My case for going solar

So as I alluded to in my last post, I've decided on installing some solar panels on my roof.

Spoiler alert!

(The panels were just installed today...but I've procrastinated on posted my internal justification.  The pics of the install will be in my next post.)

OK, so I've done a large variety of energy efficiency projects on my house including (in no particular order):

1) Geothermal HVAC w/desuperheater

2) GE Geospring ASHP Water Heater 

3) Lots of air sealing

4) Extra insulation in the attic

5) XPS insulation and sealing on the "bonus room" attic knee walls

6) Radiant barrier in the attic

7) Ecobee thermostat to optimize my HVAC operation

8) TED 5000 to monitor my energy usage

9) Installed all CFL and LED light bulbs

10) Got a HERs rating.  And then updated it after working on the suggestions.

11) Etc

So yeah, I've done a lot on the ole' house.  And the results have shown a substantial reduction in my home energy usage:  45.6% reduction since 2010.

After all those reductions, I finally got to a point that all the most cost effective upgrades/fixes were completed.   So what's next?  Well...generating my own power.  

I had gotten a quote in the past (here) which indicated that I could put up roughly 1.962 kW on the small area of south facing roof I have.  Here's the numbers of how it would pan out (from GreenSpring Energy):

1)  Solar panels (installation, permits, etc):  $10,791

2)  TIGO Maximizing system (to reduce issues with shading): $785

3)  Tax:  $503

4)  SubTotal:  $12,079

5)  Federal Tax Credit:  - $3,624

6)  State Tax Credit:  - $4,228

7)  Net Cost to Me:  $4,228

The system should produce roughly 2,577 kWh/year AFTER correcting for my shading issues.  That's being pretty conservative given that the SolarEye makes the calculation with leaves on the trees...when truthfully during the winter, I'll get more production than it estimates.  And the TIGO should help give it a boost (10-20%) by allowing for each panel to produce its own power rather than have shade on one panel affect the entire array.  Regardless, let's stick with the conservative estimate.  That ~2,600 kWh is worth roughly $296.  So the simple ROI is $4,228/296 = 14.3 years.  Using the DOE SAM tool (System Advisor Model) gives me 13.3 years as it factors in a lot more.  

Then there's the how much my home value will theoretical increase.  I realize that's "funny money" unless I actually sell the house...but factoring that in (20x the annual savings is what's considered the value) then that's ~$6000, so that would say the system has already paid for itself.  Again...funny money.

So another thing I thought about was "what if I got an electric car?"  It's true that the gasoline equivalent value of electricity is greater than the actual electricity equivalent.  So how would that work?  

Well...from Aug 2012 to Aug 2013, I spent $1,186 on gas for the ole' Prius.  So that could be some good savings.  Let's assume we compare my Prius to a Nissan Leaf:

Annual mileage = 12,000/yr

Prius = 48 mpg

Leaf = 34 kWh/100 miles

Gas Cost = $3.50/gallon

Electricity Cost = $0.115/kWh

Prius Annual Cost = $875 ($0.073/mile)

Leaf Annual Cost = $469 ($0.039/mile)

Savings = $406/year!

So getting an electric car itself is pretty cost effective...and I haven't even factored in the maintenance advantage (no oil changes for the Leaf).  So what happens with the addition of solar panels?  Well, for accounting purposes, let's say say that the additional driving energy for the Leaf is offset by the solar panel production.  Then we get...

Leaf Annual Electricity Consumed = 4,080 kWh

Solar Generation = 2,557 kWh

Remaining Power to be Purchased = 1,503 kWh

Revised Leaf Annual Cost = $173 ($0.0144/mile)

Revised Annual Savings = $702/year.

So I nearly triple the savings.  That takes the ROI to:  $4,228/702 = 6 years.

Wow...so I can cut the ROI in half if I take advantage of the solar + an electric car.  

Yes, I'm sure some nay-sayers will ask about financing the car.  However, I will note that I'm in the market for a car anyway (Jan 2014).  And after federal tax credits the Leaf (~$24k) is already the same price point as what I bought my Prius for ($24k).  So I'm assuming that nets-out.  Could I stick with the Prius?  Sure...but it's going on 108 kmiles right now which is creeping into that unknown maintenance.

What about range anxiety?  Yup, I'd certainly have to think about when/where I'd go and the charge I have.  But then again, my trips have gotten a lot smaller now that I kiddos have arrived.  For those work trips, I can just rent a car in lieu of driving my car.  Or I could just drive my wife's Mazda5.  The long family trips will be in the Mazda5...and that's why be bought it because we needed to haul the two of us, the twins, luggage, and (sometimes) the dog.

So yeah... I think this will work out.   And just think...if I can get my work to let me charge then the savings add up even more.  Or maybe I'll have to find a way to use those 5 charging stations at the light rail station nearby.