4 ms·

> 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 -

> 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.

epistasis 9y ago
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.
Freestyler_3 9y ago
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_United_States#Total_number_of_vehicles 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.
emj 9y ago
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.
- erubin 9y ago
  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.
mercutio2 9y ago
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).
IkmoIkmo 9y ago
> 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.

epistasis 9y ago

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.

Freestyler_3 9y ago

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_United_States#Total_number_of_vehicles 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.

emj 9y ago

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.

erubin 9y ago
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.

mercutio2 9y ago

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).

IkmoIkmo 9y ago

> 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.