Shade Will Degrade

Here's something that I've been meaning to check out. Although our main roof is fully loaded with panels, there is still some open roof space on the garage roof:

For a few weeks I've been thinking "When everything settles down I'm going to see about adding a few more panels here so we can generate even more power! "

The groSolar people told us that they didn't want to put panels in that space because late in the day (especially during winter) it will be shadowed by the higher main roof. I took that to mean that we'd get a lot less power out of panels that received shade during part of the day but I didn't fully understand. I thought it was analogous to putting buckets out in the yard to collect rain water: if some of the buckets were blocked for part of the day, well sure, they wouldn't end up with as much water as the fully exposed ones, but at least they'd contribute some water.





^ =





That's a horrible analogy, as it turns out. I've researched this (I surfed the internet) and learned that the shaded panels would actually degrade effectiveness of the entire system. Panels and buckets don't operate the same way.

EcoDepotUSA says:

http://www.ecodepotusa.com/Education/SolarEnergy/Modules/Modules.htm

"Once a solar cell or a portion of a cell is shaded it becomes a load and draws power instead of producing it. Watch the amp meter of your system when a hand is passed over a module and you will see a substantial drop in output."

WholeSolar says this:

http://www.wholesalesolar.com/pdf.folder/Download%20folder/solar-panels.pdf

"If even one full cell is hard shaded, the voltage of that module will drop to half of its unshaded value in order to protect itself. If enough cells are hard shaded, the module will not convert any energy and will, in fact, become a drain of energy on the entire system... Because all cells are connected in a series string, the weakest cell will bring the others down to its reduced power level."

It turns out that there are some types of panels out there that are "shadow protected" but these are more expensive and don't (yet) have the track record of reliability that the basic poly-crystalline panels have.

We're better off with just the panels we already have and no more. I'm sure the installers explained this but I didn't catch on. Just one more reason why at least in our case it's a good thing we left this job to the professionals.

Sun, Dough

Well, on the heels of the worst day yet is one of the best days yet. We generated 44.9 kwh, met all of our own needs, and exported (sold) 6 kwh out onto the grid.



I think these last two days are a microcosm of what solar power can and can't do. It can't be relied on as a primary source of power but at the same time, it's a shame on days like this to waste all that energy that drips down the sides of our houses and disappears.

Worst Day Yet

Today, yet another cloudy and rainy one, was our worst day of energy production since the system started operating two weeks ago. A mere 11 KWH!

I love this solar power thing but I'm certainly glad we're not relying solely on it. No matter how big or well-built a system is, it can't collect power it can't get to.

MUCH More Detail on SREC Process

Here's some extremely helpful information I received in an email from B.B. (CEO of SRECTrade).


http://www.srectrade.com/

We've already decided that we will be selling our SRECs through this company because they are extremely attentive (and we're not even customers yet) and they sell the SRECS at the highest price I've seen and with no commission paid by the seller.

Here's what B.B. said. He really fills in the gaps for me and I finally feel like I understand how it works.

The three things I'd like to address are Registration, Meter Readings and Timing...

Registration:

As you've figured out, you must have your system certified by the state before you can begin producing SRECs. When you get a state certification number, you can then either register directly with GATS or through SRECTrade if you choose to utilize our hands-free SREC selling service called EasyBid.

Meter Readings:

Once you are registered, there are two ways to get credited for the solar energy you produce. For systems under 10kW, you can elect to utilize estimates that are determined by the state and based on a number of factors including the size of your system, the panel ratings and your location. Most solar generators under 10kW elect this option because it eliminates the need to input meter readings. However, if you feel your meter can outperform the estimates, you can opt to input meter readings instead. For systems that are 10kW and above, meter readings are required. These readings are typically taken on or around the last day of each month by the solar owner and must be inputted in GATS before the last business day of the following month. It is actually based on an honor system, however, since GATS knows the size of your generator, it has an idea for what is a reasonable output. If you input numbers that are too high, the readings will be flagged by the system. For our EasyBid clients, we collect their meter readings on a monthly basis using a simple online form.

Timing:

Since readings are not credited until the last business day of the following month, your SRECs for month 1, are not ready until the end of month 2 and so on. Our monthly auctions occur the first Friday of each month. So any energy you generate in June will be available on July 31st and can be sold in the August 7th auction.

I hope that helps and look forward to being more helpful in the future!

Kind regards,
[B.B.]
CEO
SRECTrade
877-466-4606
www.srectrade.com

It Was a Good Day for Solar Power

Since we had a good day by the numbers I decided to post updated statistics. I'm probably going to stop tracking it by the day in the near future because the results are predictable. If it's sunny, we generate a lot of power. If we don't run the air conditioner we don't use a lot of power and have a lot of extra to sell.



All numbers are KWH (Kilowatthours)
* A negative number indicates that extra power was generated and sent onto the power grid.

