My Solar Roof - Installed November 2000 and producing electricity since February 2001

South facing roof with 96 Unisolar photovoltaic shingles covering an area of approximately 280 square feet and surrounded by conventional asphalt shingles. The "name plate" rating of my array is 1632 Watts. Accounting for normal inverter and wiring losses plus other normal inefficiencies, it should generate approximately 1300 Watts under peak sun conditions (80% of the name plate rating). From Feb. 2001 through Dec. 2001, the inverter that was used to convert the DC electricity from the shingles to AC for the grid was a Trace Sun Tie 2500. Testing of the system indicated that this inverter was significantly less efficient than it was advertised to be, so peak production was closer to 1100 Watts. The Sun Tie was replaced in January 2002 with a Sunny Boy SWR 2500U, manufactured by SMA. Production since installation of this new inverter indicates that it is significantly more efficient than the Sun Tie.

The system was installed by Innovative Power Systems and Andrew Bangert of H&H Electric. The system is connected to the Madison Gas and Electric grid through a process called net metering. Excess electricity generated over what I am using at a given time is "sold" to the grid and I receive a credit on my utility bill. My roof has been the subject of articles published by the UW News Service and the Wisconsin State Journal. For more information on solar energy from the US Dept. of Energy visit http://www.eere.energy.gov/solar/ and for lists of solar energy businesses visit energy.sourceguides.com. My home has regularly been part of the Midwest Reneweable Energy's annual Tour of Solar homes. See www.the-mrea.org.

Data on Production and Usage

Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
March 01	164	120	246	290	57
April 01	158	98	180	240	66
May 01	136	74	184	246	55
Inverter out for repair from mid-June through mid-July
Aug 01	139	71	237	305	46
Sept 01	135	79	201	257	53
Oct 01	95	58	206	243	39
Nov 01	91	74	124	141*	65
Dec 01	54	41	166	179	30
Jan 02	85**	70	148	163	52
Feb 02	131	113	108	126	104
March 02	147	124	116	139	106
April 02	154	128	93	119	129
May 02	179	145	69	103	174
June 02	171	135	72	108	158
July 02	191	155	91	127	150
Aug 02	201	164	68	105	191
Sept 02	187	153	82	116	161
Oct 02	116	90	123	149	80
Nov 02	98	78	113	133	74
Dec 02	85	67	134	152	56
Total 02	1745	1422	1217	1540	113
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 03	96	67	122	151	64
Feb 03	137	114	118	141	97
March 03	162	143	80	99	164
April 03	166	140	52	78	213
May 03	171	152	52	77	229
June 03	179	144	83	118	152
July 03	186	136	108	153	122
Aug 03	193	163	70	100	193
Sept 03	177	148	62	91	194
Oct 03	168	147	67	88	191
Nov 03	83	70	119	132	63
Dec 03	63	53	138	148	43
Total 03	1781	1477	1071	1376	129
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 04	84	65	162	181	46
Feb 04	119	96	123	146	82
Mar 04	118	97	105	126	94
April 04	178	155	71	94	189
May 04	151	122	68	97	156
June 04	165	126	95	134	123
July 04	168	133	90	125	134
Aug 04	168	138	83	111	151
Sept 04	213	187	73	101	213
Oct 04	125	105	85	105	119
Nov 04	82	66	114	130	63
Dec 04	78	60	150	168	46
Total 04	1649	1350	1219	1518	109
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 05	78	60	170	188	41
Feb 05	122	103	119	138	88
Mar 05	183	159	116	140	131
Apr 05	189	162	67	94	201
May 05	169	140	65	94	180
June 05	182	130	150	202	98
July 05	179	139	106	146	123
Aug 05	177	133	118	162	109
Sept 05	198	156	115	157	126
Oct 05	147	114	109	142	104
Nov 05	87	70	102	119	64
Dec 05	49	46	149	152	32
Total 05	1760	1412	1386	1734	101
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 06	72	56	140	156	46
Feb 06	128	107	133	154	83
Mar 06	141	119	109	131	108
Apr 06	169	147	63	85	199
May 06	152	133	56	75	203
June 06	162	106	137	193	84
July 06	179	120	182	241	74
Aug 06	162	102	160	220	74
Sep 06	140	107	88	121	116
Oct 06	120	97	99	122	98
Nov 06	75	70	118	123	61
Dec 06	78	51	139	166	47
Total 06	1578	1215	1424	1787	88
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 07	85	71	146	160	53
Feb 07	125	103	134	156	80
Mar 07	149	127	98	120	124
Apr 07	163	140	71	94	173
May 07	178	153	47	72	249
June 07	167	113	112	166	100
July 07	191	136	135	190	101
Aug 07	149	99	160	210	75
Sep 07	180	137	121	164	110
Oct 07	127	118	86	95	134
Nov 07	96	72	124	148	65
Dec 07	45	34	158	169	27
Total 07	1655	1303	1392	1744	95
Month	Generated (kWh)	Sold to grid (kWh)	Used from grid (kWh)	Total Used	Generated Used (%)
Jan 08	66	51	145	160	41
Feb 08	105	83	140	162	65
Mar 08	177	156	110	131	134
Apr 08	150	128	83	105	143
May 08	180	155	44	69	261
June 08	147	111	84	120	123
July 08	180	129	119	170	106

* New refrigerator installed 10/26/01

** Sunny Boy inverter turned on 1/4/02

Individual PV shingle strip

Attic "raceways" showing wires prior to connection to inverter

Sunny Boy inverter and other attic equipment

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