To realize the immense potential of electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) it is essential that they be charged by solar panels. It is obvious from this U. S. DoE chart that the electric power and transportation sectors are the primary sources of lost energy. Why is this?
For the electric power sector, the low efficiency of 25% for the steam electric central station power plants means that for each unit of electric energy produced - 3 units of energy are wasted by rejecting heat into the air and water. For the transportation sector (cars, trucks, planes, trains, boats,…), the even lower efficiency of 20% means that for each gallon of gasoline that powers the car - 4/5 of a gallon of gasoline energy is lost to the atmosphere via the exhaust system, engine, and radiator and only 1/5 of a gallon moves the car down the road and powers the electrical system for passengers.
Solar panels convert light directly to electricity and are thus 100% thermally efficient. An electric vehicle powertrain, EV and PHEV, by contrast is 80% efficient.
An 80% efficient EV/PHEV charged by a 25% efficient central station steam electric plant is 20% efficient - same as a conventional gasoline with no real benefit as exhaust/engine/radiator losses are simply moved to the smoke stack, cooling tower, or lake near the power plant. An 80% efficient EV charged by a 100% efficient solar array is 80% efficient - 4 times a conventional gasoline vehicle. Similarly, a PHEV that operates 80% pure electric and 20% hybrid is nearly 3 1/2 times as efficient as a conventional gasoline automobile.
My personal experiences confirm this. A few year ago we bought a 1960’s home in a beautiful location. Transforming the house for the future began with a major overhaul - sealing, insulating, functional, structural, new electrical, new plumbing, new furnace/AC, LED lighting, 5 star appliances. A standby generator fueled by natural gas provides electricity during frequent power failures due to unsightly, unsafe overhead lines when it rains. snows, or wind blows.
We decided to invest in a 3.4 kW solar system to produce clean energy. The solar array was installed on the SSW side of the house with a summer and winter position to improve performance and shed snow. The panels are connected to an Outback 3.6 kW inverter that is capable of operating in either a grid connected or stand alone mode.
After a year of experience, it was clear that the solar panels produced enough energy each day to fully charge a Ford Fusion Energi PHEV - so I bought one. The Ford Energi provides about 20 miles of pure EV driving per charge - a little more in summer, a little less in winter. A trip to town is 5 miles, grocery store is 11 miles, and the “big” city is 22 miles where the public parking lots provide complimentary EV charging. Accordingly, the vast majority of my driving is in pure electric mode. Of course, a hybrid has unlimited range and can drive anywhere. After one year, my fuel economy has averaged 100 mpg and varies between 100 and 160 MPG - more in summer.
Summary and conclusions. The design life of an automobile is 150,000 miles over 10 years and uses 6000 gallons of gasoline at 25 miles per gallon. The average car in the U. S. travels 29 miles per day. A 3.5 kW solar array the size of a one car garage or commercial parking space can produce enough energy for provide the daily mileage of the average driver with an EV/PHEV. In a 30 year life, the solar array can charge 3 EV’s/PHEV’s.
Daytime workplace solar charging can effectively double the daily mileage capability to 58 miles per day. Solar EV charging spaces are being installed for employee, private/commercial retail/office, public parking facilities. With 80% of the transportation sector being light duty vehicles, a dramatic reduction in gasoline usage and more importantly waste heat and combustion gases can be achieved.
Hybrid Electric Automobile