Re: STEM question
On efficiency.. Like cuddles says, it's complicated. And it's an area where there's a lot of dis or misinformation. IMHO, a true comparison should be like for like, ie the complete cycle. So fuel/energy production, distribution and the vehicles themselves, ie production, servicing and disposal.
For ICE, it's possibly simpler. Suck oil out of the ground, transport it, refine it, deliver it to pumps. That's relatively effficient as we've found uses for pretty much every fraction of oil, and can use some of the product in the production process, ie refineries generating their own power/heat or a tanker full of diesel running on diesel. Distribution networks exist for ICE, but large-scale distribution networks don't really exist for EVs. So to create a replacement, or equivalent requires massive investments into power generation and distribution. That's part of a cost-of-change argument balancing the cost of going EV vs any benefits from getting rid of ICE.
Part of the distribution challenge is understanding the electrical version of 'well to pump' flow. There are rough benchmarks for the cost per GW of electricity generation by type.. But they can be a bit disingeneous, ie levelised costs that exclude high cost items. So 1GW of nuclear's a convenient drop-in if it's built at an existing nuclear site. 1GW of wind or solar costs a lot more as it's distributed, and intermittent. So a like-for-like comparison should include <=1GW of CCGT as backup for the renewables. That's often glossed over because people may ask why, if CCGT's much cheaper and dependable, we're wasting money on renewables.
Then because renewables are unreliable, promoters come up with solutions. Like batteries. So take £120MWh+ renewable energy and store it in £300MWh+ batteries.. And there'll be transmission losses as well as conversion losses for storage. Then people may ask 'Why are we doing this?' when CCGT's £30-40MWh or nuclear at around £90MWh. And it gets even more expensive if you localise it, ie PowerWalls, or trying to use EVs as grid storage.
And then there's the vehicles themselves. So an ICE might be more complicated, but costs are well understood and there's a healthy service industry flogging everything from spark plugs to LS-swaps. And once the ICE's given up the ghost, it can be melted down to make EV parts. With EV's, that's not so easy, especially the batteries as there's currently no economic way to recycle those.
So a lot of issues, including trying to quantify any benefits. EV's will reduce NOx emissions, and some particulates, but potentially increase particulates due to EV's weight. And if the argument's based around health, then any benefits from going EV vs costs, especially increased energy poverty.