When summer is over and we don't use the air conditioner or the pool filter (the two biggest energy pigs) I'm 99% sure we'll have surplus every day that there isn't a thick cloud cover. But that's just a guess.

Ran Into the BP Solar / Home Depot Guy

I ran into A.S. of BPSolar over at Home Depot on Saturday so I had to break the news that we'd done a system with somebody else. He was cool about it and gave me a couple business cards to hand out just in case anybody nearby was interested in a system and wanted a local guy to run the job. Now I don't have to sneak in and out through the garden center anymore...

Electricians Lay Claim to Solar Market

http://www.philly.com/philly/business/homepage/20090611_Electrical_contractors_ready_to_embrace_solar_market.html

Interesting article in the Philadelphia Inquirer this morning. Now that Pennsylvania is gearing up for a lot more solar installations, the International Brotherhood of Electrical Workers (the electricians union) is making it's feelings known about who will be qualified to install them.

They're concerned about a provision in the new legislation that requires contractors to be certified:

"Pennsylvania's Department of Energy, for example, wants solar contractors used in the Sunshine rebate program to be certified by the North American Board of Certified Energy Practitioners."

In other words, the state is going to be investing a lot of money in this program and they don't want the work done by unqualified contractors, electricians or not.

I like what the union is doing. At the same time that they are staking their claim they are also incorporating new elements into their apprentice training so that electricians will have more working knowledge of solar technology installation:

"It's facilities include a solar structure that apprentices use to practice installing solar panels and connecting them to the structure's electrical system."

The union wants to avoid a situation where smaller contractors will need to go to the extra trouble and expense of bringing on a "journeyman trained in solar" in order to bid for jobs. Instead, they want the additional solar training done by apprentices to qualify them for solar certification.

I think both sides are right. Electricians can do this work but they should have extra training that the state is talking about. Although installing the components may not be much different than what electricians ordinarily do, the design of a system is a skill that requires knowledge and training -- at least that's how it looked to me when mine was going in.

It shouldn't take long to work this out.

SRECS and State Inspection

As already noted, I've been confused about how the SREC program will start "kicking in." I finally broke down today and called the SREC people at New Jersey Clean Energy Program (NJCEP) and I'm glad I did. I understand the process a little better now.

N. was very knowledgable and helpful. It was weird in a way -- I pretty much just said "This is Dave" and all of a sudden she knew everything about me, and even mentioned that my SREC account had just been set to "Inactive." I guess there aren't as many residential solar installations in the state as I thought.

Anyway, she cleared up the mystery about why I can't get anything to "happen." It turns out that although we have been generating power for a week, none of the 200+ kilowatthours we've cranked out will count towards any SRECs. Understandably, they don't award SRECS for power generated by systems that haven't been inspected by state officials.

Now I realize why groSolar is asking for copies of various inspection documents. I think the process is this: groSolar turns in paperwork to New Jersey, gets the rebate money, and then calls to arrange the state inspection. Then, after the system passes inspection, the SREC pump will be primed, so to speak. That's when everything will start to happen.

It's a relief to understand the process better, at least.

The Numbers So Far

I'll need to learn a less-klunky way of importing this spreadsheet. But this will do for now. Here's what the system has done so far.

Since we ran the air conditioner today (6/8) we used more power than we produced. That's a drag, but we know from yesterday that anytime we want to sweat it out we can bank some KWH.

All numbers are KWH (Kilowatthours)
* A negative number indicates that extra power was generated and sent onto the power grid.

Still Trying to Nail Down the SREC Process

The New Jersey Clean Energy Program website tells me everything I need to know about SRECS (solar renewable energy credits) except how to have them deposited in our SREC account (for which we registered on April 27). After hunting around I finally sent an email to somebody there. Hopefully they'll tell me where to start. I might even recommend that they add a FAQ about it and I'd be glad to write it.

We've generated 160 KWH in four days. It's not going to be much longer before we hit 1000 and earn that first golden ticket. I think it's odd that nobody at any point ever asked me what my SREC account number is. The NJCEP website is somewhat lacking when it comes to explaining exactly how to make the system work. I don't even understand how the SREC Commissioner even knows when we've earned one because they're not tied into our inverters (in any way I know of) and the electric meter couldn't tell them that. I see the phrase "upload your readings" here and there on the website but it can't be the honor system, could it?

I set up a spreadsheet summarizing the energy produced, imported and exported. It'll be in another post.

Data From First Full-tracked Day

For the first month we're going to track everything on a daily basis, from 7:00 p.m. to 7:00 p.m. I'll set up a spreadsheet and maybe figure out how to display it here.

The first such period just ended and here's what happened. (Please note that this 24 hour period that just ended was IDEAL -- 100% sunny, long day, not hot enough for A.C.).

The inverters tell us we produced a total of 55.5 KWHours of energy.

The meter read 15,577 KWH on Saturday evening and 15,554 KWH just now. So during that period we supplied enough for our own needs and dumped 23 KWH out onto the power grid for others to buy.

