Stanford study warns against charging electric cars at home overnight

[whitex]

this is just a guess but I suspect that the majority of people who charge their cars do so at home over the night time period.
there is a small set of people who charge while they are at work.
the TOD scheme would have almost zero impact on EV owners

Most people get home before 9pm, when the price of electricity often is discounted in the summer, delaying charging from 5pm or 6pm until 9 helps with the peak usage. Then there are people who work from home, or are retired. EVs are the largest power draw consumers in an EV household, which means they significantly affect to the peak draw (tripple or even quadruple is for most EV homes). Shifting those to 9pm does help.

PS) this is a graph of my home electicity consumption last summer. Full disclosure, my home uses a lot more electricity than a typical home, as I run a mini data center at home (think internet servers), but still you cannot miss the peaks which are all caused by EV charging (we didn't drive many miles so the peaks are short in duration).

Sponsored

 

[kort]

https://www.yahoo.com/news/america-being-hit-huge-surge-100000083.html



it's a nationwide problem - the grid needs upgrading.

I read the first paragraph of that article and it described a one time failure/blackout not rolling blackouts like in CA that you claim occur wherever there is a large population and economic activity.
your attempt to bolster your assertion is a fail.

 

[whitex]

https://www.yahoo.com/news/america-being-hit-huge-surge-100000083.html



it's a nationwide problem - the grid needs upgrading.

One time blackout is not scheduled rolling blackouts like I remember from living in California, where we'd know ahead of time the parts of the town and the time windows during which there will be no power there.

 

[daveo4EV]

it not one time only

Power outages have increased 64% from the early 2000s, and weather-related outages — many driven by the worsening climate crisis — have increased 78%.

 

[kort]

it not one time only

please stop, I have always respected your insights but you are way off on this

 

[whitex]

it not one time only

Yes, they are on the increase but not rolling blackouts. At our current home we used to experience 1 power outage every couple of years, now it's a couple of times a year, 400% increase over about 2 decades, but still not the same as rolling blackouts. Outages for more than an hour occur very rarely (knock on wood - just had one last year which was the longest ever, the one before was in 2016). All outages here are have been caused by bad weather (usually high winds, so yes, climate change is a factor), none so far have been planned or caused because of lacking grid capacity.

 

[charliemathilde]

This is a stupid argument. It’s like a few weeks of engineering work. EVs offer their customers charging schedules based on the cheapest rates, as published by their local utilities. People plug their cars in whenever they can, and the cars draw current based the calculation of the least cost to their owner.

doing that by 2035 is like a thing you have to actively try to fuck up with malice, because it’s basically an intern project.

the grid requires more investment and growth, but only slightly more than our historic rate of grid expansion. Adding EVs is basically like adding air conditioning to most homes. A huge grid expansion, but something we have easily done before

 

[whitex]

This is a stupid argument. It’s like a few weeks of engineering work. EVs offer their customers charging schedules based on the cheapest rates, as published by their local utilities. People plug their cars in whenever they can, and the cars draw current based the calculation of the least cost to their owner.

doing that by 2035 is like a thing you have to actively try to fuck up with malice, because it’s basically an intern project.

the grid requires more investment and growth, but only slightly more than our historic rate of grid expansion. Adding EVs is basically like adding air conditioning to most homes. A huge grid expansion, but something we have easily done before

This study seems very simplistic. I've been learning about the different standards, including the ISO15118 which Porsche is using. There is more to what those standards envision. Ideally everyone plugs in their cars whenever parked. The car communicates with the utility to know when is the best time to charge, and allows the utility to throttle the charge rate in case the system sees a large spike, as well, if the EV owner allows, even use the energy from the EV to temporarily feed the grid. This is why the Taycan has the timers - it's straight out of the ISO15118 - if the car knows when you want to have it charged, it can optimize your charging to help the grid and have your car ready on time. So not exactly like adding more air conditioners, unless the utility was allowed to throttle or even completely turn them as needed, and even turn them into generators somehow.

We are not there yet. International standards take forever for all stakeholders to agree to follow them, so it will take some time. Tesla was able to offer the "virtual power station" made up of Tesla walls because they don't need to "drive consensus" - just like with DC charging, they can move faster, achieve better results that way. But, DC charging is coming along, the integration of cars into the grids will come too.

Personally, I would start by not just charging TOD but also give credit to people who are willing to throttle on demand or even feed back the grid, though the latter is most complicated, so even just throttling usage on demand would be a good start (e.g. turn off EV charging for an hour when utility is having capacity issues - if they can turn off 10,000 EV's charging at 10KW each, that's 100MW of power that can be suddenly reclaimed). You could further incentivize owners to sign up for "power curve flattening", ie. a soft commitment that you will not exceed certain peak power during highest demand - that can be achieved if your EV can smooth out your power curve (e.g. draw the amount over the committed peak from your EV battery, then once your home needs less than the committed max, the EV battery charges back) - maximum flat curve plans could be much cheaper, with expensive excursions above those maximums during peak demand times.

 

[chocough]

But isn't overall electricity usage much much lower overnight regardless of EV charging?

True, in china government encourages charging in mid night. And mid night gets best electricity price. Nearly half of the day time bill

Sponsored