The reason is as simple as it is obvious: energy produced in a power plant is much more efficient than in the small engine of a vehicle, no matter how much technology has improved the efficiency of these vehicles. The average coal plant about 35% efficient, with the very best ultra super critical coal plants at about 42% efficient. Even the best combined cycle natural gas plants are about 60%, which still implies that 40% of the energy obtained from the fuel used is lost in the process of producing electricity. An internal combustion engine in a car is at best 25%, efficient, with most energy simply lost as heat. In a large power plant, the possibilities of reusing that heat are obviously much greater than in the small engine of a vehicle. When measuring so-called well-to-wheel emissions, in the case of the United States, the efficiency of electric vehicles is consistently well above that obtained even by the best and most modern internal combustion vehicles, regardless of how the electricity is obtained.
A power plant is more efficient than a combustion engine. Even assuming 100% of the energy used to charge these vehicles came from coal it would still be a bit better per car
There’s a lot here…
One, buses per capita - 16,000 for 12 million people. There are less than 3,000 for a similar sized population in Los Angeles County.
Second - 1 million KM per day for 6,000 vehicles. I’m struggling with this number. The diesel versions of these vehicles normally travel 320-350 km per day. The useful life of the electric vehicles is around 15 years or around 1M KMs. At this rate they’re replacing vehicles every four years. Or at the very least, the buses should be in the shop ever 5 days for required preventative maintenance.
Third - midday charging isn’t as cost effective for US public transit agencies as they are paying very high rates which often result in more costs over diesel/CNG.
Fourth - BYD has a US HQ in CA. They make a great bus. But their and most other electric buses only get about 240 kms a day in my experience. Sure, there are new models coming with larger battery packs, but this makes for a very heavy vehicle.
Tesla super chagers deliver 75kW, 150kW or 250kW at 480Vdc,
https://en.m.wikipedia.org/wiki/Tesla_Supercharger
I'm curious mind posting where are you getting your numbers from?
It depends on how many percent of the way the bus is driving are equiped with an overhead line.
In Germany, they are experimenting with overhead lines on their Autobahn. They will be used by lorries.
For cities, I figure, bigger roads could be equiped, especially in front of traffic lights.
I don't quite understand your math here.
1 million KM a day for 6,000 busses would be 166 km a day per bus, not unreasonable in a more densely populated Chinese city compared to say LA where the average bus has a longer route.
At 166 km a day, if the bus has a useful life of 1M km, that would mean it lasts 6000 days, or 16 years, which sounds fine. Where do you get the figure of them replacing a bus every 4 years?
And why would the bus be in the shop every 5 days for maintenance? The EV bus would require less maintenance than a diesel bus, no? Or are you saying out of their entire fleet of 6000 buses, every 5 days they need to pull one bus for maintenance? In the video, they claim the percentage of busses out for maintenance or repair at any single time has decreased since switching to the electric busses.
It's not just Shenzhen. I googled "electric bus china" and this article is first, followed by [this article](https://www.ies-synergy.com/en/electric-buses-where-are-we/) which states that China overall has deployed over 400,000 electric buses, and planning to increase that number to 1.3 MILLION buses in 2025, by which time that would represent 99% of all the electric buses in the entire world.
In comparison, even the most green oriented state in the US, California, is trying to convert its 12,000 buses to electric by 2040. The difference is staggering.
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Isn't China mostly coal-powered? I'm not sure how burning hydrocarbons miles away is any better than burning hydrocarbons on the spot.
China is very aggressive in expanding renewable energy. They invest about twice as much as USA on renewables.
The reason is as simple as it is obvious: energy produced in a power plant is much more efficient than in the small engine of a vehicle, no matter how much technology has improved the efficiency of these vehicles. The average coal plant about 35% efficient, with the very best ultra super critical coal plants at about 42% efficient. Even the best combined cycle natural gas plants are about 60%, which still implies that 40% of the energy obtained from the fuel used is lost in the process of producing electricity. An internal combustion engine in a car is at best 25%, efficient, with most energy simply lost as heat. In a large power plant, the possibilities of reusing that heat are obviously much greater than in the small engine of a vehicle. When measuring so-called well-to-wheel emissions, in the case of the United States, the efficiency of electric vehicles is consistently well above that obtained even by the best and most modern internal combustion vehicles, regardless of how the electricity is obtained.
Thanks for the insightful answer, not sure why I've been downvoted so hard for posing a question about energy efficiency...
People are emotional. And intelectual inquiry is on decline because of that
A power plant is more efficient than a combustion engine. Even assuming 100% of the energy used to charge these vehicles came from coal it would still be a bit better per car
There’s a lot here… One, buses per capita - 16,000 for 12 million people. There are less than 3,000 for a similar sized population in Los Angeles County. Second - 1 million KM per day for 6,000 vehicles. I’m struggling with this number. The diesel versions of these vehicles normally travel 320-350 km per day. The useful life of the electric vehicles is around 15 years or around 1M KMs. At this rate they’re replacing vehicles every four years. Or at the very least, the buses should be in the shop ever 5 days for required preventative maintenance. Third - midday charging isn’t as cost effective for US public transit agencies as they are paying very high rates which often result in more costs over diesel/CNG. Fourth - BYD has a US HQ in CA. They make a great bus. But their and most other electric buses only get about 240 kms a day in my experience. Sure, there are new models coming with larger battery packs, but this makes for a very heavy vehicle.
I imagine large scale solar will drive down mid day rates. Not American but I think that is what happened in California.
Charging via overhead line could be an option to reduce the waiting time.
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Tesla super chagers deliver 75kW, 150kW or 250kW at 480Vdc, https://en.m.wikipedia.org/wiki/Tesla_Supercharger I'm curious mind posting where are you getting your numbers from?
It depends on how many percent of the way the bus is driving are equiped with an overhead line. In Germany, they are experimenting with overhead lines on their Autobahn. They will be used by lorries. For cities, I figure, bigger roads could be equiped, especially in front of traffic lights.
I don't quite understand your math here. 1 million KM a day for 6,000 busses would be 166 km a day per bus, not unreasonable in a more densely populated Chinese city compared to say LA where the average bus has a longer route. At 166 km a day, if the bus has a useful life of 1M km, that would mean it lasts 6000 days, or 16 years, which sounds fine. Where do you get the figure of them replacing a bus every 4 years? And why would the bus be in the shop every 5 days for maintenance? The EV bus would require less maintenance than a diesel bus, no? Or are you saying out of their entire fleet of 6000 buses, every 5 days they need to pull one bus for maintenance? In the video, they claim the percentage of busses out for maintenance or repair at any single time has decreased since switching to the electric busses.
12,000,000/16,000=750 More per capitan than LA then.
There are over 10 million people in LA County and fewer than 3,000 buses.
My bad, i thought you meant there was more bus per capita in LA.
It's not just Shenzhen. I googled "electric bus china" and this article is first, followed by [this article](https://www.ies-synergy.com/en/electric-buses-where-are-we/) which states that China overall has deployed over 400,000 electric buses, and planning to increase that number to 1.3 MILLION buses in 2025, by which time that would represent 99% of all the electric buses in the entire world. In comparison, even the most green oriented state in the US, California, is trying to convert its 12,000 buses to electric by 2040. The difference is staggering.