Solar Calculators - pvWatts

Description: A Solar Calculator - PVWatts calculator developed by NREL's

 The National Renewable Energy Laboratory, has an online program, pvWatts that allows you to project your estimated monthly and annual solar energy production of kilowatts and solar energy value of your PV system. (Click photo right to enlarge) Listed below, our real pay back readings and the pvWatts estimates.

 Our Grid Tied Photovoltaic System Description: Array Type: Fixed, Array Tilt: 26.5° (a 6/12 roof). Array Azimuth: 180.0° (due South), DC Rating: 1.645 kW, AC Rating:1.4 kW. The system is using 7 Enphase Microinverters and 7 Schott Poly 235 watt modules. Latitude:36° N, Longitude:85° W, Elevation:598 m

	pvWatts	OurkW	Our kW		Actual	pvWatts	pvWatts	Our
	Pojected	actual	actual		Ave kW	Pojected	Energy	Energy
	kW	VEC	Enphase		Day	kW per day	Value	Value
Jan	127	085	116		3.74	4.23	$26.16	$18.02*
Feb	141	151	137		4.89	5.18	$29.05	$31.84
Mar	191	158	172		5.64	6.39	$39.35	$33.62
Apr	206	186	230		6.20	7.10	$42.44	$39.75
May	210	197	227		7.64	7.00	$43.26	$42.04
Jun	211	252	232		7.64	7.27	$43.47	$53.93
Jul	216	206	240		7.35	7.19	$44.50	$44.80
Aug	202	255	263		7.97	6.74	$41.61	$55.60
Sep	179	200	179		6.45	6.00	$36.87	$43.44
Oct	183	196	229		6.76	6.13	$37.70	$42.14
Nov	130	168	136		5.25	4.32	$26.78	$36.03
Dec	122	113	128		4.27	4.06	$25.13	$24.48
	______	_____	_____		_____		_________	________
Totals	2117	2167	2289		6.27		$436.10	$465.69

FootNotes:

Our 2011 energy value base kW rate is 0.086130, a TVA fuel cost adjustment of 0.005940, and the bonus over the base rate of 0.12000  for a total of 0.21207 ($0.212).  We used 0.20600 for the pvWatts calculator.

Posting are from the actual monthly electrical billing and are not the start date to end date for that month .

*In January we had a bit more snow then the norm, and with a tilt of 26.5° the snow took a little longer to slide off.  Also the solar panels started up 5 days into the billing period.

Updates as the VEC bills arrive.

Crossville, TN is situated at 35.88 degrees latitude and -85.05 degrees longitude.

Solar systems installed in or near Crossville can expect to receive 4.80 solar exposure (measured in kWh per square meter per day) for each kW installed. This translates to an annual yield of 1,406.96 kWh* per installed kW, at a dollar value of $106.37/ $109.74 (Residential/Commercial) at the Tennessee's average retail electricity charge.

* Based on 95% inverter inefficiency, 89% weather impact on efficiency, 95% factor of soiling, utility, and module inefficiencies.

Oct 2011  base kW rate is 0.068360, a TVA fuel cost adjustment of 0.028870, Total = 0.09723

Jan 2011  base kW rate is 0.086130, a TVA fuel cost adjustment of 0.005940, Total = 0.09207

Our 2010  base kW rate is 0.086130, a TVA fuel cost adjustment of 0.007170, Total = 0.0933

Our 2009  base kW rate is 0.086130, a TVA fuel cost adjustment of 0.005940, Total =  0.09207

Our 2008  base kW rate is 0.073470, a TVA fuel cost adjustment of 0.002900, Total = 0.07637

Our 2007  base kW rate is 0.072380, a TVA fuel cost adjustment of 0.000011, Total = 0.072391

Our 2006  base kW rate is 0.068950, a TVA fuel cost adjustment of 0.000000, Total = 0.06895

Our 2005  base kW rate is 0.062860, a TVA fuel cost adjustment of 0.000000, Total = 0.06286