As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use.
> As of 2018 coal power under construction was 236 GW, planned 339 GW, and 50 GW was commissioned and 31 GW retired
If we want to replace those new plants we'll need 100.000 of those shafts. And that's not counting the existing plants, and the other fossil-fuel based plants. Think of the quantity of concrete that involves. That's just insane. If we want to actively tackle electricity generation we need to use the most efficient low-carbon tech that we already know.
Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place.
It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time.
The most immediate need for energy storage is frequency regulation, and short hours-long dips in power output. If we can solve that we can scale renewables very far.
For days-long dips in power output, it's probably better to keep some gas power plants on stand-by. I think many areas of the world has enough of them to handle these needs already. To make it sustainable, they could be switched to using renewables fuels, like hydrogen or ammonia made from electricity. We're going to need a shit-ton of those kinds of fuels for trucks, ships and airplanes anyway, so setting aside some of it for backup power wouldn't be a huge problem.
For seasonal variations, I think trash burning power plants is a reasonable solution. Sweden and Norway has some of them, and they also provide heating to nearby homes. I mean, yeah: first of all we should reduce, reuse and recycle. But eventually our trash become unrecyclable, and burning it seems to be the best option. Modern facilities seems to be able to extract almost all harmful compounds from the waste then. There are also experiments with carbon capture from these plants, which in a fully renewable world could make them carbon-negative, and become one of several tools to help reduce CO2 in the atmosphere again over time.
And of course, nuclear would be a great help. If it can be made cheap enough again, it can be used for seasonal variations. But we're still going to need renewables. So we still need energy storage for frequency regulations and minute/hours-long dips in energy output. Nuclear power plants are NOT a good solution for that.
Not true in northern European countries. The problem isn't day to day regulation, it's the massive demand in cold snaps in winter (when there is very little wind generation - cold weather tends to have little wind). You're talking balancing 20-30GW of additional demand with little solar/wind generation for weeks/months - probably at least 1TWh of storage required for the UK alone.
Keep in mind this will only get worse as heating demand is switched from natgas to electricity.
This seems like a "running before we can walk" statement. Until we can handle day to day problems, it seems weird to worry about edge cases. I imagine as we transition to renewables and storage we will still have fossil fuel peeker plants to handle these sorts of snaps.
It won't be until our power storage is far more beefed up that we'll shut those down, and that will take years.
Right, and my point is that they aren't going to decommission all backup power until they are at the point where sun/wind/storage can actually be relied on for more than just the good days.
We have a long trip to get there, so why worry about a once in 3/5 year event? We wouldn't go a year without fossil fuels and say "Ok, that was it! Demolish all the plants right now!"
A cold snap like that can happen every 3-5 years, think really cold February. If you don't have the capacity to handle it people will die and lots of things will break. It is not an edgcase
It's actually worse than that, there are many days in winter in the UK with high demand and virtually no solar/wind output. But obviously a really cold snap would be even worse (and as you said isn't an edge case - even if it is look at the damage that happened in Texas when it wasn't accounted for)
It is when we aren't running 1 year on pure renewables. Let's worry about events that happen every 3 to 5 years when we've got 1 year of renewable only figured out.
It will take years before this is potentially a problem and by that time we'll likely have gone through a few cold snaps.
Homes in the UK are poorly insulated, likely due to a previous over-reliance on fossil fuels. https://www.theguardian.com/environment/damian-carrington-bl... Better insulation and switching to district heating where applicable could yield massive savings.
District heating still needs heat to come from somewhere. Admittedly, low grade heat like is used for heating can be stored for days in the form of hot water in insulated tanks.
Long distance power transmission is a significant political and military liability, not to mention a fantastic terrorist target.
We cannot guarantee that the UK will be at peace with every county between them and the Sahara forever. Hosting the power line would grant significant political or military leverage.
You don't want a single point of failure. Having multiple lines across a geographic space is the way to go.
It's a big upfront investment, but it could be much cheaper than storage at scale.
I think ultimately you want power transmission stretching from the UK to Japan so as the sun moves the power generation continues.
