where the lights are literally about to go out...

You are aware that nuclear power is not considered renewable by the majority of people correct? That puts Ontario at less than 50% renewable.

You're technically correct, and what I should have said was 'zero-carbon emitting sources' as was in the source.

But for practical purposes there is so much Uranium on this planet that we'll most likely never even use 1% of it. Especially when you factor in newer or experimental reactor designs such as fast breeder reactors [1] that can generate even more power and use waste materials from current systems.

So yes, it is technically not a renewable source of energy, but there is such abundance of fuel that it's not 'non-renewable' the way Coal or Gas is.

[1] https://en.wikipedia.org/wiki/Breeder_reactor#Fast_breeder_r...

Aren’t waste disposal sites effectively non-renewable uses of natural space?

The amount of all nuclear waste ever produced takes up about the space of a football field.

> The amount of all nuclear waste ever produced takes up about the space of a football field

No.

Let’s be generous and use a soccer field, which is bigger than a NFL field, at 7,100 m3.

There is about 22,000 m3 of high level nuclear waste globally, according to the IAEA. That’s the really bad stuff. There’s 460,000 m3 of intermediate level (sludge, reactor cladding, etc), and 3,479,000 m3 of low level.

So yeah, considerably more than the space of a football field.

[source: https://nda.blog.gov.uk/2019/08/02/how-much-radioactive-wast...]

How are you going from size of a field (which should be square meters) to volume (meters cubed)?

The MCG (an australian football field) is 25,000 square meters. The stadium holds approx 1,700,000 cubic metres.

"Football field" is a highly regional term.... lets not measure things in them?

Just a quick clarification. My comment wasn't clear I wanted to talk about waste from reactors specifically, but yes there is more nuclear waste if you do include all sources.

Why don't we talk about the difference between high level nuclear waste(HLW), intermediate level waste(ILW), and low level waste (LLW)?

The volume breakdown for nuclear waste is roughly LLW 90% ILW 7% HLW 3%

"Radioactivity" contribution breakdown is like so. LLW 1% ILW 4% HLW 95%

[1] https://www.world-nuclear.org/information-library/nuclear-fu...

>7,100 m3

You mean 7,100 m2. 22,000 cubic meters would fit in there if you stacked it just over 3 meters high.

The same is true for solar that is not easily recyclable.

how would solar result in areas beeing uninhabitable for decades (or much longer?) after we stopped using them?

What part of solar is not easily recyclable? The glass? Oh noez, now the world is being polluted with silicates!

If we're speaking of reality as opposed to theory, "renewables" was coined by environmentalists, and their exclusion of nuclear power has simply become part of the commonly-understood definition of term, except in the State of Utah.

And even though I get why one would believe that nuclear power should be included among Solar/Hydro/etc., it's slightly funny that proponents of nuclear power start start their pitch with "technically, nuclear is also..." when, technically, it clearly isn't.

On top of that, we are VERY likely gonna get either fusion or space based mining within the time we have left before exhausting the "easily" reached uranium.

Fusion is very questionable -- it has inherently poor features from an engineering/cost point of view, and space is a terrible place to mine uranium or thorium. Earth is actually the best place in the solar system to mine uranium, as the element is concentrated by something like three orders of magnitude in the continental crust over average chondritic abundance.

If you replace “renewable” with “not based on burning hydrocarbons”, you’ve still got a dramatically better source of electricity than what most of the world uses.

Im not sure uranium or other radiological material is really rare enough to call it non-renewable. Technically it isn't, but technically the sun doesn't last forever either. Nuclear materials can be found basically everywhere with rock or dirt, and much of it is recyclable into other nuclear materials down to the tiniest little bits. Just because we currently only want the richest and cheapest and least power intensive mines doesn't mean that is all we have available. It is like worrying about running out of iron, technically yes but realistically no.

Thorium 'the green nuke' powered plants produce 1/1000 as much waste as uranium powered ones. They're also virtually impossible to melt down though to be fair they're more expensive to build.

https://en.wikipedia.org/wiki/Thorium-based_nuclear_power

We already had thorium plants run by the TVA as late as the early seventies. Research would be needed to modernize those designs, money our government has refused to spend.

China, India and other countries have thorium research projects. The Netherlands just brought the first thorium powered plant online since the fifties.

https://www.extremetech.com/extreme/254692-new-molten-salt-t...

Thorium plants also have the unfortunate characteristic of not existing in deployable commercial form (and only very barely in experimental form).

CANDU reactors support mixed Uranium and Thorium fuel.

