Last updated: Jan 24, 2021
****If you find this information useful and are looking to order Tesla Solar or a Tesla Auto, please use my referral code to place your order to get a $100 solar award (currently) when your system is activated or 1000 Supercharger miles (currently) for a car purchase. Tesla Solar recently announced on June 19, 2020 a 20% price reduction (The Lowest Price for Home Solar) and they also now use the 340 watt panels (up from the 315 watt panels that I have). This will cover the $99 down, making it zero out of pocket initial cost when financed.*****
The following is the actual performance of my Tesla Solar system for 2020.
Location: Phoenix, AZ
System Size: 12.285 (39 – 315 watt panels)
2 SolarEdge Inverters/SolarEdge Power Optimizers
House Size: 2 story/2965 square feet with swimming pool/AC set at 77F during the day and 76F at night
Electrical Consumers: 2 Tesla Model 3s, 2 AC units, Mini-split AC, Evap Cooler (garage), Electric Dryer, Variable Speed Pool Pump
| 2020 | Total Solar kWh Produced |
Avg Solar kWh Produced per day |
Total Solar kWh Sold |
Total kWh Purchased |
Total kWh Used (Solar + Grid) |
Avg kWh Used Per day |
APS Bill |
| January | 1243 | 40 | 960 | 655 | 938 | 30 | (Previous credit balance -$6.65) Monthly cost: -$7.99 Balance: -$14.64 (credit) |
| February | 1439 | 50 | 1166 | 657 | 930 | 32 | Monthly cost: -$38.08 Balance: -$52.72 (credit) |
| March | 1719 | 55 | 1356 | 608 | 971 | 31 | Monthly cost: -$58.39 Balance: -$111.11 (credit) |
| April | 2147 | 72 | 1580 | 486 | 1053 | 35 | Monthly cost: -$88.27 Balance: -$199.38 (credit) |
| May | 2359 | 76 | 1280 | 787 | 1866 | 60 | Monthly cost: $7.34 Balance: -$192.04 (credit) |
| June | 2260 | 75 | 1065 | 1243 | 2438 | 81 | Monthly cost: $48.37 Balance: -$143.67 (credit) |
| July | 2059 | 66 | 677 | 2177 | 3559 | 115 | Monthly cost: $172.43 Balance: $28.76 (owe) |
| August | 1976 | 64 | 528 | 2442 | 3890 | 125 | Monthly cost: $219.34 Bill total: $219.32 (owe) Running bill total owed: $248.10 |
| September | 1770 | 59 | 678 | 1760 | 2852 | 95 | Monthly cost: $144.51 Bill total: $144.51 Running bill total owed: $392.61 |
| October | 1571 | 51 | 784 | 1226 | 2013 | 65 | Monthly cost: $62.69 Bill total: $62.69 Running bill total owed: $455.30 |
| November | 1195 | 40 | 817 | 905 | 1283 | 43 | Monthly cost: $8.84 Bill total: $8.84 Running bill total owed: $464.14 |
| December | 1143 | 37 | 812 | 967 | 1298 | 42 | Monthly cost: -$1.16 Bill total: -$1.16 End running total: $462.98 Note: -$1.16 credit carries over to 2021 |
| Totals | 20881 | 11703 | 13913 | 23091 |
NOTES:
May and June did not include any vehicle charging as I was attempting to use up my Supercharging miles that were expiring at the end of June.
Due to COVID, my kids were home doing online school and the AC was kept at 76F most of the day.
2020 is shaping up to be one of the hottest years on record (number through Nov 1, 2020):
See my previous posts for more information:
My Tesla Journey Part 1
My Tesla Journey Part 2
Originally posted on https://miketerrill.net/
Mike's Tech Blog 
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can you explain those numbers? what does total KWH sold mean? sold by who and purchased by who? if you produced more than you needed why did any get sold? looking at January…. and then purchased. if you produced more, then why did some get purchased. I don’t think I understand the give and take with the power company which is why I don’t understand all these numbers and credits…..so at the end of the year, you had to pay $462.98? then why a credit?
what does total KWH sold mean? kWh exported back to the electric company (APS in my case)
sold by who and purchased by who? over production goes to the electric company
if you produced more than you needed why did any get sold? it has to go somewhere and since I do not have a battery, it goes back to the grid
so at the end of the year, you had to pay $462.98? then why a credit? If what I owe exceeds the credit, then I need to pay. However, at the end of the year if there is a credit, then it will roll to next month.
I hope this helps to answer some of your questions.
I see. so even in a single month that you produced more, you still had to purchase because at any single time of the day, you’re producing more than using(have to sell back), while also producing less at any given time of the day(have to buy). so with the current drop to 8.5 cents I think to sell? is it still worth it? the off peak of 10.789 is higher than 8.5. so even off peak there will be a loss between buying and selling
It is pretty instant, meaning, if you use less than what you are producing, that electricity will go back to the grid. The rider that I got in on with APS, I export at 11.61 cents per kWh. Under the new Time-of-Use with Demand Charge plan, Summer rates are 5.276 cents off-peak and 12.414 cents on-peak with a $16.875 per kW demand charge.
Having solar has been a benefit for me and I have already seen an ROI the first full year. With the APS plan changes, I should do another analysis, but I think I will be even better off now with only 3 hours of peak time now that I am able to ‘super cool’ my home and make sure the AC doesn’t turn on at all during the peak time.
the solar companies I’m talking to are all saying not to do the demand charge. say that’s a loss that can’t be compensated. I wonder if they haven’t updated their analysis for a lowering APS buyback?
If you aren’t careful, it can be the largest line item on the bill. But if you understand how it works and how to minimize it, the lower off-peak and on-peak rates can be beneficial. My bill for August was only $134 and I have 3 electric cars. If I calculate my usage against one of the non-demand charge bills, my bill would have been much higher.
Also, the riders from APS have step downs each year, so someone getting solar this year will not get the same export rate that I got in 2019.