Arc furnaces are crazy energy intensive. But if solar power keeps doubling every 2 years, we will very soon have way more power than we know what to do with (at certain times in the day). Arc furnaces are a good way to suck up the negative electricity spot prices!

- 1.44 gigajoules (0.4MWh) is required for 1 ton of steel. In theory.

- 300T of steel needs 132 MWh, and a "power-on time" (the time that steel is being melted with an arc) of approximately 37 minutes.

---- wikipedia end -----

From https://ourworldindata.org/grapher/electricity-prod-source-s...: total world electricity from renewable was 10,700TWh in 2021. 11,600 TWh in 2023.

1.5 billions (metric) tons of crude steel were produced in 2023. 30% of it by electric power.

------------------------

(A) Let's assume that 20% of those 30% already come from renewable (which is not the case, anyway). 30x20% is 6%. It means 24% of the 1.5 billions tons are looking for renewable.

It means 360 millions of tons needs its green energy.

It means we need to find 360 millions x 0.4MWh = 144 TWh.

If we don't assume (A), we get 152 TWh.

It means we need to dedicate ~1.5% of renewable worldwide energy to replace 24% of crude steel "e-production". In theory...

We observed +5% of renewable energy production worldwide. If we wanted to make the steel *production* go green (1.5*3.33 = 5%), in theory it could be possible in one year...in theory.

Tbh, I expected a more crazy conclusion. I'm quite sure the number is off by more than 10% though. But even if it was off by 100%, it would mean it's possible in 2 years.

On a side note: it's useless anyway if those 5% are not coming with a decrease of 5% of coil&gas consumption. Which is not what's happening...

Feel free to redo the math, I can make a mistake!

Also, another thing that's good about these types of energy intensive industrial operations is they can essentially act as a sort of battery - it's a large load on the grid but (I'm guessing, someone correct me if I'm wrong) could potentially be more flexible with respect to time shifting: if it's a bright sunny day, crank up the furnaces to full speed, but if it's cloudy, back off. That helps make solar installations more economical if there is a good chance something will be there to take up extra power.

So, if we want to produce 1,888 millions tons of crude steel with solar panels, and assuming we can supply with Jichuan solar park 10 plants producing 300T of steel:

1,888/3 = 630 steel factory = 630 Jichuan Solar park = 56700km2. It's a bit larger than Croatia. For steel only. And it's assuming ideal production, only solar panel surface...So it could be Ireland actually.

As for the "nice in theory", my small demonstration is actually in this ball park, because the other dead-spot is that I account for electric production. It represent ~30PWh and worldwide consumption of energy is ~180 PWh (85% of those are from fossil).

So this 5% increase of renewable energy, of total electricity production, is actually swimming in those 15%.

Most of the world's steel is produced from ore, which not only requires three times the energy of recycling scrap but also vast quantities of carbon from fossil fuels to incorporate into the alloy. I believe there's a relatively new electrolytic process for the ore but at far smaller scale and it requires even more power.

The main obstacle for investment is political stability and alignment.

This obviously won't happen overnight. But it suggests a few long term trends for steel production to move close to where renewable power is cheapest and most plentiful. E.g. Australia is a renewables power house and exports a lot of mined but unrefined materials. Long term it makes more sense to produce aluminium, steel, etc. locally instead of exporting the ore to China, India, etc. and then re-importing it the upcycled materials.

For oil and gas energy usage, you should take into account that usable energy and energy consumption are two things. When electrifying, you typically end up needing less energy overall. The notion of replacing oil twh with solar twh is simply wrong. This is something the IEA gets wrong in most of its reports. Which is one reason why their estimates and predictions keep having to be corrected by them every few years.

A good example is ICE cars vs. EVs. A gallon of gas represents about 33.7 kwh of energy. A Tesla can do over 4 miles per kwh. Most ICE cars get nowhere near 120 miles per gallon. Anything over 1 mile per kwh of gas is actually pretty good. Especially for bigger cars. So, an ICE car wastes about 70-80% or more of its energy (heat, noise, vibrations, friction, etc.). You see the same pattern in other sectors where electrifying usually also means improved efficiencies. Most Teslas only have 2-3 gallons worth of kwh in the car. An ICE car with a tank that small would have a terrible range.

So, a doubling or tripling of electricity generation might actually be good enough to replace most fossil fuel usage.