"CANDU can also breed fuel from the more abundant thorium. This is being investigated by India to take advantage of its natural thorium reserves." [1]

[1] https://en.wikipedia.org/wiki/CANDU_reactor

Thanks, noted.

I think the reason they don't go the Thorium route is that Uranium is just so abundant -- and so incredibly energy dense -- there's not a hugely compelling reason to switch to Thorium.

Thorium reactors are breeders. The Th gets converted to 233U. But breeders of any kind are uneconomical.

Why is that?

They require an extra separation step (removing newly bred material from spent fuel, or removing fission products from molten salt). This is more expensive than just doing nothing to the spent fuel.

In the past, the idea was that nuclear would be cheap, but would run into uranium supply constraints, so breeding would save money. But that's not how it turned out. Nuclear was expensive not because of fuel, but because of the cost of the power plants. Uranium prices remain low. Also, the move to gas centrifuges reduced the energy consumed in uranium enrichment by a factor of 50.

Thanks.

My understanding is that uranium supplies remain constrained --- fewer than two decades if supplying 100% of total global generation, say. Price doesn't tell you much about total resource stock.[1] That's based on terrestrial sources. Seawater U separation in theory would extend resources considerably, but remains unproven at scale.

Thorium, other disadvantages notwithstanding, is at least more plentiful.

I'll note I'm not generally a fan of nuclear, though don't rule out any contributory role.

________________________________

Notes:

1. I'd argue generally that nonrenewable natural resource pricing theory, dating to Ricardo, but especially Hotelling, is entirely flawed. Much of it under suspicious circumstances.

Yes, but the "supplying 100% of global generation" doesn't have any bearing on current reality.

Anyway, this argument for thorium isn't something customers would care much about. It's basically "thorium would not suck as much as uranium-fueled burner reactors do if uranium gets much more expensive" rather than "nuclear power is more attractive now if we use thorium". The customer response to "nuclear as currently implemented fails badly if uranium runs out" is going to be "use something other than nuclear".

Late response, my apologies.

At some point we've got to address the question of how much energy is supplied to how many people and for how long.

Population is expected to rise for at least another 30-80 years, to between 9 and 12 billions by most estimates. These may not see US levels of energy access, but most authors project per capita energy wealth roughly comparable to present day European levels, largely as electricity. This represents multiples of present generating capacity.[1]

And energy represented by virtually any nonrenewable stock, including most fissionanbles, is finite. That's before allowing for technical limitations, concerns, wastes, risks, or other impacts.

When the U.S. was first transitioning from wood to coal, roughly 1860--1880, then-known reserves were calculated as sufficient for at least one million years at then-present rates of consumption.[2] The problem, of course, is that rates of consumption increased somewhat, by a greater rate than those of new coal discoveries. I can remember in the 1970s National Geographic adverts assuring readers that America's coal reserves were good for another 1,000 years, already a thousandfold reduction from 100 years prior. Today official estimates tend to run 200--300 years, though pessimistic ones suggest scarcely a century.[3] That's roughly 10,000 times sorter than initially anticipated, thanks largely to the Jevons Paradox: low-cost goods and increased efficience stimulate demand.

And all this before acknowledging that we simple cannot burn much more of the stuff.

So, no, I don't buy that "supplying 100% of global generation doesn't have any bearing on current reality.", as even a small fraction of a growing number, most especially an exponentially growing one, remains a large number.

________________________________

Notes:

1. 1991 per capita use, 287.8 GJ US, 75.3 GJ world, 123.6 GJ Europe. bp Statistical Review of World Energy 2020, p. 11. At 123 GJ * 12 billions souls, total global energy demand would be 1,476 EJ, vs. 584 EJ consumed 2019, a 250% increase. Total 2019 electric generation was 27,005 TWh, or 97.2 EJ, 16.6% of total global energy consumption. That works out to 3.46 MWh/capita, or about 395 W continuous per person.

2. Henry Erni, Coal oil and petroleum: their origin, history, geology, and chemistry (1865), p. 14. https://archive.org/details/coaloilpetroleum00erni/page/14/m...

3. BP's 2020 report gives an R/P ratio, reseves vs. production, equivalent to years supply at present consumption, of 390 years. This is an increase, though almost entirely due to reduced extraction, down from 22.27 EJ in 2011 to 14.30 in 2019. Consumption has fallen by more.

If we're talking about ultimate limits on Earth, solar is probably better than nuclear, just from direct thermal pollution. Solar causes a moderate increase in sunlight absorbed, but otherwise just moves solar energy around. If the albedo of the ground on which the solar modules were installed was less than the efficiency of the modules, there is no local heating, although the produced power gets degraded to heat eventually elsewhere as it is used. For every kWh of power produced, nuclear adds 3 kWh of heat to the biosphere (1 from the power produced, 2 from the waste heat of the reactor.)

