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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

#171

Post by vel0city »

bonzini wrote: post #112
shiftpgdn wrote: post #94

Earlier quoted context omitted.

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??

My home uses over 2MWh/mo over the summer, I think our peak bill this year was ~3200kWh.

Average highs these last few months has been around 100F or so and very sunny, with at least one month >100F for the high every day. Its finally "cooling off" around here, with our highs being in the upper 90s most days. Cooling >2000sqft of space, even with some decent insulation and keeping the AC to 78F in the day, uses a lot of energy. It uses ~30A @ 240V, so ~7.2kW. If it had to run 12 hours in a day, that's 86.4kWh in just a single day. Doing that for a month straight, that's 2,592kWh.

I was going to write up the math on how much my pool pump uses, but honestly it kind of turned into peanuts compared to the amount our AC usage is. The pump is 3/4HP. Running ~600W on the schedule of 8 hours a day + 12 hour once a week shock it really only worked out to 172.8kWh/mo of usage. Still though, that's 52% of your entire usage for just my pool.

Last year we probably used ~3,000kWh charging the EV. That's on average 250kWh/mo.

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

#172

Post by qqqwerty »

NickM wrote: post #115
upsidesinclude wrote: post #104

Earlier quoted context omitted.

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.

Batteries are a bit too expensive to make sense as stationary storage outside of some specialty cases right now. But EVs have been economical for a while. So while we wait for battery prices to drop, two way EV charging absolutely make sense as a transition technology. Most of those EV batteries are sitting unused for large chunks of the day, and the entire capacity of the battery is often only needed by the driver a few times per year. Adding two way charging is not a prohibitive cost, and that installation can be reused if/when an onsite battery is added in the future. The rest of the program can be managed with software.

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

#173

Post by ThatPlayer »

drak0n1c wrote: post #143
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.

Many electricity co-ops and providers in Texas offer a choice of plans, one of which is higher rates during daytime but free electricity during nights and weekends. But that allowance doesn't kick in until later in the night, so a programmable clock on the charger would be a killer feature for electric car sellers.

I believe most electric cars already support charging on a timer. I have a ChargePoint charger that does the same thing on the charger side. The app even has a choice of all the electricity providers and plans to choose it so I don't have to look it up manually.

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

#174

Post by m0RRSIYB0Zq8MgL »

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…

My post wasn't not about criticizing EVs. My post was about criticizing the energy grid. I think "slow" charging over night is the best way to use EVs and an energy grid that cannot accommodate that (because of a predominance of PV) should be criticized.

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

#175

Post by pornel »

greedo wrote: post #121
kadoban wrote: post #12

Earlier quoted context omitted.

Charge at work.

Our main campus has parking for roughly 450 cars. We just added EV charging; two entire parking slots. There's no way our company would outfit every spot with charging in any reasonable future. We already have roughly 35 EVs on the lot.

When a car is parked for 8 hours, even the slowest 3kW charger will charge 70-90 miles of range.

Low-power AC "chargers" are dumb devices, basically just wire. They don't require active cooling, and all of the expensive hardware is in the car. They could be installed on every single parking spot.

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

#176

Post by greedo »

pornel wrote: post #175
greedo wrote: post #121

Earlier quoted context omitted.

Our main campus has parking for roughly 450 cars. We just added EV charging; two entire parking slots. There's no way our company would outfit every spot with charging in any reasonable future. We already have roughly 35 EVs on the lot.

When a car is parked for 8 hours, even the slowest 3kW charger will charge 70-90 miles of range. Low-power AC "chargers" are dumb devices, basically just wire. They don't require active cooling, and all of the expensive hardware is in the car. They could be installed on every single parking spot.

Our lot isn't closed, and it's adjacent to a mall. So the only way we'd electrify each spot is with pay outlets (which is what the current 2 are). Otherwise we'd have people leeching off of the company.

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

#177

Post by zbrozek »

alexb_ wrote: post #76
zbrozek wrote: post #69

Earlier quoted context omitted.

Yeah it is. I hate having to have a process in my brain thinking about optimizing everything. So I bought solar panels and batteries. Now I no longer care. The grid can keep getting more expensive and less reliable without causing me grief.

>So I bought solar panels and batteries ...Mission accomplished?

Sortof? The chumps left behind have fewer people to help amortize fixed costs.

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

#178

Post by shiftpgdn »

bonzini wrote: post #112
shiftpgdn wrote: post #94

Earlier quoted context omitted.

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??

It's 90-100F from 9AM to 9PM (and sometimes longer than that) with 100% humidity 3600sqft mutli story house. 2 adults, 2 kids at home. 2 electric vehicles.

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

#179

Post by jeffreygoesto »

mirchiseth wrote: post #138
AceyMan wrote: post #107

Earlier quoted context omitted.

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.

Saw the Slashdot effect reference after such a long time. Not sure what % of HNers were there in the heydays of /.

More than you think? =;-{)} Wo remembers the "Anonymous FTP Sites List"?

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

#180

Post by wcoenen »

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.

Power companies can offer more than one pricing formula.

People who want to minimize their power bill can choose to pick the time of use pricing and shift some of their consumption off peak. Others can choose to pay more for the convenience of not having to worry about all that stuff. How much more, that can be determined by market forces.

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