# How does a power plant work? (Question is related to electric vehicles) **URL:** \ **Category:** Factual Questions\ **Created:** [June 18, 2022, 11:58pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439 "2022-06-18T23:58:16Z")\ **Posts on this page:** 20\ **Page:** 7
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 23, 2022, 3:39pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/121 "2022-06-23T15:39:45Z")
Are you saying powerplants run at 100% power 100% of the time because they cannot moderate their power output? ---
**Author:** ![FinsToTheLeft](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/finstotheleft/32/2930_2.png) [@FinsToTheLeft](https://boards.straightdope.com/u/FinsToTheLeft)\ **Post date:** [June 23, 2022, 4:57pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/122 "2022-06-23T16:57:38Z")
> [@Folacin](#): > > We had a manager in our office building who had all the light switches on the floors removed. You had to call security to get the lights turned on/off (there were of course scheduled times that covered most cases). My office essentially works like this, but self serve. The lights and HVAC run in occupied mode from 7AM-6PM, Monday to Friday. If you want lights and AC outside of these hours, you hit a button on the thermostat and the building automation system (BAS) activates everything for an hour. We get billed $10/hour at the end of the month. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 23, 2022, 5:16pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/123 "2022-06-23T17:16:49Z")
> [@Folacin](#): > > We had a manager in our office building who had all the light switches on the floors removed. You had to call security to get the lights turned on/off (there were of course scheduled times that covered most cases). My office was like that but it was the building that did it and not a manager. Electricity was part of the rent for the office so the building wanted to make sure the lights were off at night and on weekends. You had to call security to get it turned on. More than once I was working late and had the lights all shut off. ---
**Author:** ![Dewey\_Finn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dewey_finn/32/4222_2.png) [@Dewey\_Finn](https://boards.straightdope.com/u/Dewey_Finn)\ **Post date:** [June 23, 2022, 5:20pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/124 "2022-06-23T17:20:16Z")
At one workplace, the lights would shut off after hours but if I waved my arms in front of the sensor, they’d turn back on for a time, and then I’d have to wave my arms or walk by the sensor or throw a wad of paper at it to turn the lights back on. ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [June 23, 2022, 5:20pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/125 "2022-06-23T17:20:41Z")
So right now our solar panels are producing max power–about 7.2 kw. Almost all of that is being exported to the grid. When we get our EVs, is it greener to charge them from our own solar power, from the grid at night when demand is low, or does it not really make a difference? ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 23, 2022, 5:24pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/126 "2022-06-23T17:24:02Z")
Your utility is there to make money. I would be surprised if they bought power from you for the same as they sell it back. Which is to say, you are probably better using your own power for yourself than selling it to the utility and then buying it back. Of course, to be sure you’d need to do the math but at a guess I would opt for using my own, free power (after installation costs). ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 23, 2022, 5:26pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/127 "2022-06-23T17:26:05Z")
It’s mostly a wash. There’s a marginal increase in efficiency if you charge them with your own Solar panels. But, the economics might be complicated. What are your “net metering” rules? If you sell power back to the utility at a fraction of the cost of what you buy it from them, then you should try to use 100% of the power you generate. What is the on/off-peak power pricing? How does that figure into the money you are being paid for the power you generate? ---
**Author:** ![Ruken](https://avatars.discourse-cdn.com/v4/letter/r/f475e1/32.png) [@Ruken](https://boards.straightdope.com/u/Ruken)\ **Post date:** [June 23, 2022, 5:35pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/128 "2022-06-23T17:35:45Z")
> [@Whack-a-Mole](#): > > Are you saying powerplants run at 100% power 100% of the time because they cannot moderate their power output? Clearly not, given that the post was about modulating slowly rather than not at all. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 23, 2022, 5:40pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/129 "2022-06-23T17:40:02Z")
> [@am77494](#): > > Boilers are tubes containing steam - they need to be heated slowly and cooled slowly. Often the startup times are in days. I think it is obvious the power plants moderate their output a lot faster than in days. They do it at least on a day/night cycle and it was noted above UK power plants ramp up power during sporting matches just before a game or period ends. I think it is safe to say they have pretty fast control over the power supply. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 23, 2022, 5:44pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/130 "2022-06-23T17:44:21Z")
See this post: > [@How does a power plant work? (Question is related to electric vehicles)](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/40): > > There are a lot of anti-EV talking points knocking around, and it’s hard to address them all. I just want to focus on this specific question which is interesting: When my air conditioner turns on, does someone at the power plant have to throw another lump of coal in the boiler? The answer is (kind of) yes. Here’s how it works (imagine for simplicity there is only one generator on the system): Start with the system in balance - the same amount of power being generated as is being used (inclu… ---