(This is really a reflection of the difference between primary energy, which today is largely thermal, and delivered energy, which is largely work or chemical. The conversion to renewable energy will greatly reduce the importance of thermal energy conversion, and will not require a 1-1 replacement of today's primary energy use.)

It's not at all clear energy use will grow that much more. Lesser developed countries will use more, but in advanced countries energy use has plateaued. We are currently very far away from limits on solar energy imposed by shortage of sunlight. The Earth is hit by 100,00 TW of sunlight; global primary energy use is 20 TW.

If we're talking about limits OFF the Earth, solar is vastly more abundant than uranium (or, for that matter, artificial fusion, since the Sun fuses starting with ordinary hydrogen, not comparatively rare isotopes/elements like deuterium, lithium, or boron.)

I tend to agree generally WRT solar.

The usefully convertable fraction of solar on Earth may be far closer to present or anticipated energy demands than is commonly thought. Panel efficiency, spacing factor, lifetime, capacity factor, storage requirements, essential fuel-based needs (marine shipping, powered flight, mobile power, remote reserve generation & thermal), process energy (steel coking, Haber-Bosch, etc.) leave some large holes and very uncomfortable margins remaining.

The alternatives to solar are either secondary or tertiary options (biofuels, wind, wave) and hence, more limited, or comparatively finite (geothermal, possibly our best non-solar option, tidal).

I do largely suspect that humanity's future will be principally solar powered. The question is largely of how much energy and in what forms it will be available. And aagain, demographic trends and expectations shade strongly against pleasant transition.

I find Vaclav Smil's and the late David MacKay's works quite illuminating.

There was a commercial thorium reactor in Germany, which was a financial disaster:

https://en.wikipedia.org/wiki/THTR-300

That was also a pebble bed reactor. The kind of reactor generating all of the latest hype is a molten fuel salt breeder reactor. There's a really substantial difference between the two and the MSRE was basically a mock up of the core running on Uranium fuel salt that would have been generated in a fertile Thorium blanket salt around the core and been reprocessed into the fuel salt.

Pebble bed reactors have tons of drawbacks that don't apply to most modern Thorium reactor proposals. The biggest drawbacks to proposals like e.g. LFTR is corrosion risks which were largely addressed by the MSRE ages ago, and the chemical reprocessing equipment which again is mostly a chemical engineering problem more so than a nuclear engineering one.

To place it in the context of this compressed energy storage, when does the plant expect to be commercial viable through the method of buying energy cheap, storing it, and selling it expensive?

As far as I can find information, this plant is built on 30 millions given from the government. They have also got 17 millions from an equity round and 20 millions from a asset manager that supports building out clean-energy infrastructure.

In order to be commercial viable they need a significant overproduction in the energy grid from wind and solar which enable the company to buy cheap energy during peaks and sell it expensive during lows, and the difference need to be significant enough to pay both the energy loss, the operation cost and the investment costs. Wind and solar will also not over saturate the market beyond what is commercial viable for them, putting a short-term limit on how cheap the price can go during peaks.

The tens of millions is a pretty cheap deal compared to nuclear power, which needs billions to get the ball rolling (and that's if it completes on budget)

Its only a good deal if it produce profits. I rather have the government take a billion dollar cost in the energy sector that later turn a profit than a millions dollar cost that don't.

If neither can make a profit then that says something about the energy market. Turn off the fossil fueled alternative (or incrementally add a carbon tax until fossil fueled become commercial nonviable) and let see if the market price adjust to the point where the profitability of either goes into the green.

> I rather have the government take a billion dollar cost that later turn a profit than a millions dollar cost that don't.

Surely that ought to depend on how much profit it generates. If it only generates a few millions in profit you're still down on your money.

The first step is to be profitable, ie that revenue is higher than costs, and the second is that the rate of profit exceeds the investment cost over its lifetime.

A project is not commercial viable if it lacks either. Currently I have not heard of a single energy batter project that is profitable. The cost of buying energy together with employees and maintenance is significant above that of the revenue that they can get out. The hope is that if there is enough overcapacity in the future from wind and solar then the price will be low enough, and the electricity price during lows is high enough, that they could then make a profit. Nuclear in turn has seen mostly a drop in revenue while cost has only increased.

Choosing between two nonviable commercial options is a bad choice. I do however want an energy grid that is emissions free so one way or an other the economics need to change. Increasing the electricity price by kicking out fossil fuels is a good bet to help both technologies to be more commercial viable. Convincing wind and solar investors to over saturate the market and crash the price during peaks would be an alternative. Time will tell.

