"offsetting about 130,500 gallons of gas"Not bad considering that Tesla hasn't made that many electric cars yet (compared to their goals for the next few years), and that Supercharger stations are just starting to roll out more widely.
This also only counts charges at Superchargers, which are free to use for Tesla owners, and powered by solar power, either directly or indirectly via renewable energy credits (in Elon Musk's words: "Drive for Free. Forever. On Sunlight."), not charges at other charging stations or at home. The total number of electric miles driven by Tesla owners must be a multiple of 3.2 million.
I always say that it's better for the environment to walk, bike, or take transit. But if you're going to drive, pick the greenest model that meets your needs. Well, Teslas are too expensive for most people right now, but within a few years, electric cars will be affordable, have longer driving ranges, and the power grid will keep getting progressively cleaner (as more solar and wind power comes online and coal gets displaced -- meaning that over time plug-ins actually get cleaner), making plug-in vehicles the best choice for the average person.
Tesla's plans for its Supercharger network:
More details on the Supercharger network here.