4 ms·
Two things. First, these charts are for energy generation, measured in billions of kWh. That is very different from the problem for electric vehicles, which i
by robomartin 5y ago
Two things. First, these charts are for energy generation, measured in billions of kWh. That is very different from the problem for electric vehicles, which is power generation and delivery.
Since I can't know if readers understand the difference (you might, others may not), here's a simple example:
You have to lift 1000 kg of metal to the top of a massive 1000 meter tall skyscraper being built. It's a thousand 1 kg pieces. Let's say it takes 10 minutes to walk up to the top.
You can do this at least two ways:
One person moves each 1 kg piece up to the top, one at a time. That will require 1000 times 600 seconds, or 600,000 seconds. That's roughly seven days.
The other way is to do it all at once. We get a thousand people, each one of them grabs a 1 kg piece and, ten minutes later the entire load is at the top of the building.
Anyone can understand that these problems require vastly different scenarios.
Energy is about the total amount of work done. In this case it is the same for both scenarios.
Power, on the other hand, is a measure of how quickly this work was done. In this hypothetical, the fast delivery scenario required a thousand times more power than the slower version.
Electric cars require power. Energy is delivered over time. The problem with our grid and power generation is that it simply cannot handle this beyond a very small deployment. People driving electric cars today are enjoying the fact that they do not pose a significant threat to the existing infrastructure and generation capacity. As the numbers increase we will start having problems.
The idea of having a million or ten million cars simultaneously fast-charging today is likely an unthinkable reality.
Put a different way (just pulling hypothetical numbers out of my behind, these are not real numbers):
If we could charge electric cars over, say, 30 days, we might not need even one bit of additional power generation capacity or changes to the infrastructure. Sure, nobody would be able to drive more than once a month, but, hey, we don't need to build nuclear power plants.
However, that is not a practical reality. Tens of millions of cars will need to quick charge in 20, 40, 60 minutes. And another set of millions of cars will want to be charged over, say, 8 hours, overnight. This requires the ability to deliver power --large amounts of it-- in a way we are not prepared to do. This is both true in terms of power generation capacity as well as infrastructure, from the cables all the way to the power plants.
What the page you linked shows is an increase in energy consumption. It says nothing about power. Also, the increase you point out is only 60%, not a doubling from 1980 to 2020. Still, this is somewhat meaningless. I can consume 60% more energy if I keep the lights on 12.8 hours per day, instead of 8. I would not demand 60% more power out of the grid, I would just use the available power for a longer period of time. That's why speaking in terms of energy isn't relevant to the electric car problem. The problem is power, not energy. People need their cars charged now, right now. That requires power we cannot deliver.
- vel0city 5y agoI will acknowledge the above chart is delivery not peak power generation, but to an extent the two are related. If you don't have generation capacity, you can't increase consumption. I wish I had a chart of generation capacity over time, but I couldn't find one. Still though, it still seems to me the change from 1980 to 2000 probably indicates a pretty large change in power capacity, it's not like they managed to deliver a ton more power without making any changes to the grid and production capacity. You really think the only change in our usage in that time period is we left the lights on 60% longer? I will acknowledge I did only eyeball the chart and saw it was about 2k going to about 4k, the values are 2,290/3801 so about 60% as you say and not doubling. My bad. Still though, your argument of leaving the lights on longer and power capacity points to how EVs are still possible even with this kind of usage vs power argument. Charging my EV at home doesn't increase my home's peak power much at all. It's another 50A circuit on at my house, but it's not like it's running all the time. It's mostly running when most the other appliances in my house aren't running. So there's already plenty of capacity to serve my house 50A, my neighbor's house 50A, on and on, even with the current hardware because it was already built with the idea a lot of people are going to get home from work and start cooking dinner with an electric range and electric oven together use considerably more power than charging my electric car. For those who can charge at home, it really shouldn't change the math on power at all. I do agree power demands would increase a good bit with DC fast chargers, those would be the biggest change in our grid infrastructure. Some of the arguments of having a good bit of local battery storage to smooth out those peak power loads sounds incredibly expensive to me. However I don't think those would necessarily make up the bulk of actual charging usage. The majority of Americans live in single family homes, implying they have some kind of garage where they can charge their car and would thus have the same power argument made above. Decent L2 chargers at offices can provide adequate charging to those commuters without charging capacity at home. Obviously this wouldn't have the same time of use shift as above, but L2 charging wouldn't impose nearly as much power demands as DCFC. While DCFC is somewhat important for mass adoption of EVs, I think you might be overestimating the actual usage of DCFC. The majority of Americans would rarely need them. I haven't used one once in the many thousands of miles I've put on my EV so far. A huge chunk of the power charging so far was 12A@120V, would you really argue every home having a load like that running overnight is going to melt all the transformers? And FWIW I'm still a proponent for using diesel/petrol where it makes sense. Please don't take me as an EV fanatic thinking that Elon's self driving pure EV semi's are going to completely change the trucking industry anytime soon.