Solar power has begun to transform the world’s energy system • Hacker News Board

Re: Solar power has begun to transform the world’s energy system

#531

Post by kragen » Fri, Jul 11, 2025, 12:22 AM UTC

Retric wrote: post #506

kragen wrote: post #494

Earlier quoted context omitted.

Yes, safety is a significant disadvantage of the use of magnesium as portable stored energy, but if your ship's payload is already on fire, in most cases the shipment will not be very successful anyway, and loss of the ship is a serious possibility. If a hypothetical ship full of magnesium sinks without catching the magnesium on fire first, the magnesium will probably not catch fire from exposure to water. Perhaps if…

I agree, the point is you’re not risking something like: https://en.wikipedia.org/wiki/Halifax_Explosion “At least 1,782 people, largely in Halifax and Dartmouth, were killed by the blast, debris, fires, or collapsed buildings, and an estimated 9,000 others were injured.” “Nearly all structures within an 800-metre (half-mile) radius, including the community of Richmond, were obliterated.[3] A pressure wave snapped tr…

Not with magnesium ingots or dry magnesium, no; but, because the water–magnesium reaction is exothermic, spontaneous, and gas-producing, I'm pretty sure there's a range of ratios where wet magnesium does constitute an explosive if it's finely divided, at least a low explosive like gunpowder, so such an accident could happen.

It seems unlikely to happen by accident because at stoichiometry you need more water than magnesium, and I don't think spontaneous explosion is a real risk with magnesium. The International Magnesium Association's safe handling guide https://cdn.ymaws.com/www.intlmag.org/resource/resmgr/safety... does mention that magnesium swarf can spontaneously combust in the presence of water, but I think swarf is too coarse to explode. It recommends keeping wet magnesium swarf under water to prevent it from heating up enough to spontaneously ignite.

But presumably you'd be shipping the magnesium in the form of plates, ingots, or rolls rather than powder, swarf, or loose foil.

Re: Solar power has begun to transform the world’s energy system

#532

Post by kragen » Fri, Jul 11, 2025, 12:24 AM UTC

lukan wrote: post #495

sn9 wrote: post #483

Earlier quoted context omitted.

We have quite a bit of experience transporting hydrocarbons . . . .

We do, but even in peacetimes not without issues. https://en.m.wikipedia.org/wiki/List_of_oil_spills But the problem mentioned above was about war.

I think the idea of "peacetime" is probably outdated. Not in the sense that I think people should fight, but in the sense that their fighting will no longer be limited to certain geographic areas, and people will fight, so all of us will be at constant risk of both infrastructural damage and violent death.

Re: Solar power has begun to transform the world’s energy system

#533

Post by kragen » Fri, Jul 11, 2025, 12:25 AM UTC

Gibbon1 wrote: post #511

kragen wrote: post #498

Earlier quoted context omitted.

This is currently more or less true, but historically speaking, sovereign default has often been used as a casus belli for invasion; that's where the Monroe doctrine comes from, after all. The collapsing Pax Americana is arguably the reason we haven't seen it happen in decades, so it would be unsurprising to see it start to happen again. And of course financial considerations are often a first-order consideration in…

That most counties need to import oil and gas to keep the lights on and industry functioning means you don't need to send gunboats of yore. See Smedley Butler's rant. Now when they get in a pickle they need foreign currency. And that's how they get ya. Renewables however flips things back.

That's an excellent point, and one I hadn't really internalized. Thank you.

Re: Solar power has begun to transform the world’s energy system

#534

Post by Chilko » Fri, Jul 11, 2025, 1:31 AM UTC

gosub100 wrote: post #517

pjc50 wrote: post #353

Earlier quoted context omitted.

> Is that energy "green" ? Not very, but neither is continuing to use fossil fuels on a huge scale.

So why do it at all if there is no accounting to prove it's green? It's almost as if this movement is a scam. No CO2 equivalent publications on solar, or on recycling. It's just "do what we say or the climate will die". I reject that imperative.

> if there is no accounting to prove it's green? It's almost as if this movement is a scam. No CO2 equivalent publications on solar, or on recycling

You state this as if that's a fact - just because you haven't looked for them doesn't mean they don't exist. Here's two examples showing that wind [1] and solar [2] have good environmental payback times in my home country due to avoided emissions, a country which already has an ~80% renewable grid. Additionally, [3] is a good resource that puts the potential waste from solar farms into context with other sources (such as coal ash) and shows this is an unfounded fear. Do some research and challenge your biases before you spread misinformation.

[1] https://www.tandfonline.com/doi/full/10.1080/03036758.2024.2...

[2] https://www.sciencedirect.com/science/article/pii/S0038092X2...

[3] https://doi.org/10.1038/s41567-023-02230-0

[3 - sharing link] https://www.nature.com/articles/s41567-023-02230-0.epdf?shar...

