921–930 of 1001 posts
One guy simulated Australia's electrical grid for 3 years to show that the entire grid could run off of >98% renewable energy using the installed renewables with just a small amount of storage (e.g. 5 hours of average demand, ~10% of demand over the entire period). To me this indicates that in many energy markets where renewables are sufficiently built out, the only factor for why we aren't using them more is the sto…
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What network are you on? I'm outside Mataro and with Vodafone, got internet connection and power restored some time early morning/late night (after 02:00, before 09:00)
MasMovil / Orange. Yesterday connection went on and off while the router powered by and UPS. But since last night, the fiber does not sync with the GPON anymore.
Ouch, that sucks. Bet their technicians are on overtime already too :/ I'm guess you've already tried the true-and-tested "Turn off, wait five minutes, turn on again"?
Usually we've had lots of issues with our fiber from Vodafone (like random ~70% packet drops from time to time) but happy Vodafone seems to have recovered quickly in this case, no GPON issues here as far as I can tell.
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As an ex small engine mechanic, I'd advise against using a 2 stroke for something like that. A 4 stroke would be a better bet. Better yet would be a natural gas/propane 4 stroke, since gasoline goes stale and plugs carburetors. Small diesels could be an option but they're harder to pull start for a given size.
Do you have any small engine mechanic books you'd recommend? They're my kryptonite, but I accept it's mostly my ignorance.
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> The words "it's a miracle it works at all" routinely popped up in those conversations, which is... something you don't want to hear about any sort of power generation - especially not nuclear - but it's true. Funny thing is, those are the exact words I use when talking to people about networking. And realistically anytime I dig deep into the underlying details of any big enough system I walk away with that impressi…
"Funny thing is, those are the exact words I use when talking to people about networking" Computer networking is not the same. Our networks will not explode. I will grant you that they can be shite if not designed properly but they end up running slowly or not at all, but it will not combust nor explode. If you get the basics right for ethernet then it works rather well as a massive network. You could describe it as…
EVPN uses BGP to advertise MAC addresses in VXLAN networks which solves looping without magic packets, scales better and is easier to introspect.
And we didn't even get into the provider side which has been using MPLS for decades.
A problem with high bandwidth networking over fiber is that since light refracts within the fiber some light will take a longer path than other, if the widow is too short and you have too much scattering you will drop packets.
So hopefully someone doesn't bend your 100G fiber too much, if that isn't finicky idk what is, DAC cables with twinax solve it short-range for cheaper however.
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no one has emergency fm radios there? I thought that was pretty much ubiquitous. that's the first I'd go to check what was going on I think, other than my phone
From my personal experience, mostly just in the car. Here in Portugal there was a rather well-timed rail strike today, so a lot of people who would've taken the train drove instead and had a way to get back and listen to the radio. From what I could tell from the radio reporting, handheld radios and batteries were rather quickly sold out. I've got to give massive props to Antena 1 too, which is the national broadcast…
Indeed, visited the local hardware store and some bigger stores like Decathlon, and they were out of all batteries, gas-powered stoves and anything else related. Seems they ran out of it just hours after the power was cut too.
> I've got to give massive props to Antena 1 too
RNE did a great job, and together with the response of the previous crisis of Covid, I feel relatively safe as a Spain resident during a crisis. People around you are so caring as well, like when I tried to figure out how to open my garage door without power, a young guy stopped while passing by to ask if I needed help. Simple stuff, but gives a larger feeling of that we'll survive together no matter what.
I experienced it first hand in Madrid. This was much scarier than I would have imagined. News travelled extremely slow: phone coverage was just barely enough to receive a couple text messages every 15 minutes or so. News spread on the street, I even saw a group of 20 people hunched around someone owning a hand-held radio in the streets. Just before power was restored, things started to get worse, as the phone coverag…
The atmosphere was quasi-festive and most people were quite relaxed, enjoying an unexpected afternoon off. Younger people filled the bars which were serving everything they could. There were long lines at supermarkets and an occasional fellow toting a box of supplies, but mostly there were just huge numbers of people in the street and completely collapsed traffic flow (the police were out in force almost immediately, directing traffic). In the part of Madrid I was in about 1/4-1/3 of the population is from South America and I suspect most of them have seen this all before anyway. The only real stress I saw was from people that need a train to get home (because the trains weren't running) and a had a walk of more than 2-3 hours.
I got cell phone signal when I was near two hospitals which were fully operational.
It was interesting that almost immediately, while I was still at work, everyone said power was out in Portugal and France too. After an hour or two some were claiming problems in Germany, but this seemed already to be unfounded rumors.
Some younger people couldn't walk home because they didn't have google maps ...
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
In another life I worked as an engineer commissioning oil rigs and I’ve seen how tricky even a small-scale black start can be. On a rig, we simulate total power loss and have to hand-crank a tiny air compressor just to start a small emergency generator, which then powers the compressors needed to fire up the big ~7MW main generators. It's a delicate chain reaction — and that's just for one isolated platform. A full g…
This sounds big enough to require a black start. Unfortunately, those are slow and difficult. If an entire nation trips offline then every generator station disconnects itself from the grid and the grid itself snaps apart into islands. To bring it back you have to disconnect consumer loads and then re-energize a small set of plants that have dedicated black start capability. Thermal plants require energy to start up…
Does solar power make this process easier or harder? I know that with thermal plants you have a spinning mass that you have to synchronize, and phase shift is used to assess how hard the plant is working (and whether to trip a disconnect as we see here) But with solar, how is the synchronization provided? In like a giant buck? Or in software somehow? Does the phase shift matter as much as in the electromechanical sys…
The main difficulty is that the software of grid-following inverters tend to make them trip out very suddenly if the grid parameters get too far out of spec (they will only follow the grid so far), but once the grid is good they basically instantly synchronise.
But all large solar farms are likely to be mandated to switch from grid following to grid forming inverters eventually which will make them beneficial for grid security because they will help provide 'virtual intertia' that looks exactly the same to the rest of the grid as spinning mass does.
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My definition of technology is, “something built by humans that barely works”
Modern aircraft? Those are excellent and work well. I am thinking of a B787 and A350. More: How about medical implants, like a heart pacemaker?
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I can’t see an answer here: how does an air compressor start an engine?
The compressor pressurizes an air tank. When the pressure in the tank is nice and high, use the compressed air to turn a turbine connected to the crankshaft of the engine.
That tends to be for very large engines, where the extra plumbing isn’t a problem.