Wow. December was my first full month with my S85 and I just looked at my electric usage and cost for December 2013 vs. December 2014. 2013: 960 kwh $179 18.6 cents/kw 2014: 1596 kwh $206 12.9 cents/kw A difference of 636 kwh and a cost difference of only $27! I drove approximately 3,500 miles in December and occasionally charged at the Gilroy SC between home and work, hence the relatively low kwh increase. My round trip commute is approximately 190 miles. The key, though, was switching over to PG&E's EVA time of use plan which dropped the average cost per kilowatt by 30%. If you're not already on a TOU plan and it's available to you, get on it! Even if you're using solar (which I'll have up and running soon), TOU should save you money as you'll be credited for the higher peak rate while you're generating electricity and then charged at the lower rate when your car is pulling energy off the grid. 3,500 miles for $27 almost makes me rethink the solar investment... but for the same reasons I wanted a greener form of transportation I also want to produce clean energy to power my Tesla.