I'm the last man on Earth...how long till the power grid fails?

Factual Questions
1

We all know the setup…after some biological/chemical/nuclear/or “other” catastrophe, a lone human is left alive on all of Earth. The Quiet Earth is a good example for this genre, but The Omega Man is probably more well known.

Now, assuming this depopulation happened pretty suddenly, and wasn’t accompanied or triggered by any other catastrophic events (like WWIII)…how long would our lone survivor be able to enjoy things like the electrical infrastructure, or the phone grid? Weeks? Days? Hours? Minutes?

If they were all suddenly unmanned, would nuclear power plants drift into meltdown? How long could one expect the internet to function, untended? For that matter, would water and sewage systems work for long in the major cities?
Ranchoth

2

A few hours at most, before the intervention of an operator was required, and didn’t come.

3

Would that be in all areas? Or would somewhere say, on a major line getting hydro power be better off than someone getting most of their power from say a coal plant or something.

Or is my ignorance showing again?

4

Think about what happened in New York recently. Once you start having trouble, everything goes off.

I think it’d start through having industrial processes running unattended. Things jam, small fires start, etc., which results in progressive loss of load on the system.

It wouldn’t take very much load to be lost before voltage and frequency had increased to the point where manual intvervention was required to bring them back down again - the automatic systems have a relatively small control range.

No intervention, and the generators start to trip on overspeed or overvoltage. Now you’re getting way, way beyond the automatic control ranges of the remaining generators, and everything falls apart, very quickly.

5

Also, depends on how the rest go. If they all just disappear, or fall over dead, things might run okay for a while, in spots. If there is a panic, operators might shut things down for safety reasons, and you might not be able to start them back up.

Nuclear plants would likely shut down quickly. They tend to have failsafes that require regular human interaction to continue working.

Coal plants, and similar, would run until the fuel would end, so they would also stop fairly quickly, although it could be dozens of hours, instead of the few hours of nuke plants.

Hydroelectric plants would run for much longer, but without serious interaction, could burn out/suffer catastrophic failures, without someone to overlook them. Weeks, maybe longer.

Wind/solar power plants would last as long as their components allowed, and in the case of failure, the average one-man person could manage to swap available components fairly easily. That is, of course, as long as components were available. Year, +/-

Geothermal units could possibly last the longest, but suffer from the fact that they don’t produce much power. In addition, an earthquake could wipe them out, they are rare, somewhat complicated, etc. In perfect circumstances, they might last a couple decades, depending on the the implementation and the skill of the survivor.

All of the above could last longer, of course, but if it were me, I would tend toward the conseravative side. Anything extra would just be a bonus. Then again, what fun is it without women? :smiley:

6

Not really. It’s true that wind and solar plants would last longer since they require no fuel to run on and minimal supervision. But one dude by himself is not going to be able to swap out the turbine (which is about the size of a van) or the blade (which is about the size of a medium-sized passenger plane).

Actually, geothermal produces more than you think. They also requires a lot more maintenance that you think. Too bad you can’t post pictures on SDMB. We have some lovely ones of one of our geo-plants that just blew it’s well-head.

If I remember come monday, I’ll check out the operations reports for the wind, solar, and geothermal plants we manage. I can tell you exactly how long one operates each month before requiring encountering a maintenance problem that requires human intervention. (ie #23 WTG - Struck by lightning, 36 hours offline)

That would give an overly optomistic estimation however. The reports don’t include mundane day-to-day stuff like turning valves and switches to keep the power flowing.

7

Get thee to an Amish farm, where one can survive quite well without electricity.

8

Forget about the plants. It’s the grid that counts.

And remember that there is input and output and that they must be balanced at all times.

These days most plants are automated - but not all of them. And most homes and businesses are automated as well, in the sense that you don’t have to hold a button down for the electricity to run - but not all of them.

Assume that all humans instantly disappear. Everything that happens next depends on the particulars, but here’s what would generally happen.

The grid is now like a pencil balanced on its point. Some plants would go off right away. The grid would react automatically to some extent isolating these plants from the system and shifting resources. But the other end is shifting as well because the normal flows have been disrupted. All the portions of the grid don’t talk to one another automatically, as we’ve just seen again. Some areas would go black. Without human operators to shift the loads, the blackout would spread.

