Solar Installation Retrospective

Retrospective from our solar panel installation from 18 months ago (May, 2022).

Bottom line: We’re getting a 5.0% return on investment at the moment. This will go up to 5.3% next year with SCL’s planned 9.5% rate hikes

Solar Installation Notes

• Final total cost: $14,227
  • $20,325 initial cost, minus a $6,098 federal tax credit (FYI this 30% tax credit is available for installs in 2022 - 2032).
• Size: 6.09 kW.
• 14 x SPR-M435-WHT-AC panels, west-facing.
• Warranty: 25 years, 92% effective at year 25.
• No sales tax in WA.
• 3 bids, all were same price/watt.

SCL bills for 3 years

Solar panels installed in May 2022. Numbers are from SCL, billed every other month. Note the consumption is negative when we generate more solar that we use and electricity goes back to the grid and we carry a balance. The balance is cleared to zero at the start of every April but we haven’t had a full April to April year yet.

Service period start	Service period end	Consumption (kWh)	Service charge	Usage	Balance (kWh)	Notes
9/12/2020	11/10/2020	922	$11.11	$95.44	N/A
11/11/2020	1/14/2021	1084	$12.03	$108.73	N/A
1/15/2021	3/17/2021	1032	$11.48	$104.40	N/A
3/18/2021	5/14/2021	981	$10.74	$108.38	N/A
5/15/2021	7/14/2021	988	$11.29	$111.06	N/A
7/15/2021	9/13/2021	824	$11.29	$89.32	N/A	Annual total service charge: $68, usage: $617
9/14/2021	11/10/2021	1034	$10.74	$110.09	N/A
11/11/2021	1/13/2022	1259	$12.01	$134.52	N/A
1/14/2022	3/16/2022	1094	$12.24	$118.09	N/A
3/17/2022	5/13/2022	984	$11.45	$111.85	N/A
5/14/2022	7/14/2022	-666	$12.24	$-	666	Solar panels installed
7/15/2022	9/12/2022	-1054	$11.84	$-	1720	Annual total service charge: $71, usage: $475 (estimated $700 without panels)
9/12/2022	11/10/2022	155	$11.64	$-	1565
11/10/2022	1/13/2023	1026	$13.06	$-	539
1/14/2023	3/31/2023	698	$17.72	$17.99	0	We didn’t have the panels long enough for the balance to carry the whole winter so we had to pay a little bit.
4/1/2023	5/12/2023	-391	$9.66	$-	391
5/13/2023	7/14/2023	-1064	$14.50	$-	1455
7/15/2023	9/12/2023	-952	$13.81	$-	2407	Annual total service charge: $80, usage: $18

Monthly solar data from our EV meter

Part of the installation was a meter that tracks the amount of solar produced, electricity consumed, and net export to the grid. Here are data from all complete months.

Month	Solar Production (kWh)	Consumption (kWh)	Net grid export (kWh)	12 Month Rolling Total Solar Production (kWh)	12 month rolling total Consumption (kWh)
June, 2022	812	389	423
July, 2022	1077	530	547
August, 2022	930	355	575
September, 2022	661	440	221
October, 2022	413	527	-114
November, 2022	208	614	-406
December, 2022	87	613	-526
January, 2023	152	639	-487
February, 2023	269	503	-234
March, 2023	512	650	-138
April, 2023	696	456	240
May, 2023	988	446	542	6805	6162
June, 2023	987	507	480	6980	6280
July, 2023	1125	512	613	7028	6262
August, 2023	859	381	478	6957	6288
September, 2023	596	468	128	6892	6316
October, 2023	382	654	-272	6861	6443

Daily Solar data for July 2023 (best month)

Day	Solar Production (kWh)
1	40.7
2	41.9
3	39.4
4	38.3
5	38.7
6	37.4
7	38
8	39.6
9	38.4
10	16.9
11	39.4
12	36.3
13	39.6
14	39.3
15	36.1
16	34.7
17	35.5
18	39.1
19	38.4
20	35.7
21	35.3
22	38.4
23	38.3
24	14.7
25	32.8
26	38.6
27	37.9
28	35.7
29	32.8
30	38.5
31	38

Daily Solar data for December 2022 (worst month)

Day	Solar Production (kWh)
1	6.4
2	3.4
3	7.7
4	1.3
5	3.2
6	3.9
7	4.1
8	3.2
9	3
10	1.6
11	1.5
12	3.5
13	1.7
14	2.7
15	7.3
16	7.2
17	1.5
18	2.9
19	2.1
20	0.1
21	0.5
22	0.4
23	0.1
24	0.9
25	2.5
26	2.1
27	1.7
28	3.2
29	2.3
30	2.6
31	2.3

Hourly solar data for Jan 2, 2023 (Closest full-sun day to the winter solstice)

Hour	Solar Production (kWh)
8 AM	0.1
9 AM	0.3
10 AM	0.6
11 AM	0.8
12 PM	1.1
1 PM	1.6
2 PM	1.7
3 PM	0.6

Hourly solar data for June 4, 2023 (Best day of the year)

Hour	Solar Production (kWh)
6 AM	0.2
7 AM	0.2
8 AM	0.3
9 AM	1.1
10 AM	2.2
11 AM	3.4
12 PM	4.2
1 PM	4.9
2 PM	5.3
3 PM	5.4
4 PM	5.2
5 PM	4.7
6 PM	3.7
7 PM	2.4
8 PM	0.7