As a earlier article suggested, we need to actually do all of it if we want to reach the climate change goals. Pump more money into researching cheaper and more effective production of wind and solar plants that can saturate the market, research more effective battery solutions, kill fossil fueled power plants by aggressively tax them to death, and expand more nuclear plants.

A big problem with batteries as currently envisioned is that under a centralized utility model they don't "generate profit" per se.

Puerto Rico has post-Maria microgrids that are more resilient than the old utility model was to natural disaster, but they're making PREPA's financial situation worse, not better.

This is millions, while anything nuclear is measured in billions. And nuclear technology, including thorium, is decades old technology, unlikely to see the kind of rapid gains less mature technology frequently exhibits.

> The Netherlands just brought the first thorium powered plant online since the fifties.

Just to be clear, because one might get the wrong impression from how that was formulated (at least I know I did): what they have is a small test reactor, not a commercial electricity generating plant.

Thorium produces just as much fission product waste as uranium.

And any thorium reactor is going to have to include 238U in it, or else the effectively high enriched 233U it DOES contain would be an unacceptable diversion risk (even with 232U contamination). That means it's going to produce more plutonium than you are letting on.

That's one of the issues with current energy policy of most of the world - the terminology and thinking is stuck in the days when everyone thought the problem is we're going to run out of oil or coal or whatever.

But that's not the problem humanity faces today - we will all die of climate change decades sooner than we run out of oil or gas or uranium. We should be focused on low/zero-carbon energy and not on renewability.

I'm interested in paying 5 cent/kWatt hour that nuclear and water/dams offer. Less interested in 75 cents for locked in solar contracts.

What is the form of the "75 cents for locked in solar contracts" ? That's Canadian, so equivalent to about $500/MWh wholesale US prices?

It's in the nature of R&D investment that you can't have tomorrow's prices for things built today, so if government agreed to pay 75 cents per kWh to drive innovation ten years ago that's what you have to pay now, you can't change your mind now the work is done or else nobody will work with you in future since they've no reason to think they'd get paid.

But $500/MWh does seem high, subsidised UK solar projects from five years ago receive about $80/MWh and new ones proposed this year are expected to pay somewhere in the ballpark of $50-60 (less than consumers pay for electricity but more than unsubsidised providers are paid for it most of the time). So perhaps I just don't understand the basis on which you've got 75 cents.

Yes, their rooftop solar program initially paid 80 cents/kwh under 20 year contracts.

http://www.yourturn.ca/solar/microfit/what-is-the-microfit-p...

Not sure if it counts as innovation when one buys something for far more than it's resold for at a mass-scale.

Oh, a _feed in tariff_. OK, so that's never going to make sense as a wholesale price because it isn't one.

At the end of the day, the system operator covers the program costs via higher prices for electricity consumers (the "global adjustment").

Somehow we've ended up with a "market" price of electricity of 2 cents/kwh, and another 10c/kwh for global adjustments (includes more than just solar and wind subsidies). This is before distribution and transmission.

http://ieso.ca/power-data/price-overview/global-adjustment

I looked into the details[1] here, it seems like a minority of these charges are from wind/solar, eyeballing it, it looks like 50% or so is from Nuclear and hydro, with something like 20% other (mostly nat gas), and 20% wind.

It seems to me like it's essentially a breakdown of marginal vs fixed costs.

1: http://www.ieso.ca/-/media/Files/IESO/Market-Summaries/2020/..., page 21

I just looked at the bottom of the page I linked. Solar looks contributes about 2c/kWh to bills in summer, less in winter because there’s fewer subsidies.

Subsidies are rife, but there’s far less solar energy produced compared to hydro and nuclear. The amount of generation we get for that solar subsidy is peanuts. Nuclear is a pesky beast, because shutting down is incredibly expensive too.

It's a little unclear to me, but I think looking at just output from generation is not fair to solar. Solar has 2000 MW of installed "embedded" capacity. This is cheaper for the grid since it doesn't have to go through as much of the distribution network, meaning it has less efficiency loss and doesn't require transmission capacity. Solar makes up 60% of the embedded capacity[1] (where is the embedded hydro coming from?? lmao). It seems embedded capacity reduced demand by 5TWh in 2019[2]. Comparing this to "actual demand" from the same chart shows that it was roughly 5/140 =~4% of the supplied electricity.

