Well…our new meters were installed while we were away…and our solar is totally up and running. So…it will be interesting to see our electric bills and how they change.
Also, there is an AP we will be getting so we can see what’s what… We think the meters were installed Friday…so expecting the AP email tomorrow.
Congratulations!! What is an AP?
Our solar has been running and generating electricity since the end of November; net metering was blessed by the power company mid-December. To date, during the darkest months of the year, we produced 70% of our consumption of electricity, which includes charging our car (we have gas heat and hot water). We plan on adding AC minisplits this summer to mop up the extra electricity we produce.
An application for the phone that tracks power used and power generated…an ap.
Oh, an app! 
I usually just log into our Enphase account. Their app looks exactly the same as the Safari page. It is addictive! We now rate days by the amount of electricity we produce. “Looks like it’s going to be a 60 kWh day.” 
We are looking forward to tracking what’s what. Today, it’s bright and sunny. We have also been keeping our electric bill for comparison as well.
I am eager to follow this. I did some questionnaire on line that said if we installed solar panels, we’d make back our investment in – 25 years. We’re not going to be in this house that long. I have no idea how they figured 25 years.
We won’t be here for 25 years either…but we figure it’s also a good selling point. And it’s the right thing to do…we think.
Because of significant rebates and NEM 3.0 coming to SoCal, we priced out solar recently. We don’t have the best exposure, mostly west on the side of a coastal hill that tends to trap clouds. All bids said a 6ish years ROI. We plan to be here 10+ years so decided to bite the bullet.
Signed the contract and we’re getting the site survey this week.
I asked a friend of mine who just built a new mansion size house why she didn’t install solar panels. Her answer is that the payback period is too long in the Bay Area. Another friend calculated her electricity savings were just $1200 for the year, her first year of complete solar and she was disappointed. Her system cost around $18K. Anyone can chime in from the Bay Area?
This is the same reason we haven’t installed solar. The cost of the install far exceeds the amount of savings we will ever see.
Looking at it from a finance point of view, that is like a 6.6% return per year. How does that compare to other things she would have put the $18,000 into?
When I was getting solar, I did the calculations myself. I found the site PVWatts Calculator particularly useful to this effort. As one might expect, installers were typically generous and sometimes unrealistic in their assumptions. Now that I’ve had the solar for a few years, I can report actual numbers using the actual solar generation and actual electric costs. I live in an area of southern CA where installers typically estimated payback period of ~4 years at time of purchase (sunny with near highest electric rates in US). Some estimated 3-4 years. My actual payback period looks like it is going to be between 4 and 5 years.
Install Cost = $15k in late 2019
Tax Credit – Saved 30% * $15k = $4500
Year 1 (2019-2020) – Saved ~$2030
Year 2 (2020-2021) – Saved ~$2170
Year 3 (2021-2022) – Saved ~$2630
Year 4 (2022-2023) – Estimate savings of $3040, if electric rates do not further increase
Total of Savings Above in late 2019 $ = $13,260
I suppose it depends on the state.
Here in NJ, we installed sales tax free, got a Federal Income Tax rebate (at the time) - as in subtract amount directly from taxes, are generating Solar Credits that we turn into cash several times a year - oh, and have no electric bill.
Added together, we had needed 5 years to recoup investment.
Unbeknownst to us there were other benefits - the solar racks on the south side roof created an additional “insulation”, thus less-hot attic, and less A/C demand.
And, with less exposure of shingles to direct sunlight, chances of longer life-span of roof.
Needless to say - just like for people in many Central European countries with similar climate - for us it happened to be no-brainer. And that was before the even more efficient panels of today’s age.
We live in the area with cheap hydroelectric power and presumably low sunlight, so folks question why anyone would even consider solar.
Cheap electricity might be coming to an end. Salmon activists demand dam removal. Snowpack gets thinner, less water to turn those turbines. War on natural gas. Inflation. All of this will not make future electricity rates go down. Plus, prior to getting solar panels, we were reluctant to add AC to our house because AC is so environmentally unfriendly. Solar makes it a bit less unfriendly, so we can cool our bedroom without feeling too guilty about it.
Regarding sunlight… it was pretty cloudy here yesterday, so the solar system generated 1/2 of what it did on sunny Saturday. The cloud cover needs to be super thick for the solar to stop generating.
Finally, we have a lot of roof surface. It is useless surface. We might as well get something useful out of it!
Many people don’t realize that moderate climates can be better for solar generation, because efficiency of solar panels is best in spring and fall, as some become less efficient in summer heat.
Bottom line, if your roof surface can produce all you need to power your house over the course of the year, it doesn’t matter how moderate sunlight is at that latitude.
The PVWatts Calculator link I listed in my earlier post allows you to estimate solar generation by month at your specific address. In typical US locations, solar production is highest in early summer due to a combination of more daylight hours and the sun being higher in the sky (panels work best when angle is closest to direct overhead). However, there can be significant variation, if your location has a lot of rainy days in the early summer.
My actual average solar generation by month is listed below. In my climate, I tend to get the most solar generation in July and least solar generation in December. The specific amount generated varies wildly from day to day, depending on weather. Cloud cover dramatically reduces solar generation. Rain can drop generation to near 0. I attached an example graph, which shows my daily solar generation so far this month. My area has had a huge amount of rain and many cloudy days this month and is on pace to be by far my worst March ever for solar generation.
Jan – 380
Feb – 455
Mar – 600
Apr – 680
May – 760
Jun – 770
Jul – 810
Aug – 730
Sep – 590
Oct – 480
Nov – 400
Dec – 310
@DigitalDad was referring to the temperature coefficient of solar panels. All things being equal, higher temperatures can lead to 10-25% loss of efficiency.
@DigitalDad was referring to the temperature coefficient of solar panels. All things being equal, higher temperatures can lead to 10-25% loss of efficiency.
My solar panel’s temperature coefficient is listed as 0.16% per degree F. If average summer temperature was 20F hotter than a more optimal spring month, an average 3% increase in lost efficiency in the summer is expected. This type of inefficiency difference often pales in comparison to the other factors I mentioned like varied daylight hours, varied sun angle, and varied typical weather; such that the net tends to be most generation in early summer.
Even a 25% temporary loss would not be detrimental, I agree, but it is important to know what can affect one’s energy output and it is important to know how to compare different solar panel models.
BTW, the efficiency loss could be greater than what is expected at 20 degree air temperature difference because surfaces can get hotter than surrounding air. If there is insufficient gap between the panels and the roof, it can also lead to local excess heat. Some solar farm critics are concerned that large arrays can create heat islands similar to those urban asphalt heat islands.
If you have solar panels, what happens when you need to replace your roof??