But with heat pumps (backed up by resistive heating since we get cold enough to need it), we can still get a win there. Natural gas and coal generation can be ~30% efficient, but heat pumps can readily have a 4:1 COP or better. Even factoring in the inefficient generation of electricity we can still heat our homes with net less energy and then focus on replacing our electricity generation with less polluting sources (eg a mix of nuclear baseload, wind+solar+battery, and natural gas as a fallback)

They are sufficiently more efficient (roughly 4x) than even adding the 60% inefficiency of gas turbines and electricity transmission, charging losses etc. do not destroy their inherent efficiency advantage.

That's actually a lot less than I thought it would be. My smallish (6kW) solar system on my garage has generated 20MWh in the ~3.5 years it's been operating. I'm sure 50 tons (in theory) of steel isn't huge by industrial standards, but that's more than I'd expect from a residential array in Michigan.

One of the side problem is energy density. Your garage can deliver 6kWh at best, but it can't deliver 12kWh for 30min.

It's the equivalent of if they identified something's velocity and you tried to contradict them by pointing to its acceleration.

The 5% is for all electric sources. I don't look at renewable only but any sources (and coil&gas makes a solid 60% of it).

Your capacity factor numbers are also off ex: 29.7% capacity factor averaged over 3 years https://en.wikipedia.org/wiki/Mount_Signal_Solar.

Thermal is also much lower than your suggesting. China the world’s #1 coal consumer has capacity factors under 50% because they are using them for load following. France’s nuclear averaged ~70% for years for similar reasons. It’s only where the there’s excess natural gas and minimal solar/wind that thermal can keep high capacity factors but that’s becoming rare.

Thermal power plants pay for fuel and therefore real world capacity factors are lower as renewable generation increases. I could point to many coal power plants in the 40-50% range, but that feels pointless.

Anyway, rooftop solar isn’t representative of the grid scale solar because it’s doesn’t use ideal angles for the latitude let alone 1 or 2 axis tracking. It’s also frequently shaded by trees etc. People trying to make money selling at wholesale prices just care more about efficiency than someone offsetting retail electricity rates.

“Wind and solar supplied 12% of global electricity in 2022” that’s the number I am tracking not how many panels they happened to use. Location and other details matter. Plopping down Solar in the UK, Germany, or southeastern Australia is a poor investment. So no I don’t give a fuck about hypothetical GW in dumb locations, it’s also irrelevant to the point I was making.

> can move the needle on total CO2 emissions because the effect on grid production is much less linear then traditional thermal power plants.

Batteries + Solar means is more linear than thermal not less.

Again just track renewables by kWh over the year not simply nameplate capacity if that’s what you want to know. It’s not some secret people actively tack and report it as useful information.

As to the rest of your points, market conditions exist before you install the power plant. Initially the question is wind or solar more useful needs to be addressed. Pick solar and many choices remain.

Install solar with 1 or even 2 axis tracking and you get more hours per day of generation from the same land and panels than fixed installation but higher cost per kWh. Install it X miles west and power comes on a little later each day. Add a battery and you can shift supply within the day. People don’t just plop down panels randomly there’s a huge amount of optimization up front to maximize long term gains.

Thermal on the other hand has fewer levers, shifting the power plants location doesn’t help match the demand curve and there’s no option for cheaper but less reliable output. The economics also completely kill the idea of having batteries to cover the after work spike in demand etc etc. Right now people are trying to decide if they want a power plant that’s only going to provide 45% of hypothetical capacity while still being forced to pay the full construction costs. Net result an absolutely massive increase in how much wind and solar generation is used not just installed each year.

Literally the quote I was responding to, with a source, before you ran off on this tangent, I presume because you can't read.

You've continually failed basic reading comprehension here.

But I hardly care at this point so I’ll leave with a more simple rebuttal:

Grid scale Solar’s global capacity factor has been flat over the last several years. So kW vs kWh only matters at the local level, globally the difference is a rounding error in terms of climate change and it’s going to remain that way for at least a decade.

So installed capacity increasing doesn't directly tell you much about the future composition of the grid, particularly in the absence of significant storage or overnight capable sources like wind (which after still variable).

Fossil fuel sources on the other hand are being rapidly downscaled. And if it’s not operationally profitable to run a gas plant at reduced capacity, the plant will have to shut down entirely. This is happening to peaker plants due to battery power coming online.

the economics of gas plants become much, much worse quickly. The cost of energy from a gas plant that’s run a small portion of its planned output is much higher due to the fixed costs.