Let's say it was 20% of the GA in the summer and 0% in the winter for a sketchy 10% average of the fees. This doesn't seem too far out of line, although it is obviously a few times higher than the others, but it's not far enough out of whack that I think calling it peanuts is justified.

1: http://ieso.ca/en/Learn/Ontario-Supply-Mix/Ontario-Energy-Ca...

2: http://www.ieso.ca/en/Corporate-IESO/Media/Year-End-Data

The innovation comes after the demand for solar panels is sufficiently stimulated to warrant mass manufacturing.

Firstly, there is no hydroelectric resource left anywhere in the world, where you can build a damn of any significance. Except the Amazon, but that one is basically impossible.

Secondly, what makes this price of 5 cent/kWh justified? Does it allow reinvestment into new nuclear facilities to replace retiring plants? Does it account for proper processing, storage and disposal of all wasted without government subsidies and does it cover the grid maintenance? Currently US stores most nuclear waste in haphazard manner on site of most nuclear power-plants.

https://en.wikipedia.org/wiki/James_Bay_Project is only half-built. https://www.opg.com/strengthening-the-economy/our-projects/l... just built out another 500MW 5 years ago. There's still a TON of rivers in Canada that hasn't been dammed yet, and lots of room to expand in the areas there are.

https://globalnews.ca/news/5329835/canadas-nuclear-waste-to-... covers waste disposal in Ontario. I'm not sure why government subsidies or not would matter, it's a Crown Corp handling the disposal from the OPG. Hydro One is in charge of transmission, servicing, and fee collection, and seems to be doing just fine after its privitization.

So, in short: It's 9 cents per kWh during the day, and 5 cents per kWh during the night, because that's what it costs.

If day price is twice higher, then that's a totally different price! I am pointing it out because UK price of electricity is higher.

You are right to point out that Canada has untapped hydroelectric resource, it's by far the cheapest electricity.

However it can't supply entire energy need of most nations (some have none), and it is usually tapped wherever possible - people are usually not just sitting around ignoring it.

What's interesting is that they pour money into these alternatives, or worse, refurbish nuclear power plants at a huge cost instead of buying their neighbor's surplus of clean energy. Must be politically motivated!

[0] https://www.nationalobserver.com/2020/01/15/news/critics-say...

[1] https://montreal.ctvnews.ca/door-closed-on-hydro-sales-to-on...

I thought Quebec had a better trade in selling to New England and New York with its HVDC links: http://www.hydroquebec.com/transenergie/en/reseau-bref.html

electricityMap Live suggests both Ontario and Quebec sell to New York. https://www.electricitymap.org/zone/US-NY-NYIS

But the nature of such links is that they're often saturated if it makes sense to move power - so even if you have 10GW of electricity and New York are willing buyers at the price you offer if there's only 2GW of interconect you can only sell them 2GW of electricity.

As a result it can make sense for Ontario to buy electricity from Quebec and sell electricity to New York, even though Quebec is also selling electricity to New York.

... and NY is selling to OH/PA/etc and they're selling to Indiana and Illinois :)

Dunno if they're re-selling, or if ON/QC pay for the transmission. Dunno how all that works.

My understanding is that they could sell to both and still have surplus.

If I'm not mistaken, there's also unbuilt capacity that could be further expanded if there was a buyer around.

In case anyone is curious, hydro is the general term for electrical power from a utility, at least in the part of Canada where I grew up.

That's ... weird. But thanks for clarifying that, that really confused me.

It's weird on the surface, but it's because our entire electrical utility has roots in hydroelectric power.

Adam Beck was one of the people chiefly responsible for the creation of a public electrical utility in Ontario. I like one of his quotes "the gifts of nature are for the public" referring to his slogan "Power at cost".

https://en.wikipedia.org/wiki/Adam_Beck

Thank you for this context. I vaguely knew of the term's connection with the names of utilities, but this is some fascinating Canadian history.

At a certain point if photovoltaic panels become very, very cheap (far below the $0.20-$0.35/watt STC price to buy panels in huge quantities today), it will be economical to crack hydrogen from water and compress it into tanks, then use it to run massive fuel cells to feed power back into the grid.

Because of the significant engineering challenges in storing, transporting and refueling hydrogen at very high pressures, I am much more optimistic about the use of hydrogen in medium to large sized fixed, professionally-run facilities than I am about people driving around with hydrogen fuel cell powered cars. Or home use of hydrogen fuel cells.

that generally requires high cost or temperature catalysts and even then it's not that efficient for short-medium term

Alkaline electrolysers do not require high cost electrocatalysts, and are likely the low capital cost (and mediocre efficiency) ones to be used with intermittent renewables.

