New Zealand is famously a very old country.
SomeoneSomewhere
joined 1 year ago
Hydrogen has a major efficiency problem. Unless the electricity to create the hydrogen is practically free (i.e. grid price is zero, you're turning off generators) it's not worth it. You're at like 30% round trip efficiency whereas batteries and overhead lines are well above 90%.
Using hydrogen also prevents regenerative braking, which is one of the big advantages of battery or overhead electric.
She certainly didn't...
As in coal-powered steam trains? There's a moderate number in tourist service around the world.
Diesel or electric trains carrying coal are still very common.
Unfortunately, Project 2025 is a whole book/organisation devoted to getting effective permanent revenge.
Ah, yes. The light at the end of the tunnel is an oncoming ~~train~~ Balrog.
The NASA Vehicle Assembly Building is also a contender.
I'm not sure how many dividing walls there are inside Everett, but the VAB is basically one massive empty skyscraper.
That's an interesting point. It also implies much better efficiency at low speeds than most motors.
Given a few generations of better semiconductor, it could end up being very interesting for (railway mostly?) traction motors.
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Low speed high torque means you don't need a further reduction gearbox.
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Good performance near zero speeds mean you might not need to use braking at all aside from parking and emergencies.
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High voltages are already widely used and available - 1500VDC nominal is an older standard for metro trains; 3kVDC is common both for older overhead and as an intermediate DC bus voltage for AC overhead. Future semiconductor generations could allow direct use of 25kV overhead (~40kVDC rectified at maximum line level) without the need for an intermediate bus, assuming the dielectric fluid was good enough.
Interesting.
Needing to run in a specific fluid seems like it could pose longevity issues because a motor inherently needs a shaft to pass out of the sealed enclosure, causing ingress or egress - car AC compressors have this issue.
If you could also make the fluid an effective refrigerant, then this could be good for refrigeration compressors. Those run entirely in a sealed system anyway.
This seems to be a very high torque, low speed motor, operating at 360W 18Nm which means it's 190RPM (20rad/s).
With all the parallel plates, windage friction is going to be very high if they attempted to increase speed, which is usually the easy way to improve power density.
2kV for a fractional HP motor is really pushing things; you would need to integrate the boost converter and inverter into the motor housing. The moment you have cables above 1kVAC or 1.5kVDC, you're 'high voltage' and a raft of new rules applies.
Converting between Kelvin and Celsius is simple addition; converting between Rankine and Fahrenheit is simple addition. Converting between the two groups requires multiplication, and pre calculator, that's notably harder.
Also, all your kJ/kg/°C or BTU/lb/°F tables and factors are identical when you swap to referencing absolute zero. If you change to the other unit system, all that goes out the window.
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.
25kV railway electrification is normally very separate from local electric grids.
Grid 'reliability' issues are normally load shedding or damage at the distribution level; the 10-22kV local networks. DC networks like third rail and 1500V are often supplied from local substations.
Long distance 25kV lines are almost always fed directly from big substations on the grid backbone - here in NZ, they're all from the 220kV substations at roughly 140km spacing; I believe in the UK it's almost all from 400kV subs. Those are extremely reliable and well monitored because no-one wants to be doing a grid black start, and loss of a grid backbone substation gives you a pretty good chance of the whole grid falling over. 25kV railway electrification is rock solid.
NZ's grid is roughly 93% efficient; half of that is in the transmission (long-distance) and the other half in distribution. We have one of the worst grid layouts for transmission efficiency because most of the generation is in the deep south while the load is in the north, with an underwater section in between.
Batteries and charging is IIRC around 90% efficient, round trip. Call it 75% from generator terminals to motor terminals.
If you're not generating the hydrogen right at the generator, you'll also be incurring grid losses to get the power to the hydrogen plant.
If you are generating hydrogen at the generators, you'll then need to transport the hydrogen even further. I'm struggling to find exact figures for losses in natural gas networks, but my understanding is that leakage is several percent. Any large-scale hydrogen system could end up being similar, plus you now need a shipping industry to move the hydrogen to the point of consumption.