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Charging cars at home at night is not the way to go: study

news.stanford.edu

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Re: Charging cars at home at night is not the way to go: study

#101

Post by sempron64 »

The article predicts that even with the proposed changes, 4.2 GW of storage or other generation capacity will be necessary, as opposed to 5.2 GW without the changes. I'd advocate getting on the power supply or storage solution immediately rather than trying to change consumer habits by e.g. funding or legislating power station installations in workplaces (a nice convenience, but not one that will solve this problem).

Tesla has already built a very large power storage station in Australia https://www.pv-magazine.com/2022/07/27/tesla-big-battery-beg...

Obviously the notion of building >5GW of generation capacity on fossil fuels or nuclear in under 10 years seems wild. So it's probably going to have to be solar + storage.

Re: Charging cars at home at night is not the way to go: study

#102

Post by denimnerd42 »

parkingrift wrote: post #89
denimnerd42 wrote: post #18

I would be curious about a study done for the Texas market. From what I understand, you'd definitely want to charge at night due to the vast amounts of wind power available and the otherwise low demand. Even better would be to plug the car in at all times when parked either at work or home and it just charges when the rate is cheapest. You don't need to charge every day to refill that 20 or 30 miles.

>Even better would be to plug the car in at all times when parked either at work or home and it just charges when the rate is cheapest. 99% of people have a fixed rate 24/7/365. I live in NYC and I'm not even sure if it's possible for me to pay time of use rates. The time of day that electricity is cheapest is... all the time. I sincerely doubt there is any public or political will to change this engrained billing me…

In Texas right now you can get two meters to your home. One meter you use a fixed rate plan and the other meter you use a "wholesale" plus fee type plan, infamous example being Griddy. When the rate is nearly free you enable the outlet that charges your car.

Of course hiring an electrician and all of that would probably have a long payback period.

Re: Charging cars at home at night is not the way to go: study

#103

Post by kadoban »

guywithahat wrote: post #79
kadoban wrote: post #14

Earlier quoted context omitted.

It's not a problem, it's an opportunity to optimize energy use to match how it's now generated.

Shouldn't it be an opportunity to match energy generation to how it's consumed? No industry survives long by offering a worse product to consumers than what they had before

If consumption has a good reason to be as it is maybe. The whole reason we have lower night rates and such was due to how it was generated in the past though. Why would we continue that if it no longer makes sense?

It's something that should be looked at on the whole and tradeoffs considered.

Re: Charging cars at home at night is not the way to go: study

#104

Post by upsidesinclude »

NickM wrote: post #78
upsidesinclude wrote: post #66

This article does a poor job of explaining why there is going to be a problem and relaying the point of the study. To model the grid and power infrastructure into the future, assumptions must be made about where the power is derived. The article fails to provide the basic factors contributing to the problem, even though the study itself does a fine job. So California wants to legislate electric cars. That means highe…

If you're regularly committing a certain percentage of your car's battery capacity to powering your house, wouldn't it make more sense to just have a stationary battery at home? Otherwise you can't rely on that extra range in your car if you need it to power your home anyway, and you're just spending extra energy carrying around extra battery weight in your car every day.

If we're seriously going there , then legislate mandatory carpool or motorcycles for single occupants.

The thing is, California isn't making great policy decisions or even efficient power decisions. They are making virtue decisions.

Moving 1.5 tons of battery or 1.25 tons of battery isn't where the hairsplitting should take place

Re: Charging cars at home at night is not the way to go: study

#105

Post by DropPanda »

Gasp0de wrote: post #96
DropPanda wrote: post #60

Earlier quoted context omitted.

Surprisingly, transmission efficiency (grid to motor) does not appear to be lower with inductive methods than conductive. Numbers above 90% should be expected. A bit lower for the dynamic (in-motion) solutions, but not so much that it’s a deal breaker. There seem to be much larger savings/costs elsewhere in the system that make transmission efficiency of less importance. Cars that are stationary most of the time are…

This source ( https://batteryuniversity.com/article/bu-412-charging-withou... .) says efficiency is only 75-80% when charging inductively. Do you have any better sources for those 90%?

It’s hard to get data from non-biased sources, given that there are no commercial installations yet.

Some numbers are thrown around here (static inductive): https://insideevs.com/news/425972/momentum-dynamics-wireless...

And here (dynamic inductive): https://www.greencarcongress.com/2022/06/20220614-electreon....

From what I have heard, the transmission efficiency of the dynamic inductive solution is quite sensitive to alignment and they still have some R&D left to do there.

Re: Charging cars at home at night is not the way to go: study

#106

Post by [deleted] »

saidajigumi wrote: post #51
alexb_ wrote: post #17

>We're doing it wrong, according to a new Stanford study Wrong according to what metric? Cost? Raw efficiency? A lot of people are more than willing to give up efficiency so that they don't have to actually worry about finding a station during the day. To say that something is just outright "wrong" based on their personal preference of priorities comes off as unhelpful to me. The solution is simple. Make electricity…

This is precisely what the linked article says. From the section "Charging Incentives": “And it’s not just California and Western states. All states may need to rethink electricity pricing structures as their EV charging needs increase and their grid changes,” added Powell, who recently took a postdoctoral research position at ETH Zurich. The article also includes other interesting and more nuanced policy details tha…

[deleted]

Re: Charging cars at home at night is not the way to go: study

#107

Post by AceyMan »

notatoad wrote: post #99
GoOnThenDoTell wrote: post #55

Earlier quoted context omitted.

time-of-use is also cognitive load that can cause anxiety

it is, but that's the part that technology can actually help us with. all the internet-connected smart home stuff that companies have been trying to sell us is a bit silly when electricity is sold at a flat rate, but if my car charger, my clothes dryer, or my or my dishwasher could sit idle until electricity prices drop into the cheap zone and then turn themselves on, that internet connection becomes useful. an attit…

this just makes me think of the situation that resulted in Global TCP Synchronization flapping problem; when everyone is operating on the same premise without some random delay or other way to 'shard' the load it seems like a Slashdot effect is bound to happen.

Re: Charging cars at home at night is not the way to go: study

#108

Post by more_corn »

What? Peak electrical consumption is during the day. The big challenge for electric companies is the swing between the night trough in demand and the day peak. Night charging is excellent because it flattens that curve. Bringing demand into a straighter line and allowing electric companies to generate at a steady rate without having to cycle production up and down.

I glanced though the article and found no mention of that.

You can’t write a piece like this and begin anywhere else.

This article gets an F- for effective communication and persuasion.

Re: Charging cars at home at night is not the way to go: study

#109

Post by kadoban »

guywithahat wrote: post #79
kadoban wrote: post #14

Earlier quoted context omitted.

It's not a problem, it's an opportunity to optimize energy use to match how it's now generated.

Shouldn't it be an opportunity to match energy generation to how it's consumed? No industry survives long by offering a worse product to consumers than what they had before

> No industry survives long by offering a worse product to consumers than what they had before

That's ... optimistic, but not really true.

It also doesn't seem to match what's happening here either. How is power generation when demand is highest a worse product?

Re: Charging cars at home at night is not the way to go: study

#110

Post by m463 »

lelag wrote: post #9

It's not just about the rate. Charging at night happens because the car is conveniently parked at home doing nothing and EV owners want a car ready to go in the morning. Charging at EV station during the day is time consuming and is often expensive. I'm sure that the lucky few that can charge at work already do so...

Most EVs charging at home are plugged in from say 6pm to 7am. It would be most convenient to charge immediately but the electric rates (in california at least) are highest at 6pm and lowest at 7am.

There is choice in that equation.

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