Solar Panels. 3 months in…only 35 years or so to go :)

4 11 2010

(mmmm, pretty blue monocrystalline solar panels.)

Ok, I wanted to talk a bit about the solar panels we had installed this July (actually end of July by the time PNM –the local electric company– came out and turned on the juice). Mostly because these panels have influenced many of my thoughts and plans about some future purchases (electric cars and electric bikes). Or maybe my plans of future electric cars influenced my decision to get solar panels in the first place. Gah, confusing in a “chicken or the egg” kinda way …and not overly important anyways 🙂 .

(Looking down and southwest. Dang, forgot to close the shed door. And Hi Gracie 🙂 )

Yes it is over three months since install began in early July. Yes I yammer on endless to family and friends about said solar panels. Going on and on about how every south facing home in Albuquerque should have panels. Commenting endlessly that at least 10 years ago a “forward-looking” Albuquerque should have mandated all new construction have some solar panels. Imagine just how many homes would have solar now if Albuquerque had done that. And imagine the cost of installing a solar system coming down even more than they have.

Currently the price has come down from only “the rich and the fanatics” can afford it, to the middle class can afford it. Hopefully soon it will be affordable for all income brackets to add clean solar electricity.

As for my “yammering”, going on endlessly until friends, neighbors and even random pets all avoid eye contact with me when I walk by. Though the random pet eye avoidance is a bit more perplexing…their tiny brains should not have the ability to remember just how boring and repetitive I am.

And yes I have promised some updating of info about the panels.

But I wanted to have a bit more info before posting…hence the delay…NOT because I am lazy. Not at all.

Back on point….Some background:

Albuquerque has 310 sunny days each year. I happen to live in Albuquerque.

My roof faces exactly 180 degrees due south. Due south is the perfect direction for solar panels to face.

Those two facts alone made it a no-brainer to get solar panels. Well that and the trifecta of:

a) federal and state tax breaks combining to decrease the price by 40%. I won’t see that money till my tax returns, so you pay the full price up front. But still a good deal, and the refund this year should be fairly large.

b) the fact that  PNM would sign a 12 year agreement to buy all the energy the solar panels produce, but planned to phase out the incentive by the end of summer**.  So jumping on that was important to make the system even more cost efficient.

c) and the fact that panels and installation are about 30% cheaper than 2 years ago. Our installation total was right at 19K. 2 years ago it would have been over 27K. Hopefully that trend continues and the prices keep dropping and dropping.

So, while not cheap by any means (that’s the price of a Mini Cooper…and the panels aren’t nearly as fun to drive), it is a sound investment that will pay for itself  in about 8 years. After those 8 years the panels will continue to produce power for maybe 30 more years. In other words, these panels should be rockin’ after my heart stops tockin’. Or maybe in some form of poetic justice we, both the panels and myself,  will both stop “producing” at the same exact time. The panel will cease flowing electrons and I will cease flowing, well other less savory emissions.

But enough of that.

The Set Up:

14 panels placed portrait in two rows on my roof.

Held in place with Unirack solar mounts. Only 4 inches off the roof and very low profile. I’ve had guest over swimming in the pool who didn’t even notice the panels till I started my yammering about them.

Connected to the grid with 14 Enphase micro-inverters that convert the DC solar electricity to AC electricity that the grid and my household circuits can accept.

(see my daily production any time from the internet. Gawd I check this site way way WAY too many times each day. Every time I see “McCullough7000” I feel like a robot from the future.)

That AC electricity flows to a REC meter that keeps track of the energy produced. This is so PNM knows how much to pay us**

Then it flows to our standard electric meter. That is the fun part: seeing our meter spin backwards and seeing our bill decrease each day.

Here is a screen capture from the Enphase/Enlighten site of the highest output I’ve seen.

(each panel is independent and that helps with our shading concerns…plus its cool to see exactly what each panel is doing.)

So it seems the panels peak possible output is around 2.8 kW…But we will see if any days in June or July can best that. This was around the 20th of August. Hopefully many days from April thru August will have the panels running at peak output.

The panels are Sharp 235w panels.

(Sharp NU-U235F3 to be exact. The PDF about the panels is here:

But panels are updated very very often.The panels made this fall are likely to be a different number with slightly different specs than panels made this summer.)

I was going to install Schott Solar panels as they are locally made here in Albuquerque and cheaper. But they don’t have the all black panels and I admit to being vain. I was given an address to check out some Schott panels installed near campus. Rode my bicycle over to see them a couple of months before  having my panels installed. Decided then and there that the silver panels are fine for business rooftops or for a solar “farm” out in a distant field…but not for my rooftop.  I just didn’t like the silver edged panels nearly as much, and since I will be seeing these panels on my roof for the next 30 years…well…I went all black. They blend in more.

In comments from an earlier blog post I had a question about the solar panels from Protomech:

“I’ve done a bit of research into solar panels, payoff still seems too far.. would be interested to know what your collection rates are vs the NREL solar maps, how you dealt with insurance, and thoughts on the installation process.”

Ok. Will answer last question first. Installation: Was really quite effortless. Took a day and a half to get the panels up and installed. Then it was mostly a waiting game. The system needed to be inspected by the city. That took a week. The city wanted a small change. That was done the next day and reinspected the day after that. The system was green tagged, which means good to go, but the power on switch is then padlocked until PNM comes out to unlock it and flip the switch. That took 2 weeks. Gah…two weeks of the panels being hit by solar energy, but just doing nothing with it. Was sad, but it is what it is.

