I would start making a regulation that says all parking-lots MUST have a light-weight roof on top of them on top of which are solar panels.

Imagine all (outside) parking lots having solar-panel covered roofs.

This would be easy to enforce in regulatory terms, which regulating all of deserts is not. You want to have a parking lot? You must have solar panels as well. And it could double as a charging station.

Store owner wins because covered parking. Panel owner wins because the increased logistics are offset by free land.

Which sort of begs the question, why isn't this already a thing? Why aren't there companies going to businesses which own parking lots and saying, "Let me lease the air above your parking lot. I'll install and maintain the frames and the solar panels, manage the connection to the grid, the whole lot; I'll pay you $x per meter per month, and your customers have shade."

Yeah it’s a better use of land, it keeps the cars shaded, but no one seems to have figured how to do it economically. Even in Southern California where it’s very sunny, and power is very expensive. I just don’t think it’s anywhere close to being economical. And in other markets the economics are almost certainly worse.

Mass-production is the key to economies of scale. Government policies can play a huge role in steering us towards goals like that.

Why is America so rich? Because of car-industry. And why is car-industry so prominent? Because of the interstate highway system.

I'd argue that this is likely more challenging than it seems, with city/state/county building codes, plus just building on existing dense spaces, and add to that any grid/utility policies and associated costs to play ball

Perhaps the Inflation Reduction Act subsidies will, or should, make it a thing.

Government subsidies (incentives) is a good thing if it can save the planet and prevent the devastating floods and forest-fires and drought that is killing us now.

Snow covering the solar panels could be a problem. But perhaps even in winter there is a bit of sunlight which could produce electricity to warm up and melt the snow.

Meanwhile, the store roof entirely lacks solar.

Nearby Safeway is opposite.

I mean I'd love pricing in the externalities, but then it'd be moot because there'd be a building rather than a parking lot, no walmart, and a train or bicycle rather than a car. There'd also be plenty of roof area for solar panels in any place with a density lower than tokyo metropolis so you wouldn't even need to build supports.

Say goodbye to all rural farmers markets.

I don't know what the efficiency of the process described in TFA, but from Wikipedia I see that Electricity->Gas->Electricity has an efficiency of 30-40%. There are other alternatives like pumped hydro stations that are way more efficient.

Chemical energy is dense, easy to store, and you need methane for stuff like fertilizer.

Solar energy is basically free ($30/MWh and falling rapidly). The solutions we'lp use are the ones which scale and the ones which are cheapest for storage as it will be much more expensive than the energy.

For storing for a day, that's probably sodium batteries as the cost per MWh through is lowest.

For storing for a year, you want to minimize cost per MWh stored. Right now this looks like methane, maybe hydrogen or for heating, thermochemical batteries.

This is always claimed, and is always false. Please do not repeat falsehoods.

Existing hydro generation needs a watershed. Pumped hydro does not. All it needs is a disused hilltop and earthen dike, and not always the dike.

It doesn't always need the hill: underground cavities work to pump water up out of, and to drain into.

Batteries will always be the most expensive alternative. They will be used in limited amounts, mainly for very short-term (overnight) storage.

Do you have any good numbers on real world projects? I'm very happy to be wrong here, but all the numbers I can find are either lies from nuclear shills or using existing watersheds. Most also only focus on the cost per kW which is higher than batteries and not the relevant metric (as batteries can drain in a few minutes) for season-long storage.

Also a quick back of the envelope seems to suggest emptying and filling lake Baikal could store as much energy as about a billion tonnes of chemical storage. This seems like a reasonable upper bound which would indicate pumped hydro is about an order of magnitude short of solving the problem. Current battery production is nowhere near (total cumulative seems to be about a megatonne chemical equivalent even if it is more than doubling annually it'll take over a decade to catch up), but this is expected because batteries are optimal for short term.

Overall by gut feel it seems a more feasible to make and store ten cubic kilometers of chemical fuel worldwide than move 200,000km^3 of water around.

Dedicated pumped hydro storage is typically quite shallow, with an earthen dike (if needed at all), and the only place with high pressure is at the bottom end of a penstock. It does not need to store years of water; just a day's worth is useful.

This makes it better than existing batteries for ~1 day time scales and roughly on par with the upcoming generation of things like sodium batteries.

It's not a clear indicator as it's obviously optimized for power, but these all seem to be big advantages specific to the site which would indicate that an artificial reservoir would have trouble competing even against batteries.

Different sources have figures that differ by a bit (presumably projections vs actual) and most seem to have some mistakes. Here's one. https://www.nsenergybusiness.com/projects/fengning-pumped-st...