The solar power inverters and the electric meter are both dealing in KWhours, but I'm not bothering to do any math that mixes data from the two sources. I can't imagine a KWHour from one is similar enough to a KWHour from the other to make any such calculations worthwhile.

Learning to Monitor What the System Does

I've been walking to the side of the house and checking the PSE&G electric meter all day. When the sun is out it spins backwards, often pretty fast, as evident in this video:

That, of course, means we're generating excess power which is going out through the meter and onto the power grid. We'll get credit for those kilowatt hours (see the description of "net metering" above.)

It was interesting to watch what happened when a cloud passed in front of the sun. Earlier in the afternoon the meter continued to spin backwards but at a much slower rate. Later, presumably after the sun was approaching the horizon, the meter actually stopped altogether (meaning the system was producing exactly as much as the house required) or even reversed direction until the cloud was gone.

Also, we noticed that running the vacuum made a significant difference in the speed of the meter spin. This is probably going to make me think more about the power that various electrical equipment uses, solar issues aside. Hopefully this won't turn me into too much of a miser. I already caught myself before asking my daughter "Do you really need to do that?" when she took her boom box out back to listen to Miley Cyrus with her friends.

I was going to report today's meter readings but now as I look at them I realize I may not have read them all correctly. It's difficult to read those numbers, which are presented in a series of 'dials' rather than a simple readout.

We think we've figured out out how to read the inverters to determine how much energy the panels are throwing. We're going to record those numbers, as well as a careful meter reading, every day at 7:00 p.m. (and report the data here, of course). Maybe after a few days we'll start to understand what the numbers all mean and what the effect of running our system really is.

Energy Exporter

I just checked the electric meter. It's turning clockwise. The system is generating more power than the house is using so the unused energy is going out onto the grid. It works!

Pretty good for a cloudy, rainy day...

Online and Generating Power

We started work on this project over two years ago. Today, as of about 3:00 p.m., the system is operational and cranking out kilowatts.

We haven't yet learned how to interpret what the inverters (yeah, the PVMates) tell us. At some point we need to learn how to monitor the amount of "juice we produce."

By the way, Happy 21st Anniversary LA!

Building the System -- Day 9

The electricians are installing the two inverters, an extra fuse box and a safety cutoff. Instead of running cables up down and all around the wall, R. and D. took the time to cut the sheetrock and hide the cables inside the wall.

They even used a level to make sure these were mounted just right.

Closer look.

Rob Erlichman of Sunlight Electric

Here's an brief but interesting August 2008 interview with Rob Erlichman in the Cornell University Chronicle Online. Erlichman is the CEO of Sunlight Electric, a San Francisco-based solar panel producer.

http://www.news.cornell.edu/stories/Aug08/alum.erlichman.aj.html

"Contrary to what one can read in the popular press, we're already at a place where the lines cross between the cost of solar power and the cost of using conventional generated electricity. The reason I say that, although you don't read about it, is because most people don't take into account all of the costs of their use of electricity.

For example, if you're a utility customer and you pay your electric bill for 20 years, what do you have at the end of those 20 years? You have nothing. Your money has gone up in smoke. Wouldn't the more attractive alternative be to invest in your own power plant, and at the end of that 20 years, you own something that generates power?"

Building the System: Day 8

I feel like today was the day that reality hit us in the face. After admiring the beautiful array of panels, we're now looking at a lot of cables, wiring, conduit and junction boxes. R. and D., the electricians, are doing their best to make it look as unintrusive as possible. We may have to plant a new bush and paint some conduit when they're finished but it'll be okay.


R. and D. connecting our system to our meter and to the power grid.


These are the inverters, which will be mounted on the garage wall just above where they're sitting in the picture. Theinverters convert the power generated by the panels from DC (direct current) to AC (alternating current) before passing it through to the electrical panel / electric meter (and out onto the power grid). Energy from half the panels will be routed through each of these.

Building the System: Day 7

After a long day of installing rails on Saturday, E.F. and M. are planning on getting all 36 panels installed on the main roof today.

These guys are the greatest. After installing the first row they didn't like how it was sitting. If you look close (hard to tell from this angle) the panels and the lower roof line were converging from left to right because of an imperfection in the roof. They also noticed a dip in the center of the roof that was throwing the alignment off. Instead of throwing up their hands and saying "it's not our fault the roof is off," they removed the panels and headed off for lunch at McDonalds to plan some adjustments.

The adjustments have probably added three hours to their work day but it looks awesome now. E.F. is a perfectionist: "That first row has to be exactly right."

It's mid-afternoon here and they're working on the last row of panels.

This picture (below) was taken from the top of the ladder. That's M. against the clouds. It's hard to tell where the panels stop and the sky starts.

All 48 panels are installed. I don't think they could have done a neater job. By coincidence, I just painted the trim purple last week and it matches the panels almost as if it had been planned that way.

The electrician will be here tommorow to install inverters, etc. and put the system online.