This should push up the price of off-renewable time power, which will increase the business case for batteries. It’s a bit of a death loop.

Gas will be here for a long time yet but I predict mainstream forecasts are underestimating how quickly the tides will turn to the share of renewables

(admittedly maybe the capex for running the power lines to the facility is significant, but in the same proportion to the cost of the energy used as running transmission lines anywhere else)

there's a nice video illustrating the process at https://www.youtube.com/watch?v=T1CJ5NPW8MU. don't be alarmed, the part that looks like a major industrial accident is just what happens normally when they turn it on. a more detailed documentary with explanations, though unfortunately of an atypically large arc furnace, is in https://www.youtube.com/watch?v=eZRuVEfxIVI

in that particular case they say it runs 24/7

That was better than most fireworks displays. I checked the second video but don't understand the German explanation. Is that just the initial effects of the massive amounts of voltage?

(the power of a lightning strike is much higher than that of a steelmaking arc furnace because it has much higher voltage, possible because the conductive path through the plasma is kilometers long instead of centimeters long)

youtube has automatically translated subtitles which worked pretty well here. the relevant yt-dlp flags are i think --write-sub --write-auto-sub --sub-lang en,es (season to taste) and then the j key in mpv cycles through the languages you chose. this is also possible from youtube's web ui but enormously more awkward

They might rely on cheaper power to lower the average cost make financial sense, but that is a different than soley utilizing excess power.

If they cant rationalize the opex running 8 hours a day, there is still a problem. My understanding is that many of these plants cant even shut down and be restarted.

After, to a power grid, removing large loads are functionally equivalent to adding additional generation. So if you’re operating an arc furnace, and can shutdown quickly (which arc furnaces can), then grid operators will pay you for privilege of being able to shut you down at moments notice, and then pay even more for the electricity you’re not consuming, if the grid is forced to call upon that additional “capacity” due other issues on grid.

I’m not sure if arc furnaces today vary their usage in direct response to variable electricity prices through the day, rather than only acting as emergency ballast to be jettisoned in an emergency. But I would be very surprised if they didn’t, they’re a large enough load that they’ll have coordinate the usage with their local grid, and large enough that shifting the usage pattern to avoid high cost peaks would save them a very material amount of money.

guess i failed at that

And whether you said something right or wrong I at least would have liked to see it. Especially when it gets a callout like that.

All the more reason for me to stop engaging, isn't it?

The gist of it was that nuclear power is insufficient in and of itself because it is hard to regulate output to match grid requirements, and therefore that we need both nuclear and renewable energy sources, not just one or the other. Maybe I'm wrong, maybe I'm not, I'm out of here either way.

No, I don't think so. The skepticism all comes from your initial comment, not the followups.

> The gist of it was that nuclear power is insufficient in and of itself because it is hard to regulate output to match grid requirements, and therefore that we need both nuclear and renewable energy sources, not just one or the other. Maybe I'm wrong, maybe I'm not, I'm out of here either way.

Oh well that specific point is wrong. Modern nuclear can adjust its output quickly and within a wide range if the operator wants it to. We could run a 100% nuclear grid. The fundamental issue at hand is price, not capability, because reducing output makes the cost per watt go up.

how much do they get throttled up and down, and how frequently? i'd like to read more about this

I think in California 6% of electricity demand is pumping water. I'm almost willing to go on record and say that's the California Aqueduct and the actual number is higher. Okay I'm going to look.

https://www.ppic.org/publication/water-and-energy-in-califor...

> The water system uses approximately 20% of the state’s electricity and 30% of its natural gas for business and home use, according to data from 2001—accounting for more than 5% of California’s greenhouse gas emissions.

> Heating and other energy-intensive water uses in homes and businesses make up almost 90% of water-related energy use, while treatment, pumping, and conveyance of water and wastewater account for the rest.

That's 2% for everything which isn't heating water. Pumping is some smaller fraction of that.

Water heating is basically the poster child for “demand-response” technologies. You can easily heat your water a few hours earlier than normal with basically no consequences to the user. But you need to get reasonable smart about modelling people water usage, as people don’t tend forget or forgive a cold shower.

Regardless the point is eliminating the use of natural gas in heating water is itself a benefit.

Summary the more hot water you use the smaller the win is for tankless.

Other thing I've read and seems true is gas and heat pump water heaters cost about the same to run. I installed a heat pump unit five years ago. Works okay for two people. If you had three teenage girls and a wife that likes baths a tankless would be a better choice.

