With a modest solar array, approx. 11×33 feet, mounted on the south facing roof of the house, the net average cost to drive 40 miles daily is $0 annually, in fact, our founder driving the electric BMW325i , is currently achieving a net positive in power generation. Not only is this electric BMW325i now higher performance in every way, it is also being fueled 100% by sunlight, truly Net-Zero on energy! On the R&D lab/shop, a 5.6kW rooftop mounted and grid tied solar array delivers 17,000 miles worth of driving energy annually in the Portland Oregon area. The solar array puts its power onto the grid during on-peak time, where the BMW’s battery pack is charged during off-peak time at almost half the cost. With solar and “Time-Of-Use” power billing, a profit is made in addition to the 17,000 miles of free driving that covers the cost of tire wear, which is the only real service the vehicle has after the conversion. With a power inverter directly connecting the solar array to the electrical grid, the power meter spins backwards during daylight hours. When you come home, you just plug into the AC outlet and take back the power you generated during the day. This is very beneficial to the power grid by helping reduce the peak load during the day as a side benefit. You can size the solar array to match the power used in your normal daily drive.
Regarding the amortization of our EVDrive, Oregon shop PV array factored into the cost of driving the EVDrive BMW, we have accounted for it. In our case, the system cost after state and federal incentives was $4300 out of pocket cost. To get the $10,000 grant money from the Energy Trust of Oregon, we are required to meet at least 75% solar exposure. Since we had tall trees reducing the exposure below 60%, we needed to remove enough to get up to around 80%. The harvest resulted in 3 full log truck loads of straight fir log sections that returned $4600, prior to taxes. So our out of pocket expenses are already paid for.
We are currently on track to put greater that 5MWhr onto the grid this year (with a few weeks of best solar of the year we are at 4.7MWhr now). This results in over 17,000 miles of driving the EVDrive BMW per year, calculated by multiplying 3.5 (miles/kWhr) times kWhr (solar onto grid -which includes charging efficiency going into BMW pack.)
Now, to reconsider the emission profile with the solar array just mentioned above, there are no emissions. None. Not even battery cells venting. In fact, there will be little brake dust left behind with most of braking done with regen control now affixed near hand brake.