I imagine it will happen one day, because it would seem to make so much sense, but this is something governments could make happen a lot sooner if they put their mind to it.
Importing energy from Sahara comes with serious geopolitical issues. Do you really want to commit to peacekeeping in a huge area of Africa? Keep in mind that oil can be stockpiled much more easily than electricity, stockpiles that let you weather small storms. Importing electricity means being on top of every hint of a blip.
Wrt cold snaps being a big problem, it seems like we could just massively insulate dwelling and improve our energy use auditing, if it became necessary? Vacuum insulation panels are a bit pricey, but they’re crazy insulative for the thickness. If we’re willing to deal with thicker walls, there are a variety of other options that are downright cheap (shredded newspaper, for example).
We’ve been designing around super cheap on-demand energy for a while now, but we did manage before that.
The problem is the UK sees maybe 1-2GW of renewable generation sometimes in winter while demand is about 50GW. So you'd have to overbuild 25x to cope with these days.
Keep in mind the UK already has about 30GW of solar and wind potential nameplate capacity. Your suggestion would result in a requirement of 700GW of solar and wind to be installed. On windy and sunny days would result in probably 350GW of generation, at least 300GW more than we need.
Actually, almost none of our trash is recyclable (despite what you've heard). Plastic is particularly bad, and it's only now, with China banning import of "recyclable" materials, that we're finally seeing just how much of a farce it is.
Burying it is a form of CO2 sequestration. Burning it just releases it into the atmosphere.
But it's already out of the ground. I'd rather burn 1T CO2 worth of plastic trash made from oil and prevent 1T CO2 worth of coal or heavy oil being extracted and burnt. Not that it's 1-to-1, point is burying plastic is probably less net carbon vs burning.
> It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time.
You are only looking one half of the problem. Wind power in the UK has a power factor of about 35%. What that means is to meet the average demand from the UK electricity grid we'd need not install 3 times as much Wind Power as the demand. This is borne out in the current figures, we have some 25GW installed wind power for an average of about 6GW supplied. If we have enough renewables to meet the demand on average, a windy day across the UK is going to result in a glut of power.
If we don't have ways of storing that modestly efficiently then our only choice will be to take turbines out of service, increasing the overall cost.
That's the wrong comparison. We don't need to replace generation capacity with the same capacity of batteries. Batteries don't generate any electricity after all. We need batteries to smooth out differences between demand and generation. The total amount we'll need is very much still up in the air. Better interconnects, good use of existing hydro, overbuilding renewables, shaping demand, are all other ways to balance loads and guarantee enough power at all times, all of which reduce the need for batteries.
I think[0] we should probably be aiming for a few hours of storage, even with every affordable grid interconnect (which would help a lot with short winter days). We use less power at night — and some of what we do use is incentivised by lower nighttime electricity costs from power plants that don’t scale down well — but I expect we will continue to use some at night forever.
For the sake of Fermi estimation, I assume average electricity use in a developed nation is 1kW/person, and that average all-forms power use in the same is 5kW/person.
Transportation is almost certainly going to be batteries or synthesised fuels like hydrogen, and can only be backed by gravity storage if you have the kind of beamed power that would be banned by international treaty on the grounds of being too easily weaponizable[1].
If you’ll permit me to assume grid interconnects and lower nighttime demand than at present due to different pricing incentives, we might be able to need a mere 3kW-hours/person of electricity storage per night.
Using the lifetime cost estimates in the article, 3kWh/person/night is about $0.51/person/night for gravity storage and $1.10/person/night for LiIon. Neither is bank-breaking, but cheaper is better.
However, the volume required is a different question: 3kWh of batteries has a volume of 4.3 to 12 litres, while 3kWh of gravity storage is 1.1 metric ton kilometres[2].
You can make the distance required smaller by using more mass, but if I assume the average home mass is about 200 tons, you’d still have to raise the entire building 5.5 meters every day to store the same energy as a backpack of batteries. I do not expect construction on this scale to be the optimal solution in general, despite it being a very good idea in some specific cases such as hydro dams and preexisting deep shafts.