Or spread it around the world and run lots of interconnectors. It's always daytime somewhere in the world.

Ethanol may be better suited for this:

https://www.anl.gov/article/turning-carbon-dioxide-into-liqu...

Tank storage is challenging because at that scale you're competing with batteries which have much better round-trip efficiency. There was a DNV GL paper earlier this year which quoted a time of about 24 hrs as the cross-over point between H2 and battery tech.

Underground cavern storage lets you do inter-seasonal storage at a very low cost per MWh.

It's critical to understand that liquid and gas fuels have uncoupled per MW and per MWh costs in a way that batteries don't. You can adjust battery chemistry of course but fundamentally you're stuck with a narrow range of peak MW / MWh performance which means that if you want to build a massive battery for inter-seasonal storage (needs MWh >>> MW) you end up "buying" discharge capacity in MW that you don't need.

Hydrogen decouples the size of the production (in MW), the storage (MWh), and the fuel cell (MW) which lets you size them independently of each other.

I am also sceptical of the need for home use or vehicular hydrogen (certainly in passenger cars). You get a lot of efficiency improvement if you are able to use the waste heat from fuel cells. Yes that can be done domestically, but putting them in large urban centres and driving district heating schemes from them seems like a much more natural fit. Especially in places like Europe where total energy demand (heat and electricity both) peak at the same time in the winter as renewable generation decreases.

N.b. there are already times in the UK grid when prices are negative wholesale. Even one of the retail energy suppliers here had a few half hourly periods of negative prices a few months ago. The subsidy for hydrogen electrolysers in The Netherlands was set assuming 2,000 hours a year of operation (using the cleanest and cheapest 2,000 hrs) since that maximises the environmental benefit with the current Dutch grid.

Isn't storage a problem with large hydrogen quantities? I'm not sure what form it takes in storage, whether it's H or H2, but either way that's tiny and it's going to seep out of just about everything.

It would be stored underground, where the cost per unit of energy storage capacity is under $1/kWh, two orders of magnitude cheaper than batteries. The round trip efficiency is not good, though, and there are per-power costs too. But for very long term storage, or storage for rare cloudy-calm days over large areas, it's hard to beat.

A recent gigawatt scale PV bid in UAE came in at $0.0135/kWh.

https://www.forbes.com/sites/dominicdudley/2020/04/28/abu-dh...

"solar PV and onshore wind are now the cheapest sources of electricity generation for at least two-thirds of the world’s population"

Goderich is a beautiful town—I've been looking at getting out of the city for a while. Maybe we should look to head that way and I should start looking for a job with these guys.

This, to my naive understand, seems like an enormously good idea and seems like they would have a lot of opportunity for relatively cheap resources and developing solutions for stabilizing fluctuating power generation resources like wind/solar.

Please someone with more knowledge in this domain explain further what might be the benefits and shortfalls and pragmatism of this group.

I’m no expert for sure. I’m surprised they can be as much as 70% efficient, I would have thought the heat losses would be much greater. But clearly it doesn’t work like that.

Some of the diagrams I've seen in the past show that as the air comes out of the compressor its passed through a gravel bed before being allowed into the general mine. This picks up a lot of heat and then when the system is run in reverse the incoming air is pre-heated by the gravel bed prior to going into the turbine.

Been tracking them for a long time. They've been at "pilot" stage since at least 2011.

Personally I don't think that any form of alternative energy storage has much chance against Li-ion, which has experienced unbelievable declines in cost (driven mostly by cell phones and electric cars).

A bunch of extremely well funded compressed air storage companies have already run aground against this problem: Lightsail (Thiel & Gates backed), SustainX, etc.

I'd be skeptical unless they can somehow actually prove economics against Li-ion, but these media pieces always seem to skirt that question.

From the article:

"compared to a similar capacity battery, it's not only half the cost, the facility has a service life of 50 years, five to 10 times longer than a battery."

It doesn't explicit say what kind of battery, but a service life of 10 years suggests Li-ion.

From the area, there's a lot of people with your line of thinking from different fields. I think you'd like it, although there's quite a few small communities in SW Ontario I think are worth moving to.

Left me wondering whether this would also work in Detroit? Detroit sits atop a huge abandoned salt mine. There's a mine across the border in Windsor (Canada) but that's still actively being mined.

Goderich also has active salt mines... I'm presuming this project is using a played out branch of them.

I know people that live there. Many worry about the safety of using compressed air below the town and wonder if it would cause collapse of any tunnel in the current salt mine.

I'm definitely not a geologist but I can imagine the "breathing" motion of pressurizing and depressurizing the mines causes some movement and damage over time.

