It's not necessarily going to lead to much higher peaks. Most EVs do not need to charge continuously from the moment the owner gets home until the owner leaves home the next morning. Simply time-shifting the bulk of charging to, say, between 9 pm and 6 AM would enable vehicle charging without boosting peaks on the California grid:

http://www.caiso.com/Pages/TodaysOutlook.aspx#SupplyandDeman...

It's even better for places where renewable generation is more weighted toward wind than solar, like Texas, because wind output tends to peak while people are sleeping and demand is otherwise low:

http://www.ercot.com/content/cdr/html/CURRENT_DAYCOP_HSL.htm...

The average American drives about 55 miles per day. A typical EV uses about 300Wh per mile. That gives us a typical demand of about 17kWh of charging per day. A standard single-phase fast charger puts out 7kW and a three-phase fast charger puts out 22kW. There's plenty of opportunity to spread out that demand throughout the overnight off-peak period, because most EV users only need to charge for a couple of hours per day.

With smart metering, EVs can also feed energy back to the grid during transient demand peaks. Users won't notice if 5% of their battery is ringfenced for grid storage, but it'll provide a vast proportion of the storage capacity we need to manage an all-renewable grid.

Between the rebalancing of peak and off-peak demand and the potential to use EVs for grid storage, the widespread adoption of EVs is likely to be of net benefit to the electricity grid.

What if something unusual happens? Imagine there is a long blackout during those 9pm to 6am hours. It doesn't have to be the entire city, just a significant number of homes. The next morning, thousands of drivers find they don't have enough power to get to work. Thousands of cars are suddenly charging beyond the expected 9pm to 6am window. Will the grid be able to handle full daytime load in addition to this huge unexpected load? How much would it cost to upgrade the grid to worst case scenario? (entire city blackout during 9pm to 6am)?

If charging shifts to early-mid morning after an overnight outage, I would expect that there's enough distribution/generation capacity to handle it. Take a look at this curve again:

http://www.caiso.com/Pages/TodaysOutlook.aspx#SupplyandDeman...

Although demand at 7:00 AM is 5 gigawatts above the 4:00 AM nadir, it's still 15 gigawatts below the 5:00 PM peak. Since electrical generating and distribution systems are sized to handle those early-evening peaks, shifting charging some hours away from the traditional peaks (either direction, later or earlier) should allow vehicles to recharge daily without increasing daily peak demand.

What about places that aren't California? Even places that have more seasonal electricity demand in the winter than in the summer, like the UK, see their daily peaks in the early evening. Peak demand hours are more about human behavior than geography. People come home after work, cook dinner, turn on lights, do chores... Traditional peak demand hours coincide with this burst of domestic activity. Scheduling charging away from the traditional peak electricity times makes more efficient use of existing infrastructure and allows peak distribution/generation capacity upgrades to be delayed and minimized even with rising adoption of home-charged EVs.

Which also reminds me of 120V 15A/20A charging, which the vast majority of EVs will likely use.

It may require that electric providers require deferred charging, even to the point they set when you can. While you could defer your charging don't expect that everyone will. As we see with charging stations in areas with more EVs there are those who just don't care. We need to instruct future owners the expected etiquette

Dynamic pricing could work better than etiquette

In the UK, differential tariffs were introduced in the 1970s for the benefit of homeowners with electric storage heating. On the Economy 7 tariff you get substantially discounted power for a seven hour period overnight, often as much as 50% lower than the peak rate. Pretty much every British EV owner uses this tariff and a timed charger, because it offers huge cost savings.

https://en.wikipedia.org/wiki/Economy_7

peaks will happen if enough people do it at the same time. Almost every summer (maybe except this one), there's always that heat wave that taxes the grid. A solvable problem for sure (just like how we can now handle cell phone overload during emergencies) but lets not pretend the problem doesn't exist.

philipkglass showed how the problem is solved, he did not ignore the problem.

philipkglass showed how the problem is solved

jasonmaydie showed that even if a problem is solved it can still be a "problem"

> Peaks are going to be really big

This got me thinking, what does the power draw look like?

A Model S has two battery options

- 60kWh / 335km @ 5.85km/kWh - 85kWh / 426km @ 5.01km/kWh

So a battery will need to recharge 1kWh for each 5km traveled. The typical US commuter travels 48km per day. 50km per day / 5km/kWh is 10kWh per day of required draw.

Say 10 hours of charging per day smooths this out to an additional draw of 1kW per driver (a big assumption).

With 100M additional electric cars (there are only 165M daily commuters) in the US, the additional draw on the power grid would require 1,000GW of additional capacity.

That's a 25% increase over 2016 power generation. Compared to the 1999-2016 growth rate of 9.5%, it is significant, but seems manageable. Especially considering it'll take 10+ years for electric cars to be widely used by a significant fraction of the US workforce.