[0] Armchair opinion — I’m a software engineer not a civil engineer.
[1] Assuming they’ve read or watched any Larry Niven, the Bobbiverse, The Expanse, Babylon 5, or the news at any point in the decade following the second week of September 2001 — 'A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.'
Large scale hydro electric dams are already large scale batteries across months. The specific day of the week energy is released is not particularly relevant let alone time of day. 6.6% of US electricity is from hydro, assuming 2/3 flexable your looking at 4.4% of daily power demand or ~1 hour of full grid storage every day is already built.
Excess capacity is required for storage to work and reduces the need for energy storage. But, once you start talking excess capacity, transmission dramatically reduces the need for storage.
Assuming storage costs say 2x as much as wind generation then building excess wind capacity is worth it until ~1/2 of a wind turbines output is wasted. Thus if we are looking at 3kWh of storage that can be banked at any time of the day we are looking at a lot of excess capacity, yet somehow still supposed to have a 3kWh per night deficit.
"Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place"
We actually also do have self created gravity-based systems, where we also do the work by ourself, to have a energy storage on demand:
They work reliable and with big capacity since the very beginning of electricity. The only problem is ... scale. You cannot just build them where you want them. You need rivers and height differences.
Unless you create such systems completely artificial and there are plans to do so, but that will be very expensive.
edit:
here is a paper (in german) discussing such possibilities, to create a artificial pumped-storage out of the remains of surface mining
and my opinion is, that I am not a fan of complicated solutions, like the originial solution from the article seems to be, which is also stated as "The technology is still “incredibly immature”
There are solutions to make batteries without rare elements.
They just don't reach the energy density of lithium based ones, but that is not really a problem, when you have them stationary.
So if you could scale up production of these and in the end, have a big battery in every home/factory connected to the grid - you would have a stable grid without any need for gas- or coal powered backup.
Side note on what is currently existing with gravity.
The suiss folks are gaming the west European energy market this way.
When the French produce too much nuclear energy, the German have leftover and stop buying it 100%w
Price go down.
Swiss buy it cheap and pump water in their dam system with it.
Inevitably, the french grid align and produce a bit less. Price goes up slightly.
That when the suiss comes out, release the water into a turbine system and sell the energy for a higher price that what they bought it for to German, French and Italian grid.
I can’t even be mad at them. They have the perfect setup. But you need the Swiss alp and climate to do what they are doing.
And being freaking Swiss.
Source/Context from a Swiss news paper : le temps, in French
They describe that « system » and apparently it’s being disturb in recent years with the evolution of the German market.
Maybe I do not understand it fully (ne pas parle de francais), but where do they game the system?
You buy cheap when you have storage and sell expensive when demand goes up.
Pretty much how the market should work?
This way there is incentive to balance it out (by creating storage) - and in this case stabilize the grid.
When the grid would become more flexible, so even homeowners can do this with their solar panels and big batteries - then this should be net gain for everyone, no?
Unless gaming it, with big money, destabilises it. So some safeguards probably should remain.
You are correct, it's not gaming the system indeed. It's more something that they decided to do on their own, and rightfully so.
It's a bit innervating for French tax payers to be on that side of the bargain. But at the same time, we have nuclear power plant, those cannot react that swiftly to market demands changes... it's all fair game. They actually provide some kind of buffer service.
It's not gaming the system, it is arbitrage. However, it is pretty terrible for producers unable to exploit price swings. E.g a nuclear plant produces electricity at a fixed cost and may sell it at a loss when the price is low, but recoups the losses when the price is high. Since arbitrage smooth out the price peaks, it damages nuclear's profitability. One could say that's too bad for nuclear, others (nuclear lobbyists) say that regulation is needed to prevent electricity arbitrage.
If nuclear can offer sustained cheaper than average generation then the market would allow a long term fixed price contract — they shouldn’t need to sell their full output at spot rates. Consumers that want predictability could buy on these contracts.
How much of a swing in pricing are we talking about here? Because that storage mechanism is maybe 80% efficient. So the price swing would have to be at least that big to break even. And in that case, if they are helping to smooth out swings in demand that are that large... Sounds like they're providing a valuable service.