Re: Solar power has begun to transform the world’s energy system

#535

Post by fastball » Fri, Jul 11, 2025, 1:42 AM UTC

dalyons wrote: post #503

fastball wrote: post #366

Earlier quoted context omitted.

Or we can go full nuclear.

why? much more expensive, much slower. This reflexive "nukes are the only way" meme amongst technical folk really has gotta die.

More expensive in what way? "Cost" is what everyone quotes about why nuclear isn't great, but isn't the whole idea behind shelving fossil fuels and switching to alternatives due to downsides that are secondary to cost?

To me, renewables (solar and wind namely) have many more downsides than nuclear. So if we are doing things not because of cost anyway, why not nuclear? What do you fundamentally care about?

The power density of wind and solar is abysmal. You need to cover huge amounts of land with your preferred solution (which doesn't work everywhere) to produce relatively meager amounts of power. You need to have grid-scale storage solutions which are currently not priced in to the costs being quoted. Even if you have that storage solution you need to be significantly over-capacity in terms of production so that storage can actually be filled during peak hours.

Meanwhile, nuclear: requires a fraction of land use (good for ecology), runs continuously (so doesn't need huge storage outlays), can run basically anywhere (reducing transmission costs).

The most important note is that "nuclear" is not entirely encapsulated by existing Gen III reactors. There are many more designs and ideas that are being developed as we speak, whether more interesting (read: safe/efficient) fuel mixes, modular/micro designs, and various other improvements.

"Cost" is a merely a reflection of how much human capital is required to make something happen. I'd much rather spend our human capital on technologies that have the potential to massively increase the energy available to humanity, rather than focusing on tech which we know has strict upper bounds on power output / scalability. Solar and wind is useful in certain areas, but the idea that they can provide the baseload for a decarbonized future is ridiculous to me, unless your starting point is "I don't think humanity needs to consume much more power".

Re: Solar power has begun to transform the world’s energy system

#536

Post by Chilko » Fri, Jul 11, 2025, 1:59 AM UTC

silvestrov wrote: post #266

jillesvangurp wrote: post #164

Earlier quoted context omitted.

I think the raw economics behind the transition are very interesting. People have a hard time imagining transformative changes. They keep trying to project the current state of affairs onto the post transition state. Of course the current state is mostly the result of how things used to work and not really a predictor for the future. When things stop working in the same way, a lot of other things start shifting. For…

Steel factories cannot shutdown temporarily due to high electricity prices. They need a steady source of electricity. This needs to be taken into account. I don't know if factories can be made with better insulation so they can "hibernate" somewhat when electricity is expensive. So they might want to be located in a location with both wind, solar and hydro to ensure a (somewhat) stable price. Denmark has a lot of win…

This really depends on the pricing mechanisms & contracts that large industrial users have with their energy provider. Many users may contract out of wholesale spot prices in favour for a more predictable contracted price - and demand response could form part of that contract. Depending on the market, financial hedges are also an option.

For instance, in New Zealand we have an aluminium smelter (Tiwai point) that constitutes about ~13% of national electricity demand. The smelter recently re-contracted its electricity supply with several of the major power companies (a 20-yr agreement) which includes a component for demand response when required. NZ has a ~80% renewable grid with hydro and wind as major variable sources, which creates both hourly and seasonal variation in the wholesale spot price (dependant on wind and rain resource). In the event of a major drought that pushes up prices due to a lack of hydro (this happened last year), the agreement with the smelter means it will shutdown some of its operating lines in exchange for demand response payments. This is exactly what occurred, whereas other industrial users that did not have such agreements in place or chose to take advantage of previously low spot prices without adequate hedging were then exposed and also shut down, without being paid to so.

Re: Solar power has begun to transform the world’s energy system

#537

Post by Retric » Fri, Jul 11, 2025, 2:06 AM UTC

kragen wrote: post #531

Retric wrote: post #506

Earlier quoted context omitted.

I agree, the point is you’re not risking something like: https://en.wikipedia.org/wiki/Halifax_Explosion “At least 1,782 people, largely in Halifax and Dartmouth, were killed by the blast, debris, fires, or collapsed buildings, and an estimated 9,000 others were injured.” “Nearly all structures within an 800-metre (half-mile) radius, including the community of Richmond, were obliterated.[3] A pressure wave snapped tr…

Not with magnesium ingots or dry magnesium, no; but, because the water–magnesium reaction is exothermic, spontaneous, and gas-producing, I'm pretty sure there's a range of ratios where wet magnesium does constitute an explosive if it's finely divided, at least a low explosive like gunpowder, so such an accident could happen. It seems unlikely to happen by accident because at stoichiometry you need more water than mag…

Even magnesium powder wouldn’t detonate when you’re talking tons of the stuff on a boat for the same reason small hydrogen balloons can go bang, but the Hindenburg just created a huge conflagration. You get limited mixing due to the volumes of material involved. Even burning across several seconds is just vastly less dangerous than an actual detonation.