What pressures are we talking about anyway?

This is in my backyard (ish)! Strange given that I started https://collective.energy to create more dialogue around innovative climate solutions but never even saw the old salt mine as an opportunity

Has anyone analyzed the viability of a compressed-air energy distribution system? It could be simpler and safer than electricity distribution.

In the quantity and pressure required to match even a fraction of the existing energy grid, wouldn’t transportation be insanely dangerous? A cylinder of highly pressurized air is basically a bomb.

I was thinking more of a pipeline of compressed air.

I think they would have a similar issue. Since the compression of the gas itself is the potential energy, rather chemical bonds (e.g. fossil fuels), the pressures would need to be extremely high. This means any compromise of the pipeline would be catastrophic. That said, natural gas already causes home and pipeline explosions, so I'd be interested in an engineering study.

Live steam is another alternative, also used in industrial applications.

In what ways are compressed air safer and simpler for transmission? Off the top of my head I can only think of advantages for electricity:

* Electrical transmission lines are lighter and smaller per watt than compressed air transmission lines.

* Electrical transmission has lower inductance than compressed air has equivalent momentum.

* Compressed air vessels can fail explosively; electrical stuff just heats up.

* One has to contend with adiabatic heating/cooling when exchanging air pressure for flow rate, while there's no analogous concerns when using transformers to exchange voltage for amps.

* Electrical equipment tends to be much quieter than air equipment.

Why distribute the compressed air? If you have the ability to store compressed air, you can put a generator on top. When you have an overabundance of power, you run the compressor. It pushes air into large underground holding facilities built in various geologic formations. When you need power, you run the compressed air through your generator. Dot the land with these systems.

https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.51...

This sounds like steampunk fantasy,and very impractical.

We have thousands of kilometers of high-voltage transmission lines, imagine that's now carrying compressed air. Firstly, these lines can carry multiple Gigawatts of power, i do not think it's even possible to have a pipe of compressed air that could transport that amount of power. The most powerful air compressor in the world appears to be 28 mW in power consumption! - not output.

Secondly, how are you going to look for leaks in that thing?

Also any rupture in the line will release the equivalent energy of many kilograms of TNT.

How do I power my TV with compressed air, do I have to have a generator in my house? If so, you've just lost a ton of efficiency.

About 5% of the energy is lost in transmitting power via electricity from generator plants to consumers [0].

Losses in a compressed air energy distribution pipeline would primarily come from friction between the moving air and the walls of the pipeline. Fortunately, we can increase the pipe size to reduce losses from friction. This is because friction increases linearly with pipe diameter, while flow increases quadratically [1].

Electrical power transmission requires large amounts of land. The towers and lines are hazards to aircraft. They are fragile infrastructure sitting out in the open. They start wildfires. Compressed air using buried pipelines has none of these problems.

Air streams out of a broken pipe. It emerges from the pipe at high pressure (100 ATM?) and then expands until reaching local pressure (1 ATM). Its flow rate is limited by friction with the pipe wall and cannot be instantaneous. An entire section of pipe will take several seconds or minutes to empty. By comparison, a TNT explosion produces a small amount of 1-billion-ATM gas which expands instantly in one big burst. A broken pipeline is more like a rocket engine than a TNT explosion.

How to detect and find leaks? Listen for the sound? Fortunately, compressed air leaks pose no danger of explosion or asphyxiation.

Refrigerators can run on compressed air directly and very efficiently.

A TV would need a small electricity generator powered by compressed air. The generator could be noisy, so it would probably be in another room or outside the home. The generator could cool your home in summer. To be efficient in winter, it could use some buried pipes to draw heat from the ground.

Coal-powered and natural-gas power plants are essentially electricity generators powered by compressed air (actually steam). They are adiabatic engines and have the same efficiency problems as a small generator in your home.

[0] https://www.eia.gov/tools/faqs/faq.php?id=105&t=3

[1] https://www.fluidmechanics.co.uk/hydraulic-calculations/pipe...

Just pointing at a formula is not a good way of discussing things - you point out 5% efficiency loss in transmission lines and are implying that efficiency of a pneumatic system will be greater.

To substantiate your claim you pick some links with formulas for pneumatic systems, but leave the actual calculation as the exercise to the reader. Why would you do that?

If you have the skills to do the calculations yourself, you should do them and demonstrate that for some set of realistic parameters, greater efficiency is possible. If you either can't do them, can't find parameters to support your claim, or you can't be bothered to, then it's not fair to leave it to the reader.

I have done what I can, but it's not my speciality, so there could be mistakes.

