Solar Panels - Got a quote - Do I? Or Don't I?

OK...so this afternoon I met up with Greenspring Energy to discuss the idea of putting up solar panels on the roof.  I don't have much area...about 215 sf, by my estimate...so the system would not be large.

Anyhow, so this is the system sizing they came up with:

DC size:  2 kW
 AC/DC de-rating factor:  0.93
AC rating:  1.9 kW
Type of Panel:  Sunpower E20/327 panels
(E20 = 20.1% efficiency; 327W)
# of Panels (@~61.5" x 21.2"):  6

Expected annual output:  3194 kWh (based on PVwatts with an annual average solar rating of 5.07 kWh/m2/day).
Expected annual energy value:  $329 assuming 0.103/kWh
Estimated Price:  $12,262
Subtotal minus 30% federal and 35% state tax credits:  $4,293

Estimated ROI without any increase in dook Energy rates:  13 years
 Estimated ROI with a 5%/yr increase in dook Energy rates:  10.5 years

If I do the buy-all sell-all option, the ROI ends up being the same even at the higher $0.15/kWh due to the increase dook Energy monthly "facilities charge" of $16 vs the current $9/month.  Leave it to dook energy to spoil all the fun.  So, net metering would probably be the best option.

The system would produce roughly 28% of my annual power usage:

Feb 2011 - Feb 2012:  11,470 kWh or 947 kWh/month
Solar PV as % of Household usage:  3194/11470 = 27.8%

On some months the PV would account to roughly 54% of my usage (May-June) while during January it would only be 17% of my bill.

Overall...I'm not too thrilled about their ROI.  Having an ROI of 10-13 years is too high.  Plus, I know I won't get my state tax credits until at least 2014 because the State still owes me the second half of my geothermal tax credit.

What's interesting is that when I use the solar-estimator.org site, I get a 6 yr ROI.  I notice that the solar calculator includes the Duke Energy RECs ($82/yr) and the NC Greenpower incentive ($264/yr)....both of which are not included in Greenspring Energy's calculations.  The solar estimator also only has a 3.78% dook energy annaul inflation rate vs their 5%.   The ROI goes to 7 years if I set the inflation rate to zero and then set the electricity rate to 0.0929/kWh.  While it's not 1-2 years (like my latest mortgage Refinance)...6-7 years is still a pretty good ROI.

So...what do y'all think?  My gut says I should at least wait until Fall 2013 for the tax credits...that's assuming the tax credits survive the upcoming election...to minimize the amount of time I have to wait for the tax credit return.

Also...solar technology is evolving quickly.  New multi-junction concentrated solar panels are achieving 30-40% efficiencies: http://cleantechnica.com/2011/02/17/high-efficiency-solar-cells-getting-more-efficient-cheaper/

Who knows...in a year these bad-boys could be selling thus allowing me to get even more power from my small roof area (yes...most likely at a premium price...but if the ROI is right...)

March Bill ~40% reduction in energy use

OK OK OK....yes I've been slacking.  And by slacking...yeah, it's been a LOT.  There's no good excuse for me, so sorry! 

I will say that ever since we switched to e-billing, I don't get to see the bill when it comes...so I have to bug my wife to let me know what it says.  So there...ha!  I can somewhat blame my unresponsiveness on her, right?

We got March's bill on the 6th and here's the results:

March 2011 Bill - 953 kWh over 28 days or 34.04 kWh/d
March 2011 Natural Gas Bill- 24 CCF  over 28 days or 0.857 CCF/d -->converted--> 25.9 kWh/d
Total March 2011 = 59.91 kWh/d

March 2012 Bill = 1051 kWh over 29 days = 36.24 kWh/d
% Savings = 39.51%

Comparison to March 2010 (Townhome) = 71.10 kWh/day
% Savings = 49%

So the savings keep adding up.   Since March 2010 was when we first moved into our new home, the comparison against the Townhome is over.  On average the Geothermal system has reduced my energy consumption enough (in the 2700 sf single family house) such that our energy usage is ~16% less than the former 1300 sf townhouse.  That's pretty cool.

Below is a figure showing our home energy usage from when we moved in to date  (Note:  April 2012 is just an extrapolation from the TED data to date).  You can see that our energy usage used to varied greatly with the seasons especially in the summer and winter.  Afte we did all our housework and installed the Geothermal system our energy usage is significantly lower...one average 33%...and it would be higher except that during the spring and fall (like what we're doing now), we turn off our HVAC system because the house stays comfy day and night with simply opening up the windows. 

Money wise its not as significant thanks to the latest Duke Energy increase in rates.  But it could be worse, that's for sure.  Below is how our total energy bill has compared.  I like the fact that our bills are much more reasonable (again...the April Bill is just an extrapolation of the TED data).  Since installing the geothermal, our largest bill was the January bill (aka dated in January...but actually for December). 

I guess now the question is...what do I do next? 

I certainly do plan on installing a new HW heater in series with my existing to optimize the Geothermal dessuperheater.  Eventually I'm going to add in a Nyle Geyser ASHP to the new HW heater. 

And today, I'm meeting with Green Spring Energy to talk about solar panels.  That'll be a discussion on another post...maybe tomorrow?