I could believe that you might improve storage/cost by a factor of 10 if you found a suitable reservoir by reducing power, but that seems to back up my initial assertion that you need specific geography and to significantly change the ecosystem fairly well.

As such it seems like it is not much better than a battery for displacing fracked methane, oil, or nuclear for mediating seasonal variability (which is what synthetic denser-than-hydrogen fuel is for as it is optimized for approximately zero cost per capacity at the expense of the highest cost per joule with competitive cost per watt).

Plus batteries still have a 10-20% efficiency benefit.

We also have underground compressed air using existing deep cavities, and undersea compressed air. And underwater buoyancy, drawing floats down toward seafloor-mounted pulleys, using a winch and motor-generator on shore. Demand will not exceed our capacity to make cables and floats.

But the real answer is that there is nowhere even close to as great a need for long-term storage as you imagine, just as there is not much petroleum stored today. Petroleum is extracted and delivered continuously and reliably. Myriad tropical solar farms will synthesize ammonia year-round, shipping anywhere needed on demand, so storage is needed only until the next shipment arrives.

And HVDC transmission lines will move power from where it is being produced to where it is not, over 1000s of km, at a wholly tolerable loss rate. Much of this will move power eastward from afternoon production and westward from morning production, but also generally fill in for local production and storage shortfalls everywhere.

So Finland can have ammonia shipped in continuously all winter long, just as they ship in petroleum and NG today. Transmission lines will compete for that business.

Better than fuels at present, but inherently fragile so not a complete solution. Also those are just claimed building costs not including operation (and assuming it lasts about as long as the pv), and the natural monopoly spawned always winds up being a massive tax money sink, so it's not clear that building thousands of hvdc lines is going to work out.

AFAIU it is even less fragile because it's usually 'point-to-point', which means to integrate it into the grid you need very modern substations with the ability to 'transform' the DC into the AC of whichever pre-existing grid by means of mass cascaded https://en.wikipedia.org/wiki/Insulated-gate_bipolar_transis...

Which in turn makes the grid around these substations smart, the more, the smarter. Because you have much better ability to switch and regulate(diversion from same frequency in AC-grid due to dynamic load or failure) much faster.

Think of the difference between the large external 'power-brick' for older laptops vs. the small switching power-supplies for contemporary notebooks. Just in reverse.

Nothing? The point is transmission is extremely fragile. To physical conditions (weather, accidents, faults). To market effects (massive price gouging during those failures due to lack of buffer). And to market failures (harmful monopolies always form around private utilities and neoliberals always privatize utilities).

Then if the oceans are involved, cost becomes a non-starter.

That remains to be seen. Some people seem to think different.

https://electrek.co/2022/04/21/the-worlds-longest-subsea-cab...

&

https://xlinks.co/morocco-uk-power-project/ is just the latest of those ideas/projects. I think it was on HN too.

These are more technologies that compete with batteries, not fuels. And poorly at that. CAES in ideal sites might compete with batteries for a while yet, but the others do not. Even a single truck full of ammmonia can store the equivalent to tens of thousands of cubic metres worth of displacement storage. A cubic metre float in a 500m deep body of water can store 5MJ, or about the same as a battery you can lift with one hand and buy for a few hundred dollars.

> But the real answer is that there is nowhere even close to as great a need for long-term storage as you imagine, just as there is not much petroleum stored today. Petroleum is extracted and delivered continuously and reliably. Myriad tropical solar farms will synthesize ammonia year-round, shipping anywhere needed on demand, so storage is needed only until the next shipment arrives.

Moving energy 2000-4000km as not-electricity is strictly a harder problem than storing it for 6 months and is solved with a subset of the same solutions. The main upside is energy input is cheaper and there is less idle time. This is definitely part of the solution but comes under the same heading.

HVDC systems are a solution for most of the issues, but distant solar isn't completely uncorrelated. Also no country is going to stake their survival on a system with cascading failure modes that can be triggered by anything from war, to a heat wave, to a blizzard, to a cyclone, to a forest fire, to political games. Thus capacity for months of backup is still required.

All of this is moot anyway because your other comment led me to find sources stating green ammonia is already within 50% of cost parity with fossil fuels for the cheapest solar energy sources and ammonia fuel cells are now viable as well with the same technology. Between that and thermochemical storage, fission is obsolete immediately and fossil fuels only need one more price shock for the transition to start.

Also none of this supports your original assertion that pumped hydro meaningfully exists in a non-ecosystem-altering way.

You are always free to invent falsehoods about pumped hydro, as about anything else.

