You'll often hear that a Qualified Plug-In Electric Drive Motor Vehicle Credit is worth "up to" a certain amount.
For example, the credits for all seven Tesla electric car models were in the final phase of the phaseout schedule in 2019. The vehicle models began a phaseout for eligible vehicles bought between January 1, 2019, and June 30, 2019. Those vehicles qualified for a maximum credit of $3,750. For eligible vehicles bought between July 1, 2019, and December 31, 2019, the credit dropped to $1,875.
The credit is only worth $3,750 to someone whose tax bill at the end of the year is $3,750 or more. Let's say you buy a Tesla or other eligible vehicle and you owe $3,000 in income tax for a particular year. That's all the tax credit will be. IRS is not writing a refund check for the other $750. And an unused portion of the credit can't be applied against the following year's taxes.
If you leased the vehicle, the tax credit went to the manufacturer that offered the lease, not you.