When reading about cities in developing countries where electricity and sometimes water is only available at set hours of the day because supply cannot keep pace with demand (measures that very infrequently are also in place in the rich word, particularly during water shortages), I use to wonder to what degree total energy/water consumption is really reduced.
For example, I imagine that with electricity only supplied at set hours, people would, during these hours
if using A/C, cool their house down to the lowest bearable temperature
if using electric heating, heat their house up to the highest bearable temperature
if cooking with electricity, shift meal preparation to these hours if at all possibly
Also, refrigerators and electric storage heaters would automatically increase their consumption in the hours with electricity. Same with all other thermostat-controlled heaters and coolers.
Similarly, with water pressure only supplied at set hours, as soon as water comes on people would rush to fill all manner of containers (part of which water would then not be used), and to bathe, shower/cook etc.
So, is there research or are there utility rules of thumb about how temporary shutoffs of part of the electricity/water grids actually serve to relieve overtaxed generating/water supply capacity?
It’s more about the fact that at some point the demand stops the system from functioning. Too little of whatever service is going to everybody, and nothing functions. By limiting the load, the system still functions for the people when it’s on for them. It’s not implemented to reduce demand. It’s implemented to keep the connected load supplied with enough resources to be functional.
Blackouts aren’t caused by too much usage, but rather too little capacity.
In other words, the utiltiy really doesn’t care if you are wasting energy, but rather that too many people are using energy at the same time, exceeding their generating capacity.
So, they are 100% efficient.
Usually, the entire city isn’t shut down - the blackout rotates throughout the city, so the utility never exceeds it’s capacity. The total usage may well exceed that of a a non-blackout (although I doubt it), but that’s not the issue.
But the OP’s point still stands - if fewer people are getting power/water, but they are all using a lot more to make up for the times when they don’t get any, the load on the system could well be just as high.
Presumably in the real world it isn’t, or the system wouldn’t work.
They are not trying for the most efficient way to use the commodity. They are being forced to modify consumption, because users are not reducing usage enough voluntarily to keep the system running.
The fact that they use it more later doesn’t matter. The load has to be kept below a maximum usage or the utility collapses. They have to keep it running. The next step is to get people to use less and they can supply to more households when the people start doing that. Hopefully they can at some point supply all the loads for a city at once.
It’s always worse when you have to modify peoples activities, when they don’t do it themselves.
But say you shut the water off to half the houses in the city. The rest of the households know they’ll be next to be cut off, so they stockpile water, run baths and showers, water their gardens etc etc. Each house now uses twice as much water. Net demand is still the same, surely?
It’s a bit like how (around here at least), the major supermarkets didn’t double their income when they doubled their opening hours - people have a set amount of stuff they want to buy, and they’ll just buy it when they can. Fuel rationing per license plate number by day is similar.
As a practical matter it does reduce water usage. My landlord didn’t replace a bad well pump for a year and that left me without water for up to a day. I kept about 2 quarts in the fridge for drinking. I Put a couple toilet flushes worth in a container, and had about 2 quarts in a dispensing container for washing my hands or whatever. I knew the water was off so the toilet didn’t get flushed for urinating. I did whatever I wanted to have washed hands for in a group, so I didn’t wash up as much. It does force you to use less than you were likely to use otherwise, because if you use it all up you’re out and you can only store so much.
They may also turn it on for only long enough that people can’t get as much as they’d like too use during the down time. The size of the service entering the house restricts them to a certain maximum high flow.
When power is rationed you can’t operate everything to make up for lack of power at other times. Your stereos, televisions, computers, fans, and the like are going to be something that will save power in the end if the power is shut off. Forcing air conditioners off for 8 or more hours during the hot part of the day will save more energy than customers cooling a room later during the 8 hours they are given power.
What is being done depends on the goal of the utility. An inability to supply demanded resource can be because the item is in short supply or the maximum capacity of the distribution system is reached. If it’s a problem of limited resources available you’re more likely to find the utility is on only long enough to allow a rationed amount to each user and shut down totally a some point each day. You can also have a problem where both circumstances apply.
Transmission losses would be reduced. Let’s say the city has a creaky old water system which loses 30% of the water it sends thru the pipes. With the valves shut that loss is eliminated.
When I lived in Hermosillo, Mexico for a year, the city only provided water to certain sections of the city on a predictible, rotating basis. As is common everywhere else I’ve been in Mexico, the solution in Hermosillo was the use of sisterns (called tinacos in Mexico. It used to be that water was always available, all the time. When the population outgrew the ability to support this, the government water board adopted the rotating schedule, and subsidized the purchase of tinacos. The conclusion I draw from this is that that it’s not a consumption issue, but a peak load issue as said above.
My father-in-law’s house in Leon is considerably older, and they’ve had limited water there for considerably more years than in Hermosillo. Aside from the standard tinaco on the roof, it’s got a several thousand liter sistern built under the foundation of the house. It was designed by an architect and approved by the city for construction.
Another example. I live in Michigan and my water comes from Lake Huron. We have endless supplies of water (until Arizona and California decide to steal it from us). It’s cheap. I’m not even sure why it’s metered. It’s nothing for us to buy Canadian full-flush toilets and non-restricted shower heads. It’s just water. Yet… due to infrastructure issues, we have voluntary do-not-water days during certain months of the season. Not because the city shuts off the water, but because the pressure will drop too low and some of the pipes will start to collapse!
Low pressure can also allow the pipeline to suck in harmful things from the surrounding soil. Low pressure is a Bad Thing for potable-water pipelines.
Speaking of pipe collapse, last week while researching info for a presentation on dam failures, I came across an impressive photo of a section of the Los Angeles water system pipeline which had collapsed. Mulholland was able to salvage the pipeline by refilling it slowly.
I think so - most webservers can only handle X requests at the same time. Any more than that, and connections start to get refused (think of them being “blacked out”). This has the effect of evening out demand (lowering peak demand processing power required).
Yes, I found it on line but I did not bookmark it. I was searching for links on the St. Francis Dam which was located kind of north of Saugus. You could look for links to Los Angeles Dept. of Water and Power, Santa Clarita Valley historical info, Owens Valley water aqueduct, etc. There is a reference to this collapse (it was a siphon portion) in the book Water and Power: The Conflict Over Los Angeles Water Supply in the Owens Valley by William L. Kahrl.
Don’t be too hard on Mulholland - he was a sharp guy who did a lot of good work for LADWP. He took full responsibility for the failure of that dam, even though there was no way that he could have known about the geologic conditions which caused the failure. I don’t necessarily agree with the way that Los Angeles obtained their water rights back in the 1920’s, but Mulholland did a remarkable job with that system.