Electric Vehicles + Solar at Home

Drive Electric Minnesota recently sat down (virtually) with Jukka Kukkonen, chief electric vehicle (EV) educator at Shift2Electric (one of our frequent collaborators) to learn more about his family’s new at-home charging stations, powered by solar energy.

What came first for you, solar panels, or an EV?  How were these decisions related for you?

Electric cars came first for me, since we got our first electric car in 2012, but I’ve been following both things and figuring out how they best work together. During the last eight years, our family has driven more than  100,000 electric miles, and our driving gets cleaner every day since utility companies are increasingly producing electricity with renewables. When you shift to driving electric, you drop 75 percent of your energy consumption over night since electric motors are much more efficient. This makes EVs much cheaper to drive, and you are also drastically reducing your emissions. We decided to also add solar panels on our roof, so we installed a 2.8 kilowatt system on our house roof and later built a new garage where we installed an 8.6 kW system. We also tied this to stationary storage batteries that make our installation very grid-friendly and provide us backup power in case of a power outage.

How did you assess whether your property was conducive to a solar EV charging option? Were there any barriers to installation?

In the beginning, we had a bit of a challenge with our backyard. We have a nice maple tree that shades most of the roof space on our house, which is why we could only install one row of panels on the roof of the house. Our alley was also a bit shaded, but our neighbor cut down a big tree from her yard, and that opened  an opportunity to builda new garage with good roof space for solar panels. My friend, Jan Hubbard, is a solar designer who advised on this project, and I designed the asymmetrical roof for the new structure so that it has as much space for solar as possible. We also moved our main electrical service to the garage where we installed a new 200 amp main breaker panel. This provided capacity for solar installation and a 100 amp underground subfeed to our existing house breaker panel.

What were the initial costs associated with installation?

The first solar installation on our house was roughly $15,000, and the second installation on our garage was about the same. It’s a bigger system, but because we did a lot of the installation ourselves, and the price of solar panels had come down over the years, it evened out. Installing the charging stations was about $200 since we had power capacity in the garage. Whenever you do any electrical installations in your household, plan ahead for EV charging. This way, you can save quite a bit in the future and avoid extra work and expenses.

What do your ongoing costs or savings look like from powering your EV with solar?

It depends on how you calculate it, but if you start to look at the gas savings, it becomes apparent very quickly. And, for me, one of the things that I like about solar is that even if I can’t use all the solar energy, the extra goes back to the grid and my neighbors get to use it. I find that very valuable. I could spend the same $15,000 on kitchen remodeling, but that doesn’t produce anything. With the solar and EV charging, every day the system produces value and eventually pays for itself. We are also working to shift everything in our household to use electricity. We just recently got a heat pump water heater that I love; next, we will replace our gas dryer with a heat pump dryer. This further reduces our energy consumption and reliance on fossil fuels.

What ongoing maintenance, if any, is required to maintain peak performance with at-home solar EV charging?

It’s really very simple. I look at the data now and then to see that the system works fine. So far, there have been no issues. I will admit that sometimes in the wintertime I help mother nature a bit by raking some snow off my garage solar panels so that they start to see the sun sooner. You don’t need to do that and I don’t think it helps that much; I just like doing it.

Does your current solar output fulfill your charging needs? Will this be impacted as EV batteries grow?

Our solar panels produce about 75 percent of our annual house and driving electricity consumption. Your EV charging energy consumption depends on how much you drive. If you want to get an idea, divide your annual mileage by three, and that is roughly your annual EV charging consumption in kilowatt-hours. People usually charge their cars at night, and that is very easy—just plug it in when you come home, and you have a full battery every morning. Nowadays, EVs provide a longer driving range so that you don’t necessarily need to charge your car every night. Since we have solar panels, we often charge the car during the sunny days during weekends to take advantage of our own production. Bigger batteries don’t necessarily increase the charging needs, but instead provide more flexibility.

As solar EV charging becomes more accessible, do you see these residential installations becoming more popular?

I definitely think people will be considering it more. It will, of course, depend on the future price of solar. Utilities are moving forward with more renewable energy options as well, and I see it becoming a more competitive market, which is great for EV owners. It’s kind of like they’re pushing each other forward. My advice is to start by getting an EV. Then, sign up for a renewable energy program from your utility company, and later, you can decide if you want to add solar panels on your roof or sign up for a community solar program. This provides us with opportunities to do good things, learn more, and have fun!

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