EVs are obviously the future. My question is can heavy trucks be electrified? Here is my brief analysis. The truck can rid itself of the heavy engine, fuel tank and drivetrain. Place a motor equivalent to Tesla's "big" motor on each rear axle for a total of about 1000 horsepower. Gear the motors for a top speed of 75mph. Under the hood would provide enough volume for about 500kWh of batteries. An additional 200kWh could probably fit in other areas for a total of about 700kWh on the truck. I don't know what the Wh/mile would be, but I'm guessing about 2000 Wh/mile. This would give a range of about 350 miles which brings me to the trailer. A standard truck trailer's roof is 53' x 8.5' which gives 450 square feet. According to this map from energy.gov a typical square foot (I chose central Missouri as a typical location) provides 450 Watt hours per square foot per day. 450x450 = 200kWh/day. If each trailer has 200kWh of battery capacity then the battery could be charged from flat to full in a single day of sitting on a lot. Additionally, during a 12 hour shift of driving, the trailer would provide it's original charge of 200kWh plus the extra 200kWh that is generated over the course of the day for a total of 400kWh. Keep in mind that in the southwest you can get as much as 600Watt hours per square foot per day which would boost the amount generated. 700kWh on the truck plus 400kWh from the trailer gives 1.1MW/hr and dividing that by my estimated 2000Wh/mile gives about 550 miles. Assuming a 12 hour shift of driving that's only about 45mph so it may be necessary to have more battery capacity. Regen going downhill would be an enormous benefit. I don't know if the dual motors would even be able to keep the truck's speed under control assuming about 130kW of braking (taken from Model S's 65kW of regen times two motors). This is a relatively unorganized stream of thought, but I hope the truck makers are looking into this. There is already a well established network of truck stops so charging might be less of a factor than one would think.