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

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

#111

Post by dehrmann »

Grimburger wrote: post #39
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…

> The solution is simple. Make electricity cheaper when it's more available From the parts of the world I come from the majority of people are vehemently opposed to time of use pricing. Because that's when they use it most. They and their political representatives would much prefer to keep taking from those who consume in off-peak rather than fix the underlying mechanism.

It's probably not "taking from those who consume in off-peak." The utility knows when people who use flat-rate power use it, so they can bake that into the flat rate. But if it makes consumers feel better about the price...

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

#112

Post by bonzini »

shiftpgdn wrote: post #94
landemva wrote: post #86

Earlier quoted context omitted.

For the small amount I consume, tiny potential savings are not worth the mental hassles. I switched a residence to flat rate to avoid these mental games.

My house uses around 3-4MW/mo. I hyper optimized when I had true spot pricing before Griddy energy was disbanded by the state. My bill was extremely low compared to what I pay now.

What? My house used 4 MWh a year in 2020, with two people working from home and two kids. Of these about half (IIRC) is self-produced solar. Stove and heating are gas and I do not have a tumble dryer, but does that justify a 10x difference??

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

#113

Post by greedo »

floatrock wrote: post #40
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...

It's almost as if the logical conclusion is to invest in convenient workplace charging infrastructure so charging is simple when the car is conveniently parked at work doing nothing and the owner wants a car ready to go home in the evening... > “We encourage policymakers to consider utility rates that encourage day charging and incentivize investment in charging infrastructure to shift drivers from home to work for c…

The logical conclusion is to try to get away from needing to drive to work at all.

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

#114

Post by Schroedingersat »

upsidesinclude wrote: post #104
NickM wrote: post #78

Earlier quoted context omitted.

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

If only there were a way to encourage upwards of 50% of trips to be done via methods that take a tiny fraction of the energy with no or negligible battery without invasive freedom limiting legislation just by spending roughly as much as EV manufacturers have received in subsidy on infrastructure.

Oh well. Guess we'll have to give another billion to elon.

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

#115

Post by NickM »

upsidesinclude wrote: post #104
NickM wrote: post #78

Earlier quoted context omitted.

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

My point isn't that we should actually shrink EV batteries and use the excess for stationary storage, my point is that car batteries as a demand-leveling mechanism is not likely to be an optimal solution.

That said, it's not something that's really happening right now anyway, so the "power your home with your car at night" idea seems unlikely to take off unless there is a (possibly misguided) legislative push for it.

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

#116

Post by jonahhorowitz »

floatrock wrote: post #27
m0RRSIYB0Zq8MgL wrote: post #20

> Current time-of-use rates encourage consumers to switch electricity use to nighttime whenever possible, like running the dishwasher and charging EVs. This rate structure reflects the time before significant solar and wind power supplies when demand threatened to exceed supply during the day, especially late afternoons in the summer. So, if you have a grid that doesn't heavily rely on solar then charging at night ma…

> > Today, California has excess electricity during late mornings and early afternoons, thanks mainly to its solar capacity. If most EVs were to charge during these times, then the cheap power would be used instead of wasted. > How are people going to charge their cars during commutes? Come on, you're saying most commutes are "late morning and early afternoon"? I too would like a job where my commute in is at 11 and…

We should install solar panels over those lots at the same time. It covers some of the capacity need, cools the lot and the cars, and is an efficient use of space.

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

#117

Post by ttGpN5Nde3pK »

Crazy concept: instead of banning cars, forcing electric cars, mandating specific efficiency, etc... we _could_ work towards a world less dependent on personally owned vehicles. And yet, huge companies will continue to just get a pass for forcing people to commute to jobs to sit on a computer all day.

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

#118

Post by Retric »

shiftpgdn wrote: post #94
landemva wrote: post #86

Earlier quoted context omitted.

For the small amount I consume, tiny potential savings are not worth the mental hassles. I switched a residence to flat rate to avoid these mental games.

My house uses around 3-4MW/mo. I hyper optimized when I had true spot pricing before Griddy energy was disbanded by the state. My bill was extremely low compared to what I pay now.

What are are you using that much power for? I can’t think of much that uses that much per that you can shift to time of day pricing, perhaps pottery kilns?

Even 2MWh per month is enough to drive 2 EV’s around 50,000 miles per year each. If you’re very flexible with time of day rooftop solar could probably save you quite a bit.

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

#119

Post by Kirby64 »

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%?

Remember, when you charge your cell phone, you charge at ~15W (or less), so 80% efficiency is something like 3W of power loss. You can dissipate that pretty easily.

For a car charging, you're charging closer to 7-11kW. Dissipating 2.2kW (20% of 11kW) as heat is basically impossible. The inductive charging they're using for cars (which, are basically mostly prototypes at this point) are different and use much more closely coupled coils... so they can get better efficiency. Whether it works in practice, I don't know, but that's what companies are claiming who come out with these solutions.

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

#120

Post by myko »

kadoban wrote: post #109
guywithahat wrote: post #79

Earlier quoted context omitted.

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?

I assumed the comment meant EVs were worse than ICE vehicles (not an opinion I hold)
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