The issue with aviation hydrogen is… well, lots.

• Fuel cells are heavy and direct combustion is inefficient and tougher than burning kerosene.

• Aircraft typically use the wing structural members as the fuel tank walls. Both cryogenic and pressurised options make that a non-starter.

• Lower density means much bigger tanks.

• Self-vapourising fuel is a major crash issue.

• Round trip efficiency for H2 is still terrible.

Plants may not be particularly efficient per km^2 but arable land isn’t actually that hugely scarce.

Reducing aviation is really the only thing that’s actually going to work.

Biofuels/ethanol/SAF are much the same; often derived from corn.

In many cases, the oil/gas/electricity used for harvesting, processing, cracking etc. is actually comparable to or exceeds the carbon released by simply drilling for and burning the oil in the first place.

What I mean is that the bulk of current copper wiring goes towards distribution and consumption, not generation.

Yes, but big batteries everywhere is going to effect that if there’s copper in lithium batteries, and apparently there is.

This isn’t a big thing. This is a constant thing in every system. It’s the push and pull between efficiency and resiliency. More storage capacity is less efficient when things are going well, but is more resilient and adaptable when they’re not.

Excess storage capacity, sure.

But inflating the base battery capacity to cover people having showers at 5pm because it’s easier than storage water heaters and time/remote controls is stupid. You can reduce the base need for batteries by reducing the need for electricity in the first place and reducing the use of vehicles that need to carry batteries in place of e.g. overhead catenary.

You’re wrong in terms of long distance power lines being mostly copper, but this does seem a lot like fossil fuel propaganda.

Motors, generators, and transformers can be built using aluminium; they’re just a bit bulkier and less efficient. Very common practice.

It looks like CCA might be making its way back into house wiring in the near future, with much lower risks than the 70s aluminium scare.

The big thing is that batteries really should be a last resort, behind demand response (using power when it is available, rather than storing it for later), long distance transmission, and public transport instead of private vehicles.

That’s incorrect. Aluminium is about 30% worse by volume than copper, meaning you need to go up a size. What stopped it being used for houses was that the terminations weren’t good enough, because aluminium has different thermal expansion and corrosion properties, plus they were using much worse alloys. That’s now mostly fixed and if you’re in the US, there’s a very good chance that your service main is aluminium, and there’s talk of allowing copper-clad aluminium (CCA) for subcircuit wiring.

Per mass, aluminium is a better conductor, which is why it’s almost exclusively used overhead and in pretty significant volumes underground. The power grids were built on ACSR.

Google has removed the video through an automated process without talking to the owner of the channel or verifying who owns the video in the first place.

Honestly sounds like Hanlon’s Razor on Google’s part. No collusion necessary, just can’t be bothered to maintain/staff an actual effective system.

That’s not bad pricing wise. There’s very very little prosumer gear that’s multi gigabit and it’s all much higher price, or it’s just a PC with several NICs.

If and when we move to hyperfibre this is going to be pretty high up on the list.

I’m not sure that lossy compression on vectors is strictly impossible.

You can do things like store less colour information and simplify splines so that curves are less complex.

Lots of places also have variable limit signs that get updated based on traffic, accidents etc.

Here in NZ those seem to all be marked on the speed limit maps as 100km/h even if in some places the signs never go above 80.

Ngauranga Gorge is one such location and I believe has the country’s highest grossing speed camera.

603 for maglevs, 574.8 for steel rail, set in France in 2007 by a hotted up, modified TGV.

China holds the record for a stock train at 487, set in 2010.

(all per Wikipedia)

It looks like the article might be implying that they will be the fastest trains operating in revenue service when they enter service, but that surely needs to be demonstrated with a production train in revenue service.

Regular trains don’t run underground. Lots of opencast mines exist .

Basically all mines have an above ground terminal where whatever you mined is unloaded from your underground trains, lifts, haul trucks or whatever else onto storage piles, then loaded onto the actual long distance trains.

If the mine entry is up a mountain, then the trip down from that point will be a net energy producer regardless of anything else.

I wouldn’t be surprised if there are electrified railway lines doing the same. Regenerate large amounts of energy into the grid while descending loaded; consume a relatively small amount of energy to haul the empty train back uphill.

If you’re thinking of that CGI crane lifting concrete blocks, it’s unfortunately a really bad idea.

Pumped hydro stores energy by lifting weight uphill, instead. Water is basically the cheapest thing you can get per tonne, and is easy to contain and move.

To store useful amounts of energy using gravity, you need pretty large elevation differences and millions of tonnes of mass to move.

I feel dumber having read that.

Banning a whole country because you disliked a company?

Dealing with stuff that’s ‘almost working’ is often harder than starting from scratch; ask any tradesperson.

They also apparently cannot get their heads around the fact that people might give you a discount if you advertise their brand. Ad-supported pricing has been around for a long time; it’s not some voodoo.

Until the day comes that I get a letter in the mail from the government saying, “Here’s how much you paid in taxes, if you’re cool with that then please disregard”, I will not be satisfied.

NZ does that. More accurately, they email you to tell you that there’s a letter available online - I don’t think they send physical mail by default.

Then they pay any refund straight into your nominated bank account.

Any hard drive can fail at any time with or without warning. Worrying too much about individual drive families’ reliability isn’t worth it if you’re dealing with few drives. Worry instead about backups and recovery plans in case it does happen.

Bigger drives have significantly lower power usage per TB, and cost per TB is lowest around 12-16TB. Bigger drives also lets you fit more storage in a given box. Drives 12TB and up are all currently helium filled which run significantly cooler.

Two preferred options in the data hoarder communities are shucking (external drives are cheaper than internal, so remove the case) and buying refurb or grey market drives from vendors like Server Supply or Water Panther. In both cases, the savings are usually big enough that you can simply buy an extra drive to make up for any loss of warranty.

Under US$15/TB is typically a ‘good’ price.

For media serving and deep storage, HDDs are still fine and cheap. For general file storage, consider SSDs to improve IOPS.

I don’t remember if they fully closed the loopholes, but there are inputs that programs cannot catch unless you actually replace the OS.

Here in NZ they do a factory reset on your calculator at the start of every exam.

Even 95% is on the low side. Most residential-grade PV grid-tie inverters are listed as something like 97.5%. Higher voltage versions tend to do better.

Yeah, filters essentially store power during one part of the cycle and release it during another. Net power lost is fairly minimal, though not zero. DC needs filtering too: all those switchmode power supplies are very choppy.

I’m not sure there are any power grids past the tens-of-megawatt range that aren’t just a 2/3/4 terminal HVDC link.

Railway DC supplies usually just have fat rectifiers and transformers from the AC mains to supply fault current/clearing and stability.

Ships are where I would expect to start seeing them arrive, or aircraft.

Almost all land-based standalone DC networks (again, not few-terminal HVDC links) are heavily battery backed and run at battery voltage - that’s not practical once you leave one property.

I’m sure there are some pretty detailed reports and simulations, though. A reduction in cost of multi-kV converters and DC circuit breakers is essential.