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.

PV inverters often have around 1-2% losses. This is not very significant. You also need to convert the voltage anyway because PV output voltage varies with light level.

Buck/boost converters work by converting the DC current to (messy) AC, then back to DC. If you want an isolating converter (necessary for most applications for safety reasons) that converter needs to handle the full power. If it’s non isolating, then it’s proportional to the voltage step.

Frequency provides a somewhat convenient method for all parties to know whether the grid is over- or under- supplied on a sub-second basis. Operating solely on voltage is more prone to oscillation and requires compensation for voltage drop, plus the information is typically lost at buck/boost sites. A DC grid would likely require much more robust and faster real-time comms.

The AC grid relies on significant (>10x overcurrent) short-term (<5s) overload capability. Inrush and motor starting requires small/short overloads (though still significant). Faults are detected and cleared primarily through the excess current drawn. Fuses/breakers in series will all see the same current from the same fault, but we want only the device closest to the fault to operate to minimise disruption. That’s achieved (called discrimination, coordination, or selectivity) by having each device take progressively more time to trip on a fault of a given size, and progressively higher fault current so that the devices upstream still rapidly detect a fault.

RCDs/GFCIs don’t coordinate well because there isn’t enough room between the smallest fault required to be detected and the maximum disconnection time to fit increasingly less sensitive devices.

Generators are perfectly able to provide this extra fault current through short term temperature rise and inertia. Inverters cannot provide 5-fold overcurrent without being significantly oversized. We even install synchronous condensers (a generator without any actual energy source) in areas far from actual generators to provide local inertia.

AC arcs inherently self-extinguish in most cases. DC arcs do not.

This means that breakers and expulsion type fuses have to be significantly, significantly larger and more expensive. It also means more protection is needed against arcs caused by poor connection, cable clashes, and insulation damage.

Solid state breakers alleviate this somewhat, but it’s going to take 20+ years to improve cost, size, and power loss to acceptable levels.

I expect that any ‘next generation’ system is likely to demand a step increase in safety, not merely matching the existing performance. I suspect that’s going to require a 100% coverage fibre comms network parallel to the power conductors, and in accessible areas possibly fully screened cable and isolated supply.

EVs and PV arrays get away with DC networks because they’re willing to shut down the whole system in the event of a fault. You don’t want a whole neighborhood to go dark because your neighbour’s cat gnawed on a laptop charger.

There should be no need for tuning, tweaking, or optimizing on functionality this basic.

If you ask the processor, it will spit out a graph like this telling you what threads/cores share resources, all the way up to (on large or server platforms) some RAM or PCIe slots being closer to certain groups of cores.

Essentially no processors follow a standard. There are some that have become a de facto standard and had both backwards compatibility and clones produced like x86. But it is certainly not an open standard, and many lawsuits have been filed to limit the ability of other companies to produce compatible replacement chips.

RISC-V is an attempt to make an open instruction set that any manufacturer can make a compatible chip for, and any software developer can code for.

And the Blackadder equivalent:

https://www.youtube.com/watch?v=h6mJw50OdZ4

I’ve certainly never heard of a chicken ranch, but plenty of chicken farms.

As ‘colony breadbaskets’, with lots of land and small populations, both NZ and Aus used to export lots of meat and other primary industry products to the UK.

I believe the UK’s entry into the EEC and deprioritisation of the commonwealth led to those exports reducing and instead heading to Asia and the US.

Regardless, expecting to export beef to the other side of the world, a country with four times the cattle and a better reputation for food production, is just daft.

I don’t think I’ve ever seen any UK-sourced food in NZ other than high-value small stuff like Worcester sauce, and expat reminder-of-home products.

Swifts and Mirages can be under 900kg.

Secondhand stuff can be really cheap if you know where to look, but the drawbacks are usually power and noise.

Boeing and Microsoft: same shit, different cloud.

Biggest question to me is why you need an IP in the first place?

Yeah, YT’s current anti-adblock crusade means you need a proper ad blocker built into the browser or a third party client.

There are AdBlock options for Android that can work on apps. Generally you need to route all internet traffic via the AdBlock app which requires root, a faux-VPN, or a PiHole type solution.

It can usually only do host-level blocking but that’s generally enough.

There’s been various desktop-grade plans regarding use of nuclear rockets, both in the atmosphere and not. Never underestimate what engineers can come up with.

I think what they were trying to argue is that the mercury emitted would be no worse than the mercury already emitted as a byproduct of power plants.

Most rocket operators/manufacturers run on razor thin margins or at a loss, sustained by state subsidies or wishful venture capitalists.

It appears that the door design is unchanged from the previous generation.

The problem is not with any specific part of the design or any model of plane. Grounding the Max again will not help past fixing this specific fault.

It is the fundamental corporate culture. The same poor QA, both in design and production, affects all current Boeing aircraft.

It’s not clear, but I think they were referring to the version 1 Pi - the newer ones are much much much faster.

They’re on sale here in NZ and seem pretty popular.

Being an SUV, it’ll weigh 50% more than necessary. That outweighs almost any other sustainability considerations.

In user manuals, legal documents and communications with federal regulators, Tesla has acknowledged that Autosteer, Autopilot’s key feature, is “intended for use on controlled-access highways” with “a center divider, clear lane markings, and no cross traffic.” Tesla advises drivers that the technology can also falter on roads if there are hills or sharp curves, according to its user manual. Even though the company has the technical ability to limit Autopilot’s availability by geography, it has taken few definitive steps to restrict use of the software.

Tesla told NTSB that design limits for Autopilot would not be appropriate because “the driver determines the acceptable operating environment.”

He said Tesla could easily limit where the technology can be deployed. “The Tesla knows where it is. It has navigation. It knows if it’s on an interstate or an area where the technology wasn’t designed to be used,” he said. “If it wasn’t designed to be used there, then why can you use it there?”

In a sworn deposition last year first detailed by Reuters and obtained by The Post, Tesla’s head of Autopilot, Ashok Elluswamy, said he was unaware of any document describing limitations on where and under what conditions the feature could operate. He said he was aware of some activation conditions for Autopilot, including the presence of lane lines, and that it is safe for “anyone who is using the system appropriately.”

Tesla’s commitment to driver independence and responsibility is different from some competitors, whose driver-assistance technologies are loaded with high-definition maps with rigorous levels of detail that can tip vehicles off to potential roadway hazards and obstructions. Some manufacturers, including Ford and General Motors, also only allow the technology to work on compatible roadways that have been meticulously mapped.

Over the years, NTSB has repeatedly called on NHTSA to rein in Autopilot. It also has urged the company to act, but Homendy said Tesla has been uniquely difficult to deal with when it comes to safety recommendations. Tesla CEO Elon Musk once hung up on former NTSB chair Robert Sumwalt, said the former chief, who retired from the agency in 2021 when Homendy took over.

https://web.archive.org/web/20231210125240/https://www.washingtonpost.com/technology/2023/12/10/tesla-autopilot-crash/