Progressive is quite electric friendly. When filling up the details of the bike, they include Brammo and Zero in their list, and they have the Empulse and the Enertia.
Note that the quote webpage has a bug: You have to fill in the "Engine CC" of the bike, and it says "(cubic centimeter size - enter '0' for electric bikes)", except when you try that is says "Valid ENGINE DISPLACEMENT must be entered" - Fail.
I just entered 1, and somehow that was valid.
Rates depend on coverage. A nothing coverage costs $30, and it can get pretty expensive.
I was thinking of getting comprehensive, since I would feel very sad if somebody stole my $20k bike. And perhaps collision too.