EDIT: Keep in mind that electricity is entirely fungible. This is no different than the Swiss turning on a power plant when prices are higher. Except it would probably be too expensive to have a power plant just sitting there idle when the price isn't "high enough".
> it would probably be too expensive to have a power plant just sitting there idle when the price isn't "high enough"
This is exactly what is done, and pretty much inevitably must be done - grids need spare capacity that can be relied on to spin up rapidly when demanded, that's usually done by gas turbine plants.
I did a bit of scratch math with the notion this might be more suited for individual, home power storage rather than grid supply - You need something in the order of a 5m tall tower bearing 73 tonnes to store 1 kilowatt hour (even then, ignoring conversion losses). So that's the weight of ~ten class-4 fully laden heavy trucks.
Once you can get it up in the air then the higher you can go you're doubling your storage in a linear fashion. Hoist one of those trucks to 50 meters (perhaps you have a handy cliff in your backyard) and you've stored as much as the ten trucks did at 5 meters.
So yeah scale seems hard, but the low technology/materials requirements and potential for gradual scale-up make this worthy of deep investigation. I think there's a lot of wandering off into dead-ends as far as limitations go though - Solutions that depend on a lot of concrete pouring, for example, are a no-go if the end goal is reducing atmospheric carbon.
Yes, but only once. This is energy storage not energy source for the purpose of human utility. The ability to pull that 1kw of potential energy back up (with some renewable source eg wind turbine) to be output over again is where the comparison breaks down.
A fairer comparison is current battery tech, you can pack something like 40kwh in 200kg of batteries (rough guess based on leaf ev battery modules). So vastly more in the same space/weight. But those are complex and energy intensive to manufacture, and have limited lifespans before further energy investment is required to recycle/replace them. The relative simplicity and long lifespan of gravity storage seems like it has potential. Not to mention the potential for owner/operator to self install, which could be great for developing nations.
Absolutely, useful just to illustrate the scale we're talking about for a given amount of energy stored as a real-world analog easy to recall.
Assuming you used cast iron as weights that has a density of ~7800kg/m³ at regular temperatures, so you're looking at about 10 cubic meters for that 1kWh of potential energy storage using an abundantly available, non-toxic material that will endure.
I can imagine this tech all packed up in a standard 40ft shipping container and dropped on premise.
This would be rather simple tech, that can supplement solar and wind on your farm, lodge, campsite or island. Another piece in the puzzle for smaller scale independence.
Not to replace metropolis-scale energy demands, as grandparent implies, but to smooth out fluctuations on hourly, household scale.
I imagine chemical batteries would be easier to ship and install, and require less maintenance. I really can't imagine any mechanical system that involves plugging and unplugging a load (or anything more complex than that) to be useful at small scales.
There will be a maximum drop rate that is supported by the machinery being built, and it seems reasonable, though not mandatory, that a 5x weight system will be designed to handle more generation than whatever it's 5x of.
Construction material is a meaningless metric. If you compare coal or gas plants you need to consider the materials they consume and infrastructure needed for fuel transport. This is a big number, many times the material used for the plant itself.
The only meaningful comparison is material used vs solar. Once these things are built they use near zero resources. For everything else you have to keep mining shitloads of material forever.
How much coal do we have to mine for coal plants? How many gas wells and pipelines for gas plants? What about transport? How much does it take to mine and process all the uranium into fissile isotopes for nuclear?
With wind and solar you plop the thing in a field and get years, maybe decades of energy with no input.
I'm convinced that all these land use and building materials costs studies are just FUD funded by the fossil fuel industry.
Please link to a source/calculation where a wind turbine uses more resources than a coal plant to build. I mean, you can even do napkin math and see that there’s no way multiple buildings and vast mining infrastructure take less material than a turbine farm.
If you want to take a coal plant, you have to compare it with something that's comparable.
A coal plant is a 1000MW machinery. A wind turbine is in the order of 10MW. Also, turbines have a very low capacity factor so you have to double them to guarantee their output and combine them with storage. So it's 1 coal plant vs 200 turbines at the very least.
