Living along the Wasatch Front in Utah, I was really curious before taking delivery of my X how grades would effect the range of the car and how well the regen would recapture energy spent in hauling the car up a mountain grade. I think my latest cahrge may help everybody. I was really impressed by the outcome. So Thursday night I charged my X90D to full range 260 miles.. The travel since then has included the following.. From my home in Cedar Hills, Utah at 5000' exactly, 52 miles to Montage at Deer Valley Resort (Park City) at 8300' elevation (for the Tesla Roadtrip event), via Heber City Utah. On arrival I showed 175 rated range remaining.. (so that 3300' altitude gain cost me 33 miles rated range.. That is consistent with the 10 miles per 1000' altitued gain I've heard before. Then back home via Salt Lake City through Parley's Canyon. Then a couple of short trips from home down into American Fork, involving ~ 400' descent and then climb back home. Finally a round trip from home to Draper Utah that was a total of 36 miles and 1100' net loss of altitude outbound and then the same gain ...returning The Attached picture of my trip display at the endo of that 165 miles I think tells the whole story... 165 miles driven, rated range remaining 90 miles... so I have gotten only 5 miles less than rated range. NO I didn't drive like a granny the whole time! So, in my opinion regen is VERY effective as far as I can tell at delivering potential energy back into the battery so that grades do not affect range that much when the net altitude change is zero!