Toggle, the short answer is I don't know. Although there is a third rate tier for residential consumers that penalizes you quite heavily if you fall into it. The same is true with water, which is also a city-owned utility.
City Light (our electric company) used to really push electric everything, but in the 70's they made a decision to not build additional capacity, and rely on conservation. It's actually worked quite well for them, thanks to their numerous dams and the Bonneville Power Administration, which is sort of a non-nuclear version of the TVA. Normally, the city-owned dams can handle the load, and can even make some nice income off of selling excess.
Generally speaking, the only places with electric heat are post WWII apartment buildings, and some post WWII single family stuff, and it's almost exclusively baseboard. There are some neighborhoods where you still see a lot of forced air electric, but they are few and far between. Heating oil is probably the predominant fuel source for heating, followed by natural gas, which is a late arrival to many Seattle neighborhoods.
Personally, we converted to natural gas from heating oil because we wanted a tankless h2o heater, and needed to replace the furnace. Since the electric hot water tank went away, we have saved about $50 a billing cycle, although that might have been a function of a faulty water heater as much as anything else.