Oslo, Norway is the Tesla capital of the world for a few reasons.

Firstly, All of new cars are 29% Electric in norway and in the US it is less than 1% but what is more interesting is the Government's Policies on Electric Cars. If you own a Electric Car in Oslo you get free parking ,HOV lane (less traffic) ,no registration fees, tax deductions, free charging and on the business side, Tesla does not have to pay sales tax so Teslas are cheaper in Norway then in the US.

All Electric Cars get FREE charging, and even a toll fee gets cut for when entering Oslo if you own electric. While Norway is a Fossil Fuel producing Country it only extracts the Oil and Gas they don't burn them so nothing gets released into the Atmosphere.

With the new Paris Agreement I think there will be a big Spike on similar things happening in Countries around the world. Look forward for a Green future

Here is a good video on Oslo by Vox.