Same issue with grain silos exploding because of the mixture of fuel with oxygen, but flour just burns etc.

Re: Solar power has begun to transform the world’s energy system

#538

Post by kragen » Fri, Jul 11, 2025, 2:26 AM UTC

Retric wrote: post #537

kragen wrote: post #531

Earlier quoted context omitted.

Not with magnesium ingots or dry magnesium, no; but, because the water–magnesium reaction is exothermic, spontaneous, and gas-producing, I'm pretty sure there's a range of ratios where wet magnesium does constitute an explosive if it's finely divided, at least a low explosive like gunpowder, so such an accident could happen. It seems unlikely to happen by accident because at stoichiometry you need more water than mag…

Even magnesium powder wouldn’t detonate when you’re talking tons of the stuff on a boat for the same reason small hydrogen balloons can go bang, but the Hindenburg just created a huge conflagration. You get limited mixing due to the volumes of material involved. Even burning across several seconds is just vastly less dangerous than an actual detonation. Same issue with grain silos exploding because of the mixture of…

Yes, that's why I said, "dry magnesium, no". A pile of dry magnesium powder only burns at the surface as air diffuses into it. If you have it mixed with the oxidizer so that the flame can propagate through the whole mixture, it will, and the propagation speed is determined by factors like the reaction speed, gas production, and thermal conductivity. The reaction speed in turn is governed by the particle size, since the reaction only takes place at particle surfaces; it goes to completion faster when particle size gets smaller.

Small hydrogen balloons do not in fact go bang; they just create small conflagrations. What goes bang are small balloons filled with a near-stoichiometric mixture of hydrogen and oxygen, such as you get from the simplest forms of water electrolysis.

The stoichiometric mixture of magnesium with water is 1.36 grams of water per gram of magnesium (which is 1.74g/cc, so this 58-wt%-water mixture is 70% water by volume), the enthalpy of formation of H₂O is -285.83kJ/mol, and the enthalpy of formation of MgO is -601.6kJ/mol. So this reaction:

    Mg + H₂O → MgO + H₂

yields 315.8kJ/mol, which is to say, 315.8kJ per 24.3 grams of magnesium, or per 58 grams of mixture, about 5.4MJ/kg, about an 18% higher energy density than TNT. And the hot hydrogen gas produced will carry the heat produced by the reaction into nearby areas, igniting them and resulting in a flame propagation velocity that's higher than thermal conduction alone.

For a large enough particle size, you won't get an explosion, and you may even lose most of your water as steam; but for a small enough particle size and an oxidizer concentration close enough to stoichiometric, you will. Some nanothermites consisting of magnesium nanoparticles with an oxidizer such as iron oxide even reliably detonate.

So, it's a potential safety hazard, but it seems like one that should be easy enough to guard against.

Re: Solar power has begun to transform the world’s energy system

#539

Post by marze » Fri, Jul 11, 2025, 3:22 AM UTC

privatelypublic wrote: post #527

marze wrote: post #464

Earlier quoted context omitted.

Transmission lines are a interesting idea, but expensive. Once solar is cheap (like now, as it already is), you can put in 3x what is needed on a sunny day, and power everything on cloudy days. Solar runs on cloudy days. Night obviously requires a different solution. Start by installing solar over all parking lots. To think that you won't be able to run a 100% solar/wind grid is a bet against human ingenuity. If gene…

You missed a huge upcoming one: EV's. I firmly believe that paying EV owners with vehicle-to-load capability will soon be used to smooth out peaks and troughs in the grid. Maybe in the future even systems that use DC fast charging contacts to get the huge DC voltages needed for an external inverter capable of powering several houses.

As in, "an electric vehicle fleet that charges during the day and powers the grid at night if the owner opts in"?

Re: Solar power has begun to transform the world’s energy system

#540

Post by seanmcdirmid » Fri, Jul 11, 2025, 3:29 AM UTC

jillesvangurp wrote: post #175

The article doesn't mention a technology that deserves some attention because it counters the biggest and most obvious deficiency in solar: the sun doesn't always shine. That technology is cables. Cables allow us to move energy over long distances. And with HVCD cables that can mean across continents, oceans, time zones, and climate regions. The nice things about cables is that they are currently being underutilized.…

HVCD Was supposed to be the answer for china’s big renewable energy surplus out west while most of its energy needs are in the east, but for some reason it hasn’t worked out so they are leaning on nuclear and coal more for eastern power needs. I guess when the imbalance is huge, it’s not that easy. They could move more manufacturing out west, and I think they are doing that to a point, but water supply becomes an issue at that point (and it will always be easier to move energy than water!). Still, I wonder if we will see the rise of cities like Lanzhou that have cheap electricity, the same thing happened for Seattle and aluminum smelting via cheap hydro power (also why boeing started there)

They don’t invest in gas much because they have to import it all, though it will be a long time before they use electricity for cooking as opposed to natural gas or propane.