Electric Vehicles are becoming more and more popular. I have also noticed that there are more all-electric vehicles, in addition to plug-in hybrids. (Check out this LA Times article about electric vehicle sales.)
Not only is California the largest car market in the country (10% of all car sales), Californians buy almost 50% of all plug-in cars bought in the United States!
Often, new construction homes include a 220 Volt outlet in the garage to power an electric vehicle. As more people are buying electric vehicles, many buyers appreciate this upgrade.
So if you’re planning to install a solar system, how much solar do you need to power your electric vehicle?
This article explains how to:
- Calculate how much electricity you will need, based on mileage.
- Determine how many solar panels you’ll want to add to your system.
- Estimate how much the additional solar panels will cost, with or without the federal tax credit.
How Much Electricity Does an Electric Vehicle Use?
A good rule of thumb to use is that an EV will use about 1 kWh per 3 miles driven. For example: if you drive 12,000 miles per year, and you charge up primarily at home, the EV will need about 4,000 kWh/year.
(12,000 miles/year) x (1 kWh/3 miles) = 4,000 kWh/year
How Many Solar Panels to Power an Electric Vehicle?
Once you figure out how much electricity you need to produce, let’s convert that to solar panels.
Under ideal conditions, 1 kWdc of solar panel capacity will produce about 1,478 kWh per year in the San Diego area.
So here’s how to calculate how much solar we need to produce 4,000 kWh in a year:
(4,000 kWh/year) / (1,478 kWh/year/kWdc) = 2.7 kWdc
Rooftop solar panels these days have a capacity of about 330 Watts each. In conclusion, you would need about 9 extra 330W panels to get 2.7kWdc of extra capacity.
(2,700 Watts) / (330 Watts/panel) = 8.2 panels = 9 panels
How Much Will I Pay for the Extra Solar Panels?
To get an idea of what that would add to the cost of a solar installation, it currently costs about $3/watt to install a residential rooftop solar system.
An extra nine 330W panels would cost about $8,900.
(9 panels) x (330 Watts/panel) x ($3/Watt) = $8,900
With the 26% Federal Investment Tax Credit (through 2022), the net cost would be about $6,590.
($8,900) x (100%-26%) = $6,590
More Solar Information
If you’re considering a solar system, you can have an installation professional help you with your system purchase. They can help determine the appropriate system size, and also obtain bids from multiple solar contractors. In most cases, there is no additional charge for this service.
If you’re looking for financing options, read my Financing Green Upgrades article.
You can also read my Solar for Homeowners article series.
If you are considering selling your home after installing solar, be sure to read my Selling with Solar article.
As always, feel free to contact me with any questions.
Thank you for contributing to this article:
Kathy Nicholson, NABCEP Certified PV Installation Professional™, Certification # PV-102216-014913 – Kathy is an energy consultant and designer of home solar and storage systems. She can be reached at 858-705-0860.
