It’s been a bit since I updated the news on our Solar system. December went well. We generated 1121 kWh, and consumed 912 kWh, meaning that we sent an excess of 204 kWh back to the grid for credit. Our lowest power generated was December 6, with 12.6 kWh. Our best day was 54.1 kWh on December 2. That makes December the month where we generated the least amount of power of any month so far. Not surprising, since December has less daylight than any other month.
Temperatures for December were mild, so we spent most days with the windows open and the HVAC turned off, so we didn’t use a lot of power, which contributed to an excess. At the end of December, we had a total credit of 1121 kWh in case we ever use more than we generate, and it turns out that we needed it for January.
January was rough. There was a lot more cloudy days than there have been, and this month had the lowest average temperatures for any month in more than a decade. All of this contributed to our shortfall. There was a stretch of days from the 13th to the 23rd where 6 of those 10 days saw us generate less than 10kWh each day. We generated 1190 kWh for the month, still more than December, but we used 1238 kWh. Our highest use day was January 22 at 63 kWh. That was the day that the big snowstorm hit the state, and our temperatures dropped below freezing here, although it didn’t snow.
According to my weather station, the average temperature was only 54 degrees for the month. Since we maintain an average inside temperature of 70 degrees during the winter (68 at night, 72 during the day), the HVAC was warming the house against a 16 degree gradient.
Our bill didn’t change, thanks to our banked power that we have sold to the grid.
One small problem with our system has required a call to our installer, who put in a work ticket to Tesla. Our control system has been exercising the batteries by running them down to zero. It’s supposed to do that every 90 days, but it’s been doing it every 20 days. We are waiting for more word on why it is doing that.
5 Comments
Boneman · February 2, 2025 at 6:12 am
Moved to SW FL in 2012. This “winter” is the first year we have ever actually turned on the “heat”. It’s been quite a chilly one. Good for you with the system. What was your projected ROI? Hopefully you’re on track there.
Excellent to see this working for you! Bravo!
Tom235 · February 2, 2025 at 11:31 am
“January was rough. There was a lot more cloudy days than there have been, and this month had the lowest average temperatures for any month in more than a decade. All of this contributed to our shortfall.”
What you experienced for a few days is normal for more than a few days in much of the country this time of year. Solar has its uses but is not the energy panacea that some claim. Waste of money in many places.
(I was in northern Florida in the mid-70s. Had 2″ snow. No big deal for me but I had friends who had never seen or been out in falling snow before. Was in Tidewater VA a decade or so ago. They had 11″ or more. I was days new there and didn’t realize their attitude to the stuff. Was out driving around and wondered where the traffic was)
Divemedic · February 2, 2025 at 12:06 pm
I am well aware of the limitations of solar. There was a lot of consideration made for cloudy days with reduced winter daylight hours. Check out the entire process that was involved by following this topic.
lynn · February 3, 2025 at 3:53 pm
I must admit, I am tempted to throw some solar panels on top of the 1,200 ft2 garage with a Tesla Powercell. The cost is probably around $40K.
I suspect that the Texas will move to Time Of Day rates in the future, maybe the near future. Not to the the total extreme but enough to force people to install solar or air conditioning freezer systems (make ice all night long in a chest freezer then vaporize during the day).
Divemedic · February 3, 2025 at 5:12 pm
Call it about $1100 per panel, and $8000 per powerwall.