In 2011 about the smallest solar system I could afford was a 1.2-kilowatt system, which cost me around $10,000.
It’s always been the dream to have a solar system big enough to power my entire house, and charge my EV all by the Sun and for free.
Fast forward to 2020, and I’m happy to say that I’ve officially made that a reality. I upgraded my system and spent just as much money as I did in 2011, about $10,000.
Today in 2020, that $10,000 got me a three-point-six kilowatt system, and now my entire system is nearly five kilowatts.
We’ve written several articles on solar and Tesla and will continue to do so, but in this one, I wanted to talk about how amazing it is to power your entire house and your car, all for free.
Buying my performance Model 3 has resulted in substantial fuel savings because my other car is still gas. At 20 miles a gallon, if we drove at 12,000 miles a year, it would cost about eighteen hundred dollars in gasoline at $3 a gallon here in California.
For the Tesla Model 3 to drive the same twelve thousand miles at an efficiency of three and a half miles per kilowatt, which is lower than what Tesla says, my driving habits or performance model don’t quite get to that level.
Even then, Tesla would only cost me about $300 to fill up, and that is because I have a particular time of use plan that gives me cheap electricity from midnight to 6:00 am.
Now that I have solar panels, I can charge my car and my house, and I still have a negative bill. I have a home automation system called indigo, and I have some custom scripts that will take all my energy usage and break them down by the time of day.
Using https://grafana.com/ I have some visualization and some charts to show how my house uses electricity. You’ll see these big green spikes, and the green means that it is off-peak, and in San Diego, it is our lowest price at only nine cents.
You can tell from these big spikes; this is my Tesla, nothing in my house uses as much power as my Tesla does when it’s charging.
When I charge my Tesla, it uses between 50 and 60-kilowatt hours based on how depleted the battery was. I charge it when it gets to around 20 percent, and I charge it up to about 85 percent.
To understand how my billing works, you have to look at your bills and figure out if you have a time of use or not. Time of use means that your electricity is charged differently based on the time of day.
As a residential customer, your most expensive electricity is probably between 4 & 9 pm, and that’s because that’s the time when people come home from work and run their air conditioning and everything else.
On my chart, you can see that that is in red. My off-peak is midnight to 6 am when everyone’s asleep, and that’s when you should try to do dishwashing and all the other things that use a lot of electricity, including charging your car.
On peak is 4 to 9 pm everything else is off-peak. If you see my charger, you can tell my solar panels are working most of the time during this off-peak period, between 8 am and 6 pm they are generating most of the electricity.
What’s good with solar, especially in the summertime, is with a bigger system generating electricity even further into the night, including the peak time.
My solar panels usually work on the off-peak period, between 7 am or 8 am until about 6:00 pm when the solar curve is doing its thing.
As you can see, even during the on-peak period, I’m negative around negative seven killed hours so far for the month, and that’s because, between 4 pm and 6 pm, my solar system is still putting out a little bit of energy.
Not as much as at noon, but still something. That is how my energy usage and generation breaks down by these different buckets.
You have to remember that these different buckets are charged differently. For example, in the summer, you could use 3 kWh in the super off-peak period between midnight and 6 am for the same price as a 1-kilowatt hour in the off-peak period.
That means that if my solar generates 1 kilowatt-hour during the off-peak period, it’ll offset three cold hours during the super off-peak period. The on-peak is five times higher than the super off-peak.
You can see that the solar system is doing more work than you think. Even though I’ve used 150 killed hours, mostly Tesla charging it, I have a negative balance, and that’s because the solar panel is generating energy at the off-peak period.
I can run my entire house. I have two refrigerators, a wine cooler, a double oven, and a Tesla. I haven’t run the air conditioning a lot, and if it was warmer and the air conditioning was running more instead of a negative thirty dollar balance, I probably would be around zero.