This will make a small dent in the 7.5% at scale.

If we create half as much concrete waste as demand, that 7.5% could drop by half.

It is hard to imagine it being cost effective to transport it to recycling centers.

The issue is whether the extra transport would offset any benefits - which I'd say is unclear. i.e. even if you had to truck this stuff to ports and put it on ships...that could be worth it, because we already truck every component of concrete around.

If old concrete can be turned into new cement, that is extremely valuable compared to using it as grit.

There are some logistics and energy questions, though. Transporting old concrete to the nearest steel plant could be too expensive to be worth it. And arc-furnace steel plants are still the exception, not the rule.

There's a lot more to environmental responsibility than just carbon. Killing all the fish to reduce carbon isn't an answer. Of course we're not talking about doing that, but aren't we? How do we know?

History tells us that government has repeatedly destroyed ecosystems while trying to repair or preserve them. The Grand Canyon, African elephant, countless small lakes and canyons around the US.

All of these were well meaning projects to preserve, protect, and repair ecosystems.

Responsible environmentalism is far more important than reducing carbon, is my point. So let's do both by asking questions.

Part of what makes the article and methodology linked here interesting is that it a) uses waste heat which b) is already theoretically able to come from renewable sources and c) can be used to to support manufacturing of structural components further upstream in the lifecycle of cement/concrete.

something like 15% of the material that gets carted to landfills is old concrete

generally speaking, old concrete is used in new concrete as (very) coarse aggregate. alternative coarse aggregate is mostly angular crushed stone, like the track ballast you see around railroad tracks. this is made by dynamiting deposits of limestone, granite, or basalt and feeding it through a rock crusher. while this sounds violent and energy-intensive, it's nothing compared to running a cement clinker kiln. most of the cost of coarse aggregate is from the cost of shipping it, not the cost of the energy needed to crush it; as wp says

> Large stone quarry and sand and gravel operations exist near virtually all population centers due to the high cost of transportation relative to the low value of the product. Trucking aggregate more than 40 kilometers is typically uneconomical

This one is large enough for several companies to make a living. What means it's large enough to care about.

So how do you account for this – temporary – CO2 emission when doing your calculations?

Often it depends on the story you're trying to tell... lying with statistics and all.

this is one of the reasons that green building promoters are advocating a return to lime cement for cases where it's applicable

The 2023 prediction updated the reference case to closer to 40% in 2050 (again some go higher).

That's a big jump in two years.

i.e. the solar industry won't start installing solar panels at an ever higher rate if the amount of solar penetration is almost 100%. In fact the relative value of installing panels will decline as we get nearer to it. Arguably that's already happened - i.e. power prices going negative scrapes a lot of the shine off private industry funding them.

Versus say, a natural process where while this might happen, the bounds aren't limited by humans making economic decisions for themselves (which of course, when you think about it also implies dangers in extrapolating effects of natural processes like climate change - the rate of some downstream parameter going up and looking linear and shallow could just be a very large system in the middle of moving into an exponential phase which extends well beyond our ability to manage it).

to look at it another way, when will we have so much solar energy production that it's hard to find a market for more solar energy at costs similar to present plant costs? right now a megawatt-hour of solar power costs usually about 25 dollars, half to a third of the cost of a megawatt-hour of power from coal or oil. the energy transition has, roughly speaking, cut the cost of energy in half. in sunny places, it's even cheaper. that means many energy-intensive industrial processes that were previously unprofitable have just become very profitable. how will that reshape the economy?

it's hard to say in detail, but clearly, as those ramp up, energy demand will increase

if you think the answer is '100% of current world electrical generation' or even '100% of current world marketed energy consumption' you've imported the implicit assumption that this seismic change in the energy market, unprecedented since the early days of the steam engine, won't reshape the economy at all and won't increase energy demand at all. this seems like a very implausible assumption

a more plausible endpoint is '100% of the sunlight that hits the earth'—once we start approaching that endpoint, we'll have problems like oxygen-producing algae dying off in the ocean because it's not getting any sun. that starts to become a problem at roughly 1000× current world marketed energy production, 10 doublings, so, around 02050

You are correct though that a naive prediction of constant doublings is definitely wrong. China is showing signs of slowing over the last month due to transmission and storage bottlenecks in a few locations. BNEF has an article about this.

Only short term. Humans quickly find ways to use power. There are so many energy-intensive tasks, humankind will not have enough power for a long time.