PVs solve net energy needs. Perovskites might even make them do so without needing strategic mineral reserves. But they don't really provide energy security, and keeping fossil fuel infrastructure working for 1 month in 30 is extremely costly.

> You are always free to invent falsehoods about pumped hydro, as about anything else.

Then show the real numbers. I did. Demonstrate it being viable as a significant portion of primary energy in a typical country as a new project.

To make it impossible to mine more fossil fuels even for a mixture of slave-driving sociopaths unrestrained by law and theocrats actively seeking apocalypse we need to be able to use a MWh at night in mid winter that was produced at 2pm in summer for less than around $40 and then do it another billion times without hitting some resource limit. Hydrogen with storage is shockingly close, and if synthetic ammonia/methane or metal hydride get over the line, noone will look at fossil fuels again.

You seem to be telling me that pumped hydro is already there, but I can't find a decent source agreeing with you (or any numbers dealing with this use case for that matter).

There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up.

And I can attach a washing machine motor to my water tank. If it produces basically nothing and costs double the alternative, it's not relevant to the discussion.

> There are actually dozens of shallow reservoirs behind earthen dams way high up in California's Sierra Nevada mountain range, many almost a century old, constructed with bulldozers that used pulleys instead of hydraulics, hauled up there on fantastically bad cart-track roads. The reservoirs feed penstocks down to Pelton wheels thousands of feet below. For storage, they just attached pumps to the penstocks to push water back up.

So there are no new projects which not destroying an ecosystem that are on cost parity with batteries then?

Also as an aside, how pathetic is capitalism as an organizational system that we can't achieve the types of things that were done with horses and carts and pulley bulldozers in the past?

But pumped hydro is a completely different proposition.

Meanwhile, each dollar diverted to nukes from building out solar+wind+storage brings climate catastrophe nearer. The immediate cause for catastrophe will be global thermonuclear war triggered by ... more subtle ... effects of the change.

People like to equivocate this with making entire countries uninhabitable or ongoing destruction.

It also requires vast quantities of concrete (and thus has high one time emissions)

We should still avoid it where we can now that we know better.

It’s not that great for river fish, either.

- Is at a site of a type that is available with over 100x the capacity of fenging (ie. a hill with a dirt berm would count if there are 4000GWh of hills that could be plausibly used somewhere). If it does this it will help, but is still several orders of magnitude shy of replacing fossil fuels.

- Fulfils your criteria about not destroying an ecosystem.

- Is not built on top of a past project unless there are enough of whatever the past project is to fulfll criterion 1 (ie. a quarry or mine is fine if there are many similar mines or a handful of immense ones) or the cost of repeating the project elsewhere is included.

- Can empty its reserves in 2 months

- Doesn't take up a prohibitive amount of surface area (is at least 20kWh/m^2 or at most 10x the size of a solar array to fill it).

- Has an operating cost under $30/MWh of stored and produced energy

Otherwise pumped hydro does not meaningfully exist as it cannot beat batteries (the thing that is a long way from being good enough to replace fuels) or must destroy a watershed or other ecosystem.

There is no shortage of land to use for elevated reservoirs, and (again) no implied threat to watersheds in building them. There is no need for "at least 20 kWh/m^2". Reservoirs have many uses that all add value. They may store energy and water, provide recreation, habitat, irrigation, and a site for solar, all at once. There is no need for them to store 2 months' power. There is very little economy of scale: a dozen reservoirs are as good as one. Construction cost is not proportional to capacity. At worst, it goes as the square root, to build the perimeter dike.

Extraction rate is a question of how big and how many Pelton wheels attached to generation equipment you care to install.

And, as always, immediate and local cost will dictate choice. There is no need for universal numbers or a single answer for everybody.

Further intntional misrepr#sentation. Batteries solve the short term storage problem (especially sodium ion batteries). You're proposing a much worse solution to the short term storage problem as if it is relevant to the remaining unsolved problem (long term storage). Solving the long term (in space or time) storage problem yields solar supremacy -- conditions in which it becomes untenable to open a new fossil fuel facility or even keep existing ones open in 10 years even with trillions in ongoing subsidies.

> Construction cost is not proportional to capacity. At worst, it goes as the square root, to build the perimeter dike.

You need to make it deeper, or use more land. And when the largest project in the world is at cost parity with batteries in spite of using an existing project and river, that's a damning indictment of anything smaller.

The "largest project in the world" is, by definition, not representative.

There is, because it is the main impedement to the universality of renewable energy.

> The "largest project in the world" is, by definition, not representative.