**Author:** ![echoreply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/echoreply/32/3641_2.png) [@echoreply](https://boards.straightdope.com/u/echoreply)\ **Post date:** [June 23, 2022, 5:58pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/131 "2022-06-23T17:58:12Z")
> [@Dewey\_Finn](#): > > At one workplace, the lights would shut off after hours I occasionally worked in a building in the UK that was like that, but instead of the lights it was the _toilets_ that shut off after hours. The urinals did an auto flush every 10 minutes or something, and there was no manual override. Nights and weekends they did their manual flush every few hours. Thing was, the building was a lab, so they tried to run lots of the equipment 24/7, which meant that after hours the building was less occupied, but it was never vacant. So at any given time after hours, there was likely to be one or more urinals stinking up the place, waiting for the flush timer to go off. That’s a long way from EVs and power generation, so I’ll try and tie it back: Be sure to completely understand the problem before trying to solve it. More EVs means necessary upgrades to the power grids, say many who don’t charge EVs. Time shifting EV charging is easy, and easy to put in financial or technical pushes to make people do it (which has been said many times in this thread, and others). ---
**Author:** ![Folacin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/folacin/32/3195_2.png) [@Folacin](https://boards.straightdope.com/u/Folacin)\ **Post date:** [June 23, 2022, 5:58pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/132 "2022-06-23T17:58:49Z")
> [@Whack-a-Mole](#): > > I think it is obvious the power plants moderate their output a lot faster than in days. That’s a plant that is up and running. The reference to ‘days’ is how long it takes to do a cold start. ---
**Author:** ![Whack-a-Mole](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/whack-a-mole/32/141_2.png) [@Whack-a-Mole](https://boards.straightdope.com/u/Whack-a-Mole)\ **Post date:** [June 23, 2022, 6:00pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/133 "2022-06-23T18:00:57Z")
My original point that was being responded to was how fast a power plant can adjust its output. Ask @am77494 why they got on about starting a power plant from zero. ---
**Author:** ![smithsb](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/smithsb/32/12107_2.png) [@smithsb](https://boards.straightdope.com/u/smithsb)\ **Post date:** [June 23, 2022, 11:10pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/134 "2022-06-23T23:10:42Z")
> [@Whack-a-Mole](#): > > Your utility is there to make money. I would be surprised if they bought power from you for the same as they sell it back. We got into solar in Hawaii under the old system. Hawaiian Electric buys our excess power at the retail rate [what they charge customers - not a typo]. This changed for systems added later [I believe they get only the current wholesale rate]. We get a nice check every quarter ~$300, It would be more but the wife likes air conditioning. I’m also the Prince of Darkness going around shutting off lights. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 23, 2022, 11:37pm UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/135 "2022-06-23T23:37:44Z")
OK, with a sweet deal like that, you’re definitely better off selling your expensive daytime solar power to the utility, and buying cheap night power to charge your car. Most folks won’t get such a sweet deal, though. ---
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [June 24, 2022, 12:03am UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/136 "2022-06-24T00:03:16Z")
Some people can get an even sweeter deal. This is new for Tesla Powerwall owners: > **[Emergency Load Reduction Pilot | Tesla Support](https://www.tesla.com/support/energy/tesla-virtual-power-plant-pge)** > > Participate in the Emergency Load Reduction Program (ELRP) pilot offered by Pacific Gas and Electric Company (PG&E) and support the grid while also earning compensation and maintaining your energy security. Charge the battery (with solar or not) during off-peak hours, then get up to a whopping $2/kWh during emergency load reduction events. That’s a really high price, but probably still cheaper than maintaining and running peaker plants that only run during a handful of peak load events. ---
**Author:** ![Tride](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tride/32/13907_2.png) [@Tride](https://boards.straightdope.com/u/Tride)\ **Post date:** [June 24, 2022, 12:27am UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/137 "2022-06-24T00:27:00Z")
Well, it’s simple net metering, and no evening discount. The meter moves left, or it moves right, all at the same rate. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 24, 2022, 12:29am UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/138 "2022-06-24T00:29:17Z")
Then I would think that charging during the day would save you a few pennies. ---
**Author:** ![filmstar-en](https://avatars.discourse-cdn.com/v4/letter/f/50afbb/32.png) [@filmstar-en](https://boards.straightdope.com/u/filmstar-en)\ **Post date:** [June 24, 2022, 12:49am UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/139 "2022-06-24T00:49:48Z")
Accommodating the charging demands of EVs is much discussed issue, but the elephant in the room is home heating. I n the UK there is an extensive pipe natural gas network used for central heating and hot water. Over in France they use electricity instead and the figures for electricity consumption are about twice that of the UK. Weaning the UK off natural gas will require a big upgrade to the grid that will probably be as significant as the extra demand for EV charging. Is suspect that most electricity grids are going to require a redesign to accommodate renewable power generation, domestic solar generation, the demands of EVs and home heating unless air and ground source heat pumps become a lot cheaper and easier to install. In addition they can buy in extra power through HVDC interconnects to other grids that have a surplus. This is a LOT of design changes and grids are going to require some major investment over many years. Whether the power utilities are prepared for it, that is the big question. These projects take a lot of planning. ---
**Author:** ![eschereal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/eschereal/32/18939_2.png) [@eschereal](https://boards.straightdope.com/u/eschereal)\ **Post date:** [September 15, 2022, 10:06am UTC](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439/140 "2022-09-15T10:06:52Z")
> [@Ruken](#): > > We generated 39.2 quads of electricity in 2011 and 36.6 in 2021. Meanwhile we use over 24 quads of petroleum for vehicles. So there’s not much spare capacity compared to the potential need. My question is, if you replace 24 quads of petroleum use with the distance-equivalent in BEV usage, what does that come out to? 10 quads? Less? Because one of the reasons there can even be BEVs is that they use so goddam much less energy to do the same thing. To suggest that we would need those same 24 quads to move a full fleet of electric vehicles is passing ridiculous. [Previous page](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439.md?page=6) [Next page](https://boards.straightdope.com/t/how-does-a-power-plant-work-question-is-related-to-electric-vehicles/966439.md?page=8)