I think that's the real loss here. Rental vehicles are a big source of cheap used cars. Having a steady flow of EVs from there would have brought down used prices and made them more financially accessible. Shame we won't see that now, at least in the near future.
Australia is transitioning >3% of their electricity supply to solar per year and still accelerating. Rooftop solar is near 50% uptake. Combined with wind, they are on track to almost fully in the next 10 years. So there will be soon.
The grid was much nearer to collapse seven years ago when there were actually brownouts, and renewables have been entirely responsible for its improvement. Moving toward renewables and keeping the lights on in Australia are the same thing.
The article you linked is from 2017. 80% of Australia's solar was installed after that came out. Hard to argue that it's somehow responsible. Seems like your knowledge is a bit outdated.
You make it sound like they have no alternative. A literal majority of the city uses the trains regularly. The person you're describing can just live within walking distance of a station. The $20k they arent paying for the car and tolls should be just about enough for the rent on a 1 bedroom.
I worked at Reddit in the not so distant past. The entire recommendation system lived in 3 repos. I'm pretty sure there are just 2000 repos because the onboarding tutorials have you create one, and that number is probably around the number of engineers that have worked there. I'd guess 100-200 have some production component.
If this is the case, then why in the world wasn't that mentioned in TFA? I'm not questioning your comment but it strikes me as odd that there would be no attempts to clean any of that up.
When I got the responsibility for our aws accounts and github repos there where over 1000. 99% are not used, and closing them down is a PITA since AWS only allows you to close 10% of your accounts per month and finding out who actually uses a github repo can be hard (if it is not commited to regularly). My predecessor didn't care as long as they don't cost too much, which is a reasonable stance but I want to know what is running.
I'm working my way through them but it takes quite a bit of time and checking in with people on what is actually used.
Besides that there is some prestige in saying that you handle 2000 amount of repos instead of it being "we have 20 prod repos and 1980 personal playground repos with one commit"
It's not just via the GUI. I have a script (which uses their API and SDK) that I run every month to delete the next batch until it runs into the deletion limit and a calendar reminder every month to run the next batch.
Why would it be? That doesn't look good at all - why not clean them up periodically, or simply after onboarding? - and this makes them seem more capable than if they were managing 1/10 the number of repos.
(This is assuming GP is correct. I have my doubts)
There is a good Volts[1] episode[2] on it. TL;DR the thing that limits how much power a line can carry is heat dissipation, which depends on weather. We used simple heuristic models to back out what we considered safe operating currents historically, but if you use sensors to enable a more data-intensive approach, you can operate closer to full capacity.
> So an alternative title is " ... is reducing safety margins by 50%".
Not necessarily. The _actual_ current limit depends on the climate conditions, and with static line rating the safety margin actually varies. So while dynamic line rating might reduce the safety margins when the conditions allow running more current, it can also increase the safety margin in case of a particularly hot summer.
Engineering in buffer for safety is one of the most common practices.
I mean hey if you wanna roll the dice standing up next to some high pressure hydraulic gear on machinery that's running a few psi away from failure because it's super efficient be my guest.
But I'm not gonna enjoy the one day in 10000 when something goes a Lil awry and you get cut in half because old mate ordered hoses without steel sheathing because the unsheathed ones were rated for the same pressure but were cheaper and more cost efficient.
That's some 1950s old world business ideology there.
Also another example. All lifting straps for cranes and lifting hardware is generally capable of 3x to 4x its safe working load. Buffers are everywhere and they save lives.
Accuracy and safety margins are two different things.
Suppose you have to spec the capacity of a line regardless of what temperature it is, because you're not going to measure it in realtime at all. You estimate the highest temperature will be 105 degrees F, calculate the capacity at that temperature, add e.g. a 20% safety margin, and call that the capacity of the line.
That means when it's 40 degrees F, you could be operating with a 200% safety margin, which is unnecessarily conservative and wasteful. Conversely, because you're not measuring the temperature at all, your high temperature estimate could be wrong and there could be a day that it's 115 degrees F, your safety margin is completely gone and the line burns out. Whereas if you were monitoring the temperature, you'd lower the capacity of the line that day to still have a 20% safety margin and not have problems.
This is a timely debate in engineering. Historically, it would be customary do the most conservative reliability analysis possible, right up to the point of accounting for physically impossible parameter combinations, just to ensure enough margin to trade at some point in the future when things inevitably don’t go as planned.
Now, technology has advanced to the point where all the low hanging fruit are gone in terms of performance optimization, and we’re better able to determine how close to the “cliff” we are, with tighter uncertainty bounds, than ever before with probabilistic design methods. By this logic, we should be able to squeeze out margin that was never needed (or never there) in the first place.
No safety professional would trade away margin you say, but the engineer is often between a rock and a hard place when a few percent traded away in margin translates to multiple millions of dollars in cost reduction or profit. Is it unethical to remove margin if your Bayesian UQ calculations are saying you’re still safe, if not safer than you were under the other methodology?
This tension is going to keep on building as AI-enabled solutions start penetrating more and more into traditional engineering fields, with as-yet unknown consequences.
trading margin is perfectly fine if there are compensating mechanisms.
for example automatic circuit breakers and other sensors and actuators that can reliably respond to the critical conditions
if we can double the line current by trading margin, and only need to add few sensors and automatic breakers here and there - thats perfectly fine. You will double your current without building a new line basically
In the end all engineering is about economy and compromises. The idea his to keep the margin for safety but to improve utilization. That's a tricky problem and indeed if the measurements are inaccurate then riding closer to capacity will result in safety issues. But that's not the intention here (though if gear is marginal then it may well be a possible outcome in some cases).
the point of safety margin is to account for the unknown. if you learn more, you can safely reduce the margins. cranes have 3x margins because they're being operated by construction workers who aren't carefully measureing everything. Rockets otoh often only have ~10% margins. The more uncertainty you remove, the smaller you can push the margins.
One of my closest friends was killed in a workplace accident due to the implementation of the safety switch in the device he was operating.
Elevated work platform. He was working underground. They use a small joystick with a safety button on top to control the up and down action of the machines. His offsider was directing movement from the ground.
Ewp hit a obstacle and bounced, my mate ended up falling over the side rail and in the process fell on the lift switch. Pushed it up and pushed the safety switch in because it was located on top. He got crushed and killed between the ewp and the mine roof.
This was a safety device that was specifically put in to increase the safety of the machine. The engineers overlooked this aspect of its implementation during design. Now they have cages over the lift control. That lessons learnt in blood.
Needless to say from this experience I never assume an engineer has thought of all dangers and certainly hasn't engineered devices to be as safe as they can be. It's a downside of designing from the office and not the field. Its also why field monkeys like me get called in to talk to engineers and provide consult. There's a lot yo be learnt when you work on the tools that you don't get in textbooks.
