IRA doesn't impose mandates, it extended the EV tax credits, lifted the sales cap (previously 200,000 vehicles) and added requirements that the vehicle be produced in North America ($3,750 of the $7,500 credit) and a certain proportion of the battery pack has to be produced in the U.S. or be made in countries for which the U.S. has a free trade agreement with (Not China, obviously) at a escalating percentage (the other half of the credit). Which is designed to bring manufacturing jobs and spur investment in domestic production, which has generally worked (so far) for that purpose.
The IRA also added battery manufacturing incentives that provides credits for the battery manufacturers if they are made domestically, so from a battery perspective it's getting credited on the transfer from the battery manufacturer to the EV manufacturer (or grid battery manufacturer) as well as at point of sale to the consumer (renewable storage, or EV battery).
There are no federal mandates that exist that ban the sale of ICE vehicles by any date. The only thing that has occurred is Joe Biden setting goals for EV adoption by 2030 and 2035 (50% and 100% respectively, I believe).
The "mandates" are a tangential effect of the CAFE standards that are being implemented over the next decade that make it substantially more difficult for a large proportion of a manufacturers vehicles to be a pure ICE vehicle. What will ultimately happen is that some proportion (likely the majority) of vehicles will be all electric by 2035 and some proportion will be PHEVs, with an ever decreasing proportion operating purely on gas.
The only governments that have an official policy to outright ban ICE vehicles are liberal nitwits on the west coast and the northeast, that don't produce the vehicles (I.e. they can't ban their manufacture) and would have to rely on the rest of the states to follow their lead for their "bans" to have any effect. California tried to mandate that 10% of all vehicles be electric by 2003. How'd that work out? Quietly went away with no one even remembering it happened.
And as a point of clarification, EVs do produce fewer emissions over their useful life, regardless of the "cleanliness" of the energy source, it's just a matter of how long the payback period. Dirty energy? 7-8 years, U.S. grid mix? 2-3 years. Solar/wind? Less than a year. (These are on the high side of estimates). That "cleanliness" is a small part of why I appreciate them, but it's not GHG that I care about, it's particulates/air quality improvements.
The primary reason I like EVs is the long term transportation cost savings they will provide in a mature, rather than early adopter, state. Look at those Model 3 specs and imagine a charging infrastructure that is 2-3x more well distributed. 300 miles of range will be the bare minimum in 3-4 years.
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