Cost of the energy plant upgrades with tax breaks $35,000
Cost of the energy plant upgrades without tax breaks $54,000
Achieved Savings after four years $23,720
Projected savings after six years (cost parity) $38,196
Projected savings after nine years (cost parity with no subsidies) $59,910
Projected savings after 30 years $155,980
Projected savings after 30 years (adjusted for rising gas and electricity cost) $445,000
This post is going to be a little techie. This will definitively describe to you how our home energy plant and electric car fueling station is far less expensive than utility supplied electricity and gasoline for a gas car with or without government subsidies. This is our actual experience as a typical family and home owner, car driver.
Julie and I constructed our home and moved in in late 2006. Our base year before the installation of Solar PV was 2007, January 1st 2008 we turned on our first 4.5KW solar pv station.
 |
| you can see how it went down in 2008! |
Our cost associated with our original 4.5kw solar PV system was $20,000, 2 years later we added a 3kw system to power the electric car for $12,000. We have also upgraded our lighting in the home to LED and CCFL for a cost of $3,000.
The total cost for our home energy upgrades was $35,000.
Without any state or federal grants or subsidies the cost would have been $54,000.
We are approaching the end of our fourth year for the system, I am rounding to four complete years. Our average energy bill for the home and the electric car has been $290 per year for the past 4 years.
This represents a four year savings in energy cost for the home of $18,520 ($19,680-$1,160)
We have been driving Mini-E #183 the past 2 years 15,000 miles a year, saving $5,200 in gasoline cost. The electricity cost is included in the above $290 per year figure, so a net savings of $5200 a year.
Our total savings to date after four years of solar PV powering the home and two years powering our Mini-E equals $23,720.
Adding two more years, 2012, 2013 at an annual savings of $7238 ($7,528 minus $290) equals $38,196
This is a six year savings in utility energy cost and gas cost of $38,196. (Parity with original energy system cost) Our ROI on home solar compared to utility provided energy is 12%, the ROI on solar electric fuel compared to gasoline is 33%
The Solar PV system will provide energy for 25 years warranted and well beyond. A simple calculation of taking that six year savings number and multiplying it by five for 30 years of energy production yields $190,980 or a net total savings of $155,980 ($190,980 minus $35,000)
That simple calculation is in today’s dollars and does not factor in the rising cost of future electricity and gasoline in the next 25 years. Remember solar is a fixed price (the sun has never raised its price) and gas and electricity will continue to rise in cost.
The real savings adjusted for increasing gas and electricity at 5% a year is nearly $450,000
 |
| first year, $7528.00 |
Cost of the energy plant upgrades with tax breaks $35,000
Cost of the energy plant upgrades without tax breaks $54,000
Achieved Savings after four years $23,720
Projected savings after six years (cost parity) $38,196
Projected savings after nine years (cost parity with no subsidies) $59,910
Projected savings after 30 years $155,980
Projected savings after 30 years (adjusted for rising gas and electricity cost) $445,000
Multiply our experience by 100 million American households and you have national energy independence, a much healthier, cleaner USA, and much wealthier families and a country.
That’s our experience and our simple road map, take a drive with us :)
Thank you Stellar Solar and BMW Mini-E for making this a reality.
Cheers
Peder
Mini-E # 183, 30,000 sunshine powered miles
Peder,
ReplyDeleteYou're better with crunching numbers than I am. Thanks for this!
Two questions/observations:
1. Did you factor in the cost of replacing your solar inverters, somewhere between years 12 and 15?
2. Your $38k gets you, or me, one Volt. Another $30k gets each of us a LEAF. Meanwhile, some of us -- including us -- can drive age-old gas cars that we've paid off decades ago, but have maintained well enough to keep maintenance costs relatively low. Basically, it seems like you're assuming a new gas car vs. new electric car comparison in your scenario.
Of course, even if you include, say $70k for 2 new EVs, and $40k for your solar/energy efficiency upgrades, you're still in good shape -- over an extended period of time.
The financial challenge for most of us is coming up with the cash for the solar and EVs, and, for us, specifically, making the leap from more than a decade without car payments in a 2-car gas "clunker" household, to a household with 1, and eventually, 2, pretty hefty monthly payments for new plug-in vehicles. http://solarchargeddriving.com/editors-blog/on-evs-a-phevs/737-efficient-gas-clunker-cheaper-than-a-new-ev.html
Hi Christof,
ReplyDeleteI may need a new inverter somewhere along the line in the next 25 years . Mine is warranted for 10 years and should last twice that long. Many new systems have the enphase converters that are warranted for 25 years thus no need to replace. In any event it would alter the cost by adding $1,500 t0 $3,000 to the 35k total energy plant cost.
There is a saying in preservation that the greenest brick is the one already in place. This addresses the embodied energy of old buildings and that the replacement calculation is missing in how green our new buildings are. Essentially we overlook the energy required to make the original building.
For cars, I would say that for all but the least efficient cars or for the highest mileage drivers, the greenest path would be to drive your existing car until a new one is needed. At that time buy the most efficient electric car you can and power it with renewable energy.
So that would be the greenest path in my opinion. My path is a new car every three to four years, with my old car going to an appreciative buyer who gets a great deal. So the car continues its life with a second driver after I am done with it.
I think the main goal is to go solar/EV when you’re ready for a new car either when the old one wears out or your ready to sell your car to a second party.
It has always been my belief that we should finance home solar PV on our buildings and not on the person who occupy the buildings. A building never moves (ok hardly ever) but we as a population move every 5 years on average. Hopefully we can get to that kind of financing soon.
Christof Feel free to repost this piece on your site if you want.
Cheers
Peder
We have considered solar many times because we like the idea of using clean energy. But, we currently average less than $40 per month of electricity for our 2100 sq ft home. So, it just hasn't made financial sense, yet, because the payback period is too long. Maybe if our next vehicle is an EV.
ReplyDeleteHi Travis, Good for you for being so efficient. For the lower tiers of energy use in SDG&E service area, the cost is about half, thus the payback is twice as long. This sounds like a similar case for you and is not cost effective until that electric car ends up in your garage:)
ReplyDeleteIt’s too bad that those who save the most can’t get solar to pencil and that those who are large users in the higher tier can get it to pencil.
It’s like we are rewarding the large users.
Our home includes a three bedroom guest house and a temp controlled 450sq ft wine cellar so we were using about 1400kwh per month. The lighting change out and some other modifications reduced it to about 800kwh and then the solar PV took care of the rest.
The best strategy is to use as little as possible, then conserve as much as possible, then when possible knock the remaining usage out with renewable generation.
You're much better at the use as little as possible than I am
Cheers
Peder
Peder:
ReplyDeleteHave you considered in your calculations that your roof might last longer as the energy absorbed by the panels is no longer transferred to the roof? I'm thinking the panels may be shielding your roof.
Just wondering.
Paul