How do you calculate cost per watt? Is this a good deal / systeml?

[Beachnut]

I know, dumb question, but how does this work? If I take my total cost for my 3.06 kw 12 panel installed system, (includes 12 REC255PE Blk., Fronius IG Plus 3 kw inverter,), which will cost me $8078.00 and divide it by total output of 3.06kw it equals .02639--- Is that my price per watt? How do you figure it out? Sunrun took it further in saying that for $8078.00 over a 20 year period, I would be paying .097 cents per kw over the life of the contract. They figure a .5% decrease in panel production each year, for 20 years, with first year guaranteed production stated to be 4467kw. Is this a good deal? Or over priced?

Thanks for the help.. Sorry I can not do math!

[SunEagle]

I know, dumb question, but how does this work? If I take my total cost for my 3.06 kw 12 panel installed system, (includes 12 REC255PE Blk., Fronius IG Plus 3 kw inverter,), which will cost me $8078.00 and divide it by total output of 3.06kw it equals .02639--- Is that my price per watt? How do you figure it out? Sunrun took it further in saying that for $8078.00 over a 20 year period, I would be paying .097 cents per kw over the life of the contract. They figure a .5% decrease in panel production each year, for 20 years, with first year guaranteed production stated to be 4467kw. Is this a good deal? Or over priced?

Thanks for the help.. Sorry I can not do math!

The math is $8078 divided by 3060 watts = $2.639 / watt.

The panel production and cost is in "kilo watt hours" or kWh. So you would be paying $0.097/kWh and the system produces 4467 kWh in the first year.

[Beachnut]

Well with that math, I just made a killer deal as with the $700 in rebates i will be getting from my friends referral, lowers my overall cost to $7378.00 for 3060 watt system, or $2.41 per watt. I do not know if this site is at all accurate, but according to it the average CA residential system below the 10kw size is $5.65 per watt!

http://www.californiasolarstatistics.ca.gov/

I just hope there are no "surprises" around the corner when it is actually installed.

Beachnut

[megalo]

You have to make sure you are comparing the correct price - you need to be looking at the $/watt BEFORE any of the state/local/federal incentives to get a real feel. $5/watt is an average pre-incentive price in a place like Southern California, but rebates and the federal tax credit can bring it much lower.

[Beachnut]

You have to make sure you are comparing the correct price - you need to be looking at the $/watt BEFORE any of the state/local/federal incentives to get a real feel. $5/watt is an average pre-incentive price in a place like Southern California, but rebates and the federal tax credit can bring it much lower.

It would have been $12148.00 cash price, no tax incentive, no rebate price, so that would have made it $3.96 per watt. (12148 / 3060 = 3.969).

We opted for Sunrun lease due to a need for a new roof in 20 years, and living 3 blocks up from the Pacific Ocean, corrosion is a big concern! Having a production guarantee with all the fog we get around here will be great, and a warranty that the salt air corrosion will not cost us anything, was worth going lease!

[Naptown]

How far are you from the airport?
Generally that is where weather data is collected so they may have taken the fog into account.
Also read the lease carefully. Most leases allow for an adjustment in the output guarantee if the first year variance is over x%

[Beachnut]

How far are you from the airport?
Generally that is where weather data is collected so they may have taken the fog into account.
Also read the lease carefully. Most leases allow for an adjustment in the output guarantee if the first year variance is over x%

We live about 14 miles from the airport, but it is inland about 10 miles from us, over the coastal hills. Rec Solar's headquarters are there, so they are for sure aware of the typical weather patterns for this area. Thanks for the heads up to look for the potential of a variance of output in the contract. I could find nothing in there stating anything other than at construction of system, they may have to make changes, or adjust the output rating, however, any change equates to written notification, and my ability to agree to the changes,, or back out of the deal within 5 days of notification.

They way I see them getting around the "output guarantee" is I think they build in a fudge factor of under rating the output of the panels, so they know they will probably over produce. Then the entire 20 year term contract is built on each year's uber conservative calculation of output, which is cumulative, year after year. With a .05% decrease in production each year due to panel degradation. (2 years = a 1% reduction in output, but the cost per kw goes up inversely for reimbursement from the guaranteed output. It goes up .05% each year, too, starting with .101 cents per kw, ending in .175 cents pkw at 20ith year). So in my question to Sunrun, If i overproduce the first two years, will that total amount of kw's for the first two years of contract be able to make up, or offset for a short fall of output on say the 3rd year of production, if we had a real bad wet winter, or fogy summer? They said, yes, it IS ALL A CUMLITIVE output production guarantee. So the contract has a page with 20 years on a chart, showing exactly how much kw production the system is guaranteed to produce, with first year stated to be 4467 kw, but on the chart it shows the 1st year as N/A, 2nd year as 8742kw, 3rd 13080kw, 4th year 17,397kw, down to the 20ith year at 83469kw. So more than likely, good "over production" years, will wipe out the bad ones... Good news though is the contract "term" is for production of 83,469kw, and 20 years, so if i reach the 83,469 kw in year 18.5, the contract warranty of equipment continues, till the end of term, or at the end of the 20ith year, and no charges for any "over production" can occur.

I am happy for now, and hope to stay that way!

[bcroe]

first year stated to be 4467 kw

I'll bet, it really says 4467 kw HOURS. Bruce Roe

[SunEagle]

I'll bet, it really says 4467 kw HOURS. Bruce Roe

Thats what I said in post #2.

[Beachnut]

Yes, kwh. laziness... That does not change the numbers though, does it?

[SunEagle]

Yes, kwh. laziness... That does not change the numbers though, does it?

It does not change the number but it clarifies the design by using the correct units.

[bcroe]

Units

It does not change the number but it clarifies the design by using the correct units.

When the correct units are used, I get confidence the author
understands what he is saying, and calculations make sense.

No units doesn't bother me a lot. But wrong units makes
me think "this doesn't make sense". Then I have to go on a
mind reading exercise to try and figure out what is really meant.