CA AB2663

Defines "dimethyl ether-propane fuel blend" as a motor vehicle fuel and requires it to meet ASTM International specifications or interim specifications established by the Secretary of Food and Agriculture, with a minimum antiknock index of 87.

Exempts dimethyl ether-propane fuel blends from the requirement that motor vehicle fuel retailers display prices for the three major grades of fuel on their premises.

Sets the state excise tax on dimethyl ether and dimethyl ether-liquefied petroleum gas fuel blends at $0.06 per gallon, effective July 1, 2021 (compared to the standard $0.18 per gallon rate for gasoline).

Allows owners or operators of vehicles using dimethyl ether or dimethyl ether-liquefied petroleum gas fuel blends to pay an annual flat rate fuel tax ($36-$168 depending on vehicle weight) in lieu of per-gallon fuel taxes, commencing July 1, 2021.

Makes fuel sellers not liable for collecting or remitting fuel taxes when a vehicle owner or operator provides written representation that they have prepaid the applicable annual flat rate fuel tax.