Most major power plants would shut off automatically as soon as this happens. All the nuclear power plants in the northeast did during the blackout. No meltdowns.

How long for this to occur? Probably no more than minutes.

The longer the system went without human intervention, the wider the blackout would become.

Worldwide, you would see this pattern recur with regional variations.

Some areas, some buildings, some places would retain power for a while. Many businesses these days - ironically, a much higher percentage in the third world where they are used to blackouts - have backup generators that would automatically go on when the grid failed. These would stay on until whatever powered them - gasoline or propane or whatever - ran out.

In industrialized countries, water and sewage systems run off the grid. They will also stop very soon. And unless you had a Day the Earth Stood Still situation in which the alien kept all the planes flying and stopped cars without accidents and whatever, there would be a million crashes, fires, and catastrophes that would damage a fair amount of society.

Beyond that, the scenarios are just too numerous to make sense of them. Certainly some survivors could live on: VernWinterbottom already mentioned the Amish and there are millions of people elsewhere in the world who don’t depend on electricity.

But there would be no Internet. And no SDMB. So why bother living?

9

I’m guessing if he were the last man on Earth, he wouldn’t care too much about the lack of a phone grid.

10

Note that these examples assume that the grid is “healthy” elsewhere, and that the turbine is not overspeeding.

A coal power plant can typically “coast by” for no more than a few hours without operator intervention. It would be very easy to have a cascade failure that ends up bringing the whole thing down. A bunker goes low on one mill, and the unit sees a sudden drop in steam temperature without changing the turbine valve positions, and … shutdown. Or an alarm goes off for too long. At best, with all things operating perfectly and the bunkers full, a coal plant might go for a day before fuel starvation.

A natural gas turbine, on the other hand, will run until line gas pressure drops too much.

A natural gas boiler would be in the same situation.

An oil plant (where they exist, which is not many places in the US) might go for a few days, under ideal conditions.

The key thing is the grid - once the first plant fails, it’s likely to start a domino effect. Plants need to have a load to deliver their power to. It’s like the analogy I said before - hold your car at 80MPH down the highway, keep your foot on the gas pedal without moving it, and shift the car into neutral. What happens? The engine revs up until the rev limiter is hit, or else it explodes. This is a very good parallel to what happens at a power plant when it’s under full power delivering a load, and suddenly that load is removed.

Expanso, ALL plants are automated - but the extent to which they are automated varies tremendously. Only natural gas turbines end up being essentially “start and forget”.

11

Right. I was using “most” because there is always some weird little odd piece of generation equipment - which might not even be part of a utility - out there that the nitpickers will otherwise pounce on.

And look what still happened! :slight_smile:

12

A little off subject, but it would seem if that one person needed power they could get along very nicely going down to the local home depot and declare salvage rights on a generator. Fuel can be obtained by siphoning from cars at 1st, and if needed a generator can be hooked up to a gas pump.

13

Can you drive a big truck?

Just get some gas generators and a few tankers of gasoline.

You will be too busy playing with other things anyway like a trip to area 51 to try to fire-up the space ships they have there - lol

14

Here’s a slightly off-point question, but what about the viability of the fuel? Assume the normal electric grid crashes in no more than a few days and you’re on generators run on gas. If you’re alone or just a few people, you could run on gasoline generators for years based just on what’s stored around you in tanks, cars and processing facilities.

But doesn’t gasoline have a limited lifespan of just a few months/years? How long could you last before you’re just out of luck with fuel powered electrical generation?

15

Gasoline has a limited life, true. But there’s also LNG, LPG, and oddles and oodles of tanks of propane and acetylene. You could get heat and fire for cooking for some time.

Or, you could get coal from the pile at a coal plant. It will degrade somewhat, but even 10-year old still can have more than 50% of its heat in it.

16

There’s another kind?

17

I guess there’d be the one-woman type of person?

Anyway, I wouldn’t count on the grid either. Get down to a marine supply store, or maybe somewhere catering to mining/ forestry camps, and loot a personal hydro-electric generator. About 16" cubed, fed by a 1 1/2" pipe ran a few hundred feet up a stream, they generate on the order of a half-kilowatt, which was enough to power a research station I was on a couple of years back.