In San Diego, we get lots of Sun, and the weather is usually between seventy and eighty-five degrees, so the air conditioning usage isn’t as high as other places like Phoenix, Arizona.
This gets into two things that are important to me, saving money, economics, and two is reducing our carbon footprint.
All the computers and TVs in this house, plus all of our driving in the Tesla are all covered by the solar panels.
And because a vast area of our roof is covered in solar panels, the Attic stays cooler, and the house stays cooler, so it needs less air-conditioning. Talk about a win-win.
As a result of having our Tesla, the last time I pumped gasoline in our Honda Pilot was on March 20th, and I have not had to go back to a gas station since then because we drive our Tesla to do pretty much everything.
My ad on solar system in 2020 cost about $10,000 and the investment tax credit for the U.S. is 26% for 2020. That drops to 22% in 2021, and then it goes away for residential customers altogether in 2022.
The total cost of the solar system was $10,000; the tax credit will refund me $2,600, which results in a total system cost of $7400. My average electricity bill is around $130 a month, sometimes higher, sometimes lower, but the average is $130.
If I saved $130 a month for the entire year, my buyback period is 4.7 years. Just to be safe considering those baseline fees that happen no matter how much energy you use, let’s say it’s five years.
In 2011 my first system took about nine years to pay off, and now in 2020, my new system will pay itself off and almost half that time, but it gets even more interesting.
With my Tesla Model 3, I got a $2500 rebate from California for buying the Model 3, and I think that finishes in 2020, just like the federal tax breaks.
I used that twenty-five hundred towards the solar to see some of these different rebates work hand in hand. I can think of no better way to spend my tax credit on buying an EV than on buying more solar panels.
This has been a long-term dream, and partly it’s economics. I have no bill, and, as a net energy metering customer, I have officially stopped paying monthly bills to the utility company, and now I’m going to be yearly bills.
Maybe there’s a couple of scorching months where the ACS is turned on, and I have a little bit of a bill, but then other months, it’s negative. They’ll true-up my entire bill for the entire year, and I’ll make one payment, and base my projections, I believe it’s going to be zero.
There will be some baseline fees that are tacked on no matter how much energy you use, and I think that’s going to be about a hundred to two hundred dollars, so that will be all I have to pay.
The second part is environmental, and that is where I’ve always wanted to be more energy independent, and now I am.
When I look at my monitoring software, I can see that my house isn’t the negatives almost the entire day.
That’s a powerful feeling because now I know that even if the power went out, I have enough solar to generate all the electricity my house needs, and I can even drive my car.
I would have to change my habits a little bit. For example, my home automation software can tie into my Tesla, and I can program it to start and stop charging.
Let’s say the power was to go out. I have no grid, I could say between 11:00 am and 1:00, or 2:00 pm when the solar generation is the highest, and I have all this excess energy.
I could have the car charge at a specific rate to consume that extra energy. When 4 pm rolls around. The solar generation drops off; I could have the car stopped charging.
I currently let it go down 20%, and I charge it all the way back to 85%, but that’s because I have a grid.
If I didn’t, I could still make this work and power my house and my Tesla, and you can’t forget that you need to get a tesla powerwall.
This ties into the third benefit of emergency preparedness and the need for a power wall. Currently, without a power wall, if my power goes down, my microinverters will stop detecting the grid and completely shut down.
My house will have no power, but the power wall will absorb excess energy and charge the battery pack up. The Powerwall will then discharge power into my house so I can run my house even if the power went down.
Lower carbon emissions, lower carbon footprint, save money, have no electric bill, drive on the Sun for free, and be prepared for emergencies.
It was my dream in 2011, but in 2011 there wasn’t a Tesla I could buy. There was no 300 mile EV, and solar panels were expensive to buy, the system I bought in 2011 would have cost me about forty thousand dollars.
As a young new homeowner, I didn’t have that kind of money; I’m so glad I waited because I can happily say the dream is a reality. I can run my entire house and my car on the Sun for free.
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