But coal plants use an absurd amount of coal and everything they don't burn ends up as ash.
And have you been close to a big coal plant? They're massive. A coal plant probably used more land than 200 turbines and unlike turbines the land is unusable.
Coal plants use many times their mass in coal during their lifetime. If you're looking at total materials needed over the lifetime of the plant, I wouldn't be surprised if coal was 100X higher than 200 turbines.
It does far less damage than any other source of power. Unlike solar, it uses no space. Unlike fossil fuel and nuclear, it uses no continuous inputs.
Coal and gas plants use many times their weight in materials for a lifetime of operation. Nuclear probably does too because the massive waste involve in uranium refining.
What do you suggest as a greener power source than wind?
So? How much resources does it take to mine thousands of tons of coal a day, or billions of BTU of natural gas?
With solar and wind, you put it up and you're done. No more inputs. It chills in the field.
With coal and gas you're feeding shit tons of material into it every day. And you always need more, for the life of the plant.
It's bonkers you think the amount of steel and concrete that go into a turbine are anywhere close to comparing to the raw materials other power sources consume.
Turbines require steel and concrete. So does every other building above 5 floors
The problem with wind is storing the energy. I live in the Pacific NW and when you drive through the Columbia Gorge you see hundreds of these windmills. I have have visited the Wild Horse Wind facilities and they store energy using batteries -- terrible. The dams below can back up water, but wind blows whenever is may. The dams also provide safety from flood, a waterway, recreation, ... windmills just pollute the sky, kill song birds, and can not produce energy on demand nor store it effectively. Talk to engineers for Bonneville and they mock the windmills.
If they are going to use wind why not pump water up from the Columbia River up to the top of the surrounding hills? Use the potential energy at least.
Are you actually complaining that wind is bad because it ruins the view?
Windows, cars, and pet cats kill multitudes more birds than windmills
Hydro plants do use wind to bank energy. Either by shutting down and banking water when the wind is blowing, or even running the pumps in reverse.
I agree with you that energy storage is a big problem with wind. It is with solar too. But we can get near 50% wind and solar before it becomes a problem since much more energy is used during the day.
Dams also have a finite lifetime, something nobody really talks about. They silt up over 50-100 years until they're completely full. This is a bigger problem in places like China with turbid water but happens everywhere eventually. The sun will shine and wind will blown till long after we're gone but dam sites will be gone eventually.
You misunderstand the impact of the dams on the ecosystem. Salmon are hanging by a thread in the Columbia, and only a very aggressive hatchery program has kept them from collapse.
Essentially all buildable sites have already been built, and there's a growing awareness some existing damns need to come down. The Gorge is not some great untapped resource for pumped storage that people were too distracted by wind power to discover.
I'm friends with an environmental economist that did the analysis while working for the state of Oregon. He also was involved in the reports that shut down Boardman. The information is accurate.
Your assumption that we need that much storage is simply wrong. This pops up in just about any article on HN mentioning batteries. Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage and that therefore we need coal/nuclear/etc. (i.e. really expensive ways to generate energy) because buying so many batteries is obviously stupendously expensive. It's a popular argument with nuclear proponents and with the fossil fuel industry.
The reasoning roughly goes like this: wind and solar capacity varies because wind doesn't always blow and the sun doesn't always shine. This is very obviously true of course. Except these effects are local, temporary and typically result in a reduced capacity rather than a complete collapse. You always get some output out of solar panels (except at night). And wind turbines might stop spinning but it's extremely rare for that to be a continent wide thing. Offshore wind is pretty reliable. Also these effects are kind of predictable via weather forecasts so we can plan for them. Same with seasonal patterns. Simple cables rather than batteries are the key technology that we need. And we mostly have that in place already.
The grid connects power plants via cables. So, we can compensate for local dips in power with remote peaks. What matters is the collective performance of the grid. That still fluctuates but not nearly so dramatically that you'd need a lot of battery. E.g. the European grid is very connected. So, you might get power from Norwegian hydro, North Sea offshore wind, German on shore wind, solar plants in Spain, France, Germany, etc. or any of the gazillions of solar panels on people's houses. And of course there are coal, gas and nuclear still on the grid as well (for now).