Finally PNM came out on a rare raining day and flipped the switch in a slight drizzle. Still enough energy produced to weakly spin the meter backwards.

Collection rates. Only have 3 months of data, but seems to give me some insight of how my collection rates are going and should play out.

One: I have a fair amount of shading. This is one of the reasons I only had 14 panels installed (that and cost). I would have loved to cover the whole roof with panels and really get a ton of production from my roof, but adding more panels will wait till the large, 50 year old Mulberry in the back southwest corner of the yard dies.

If you go to the NREL site and work up my system you get this info:

I was told by my installer these same numbers, that basically my system should produce around 5500kWh a year in energy here in Albuquerque. But they cautioned me that because of shading it will actually be around 5000, maybe a bit more.

From my numbers these last three months it does look like our production will be close to that. It seems my panels make quite a bit more than the numbers stated by NREL in the summer when there is no shading at all (all my tree shading is to the south…when the Sun is going straight over head in May through Aug I have no shade issues at all) and a good bit less in the Fall through Spring when the Sun is lower on the horizon.

So May through August I will likely produce about 400 more kWh–I made 100kWh more this August alone.  April and Sept my numbers should be neutral-I made 30kWh more this September.  And Oct through March the panels will produce below expected-I made 100kwH less this Oct due to shading. So, it seems, my output should be around 5300 kWh instead of 5500. No reason to chop down the tree for that small decrease in production.

When we put in our pool last summer we did take down one tree…but we still have our large tree to the southeast and our neighbor has a very large tree to the southwest. None are a problem in the summer, but the other seasons we see shading (I wonder if it will be less when the leaves fall. That seems like it would, but solar panels are quite sensitive to any shading and even leafless tree branch shading will decrease production).

Tree to East. Delays morning production.

Tree to the West that cuts short late afternoon/early evening production.

The pine trees out front do not cause any shading.

(But you see the shading from the South tree quite easily.)


Alright, that is enough about my panels…now just bit about the cost efficiency.

**How PNM pricing works is confusing…so let me explain a bit in detail……We signed a 12 year agreement with the local electric company, PNM. For the next 12 years PNM buys all the electricity we produce. So if we produce 5300 kWh a year, PNM buy all 5300 kWh, even though we use it. It is as if we are a mini utility company and sell our production to them.

So panels make electricity. Electricity flows to a REC meter that records every kilowatt they produce. PNM pays us for those kilowatts. Then electricity flows to our regular electric usage meter. During the day that meter flows backwards (this saves us even more money) and electricity goes back to the grid helping PNM provide clean electric power to the neighborhood. A win win.

So our monthly electric bill is a negative number–On average our bill was about 80 bucks. But now PNM pays us about 40 bucks a month instead. So overall saving of about $120 a month…or about $1300 or so a year.

So, system costs around 18 to 19K, minus about 8k in federal and state rebates. So final system costs are just under 11k. Now we save $1300 a year in never paying an electric bill and instead collecting on average 40 bucks a month from PNM. So in just over 8 years the system pays for itself and any future savings is profit.

So from year 8 to 12 we will make about 5k in profit. Not bad. And from year 13 to whenever the system needs updating (30 odd years from now) we will still be turning the meter backwards and saving money, though not as much as PNM is unlikely to continue paying for all the energy we make.

So basically it pays for itself, makes a bit of money over that and also lets us have clean energy coming into our house from the roof, and lets us share some of that clean energy with our neighbors. YEA.

Complicated I know, but also kinda simple. The panels have no moving parts, nothing to oil or maintain. No filters to clean. Nothing. They just lay there and work when the sun shines on them. Simple.

As for installation….Had the company do it. Took a day and a half. No biggie. They did sit on the roof for about 3 weeks doing nothing until the local power company came out and flipped a switch…so that was a minor frustration. But all in all it was a smooth and painless procedure.

As for insurance. They just asked if we wanted to increase our insurance, but we already insure the house for over the replacement costs. So no real need to add more. The insurance company didn’t think the panels made the house more dangerous, so our rate didn’t change.

See I told you I was boring when I talk about my solar panels….

Next Electric Cars and Electric “Powercycles”…I imagine that will be much more interesting.





3 responses

5 11 2010

Wow Gavin, Way great info and photos. Unfortunately I could only get about half way thru cause I need to get to the gym and then taking a group up to the Allen Houser Compound near Santa Fe. Hopefully get to the rest of this tonight.

9 07 2012

310 sundays in a year? thats insane. over here in germany those numbers are around ~100 days, depending on the location, and we’ve gotten that far: (e.g. yesterday: about 50% renewables through the day).

our photovoltaik-energy-generation-cost ist about 13.7 EUR-ct / kwh, so your 8.7 USD-ct / kwh are about / less than our average price on the energy market.

Energy price @ home is still about 25 EUR-ct / kwh, our electricity-companies rob us real good 😐

Im thinking about going full in, buying a lot of batteries and be completely autark – it could be cheaper in less than 3 years.

9 07 2012

Yeah, I love our panels, but I’m hella jealous of Germany. We could and should be doing that here…We have so much sun, and still use sooooo much oil and gas and coal.

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