I was right with you until:

> an additional draw of 1kW per driver

> 100M additional electric cars ... 1,000GW

Looks like you're off by an order of magnitude; that should be:

1kw (continuous) * 100M drivers = 100GW (continuous)

for the typical commuting patterns. That's a lot of power of course, I agree it would increase cumulative consumer demand for electricity by about 25%.

But the key is that this is nearly perfectly dispatchable demand. It won't cause anything like the same disruption to the grid as non-dispatchable, or even weakly dispatchable demand like air conditioning (which can flex how much is consumed briefly, but will annoy users if it varies across too long a time span).

Thanks, that's some good info.

10kWh × 165M on the night grid, that's big impact.

I went and got the miles travelled per year and the total nr of vehicles, you are not far off. although we are forgetting that most traffic is during weekdays, and the size of the cars varies (and with it the usage) For convenience I don't do anything with the size of the cars.

"According to the Bureau of Transportation Statistics for 2012, there were 254,639,386 registered vehicles. Of these, 183,171,882 were classified as "Light duty vehicle, short wheel base", while another 50,588,676 were listed as "Light duty vehicle, long wheel base". Another 8,190,286 were classified as vehicles with two axles and six or more tires and 2,469,094 were classified as "Truck, combination". There were 8,454,939 motorcycles also listed along with 764,509 buses." https://en.wikipedia.org/wiki/Passenger_vehicles_in_the_Unit...

250m vehicles in us, if 150m of those are electrical at some point, and the number of miles driven total might be 3.5T miles by then (3.5×0.6=2.1T) 2.1/150m/313×1.6 (6 days of driving a week, and miles to km) comes to 71 km per day, which is 14 kWh (6/7 days) of required draw. I think it is manageable like you said, considering that it will take a while.

If most people used electric bicycles instead it would be about 1kWh per day instead +-100%, on tenth of the energy consumption, that would lead to more productive work hours, and less time spent at hospitals, and less issues with the big killer diseases affecting heart and lungs.

that would be great, but many areas in the united states are not very friendly to bicycle (even electric bicycle) commuting. better urban design has important implications for all kinds of things about how we live our lives, sustainability especially.

This type of demand is far different from that 9.5% growth rate, and far more manageable, precisely because it happens during off-peak hours. At night, transmission lines are uncongested, and the wind (typically) blows more.

> Especially considering it'll take 10+ years for electric cars to be widely used by a significant fraction of the US workforce.

This is key, plus I think we're overstating how fast this will happen.

In 2016 we're still at sub 1% of all new car sales being electric, at 0.9%. i.e. for every 100 cars we're adding to our roads, not even one full electric car is added. Not to mention about half of the electric cars are hybrids.

Average age of cars is about 12 years. So if the 1:99 ratio is overturned say in a decade to favour electric cars (which seems ambitious itself[0]), it'll take at least another decade to phase out existing cars and see the fleet get replaced by new, mostly electric.

So 10+ I think is conservative, it's probably 20+.

Another thing to mention is that we can generate a lot more electricity with our existing capacity than we do. Why don't we? Because at night the demand simply isn't there. But with a software-based transport & fueling system that EV offer, a lot of this extra demand can be shifted during times of low-demand, without needing to install extra capacity, but rather just not taking as much capacity offline nightly.

Finally, I cautiously expect a shift away from personal transport and public transport, but towards semi-public/personal. i.e., I'd be quite feasible if you could hail a self-driving pod in 20 years, get in, have your destination set via whatever has replaced our smartphone (e.g. software assistent), and get out, paying automatically, a la uber today. The pod drives according to your personal wishes, but it's part of a shared public transport system. I expect this to make driving safer and more fuel efficient in driving behaviour, more efficient in terms of capacity (no more 4-seater cars full of 1 person, no more driving around with vacation-level storage that's mostly empty on 9/10 trips), more efficient in terms of size (lighter vehicles, less crumple zone required). This shift too may significantly increase the km per kwh spent in the next few decades.

[0] As for whether electric becoming the majority of car sales within 10 or 20 years is feasible... a little context: it must be noted that the US sold 96k electric vehicles in 2013. In 2016 it's 157k. Growth rates are a little under 18% yoy. If you'd grow at 32% a year, which is twice the annual growth rate compared to the past few years, you'd sell 2.5 million electric vehicles in 2026, annually. But the US sells more than 17 million non-electrics annually today, so you're still not making a huge dent. That's a shitty calculation of course, but it's some context. Typical forecasts predict something like 30% of new car sales to be electric in 2030. Again, that's new sales. About 8% of cars are retired each year, if you replace them by 30% electric cars, it takes about a decade after 2030 to even get to 30% of the actual car fleet to be electric.

So all in all, I don't really think the grid is the biggest challenge here, although there are obviously very large investments to be made.

I think the expectation is that as the grid slowly gets "smart" this will reduce the peaky-ness of demand generated by electric car charging. If the price of a kWh is dynamic based on current use then the combination of smart charging stations & locally installed batteries should even things out a lot.