Firstly, what does it look like to have a pneumatic system transfer 4 GW of power? I have used this PDF on sizing cylinders, and made the assumption that the pipe and the cylinder would be of the same size. http://www.gearseds.com/files/chp2-5_diff_work_energy_pneuma...

With the help of a calculator at: https://www.sensorsone.com/pressure-and-area-to-force-calcul... I have arrived at a pipe with the inner diameter of 2 meters (!), pressure of 100 atm, and the speed of air at half the speed of sound (125 m/a). How Thick is the wall of the pipe? Using the calculator at: https://www.engineersedge.com/calculators/pipe_bust_calc.htm... details here: https://whatispiping.com/pipe-thickness-calculation-per-asme...) It comes out at 3 inches thick, for steel, with 50% safety margin.

How much is this pipe going to weigh? Here is a pipe weight calculator: https://wcalcul.com/pipe-weight-calculator - It comes out to 4.1 tons per meter. This pipe is quite similar to those used for gas transportation, but it's about twice the width. Certainly doable, but this is >10X times the material needed for high-voltage cables.

To calculate pressure drop, i have used a calculator at: https://www.engineeringtoolbox.com/pressure-drop-compressed-... - I end up with 0.3% for 100 KM, which is is roughly in line with HDVC: "Depending on voltage level and construction details, HVDC transmission losses are quoted as less than 3% per 1,000 km"

So I am surprised that it's even theoretically possible. There are obviously many unaccounted losses - valves, turns, distribution to smaller pipes, etc. Casual glance at compressed air storage, which has none of the distribution issues, shows that their efficiency maxes out around 70%.

Electrical transmissions lines can be and sometimes are placed underground, especially the DC variety - earthworks are very expensive and that why it's not usually done.

Now, safety - have you seen tyre explosions on a truck? They regularly kill people, and they are 10- times lower pressure than this pipe would be.

You point out fragility of powerlines, compared to what? Do oil and gas pipelines need repairs any less often that powerlines do? How many fires were started by high voltage powerlines? Substantiate your claims.

Everything indicates need for a lot more equipment than is required for dealing with electricity, I think the pneumatic system would be much more expensive and dangerous.

Hydraulic power distribution systems did and do exist. Your dentist and auto mechanic both very likely have one based on compressed air, and they're popular among certain Amish for shop power.

Large-scale systems were built in the 19th century, especially in ports, where large intermittent loads were required, especially for lifting and operating canal locks.

Disadvantages include size, limited range (up to several kilometres, but generally far less) leaks, limited capacity (high applied force but limited energy storage), controls, etc.

Electric power distribution is the diect analogue of such systems, and is in virtually all regards superior, more flexible, cheaper, and more readily and precisely controlled, though hydraulic power distribution existed in London, England, as late as 1977.

https://en.wikipedia.org/wiki/Hydraulic_power_network

When the original Niagara Falls power station was in its planning stages, the planners were uncertain on how they would distribute power, and were considering using compressed air before they decided to generate electricity instead. Unfortunately, they specified turbines that operated at 250 RPM, making it impractical to directly produce 60 Hz AC, or 30 Hz for that matter, which would have made frequency converters relatively cheap. Instead, 25 Hz became a North American standard for industrial power, and a few legacy customers remained as late as 2006. [0]

Much of Amtrak's Northeast Corridor, and SEPTA's rail network in the Philadelphia area, still use 25 Hz for traction power, provided from converters or from a few hydroelectric plants that have 25 Hz generators.

[0] https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=4412948

Yes, apparently that has been done.

https://www.lowtechmagazine.com/2018/05/history-and-future-o...

Thanks for sharing that article.

I think the most promising application of distributed compressed air is in refrigeration, especially if the power source is not an adiabatic process.

But is it scalable?

There only needs to be one no?

No. Much as one battery would not be sufficient, this storage station that can only power half of one small town for five hours is insufficient storage for the province, much less the country.

It doesn't have to power the town, it only has to pull power when it's abundant and deliver power when it is not abundant. Using the resource more as a market balancer. There are many examples of this being profitable.

To get a salt cavity just pump in water in salt deposit and pump out brine. It can be used to store H2, CH4 or compressed air, from 70 to 200 bars. H2 is way more energy dense, but has a lower efficiency round trip. There is many salt deposit around the world.

Disposing of the brine is a bit complicated when you have nothing but freshwater lakes around :)

I'm guessing they're planning on using the existing caverns from mining.

Unsure if they plan on expanding.

Can't they just evaporate off the water and use the remaining salt to treat roads in the winter?

66% efficiency sounds amazing for compressed air. I was expecting 10%.

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