You can desalinate water or mine crypto. And if we have robots that are comparable to human capability, you can just scale production of everything endlessly.

Nuclear reactors can produce very high temperatures, but in most reactors the heat is moved to turbines using water. Are there ways to move the heat at the high temperatures required to melt steel? (AFAIK, even molten salt is too cold.)

Yes, you could potentially use waste heat from a reactor to preheat the tundish, and maybe the scrap and ladle. Nucor preheats using natural gas to save on electricity. No need to bring everything up from room temperature on electric power. A nuclear reactor immediately adjacent to a steel caster is probably not a great idea.

Most cement ends up as concrete.

Crushed concrete of various sizes is a valuable aggregate used as a cheaper alternative to crushed stone for road building etc.

In my area any time I see an ad selling crushed concrete it's gone by the time I ring. Perhaps because we have clay and sand soils around here there is a permanent shortage of such things.

Concrete rubble is also salvageable on the job site. Recycling would require transporting to a mill, crushing, separating, transporting to a furnace, and then the process described in the article starts.

Would be great to have a discussion of some other promising non-carbon energy sources, such as drilled geothermal.

Slightly off-topic - gen pop are often surprised when I mention that NET-ZERO == MAX-CO2 == MAX-HEAT. People often assume that getting to net-zero is 'mission accomplished' .. but its the area under the curve that counts, the total CO2/GHG equiv put up there, as it stays around for a long time.

If we are nearing +1.5C today, with temp rising at around 0.25C to 0.3C per decade, at current long plateau of max emissions.. we will likely be somewhere in range +2.5C to +3.0C by the time we reach net-zero, possibly by 2050.

I'm not sure that +2.5C is survivable for large human populations .. hence the above concerns prompt one to look at things like SRM - putting up sulphur particulates to increase cloud cover, so less sunlight is absorbed by the oceans, exerting a net cooling effect [ as we did with container shipping fuels until recently - until the fuel was mandated to contain less Sulphur ]

IMHO, we engineered our way into this mess by geo-engineering a CO2-rich hot biosphere, and we will need to engineer our way out of it - it could be worse, we seem to have a lot of technologies that can replace carbon-fuel and store energy and arguably reduce heat.

1) Compulsory reduction in CO2, methane, etc. SRM is just kicking the can down the road. It cannot be band aid for more pollution.

2) The system needs guaranteed constant funding, as again, it's kicking the can down the road. If you suddenly stop SRM after 20 years, you get 20 years of climate change increase all at the same time.

Also, it needs the greatest diplomatic push in human history to get nearly every country on-board with the plan. All countries will be affected by this. Without buy-in, it could lead to conflict. For example, Russia is looking forward to higher temps and a longer crop growing season.

I do know that I personally was typing a comment on a climate change related thread and after posting, noticed the post had been flagged and removed.

Also.. another HN user commented that "political" articles on climate change are flagged, which they saw as a good thing.

.. I think by law of averages there should be more articles on climate change science / tech on HN.

I think the community is mature enough to disagree and discuss... and down-voting is a better way to remove low quality posts than flagging.

I would like to see stats on flagging.. and maybe a word cloud or sentiment analysis on what posts are flagged .. a public registry of flagged articles and reason for flagging would be ideal.

Seems quite wasteful, surely there's a better way with some planning and foresight.

This is a really good idea, but it is important to keep in mind that even if all of the steel production in the world (~100 Mton/y) shifted to this method, it would only have a negligible impact on the cement production (~ 4 Gton/y).

https://www.statista.com/statistics/267264/world-crude-steel...

In 2022, a total of around 1.9 billion metric tons of crude steel were produced worldwide.

EDIT: however, your intuition that the impact on cement production would be tiny is correct.

This report indicates that producing new steel from ore requires about 270 kg of limestone per metric ton of steel, or 88 kg of limestone when recycling steel in an electric arc furnace:

https://worldsteel.org/wp-content/uploads/Fact-sheet-raw-mat...

World steel production is about 35% recycled, 65% new from ore. So this new Cambridge research, which applies to recycled steel, could displace about 59 million metric tons of limestone consumption. That is small compared to billions of tons of global cement consumption. It might be locally significant for municipalities that have electric arc furnaces for steel recycling.

Metalysis (which exists, I want to see more roll-outs in more materials, particularly iron and steel).

At least one of "cheaper storage" or "the political solution to create a global power grid that I already know is both possible and affordable on paper" (c. 230 bn USD of aluminium).