Yes. Extremely large, recent infrastructure projects by the CCP tend to have vastly lowe stated costs than anything smaller or in another place. If it's unusual\y expensive, show me one which is representitive. Show me a breakdown of a small project (or any project) which uses a typical hill and costs less than projected battery costs at time of completion.

https://www.get-h2.de/en/project-lingen/

Power-to-gas has been the proposed solution for seasonal storage for a long time now. Few people who are interested in the topic believe that current battery technology can scale to store a couple of weeks worth of power. Maybe something like iron-air batteries, but the proven technology is elecrolysis optionally followed by upgrading the hydrogen to methane or ammonia.

Although the carbon emissions would be net neutral, Such a system would not be greenhouse gas neutral. Some methane from the natural gas plants will leak out. This is a gas that is 25 times more potent than CO2 over a 100 year timeframe [1].

Nitrous oxide, which is a byproduct of the combustion process, will be emitted and this gas is 298 times as potent as CO2 over a 100 year timeframe.

[1] https://www.epa.gov/ghgemissions/overview-greenhouse-gases

This is a solved problem. Please do not engage in idle, misinformed concern-trolling.

Point here being that you could avoid this whole class of problem with energy storage technology. Although Lithium Ion batteries present their own technical issues to solve, there are other energy storage technologies that show promise [1].

Regarding your comment, you took a leap in assuming this was assuming it was idle, misinformed concern-trolling. It could be that I am ignorant of the NOx scavenging, it could be that I am aware of it and take issue with it. Both possibilities you ignored.

Please review the HN guidelines, you may find this passage relevant,

Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith.

[1] https://aresnorthamerica.com/nevada-project/

Deserts are a dumb place for panels because the panels get hot and dusty. Heat cuts both conversion efficiency and panel lifetime. Accumulating dust can block as much as 80% of light.

The best place to site panels is floating on reservoirs and canals, where temperature is kept in check. Nobody knows how long floating panels could last. At the same time, they cut evaporative loss and biofouling, and provide complex habitat under for water creatures.

Next best is in farm fields, in rows with room for a tractor and equipment between. There, they cut heat stress and water loss, and run cooler than in desert or on rooftops. Most plants can use only a very limited amount of full sun in a day, and just endure more, welcoming shade. The panels produce year-round, complementing seasonal farm revenue.

A good way to deploy in fields is bifacial panels in vertical fence-rows running north-south to pick up morning and afternoon sun, during peak demand. Panels stay cooler, don't gather dust, and are out of the way of farm equipment; and fence mounts cost less than others. This works well in pasture, too, where livestock keep down weeds and benefit from shelter. (E.g., sheep produce better wool.)

For some crops, growing directly under (near-) horizontal panels protects them from harsh weather, often multiplying yield. A T-shaped mounting is practical here, with room under, and a gap between, for farm equipment.

Since the land is doing something else of value, there is no need to pack panels as tightly as they will go. There is way, way more viable dual-use farmland than could ever be needed for energy, so only the best places for it need be used.

Hydrocarbons are a poor choice of storage medium, because you need a source of carbon to make them, which is then released into the atmosphere when you burn it.

Hydrogen just needs water for feedstock. It is easily stored underground, including in used up fracking fields. It may be transported in liquified form, similar to LNG.

Ammonia needs just water and air as feedstock. It stores in liquid form under light pressure at room temperature, and transports well.

Hydrogen and ammonia are both massively valuable as feedstock for myriad industrial, transport, and agricultural processes, so when your tankage is full, all your excess production may be sold for ready cash.

If local storage looks likely to be used up, and you can't schedule power from a transmission line, you order a shipment of ammonia from any of many tropical solar farms.

Let's say renewable electricity generation capacity increases significantly (which needs to happen as we all know), then due to fluctuations around the year of solar irradiation alone there need to be weeks if not months worth of electricity storage (in whatever form).

Ammonia is exactly that, storage of energy that gets converted to electricity, to keep up with grid demand. Ammonia then _is_ your weeks/months worth of storage.

Do you think utilities store months of fuel, nowadays? Or do they rely on regular deliveries? Do you think relying on regular deliveries of ammonia, in winter, would be much different from relying on deliveries of NG year-round, as today?

Yet I'd assume _most_ places in the global west still have fluctuating irradiation and wind to a degree that makes weeks worth of storage necessary.

> Do you think utilities store months of fuel, nowadays?

The utilities probably only to a certain degree. But it doesn't really matter who stores the fuel, right?

> The United States has the world's largest reported strategic petroleum reserve, with a total capacity of 727 million barrels. If completely filled, the U.S. SPR could theoretically replace about 60 days of oil imports. [1]

These reserves are of course not used to supply power plants.