All of that failing 100% at the same time is simply not a thing. Not even close. It's not something grid operators plan for. It might dip by 20-30% but it might also peak by that much. And it's likely to average out over time in a very predictable way. All that means is that we need to have a little more capacity. 2x would be overkill. 1.2 to 1.3x plus some battery will probably do the trick.
Batteries on the grid are intended for and used exclusively for absorbing short term peaks and dips in both supply and demand. Short term as in hours/minutes; not days or weeks. They are very good at that.
This is why modest amounts of lithium ion batteries are being used successfully in various countries. These batteries can provide large amounts of power (MW/GW) for typically not more than a few hours. The reason that is cost effective (despite the cost of these batteries) is that taking e.g. gas peaker plants online for a few hours/minutes and then offline again is expensive and slow. And of course with cheaper wind and solar providing cheap power most of the time, gas plants are increasingly pushed in that role because they are more expensive per kwh to operate. Gas plants on stand by still cost money. And turning them on costs more money. Batteries basically enable grids to have fewer (and eventually none) of those plants. These gravity based batteries have the same role. It's a cheaper alternative to lithium ion batteries.
Currently, clean energy is the dominant form of energy in many countries already (e.g. Europe, China, parts of the US). In some countries it's well over 50%. This proves the point because these grids don't feature a lot of battery currently and the combined capacity of peaker plants (i.e. not operating continously) is far smaller than the presumed need for batteries. If you were right, these countries would be facing massive blackouts all the time as their dominant form of energy disappears for days/weeks on end. That's obviously not a thing.
The cheapest "energy storage" is bandwidth and demand based billing.
The required battery storage cost to guarantee my 3 KW electric clothes dryer could theoretically operate 24x7 when needed after three weeks of cloudy windless weather at midnight is staggering. The alternative is demand based billing and program my dryer to never accept a KWh that costs more than say, seven cents. On a minute by minute basis I don't care if my "hour" dryer cycle takes 65 minutes because a cloud passed overhead and it slept for five minutes. Its also worth considering that "in theory" people who design for max theoretical load MUST assume my clothes dryer will run for 24 hours a day 7 days a week, when in practice I have never done more than five hour long loads of laundry in a row, and that was after traveling out of country for two weeks (after zero electrical demand for 14 days)
Even data centers can do stuff like vmware vmotion running virtual hosts off a cloudy cloud data center to a sunny cloud data center with no user interruption.
The idea that the wall outlet is an infinite source of energy is going away, or if its demanded for a hospital operating room or nuclear power plant or something, those KWh are going to cost like $5 or something similar and that's just how its going to be. Its not going to be that much suffering; right now my multi KW airconditioner instantly starts up when the thermostat says go, and in a decade maybe the electric company contract says it's guaranteed to start within the next ten minutes 99% of the time, and that sounds like a nice deal if it cuts my bill in half and eliminates CO2 output.
Problem is: how are you going to convince great numbers of people to alter their daily routine that might also be quite synchronized across a country's population?
Like tea time in the UK where apparently millions of people turn on their kettles (2 kilowatts each) in synchrony to get some hot water.
What if they also like to cook something with their stove (another 2 KW) to get a nice dinner, around the same time?
He told you: Dynamic rates and appliances that let you adjust their behavior based on rates. Have people pay based on the demand and the most able to alter their usage will do so.
I'm skeptical-- but probably for different reasons that you.
W/ PG&E and MCE the utility can't even manage to tell me my current rate-- determining from my bills requires solving a linear system in three unknowns, requiring three bills. And the rates change quarterly, so I can only determine the rates at the moment they no longer apply. The rate scheme also has various non-linearities such that my total rate depends on my overall usage over the year and as a result my true marginal rate is unknowable at any given time. I dunno how rates are supposed to incentivize behavior when they're so opaque.