Cheaper solutions to improve the insulation and cooling in older buildings.

Industrial scale Sabatier process.

From actual paper: https://www.nature.com/articles/s41586-024-07338-8

Recovered cement paste (RCP) is not commercially available at scale at present. . . . The value of the improved recovered aggregates is not at present high enough to cover the extra cost of processing, so RCP is currently landfilled. However, the know-how and the technologies required to produce RCP at scale exist. [22]

22. Thermomechanical beneficiation of recycled concrete aggregates (RCA): https://www.sciencedirect.com/science/article/pii/S095006182...

The cited paper does not support the assertion that tech to recycle concrete into RCP exists. The paper discusses removing adhered mortar (AM) from recycled concrete aggregate (RCA).

This is the root climate challenge as it drives all the incentives to exceed our energy/CO2-budgets. Turns out we are witnessing what happens when you run exponentially growing feedback into the logistic function.

Many are sceptical whether we can solve this capitalism-problem without fundamental changes to the system, that would leave you with a system that is no longer about capital. I am convinced there are many ways to solve that, but first we have to acknowledge the driving force behind climate change isn't technology, it is the need to grow markets and populations.

Is their cleaning contractor also net zero?

With promises like these the devil is in the details. You could have one true in spirit net zero company on the one side and another net zero shell company that has 1000 crazy polluting sub-contractors.

Given the fact that many big corps can't even prevent child and slave labor within their supply chain, I have to say I believe it when I see it.

This is a rather unique perspective, I think. Maybe I'm missing something, but isn't the decline of child labor mostly due to laws? I'd say the constant stream of child labor scandals implies that the market is a force opposing the protection of children more often than not.

As I said I have no hard opinions on the fix this needs. But it needs to credibly needs to address the core problem. I have yet to see a market solution that does that instead of say, selling yet another product.

Regulation is another thing. I believe it could really deliver a fix. But so far it it seems a true regulatory fix will come only after the cost of climate collapse is paid by the people who extract money from the system (and by that time we will have passed multiple points of no return and seen untold pain and suffering by those people who do not benefit of this capital).

If you're against revolutions, I'd argue you should be for strong regulatory measures that should have happened yesterday.

Isn’t time and attention the only limit?

Here’s a brief history of capitalism: Running out of whales? Develop ground oil. Running out of elephant tusks? Develop plastics. Running out of intact forests? Develop carbon markets. Earth running hot? Cool it down. Too much carbon? Develop renewables. It’s all happening. Not at the pace you want — but do you really want to trust that a revolutionary new economic governance would deliver these outcomes as quickly or efficiently?

I agree that “the point of no return” is a real risk — thawing permafrost and all that. But this is why we need to figure out geoengineering rather than banning the science of it. We can’t be so romantic as to think that we should leave nature untouched. We are nature and it is our existential need to figure out how to sustain ourselves. I think progress has been fantastic. It’s all happening— we just need a bit more time for the energy and AI transitions to happen.

I believe that this optimism is both rationally founded — and probably critical for creating a shared social vision for positive outcomes. We need to know where we are going — and man, it looks good! There will be so many resources to support all human needs — and even most human desires. Let’s not break things.

That is probably a more profound question than you might think. But one answer is, because we are in the saturation area of the logistical curve. Just like the feedback of a guitar amp infinitly amplifying itself, there is a point where it won't get any louder as you run into the physical limits of its electrical components, changing the sound of everything fundamentally.

We are limited because our earth is a globe with a atmosphere so thin, if you scaled the earth down to the size of an apple its peel would be way thicker than the Earth's. It is limited for the same reason my living room is limited: It has a certain geometric extent and that's it.

Let's say I put stuff into this room. If my goal was to put 5% more stuff into that room each week you probably would angle your head and ask me if I was crazy. Rightfully so.

Now my point was precisely this: growth sucks as an organizing principle in a world of limited resources. It would be better to figure out how to make use of the resources in a better way. Ans we even know how to do this on a smaller level.

But somehow we ended up with a ruling class that well.. doesn't profit from extracting value from putting more stuff into the room, so we do just that.

So they can only "recycle" this concrete as a substitute ingredient during steel making? That cannot scale. We would have to start making epically more amounts of steel in order to process even 1% of the concrete that we would want to recycle.

Pretty cool hack!

It may take 10 - 30 years to observe changes. and if all is well it can be adopted at scale and/or possible problems detected can be mitigated.

Move fast and break things is not a real way to approach climate change.