If you had to choose, and we chose both eventually, is it better to get solar panels or an electric vehicle to save carbon dioxide emissions first? In this post, we’ll look at our solar panels for the last two months and compare it with our Model 3. For most people, solar panels will have the lower cost commitment and generate higher C02 emissions offset. An electric vehicle will make sense if you drive a lot of miles a year. To the numbers!
It’s a bit trickier figuring out how much our Model 3 has saved in carbon dioxide. One thing we have to account for is that the grid where you draw power will be a different mix of nuclear, coal, natural gas, wind, solar, and hydropower. This will impact how many pounds of carbon dioxide we are offsetting. As a comparison, we’ll use our Odyssey, which gets 22 miles per gallon / 35.2 kilometers per gallon / 9.31 kilometers per liter.
The eia.gov has detailed state pages for electricity use and carbon dioxide produced per MWh. Texas is 22nd highest in carbon dioxide emissions. Wyoming and West Virginia are #1 and #2. Washington is #50.
As of May 25th, our Tesla has driven 38,866 km’s (24,291 miles) and used 6.579 MWh to charge over three years. That gives us 6,190 pounds of CO2 used in energy production to charge the car (2,814 kg), or 2,063 pounds a year. Let’s call that close to one ton.
At 22 miles per gallon, the Odyssey would have needed 1,104 gallons to go the same distance. NASA tells us each gallon of gasoline generates 20 lbs of CO2. That works out to 3.68 tons of CO2 a year (1,104 *20/2000/3 years). So, our Tesla saves about 2.68 tons of CO2 versus our Odyssey for 8,100 miles a year. Even if we drove double, our savings would be 5.36 tons. We have to factor that more CO2 emissions would be generated from the drilling, transportation, and use of natural gas, which makes EV’s a bit better.
I don’t know how Sunpower came to their numbers, I plan to ask them. If a similar 2 tons is saved every two months, it should be possible for the systems to save 9 tons of CO2 easily per year (as winter will generate less electricity than summer).
Bottom line: $35,000 solar panels (22 panel system) without the US tax credit saves about 9 tons of CO2 a year.
$51,000 Model 3 (I’m excluding the $6,000 we paid for Autopilot) without the US tax credit saves about 2.5 tons of CO2 a year, compared to an Odyssey and driving ~8000 miles a year. If we drove double, we could save close to 5 tons a year.
What would I recommend? As we said at the start, for most homeowners solar systems make more sense than an EV for the cost paid and CO2 offset. Both should be done. If you had to choose one, go with solar panels first. Same for corporate apartment owners, but I don’t see them having the interest to add panels and help their residents.
Winner:
In following articles, we’ll compare heat pump water heaters versus solar panels, and heat pump air furnaces against solar panels. We have an opportunity to design a fully electric house, these calculations are important to us. It does show the world should emphasize solar over EV’s to reduce CO2 use faster, especially in areas using coal or natural gas for energy with good sun.
With peace, hope, and love (except for the US Supreme Court justices voting to destroy women’s rights),
smilingdad
smilingdad 