So I like to imagine a future with smart electrical panels and appliances where their behavior can be rate shaped in realtime, ... but then I encounter the actual behavior of the PUC and utilities and a future with demand shaped by economics seems distant indeed.
Sounds like you're mostly unaware of the issue that trying to compensate region, country and sometimes even continent wide lows/peaks would require many gigawatts of transmission capacity in the form of cables in arbitrary directions. Even if the European grid is well interconnected it's painfully far from handling such situations.
And that is not even accounting for the fact that right now only a small proportion of total energy use is transmitted electrically, which means that with future energy generation becoming greener being strongly tied to having more solar/wind (which is also electrical), there will anyway have to be a massive increase in grid capacity.
> Currently, clean energy is the dominant form of energy in many countries already (e.g. Europe, China, parts of the US)
Just not true. Yes, some countries are (Iceland is one of the few) but most European countries are far from what you claim.
Maybe you meant energy transmitted as electricity instead of all energy.
> Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage
+1 for the post, but I don't see this that much.
Whenever I see the debate come up, it's when someone is directly comparing the cost of solar to nuclear/natgas without factoring in the additional cost of batteries and DC lines, which obviously leads to an invalid (or at least incomplete) comparison.
I'd like to add that with the rapid electrification of car- and soon truck and ships- fleets, we are already rolling out that giant battery-pack, as we speak.
So 10E6 sounds practicable and, as discussed previously, may be a significant overestimate of actual need. Suspect 50 year life cycle costs and various environmental and political externalities would be substantially lower for gravity-based solutions. But who knows?
Concrete requirements? About 10E10 tons of concrete are consumed worldwide each year.
Again, 10E6 doesn’t look so big, but might involve some engineering cleverness.
But 10E6 big, capital intensive, fairly generic things can justify a lot of engineering cleverness in that one generic design. Geotech would need a lot of thought.
You are absolutely dead on right. We need to stop trying to bang on a model that isn't working and be willing to think even more outside of the box.
All of this is essentially ways to create hydroelectric plants without the water. If we can find a way to create more of them without massive disruption it'd probably be the most effective.
We need to find a solution that isn't just based on good wishes.
> As usual everyone is fixated on price when the real hurdle will be scale
If it's way too expensive (and there's no obvious way to reduce costs), then scalability is irrelevant, which is probably why people are fixated on it. We need both scalability and price to be favorable.
Batteries do not replace power generation capacity directly.
They can, however, be configured to cover huge surge loads for short moments, or smooth out small discrepancies over a longer span, in more or less the same footprint.
If you want a GW of coal, you need a GW plant, whereas with batteries you can decide between a gigawatt-hour or a 1000 megawatt-hour using a similiar footprint (scale to capacity of chosen technology).
This reduces the need for significant unclean backup capacity, and either decommissioning them or reducing their usage.
Does it? If you use iron instead then we only need to know that it has eight times the density of water. Multiplying a volume by eight is not a lot; it's only twice the size in length, width, and depth.
So let's imagine replacing a typical hydroelectric power station [0] with a 'gravicity' system. Supposing the same depth you need a system of about one third of its length and its width and then fill it to the brim with iron. And of course do not forget to install cranes that are able to lift this iron to another space about 200m lower and back up.
By the way, for concrete blocks it would only be a volume factor of 2.5, which would mean about 36% more in length, width and height.
All in all, the amount of space that can possibly be gained with these systems seems pretty minimal to me.
Maybe our expectation that we can match generation to consumption with storage, is just plain wrong.
Maybe all we need is to have massive overcapacity of renewables - if we have 10x more solar than we need, even the most cloudy day will still provide power.
For reference (https://en.m.wikipedia.org/wiki/Coal-fired_power_station):
> As of 2018 coal power under construction was 236 GW, planned 339 GW, and 50 GW was commissioned and 31 GW retired
If we want to replace those new plants we'll need 100.000 of those shafts. And that's not counting the existing plants, and the other fossil-fuel based plants. Think of the quantity of concrete that involves. That's just insane. If we want to actively tackle electricity generation we need to use the most efficient low-carbon tech that we already know.
Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place.