Solar and Electric Vehicles (PV + EV)

With a rooftop solar system generating clean energy, and an EV using clean energy, you can enjoy a superb alternative to dirty expensive electricity and dirty expensive transportation at the same time.

Natural gas still provides about half of all electricity generated in California. While natural gas is promoted (most loudly by the natural gas producers) as much cleaner than coal, several recent studies have shown that leakage through the exploration and production process from drilling to storage to transportation to refining and combustion in power plants, may release as much greenhouse gas per unit of energy as coal. Although less toxic than coal, natural gas can pollute the water (such as the infamous “Light Your Water on Fire” YouTube video) and air (such as with the 2105 Aliso Canyon gas leak in California) .

Once rooftop solar panels are installed, you’ll start generating 100% clean energy. This will continue for at least the 25-year warranted life of the solar panels. When you charge your EV at your solar-powered home, you won’t be sending energy directly from your panels to your car (especially when you charge at night!), but you’ll be driving with “net zero carbon” by providing as much energy to the grid as you take from the grid.

When your EV is charged with solar energy, you can drive your clean, quiet, responsive, low maintenance, conversation-starting EV in the carpool lanes and express lanes even as a solo driver. The Bay Area is fortunate to have many public charging stations, with more on the way, and there are now several models of EV with a range of over 100 miles:

• Audi eTron – 204 miles
• BMW i3 – 153 miles
• Chevrolet Bolt – 238 miles
• Ford Mustang Mach-E – 230 miles
• Hyundai Ioniq – 124 miles
• Hyundai Kona EV – 258 miles
• Jaguar I-Pace – 234 miles
• Kia Niro EV – 239 miles
• Nissan LEAF – 150 miles
• Nissan LEAF PLUS – 226 miles
• Tesla Model 3 Long Range – 310 miles
• Tesla Model 3/ Standard Range – 240 miles
• Tesla Model S Long Range – 370 miles
• Tesla Model S Standard Range – 285 miles
• Tesla Model X Long Range – 325 miles
• Tesla Model X Standard Range – 255 miles
• VW e-Golf – 125 miles

What does it cost to drive these EVs on sunshine?

To get started, there’s one number that’s handy to know: 3.5 to 4 miles per kilowatt-hour (kWh). Just about every electric car will go 3.5 to 4 miles per kWh. Unlike gasoline cars (known to EV drivers as ICE cars, for Internal Combustion Engine), which range from under 10 miles per gallon to over 50, EVs have very similar efficiency ratings. A 100 horsepower Leaf and a 500 horsepower Tesla both travel 3.5 to 4 miles per kWh. The Nissan Leaf with a 30-kWh battery will go about 107 miles. That’s 3.6 miles per kWh.

How much does your electricity from the grid cost? You can determine this from your PG&E bill. The Bay area EV off-peak average is about 12¢ per kWh, and 12¢ worth of grid power would drive your Leaf 3.6 miles. That’s 3.3¢ per mile.

How much does an ICE car cost in fuel? Say you have a 30 MPG car. California just raised the price of gas by 12¢ per gallon and the average in the bay area is now a little over $3/gallon. 30 MPG at $3/gallon means your fuel cost is 10¢ per mile. Great, your EV is already 67% cheaper using grid power!

How much does electricity from your solar panels cost? This involves dividing the total cost of your solar system by the total number of kilowatt-hours (kWh) it will produce over its warranted 25-year lifetime. It will depend on the price of your solar, and the math is a little complex for this article. However, a typical SunWork system, such as our 500th installation was $7,286 for 3.48 kilowatts. Add $1,000 for an inverter that will need replacement over 25 years because in this case, the inverter has a 10 year warranty. The 3.48 kW system will produce about 115,000 kWh over 25 years. Divide $8,286 by 115,000 kWh means the 25-year cost of electricity will be 7.2¢ per kWh. This is one third the cost of grid electricity now, and it’s set for 25 years, while PG&E rates are likely to climb.

Cost per mile

10¢ Internal Combustion Engine car
3.3¢ EV with grid power
2¢ EV with SunWork solar system

At 7.2¢ per kWh for solar and an EV’s 3.6 miles per kWh, that’s 2¢ per mile, which is 20% of the cost of the ICE car. And that’s just the “fuel.” In an EV there’s no need to change the oil, there are no valves or pistons or intake manifolds or catalytic converters or fuel injection systems, or smog checks. There’s barely a transmission in an EV since most have just one gear.

Rooftop solar plus with an electric vehicle gives you much cleaner, much cheaper energy and transportation. PV + EV is our future, and there’s nothing mysterious or unproven about it. Consider joining the hundreds of thousand Californians who’ve already gotten started.