Obviously the total consumption will increase dramatically. If this shift takes place the society-wide energy mix will include a lot less petrol/gasoline/diesel and lot more electricity.

Hopefully the prices of solar & wind will continue to fall and the shift in this mix will be massively to the advantage of the environment - and to the quality of life in our cities.

> Wonder what the future holds.

I hope it holds a great shift towards decentralization of energy production. Not complete decentralization, but a blend of massive power plants like today, and lots and lots of homes with solar panels on roof tops and the like.

I also hope fusion research is accelerated. Fusion in the sky, plus fusion down on Earth, that would cover a lot of bases. Portable fusion reactors would also truly open up the solar system - ride the fusion torch to your destination, power your habitat with fusion reactors.

EVs at home charge at night, solar panels produce energy during the day.

Counterpoint: EVs plugged in at work charge during the day. Scaling up charging infrastructure at work probably pays for its own deployment in reduced energy storage costs. If the underlying economics are there, it's "just" about getting the incentives right.

An always-connected EV fleet can dispatch charging from a central load-leveling server, passing a percentage of the utility revenue along to incentivize the EV owner. Such a car would always Do The Right Thing(TM) with respect to TOU/tiered metering, real-time (or forecast) renewable generation, local distribution grid loading, and the availability of any extra baseload generation at night.

Personally I would want the option to always immediately charge the car to X miles of range (to drive to the local hospital), and to always charge to Y miles by Z:00 every day (for commuting). Subject to those constraints, the service provider is free to shift around the charging schedule to suit conditions on the local electric grid. The more leeway the service provider has to shift charging around, the more the EV owner earns.

Obviously Tesla is pursuing this, but I hope they have competition.

> EVs plugged in at work charge during the day.

Good idea, but the infrastructure would have to be tied to the building, not to the companies operating in it. A lot of companies change offices all the time, and then there are all those small companies that can't afford to build this sort of thing.

So it would have to be part of regular infrastructure just like running water or comm/data lines.

> Peaks are going to be really big on the power grids

Can you supply some supporting documentation for this? All the studies I've seen have shown that the charge cycle is very flat, can be centrally demand controlled, and essentially "fills in" the night-time slump that saps much of the generating profit from major types (e.g., thermal) of generator plants.

If every household hooks up, and all the trucks? Currently there is more investment in solar/wind, one is always unreliable and the other is certainly off at night. Now a grid of batteries might be enough to fill up the gaps today, but once that night slum is no longer a slum, who knows how big batteries you'll need.

We're still at low levels of renewable penetration on our grid; once over 50%, all these vehicles become a fantastic source of "negative" demand response. Current demand response asks customers to decrease consumption when there's peak usage and the grid is strained. Negative demand response is a signal to consume electricity when a free-on-the-margin source like solar would otherwise be curtailed.

The massive array of car batteries becomes an absolutely wonderful source of both positive and negative demand response. Currently, almost no one insists on driving around with a 100% full fuel tank. Those with electric cars commonly keep them around 80%. And daily usage of the battery is nearly always far less than 50%. And a decent sized EV battery is 1-2 days of household electricity usage.

If a significant chunk (20%-30%?) of our electrical demand is for battery-powered transport, we've solved a huge problem that comes with high wind and solar penetrance on the grid, without having stationary batteries. As car batteries age and have reduced capacity, they will potentially have a second life as stationary storage, where power density doesn't matter as much.

This means, that if we are able to install chargers at a percentage of workplaces, that car batteries will be able massively smooth out not only the daily duck curve of demand, but also deal with fluctuations where some days have more production and others less.

What are your thoughts on home batteries? Assuming the decline of battery prices is a major influence in the uptake of electric vehicles, I'm wondering if a similar uptake in home batteries (alongside residential solar) would mitigate stress on the grid.

With smarter grids that support dynamic realtime pricing of electricy to end users, I think electric cars, home batteries and even appliances like fridges, refrigerators and washing machines can help balance supply and demand in the grids, using electricity, pausing consumption or pumping it back into the grid as needed.

The UK government recently performed an industry consultation on this subject and has released a plan to:

* remove barriers to smart technologies (such as storage and demand-side response)

* enable smart homes and businesses

* improve access to energy markets for new technologies and business models

https://www.gov.uk/government/publications/upgrading-our-ene...

Home batteries would have to hold more than the car.

This will still put the baseline of the grid higher, just averages it out possibly taking more when its a good time. I think batteries should be hosted/hooked up by the power company, so they can attach them to a power management system. (I think that already exists)

I left out the "where will we get all this power" part, because that is already discussed a lot. I just wonder if the power grid will be able to handle this immense increase in usage, even if spread out. You still need to transport it.

edit: I think the powering down of offices and business makes enough room for the evening to use more.

What reason is there for a home battery to hold more than a car?

You can drive your car empty faster than your home battery might charge (due to supply/demand), and it is possible to give back to grid if there is a peak in your area.