But I'd bet as soon as the renewable slice of electricity generation exceeds some 50-60 % of total supply, the authorities will not have days but weeks or maybe months worth of natural gas or hydrogen or ammonia stored to supply the grid (with according power plants) over extended periods of low renewable generation.

Just thinking about how essential the electric grid is for society to work, convinces me that it won't be days worth but significantly more.

[1] https://en.m.wikipedia.org/wiki/Global_strategic_petroleum_r...

As to deliveries from around the world. Any country will of course make a trade off between the political goal of independence or self sufficiency and economic considerations. Countries that have sufficient renewable electricity generation potential to be independent from external supplies will rather try to avoid external dependency, don't you think?

Which would require storage.

Also, imagine what happens as combustion engine cars get replaced more and more by EVs. The strategic petroleum reserves probably become less important and grid stability becomes more important. And I don't think the EV batteries are going to provide enough buffer to enable a stable grid all year round.

You miss the point about the tropics, again. Places with reliable insolation will be exporters of synthetic fuel. None will have monopoly power, because the sun shines on them all equally. Northern countries may buy as much as they can use from them, so will not need more storage than for the time until the next shipment.

The US keeps a "strategic petroleum reserve" specifically because it has been subject to embargo by a limited group of producers. There can be no such embargo of synthetics from renewables, so no value in any such "strategic reserve".

Imagine some non tropic country were to gradually increase its renewable electricity generation capacity. Solar on more and more roofs. The country now reaches a capacity that matches its peak electrical power consumption when the sun shines at noon and the wind blows everywhere.

Now there are two possibilities.

A. They stop increasing generation capacity. When generation is _below_ peak (because evening and no wind) this country has to rely on storage or imports.

B. The country continues increasing renewable generation capacity, so when the sun shines and the wind blows, they have excess electricity. Which they can store in batteries or as hydrogen or derivatives.

Why should any country choose A over B?

And why should they not continue to increase capacity (until all reasonable surfaces are covered) in scenario B until they maybe even are independent?

I'd say the only reason not to do that would be if imported energy were cheaper.

Clearly B is better, but they get to A on the way there. On the way to B, they may find they import power infrequently enough that they prefer to stop building out. That is a legitimate choice for most.

Cost is all-important, in energy policy.

But I wouldn't worry about putting them in a landfill either. They're not particularly dangerous.

Voicing worries about used up solar panels is cheap concern trolling.

This is called a dystopia.

Is a desert covered in solar more or less a dystopia than the smog clouds that currently engulf LA?

Not sure how that'd work. To get over 50km range you need a gas engine that provides 100% of the power to the car at highway speeds. A small engine won't pull that off.

There are motorbike engines which produce 30kW (double or triple what a tesla needs to cruise) and can be lifted with one hand. Detune it for longevity, efficiency and noise, add a 10-15kW stator and a 10L tank and you can have a range extender which would take up less than half the boot of a sedan.

If we find our collective sanity and allow travelling long distance at 80km/h that halves.

Hell if we could get our act together and design sane sized vehicles with universal standards you could just stop and swap out a pair of 30kg batteries every hour or two.

>>> If we find our collective sanity and allow travelling long distance at 80km/h that halves.

I'd never want to travel 500km at 80km/h. That is nonsense. Also, having 30kW engine in a car on a highway is a life threatening risk, since you cant easily escape dangerous situations (overtaking other vehicles and acceleration at higher speeds takes way too long) - and we're not even talking about so absolutely hip and unnecessary SUVs or a fully loaded car.

This is solved by having small batteries where fires can be contained and directed out of the vehicle and by using safer chemistries like LiFePo4.

> I'd never want to travel 500km at 80km/h. That is nonsense.

Just because you don't want to shouldn't mean you get to make everyone everywhere carry around 2-4x as much vehicle and battery as they need just to save 20% trip time.

A status quo where a vehicle can travel at a relatively sane, safe (half the collision energy, and braking distance), and efficient speed without fragile ego'd babies going completely postal because they have to wait 30 seconds to overtake is one where people who don't travel often can live with a vehicle that costs a quarter as much, weighs half as much, produces 1/16th the road wear and uses half the energy.

> Also, having 30kW engine in a car on a highway is a life threatening risk, since you cant easily escape dangerous situations (overtaking other vehicles and acceleration at higher speeds takes way too long) - and we're not even talking about so absolutely hip and unnecessary SUVs or a fully loaded car.

You're not burning 200kW for the whole trip. You'd still have your electric motor and batteries, you only need the average power from your range extender. Or if the base range is 50km, your range extender only needs to provide 3/4 of the energy to give you 2-3 hours of time between charge breaks (which will be short)