alexb_ 6d
>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 cheaper when it's more available, and people will use it. You don't need any complex "AI" like people in this thread are saying, you just use natural market forces and the problem fixes itself. Too much energy being used at night - price increases. It's not complicated, and it's what we're doing already. People don't need a Stanford study to convince them to get their energy for cheaper.

upsidesinclude 6d
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 higher demand in a shorter period of time. Meanwhile Calofornia wants to legislate 'clean' or 'green' energy production. If that's a design limitation then the outcome is a shift away from what is the normal situation we face with energy use today.

Energy use at night with a highly solar derived power system requires significant storage and efficiency loss. Charging all of California's electric cars in 2035 will be a demand that far surpasses anything seen today. These things that we see causing rolling black outs and brown outs, like AC use spikes in summer will be a blip compared to the consistent vehicle charging demand.

Interesting, though, the electric vehicle adoption basically negates the storage problem if a parallel infrastructure of charge back from homes at night is implemented. Charge your car at work in the sun and use it to power your home at night.

denimnerd42 6d
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.

elzbardico 6d
Of course, it is far more efficient system-wide to charge electric cars around noon, where photovoltaic energy produces a surplus of energy with zero marginal economic value.

It is an elegant way of solving at least part of the storage problem and the mismatch between peak power and demand times.

digdugdirk 6d
"Electric vehicles will contribute to emissions reductions in the United States, but their charging may challenge electricity grid operations. We present a data-driven, realistic model of charging demand that captures the diverse charging behaviours of future adopters in the US Western Interconnection. We study charging control and infrastructure build-out as critical factors shaping charging load and evaluate grid impact under rapid electric vehicle adoption with a detailed economic dispatch model of 2035 generation."

The opening lines of the actual study paper. Wanted to put that out into the mix before this turns into another Soleus Pushup debacle.

That said, I think University of Houston actually did a better job with their press release than Stanford did, both in clarity of explanation and in the quality of presentation. I'd like to hear some thoughts for/against though.

rr888 6d
We really need a way for power hungry smart devices to charge by spot pricing. By default your car charges when rate is low eg windy nights and sunny lunch times and not a heatwave. Having Night and Day rates is too simplistic.
cortesoft 6d
It sounds like the real issue is that the time-of-use rates are wrong. Just adjust them to match the actual energy production/demand, and the behavior change will follow.

My solar, battery, and car setup automatically adjusts to the rate for power. It sends all my energy to the grid when costs are high and I get the most back, and uses the battery at that time... and then charges the battery when rates are low.

Set the rates to be accurate and the system will work itself out. I am not going to use more expensive electricity just because the rates are set wrong.

lelag 6d
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...
m0RRSIYB0Zq8MgL 6d
> 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 makes sense.

> 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?

guywithahat 6d
This is a very California problem caused by very California policies
Animats 6d
"more than 5.4 gigawatts of energy storage would be needed if charging habits follow their current course."

Gigawatts are a unit of power, not energy. Storage is measured in gigawatt-hours. Stanford's PR department should know this. The question is, how much storage is needed to make it through the night?

The biggest pumped storage station in the US [1] generates 2.7GW of power and stores 24GWH. So, two of those, somewhere in the Sierras, should cover a night of charging.


mise_en_place 6d
I would love to charge in public while doing errands but every supercharger station is always occupied. I am forced to charge at home for this reason.
sempron64 6d
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

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.

badrabbit 6d
I need ELI5:

electric cars have very large and heavy batteries right? Why is it prohibitively difficult to replace them on demand? What if there were 2-3 batteries charging at home or hundreds at a "battery station", where you would park at a spot/drive-thru garage and have a hydraulic machine drop your old battery and lift in a new battery and the whole swap can take no longer than the time it takes to fill up a has car and you have less queues. Why is this not possible?

If it takes an hour to charge a battery and a battery station has 200 charging at any given time, and it takes 2 minutes to swap a battery then 6 charging bays can replace batteries for 180 cars leaving 20 extra batteries for defects and other issues. Couldn't such a charging station be implemented on a similar lot and budget of constructing a medium size gas station (at least a dozen pumps and around 1 acre lot).

A charging station that is twice as efficient with a 30min charge time can do 2 cars at most in one hour. You need 90 charging station to reach that efficiency even without considering the queues.

I just don't get it. Governments around the world and spending trillions on this stuff so why is there no clear answer on this?

CameronNemo 6d
This will happen when/if TOU rates change, which will happen when/if solar gets built way out... There is a lot of inertia in the grid. No need to rush things and mess with incentives without good reason.

Being receptive to and prepared for employers who want to offer EV charging is a good idea, but it is definitely early days. No need to panic and implement a bad solution.

exabrial 6d
I know this is against the grain, but I do think clean hydrogen is the future fuel.

I know hydrogen is less efficient than Battery-Electric, but it's not about efficiency, it's about convenience.

One can transfer millions of joules at the petro pump in a few minutes without having to actually "handle" said joules.... but to transfer hundreds of joules with a battery-electric vehicle, one currently must actually "conduct" or directly "handle" all of the power that will eventually be used to propel the vehicle. Gasoline in a sense, "compresses" the energy for transfer...

That being said, Battery-Electric is a "here and now" technology. Perfection is the enemy of progress, so I'll gladly take a 1000HP Battery Electric GMC Hummer thank you.

timwaagh 6d
The market would come to the same conclusion in time but only if they are right. The conclusion about the need for incentives is therefore wrong. It will just encourage rent seeking and destroy efficiency. It's important for the government to support optimal price finding instead by removing possible oddities in how energy prices are created.
musicale 6d
Didn't we just get a Flex Alert in California telling us to not use power between 4 and 6pm?
nmstoker 6d
Did anyone get the sense the article was dancing around the main point with vague language? They left it ambiguous about whether they meant effectively all charging should switch to the day or a portion should switch (to give some kind of optimal balance).

I haven't looked at the model but it seems really odd to think that there shouldn't still be some night charging, to soak up the fixed capacity that's there to cover variations in solar/wind.

CalChris 6d
This all depends on the local energy mix at night. If the local mix has a lot of nuclear or hydro then charging at night is a good idea. If instead it has a lot of gas or coal then it is a bad idea. It depends on whether there is cleanish energy available at night. There is no single answer.