Tigo no go

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I plan to post a follow up to my solar PV post with a few more things you probably didn’t know about solar but that’s not this post. Instead, I want to rant if I may on one particular piece of my solar setup that annoys me.

It should seem pretty obvious that shade is the enemy of a Solar PV installation. That’s fine, you might say, but what if my panels are only partially shaded? Well, in an array of panels a few shaded cells can muck up the power supply far more drastically than it would at first seem. This paper sums up what happens:

In a series connected solar photovoltaic module, performance is adversely affected if all its cells are not equally illuminated. All the cells in a series array are forced to carry the same current even though a few cells under shade produce less photon current. The shaded cells may get reverse biased, acting as loads, draining power from fully illuminated cells. If the system is not appropriately protected, hot-spot problem can arise and in several cases, the system can be irreversibly damaged.

Irreversible damage? To my expensive solar installation? Yikes! What can we do?
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Six things you might not know about solar panels

Solar PV deck

Solar PV deck


Recently a neighbor asked about our home’s solar photovoltaic (PV) system. Since he’s not the first I thought I might write about our system, specifically a few things people might not know about PV systems. This reflects my experience and may differ from others. As always, your mileage may vary.

Solar PV is not rocket science. Solar PV literally once was rocket science, as one of its first practical applications was to power orbiting satellites. Apollo astronauts even left solar panels on the moon. Fortunately, a PV system no longer requires a NASA-sized budget nor an engineering degree. While the jargon may be confusing at first, you’ll quickly learn what’s what and things will start to make sense.
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Renewable energy is clean, cheap and here – what’s stopping us?

Great article on the solar revolution.

Solar will be the cheapest form of power in many countries within just a few years. In places such as California and Italy it has already reached so-called “grid parity.” Onshore wind, on a piece of land not constrained by years of planning delays, is already the cheapest form of energy on earth. These are not wild claims – those are figures from General Electric, Citibank and others.

Newly built solar plants are already considerably cheaper than new nuclear plants per kilowatt hour of electricity produced and we are almost at the stage where we don’t need a guaranteed price known as a feed-in tariff because solar energy will compete head on with conventional energy.

via Renewable energy is clean, cheap and here – what's stopping us? | Ashley Seager | Comment is free | guardian.co.uk.

Fields of electrons

White Post Road solar farm in Bath, NC

White Post Road solar farm in Bath, NC


I found a page about this solar farm in Bath, NC yesterday. It quietly generates 15.5 MW over 85 acres, selling the power to Duke Energy.

Earlier this year, Duke Energy shelved plans to build another reactor at the nearby Shearon Harris Nuclear Plant. The plant property encompasses over 20,000 acres. If Duke were to build a 20,000 acre solar farm on the Shearon Harris property it could generate over 3,000 MW of safe, clean electricity: more than that produced by 3 nuclear reactors. The cost would be about $3 billion, which is 1/3rd of what just one reactor would cost to build.

While nuclear plant construction costs continue to skyrocket solar PV costs continue to plummet. Which technology does it make sense to invest in?

Inverter clue?

Over the past few days we’ve had too much gorgeous sunshine for me to let our power station go idle. I had the inverter on all day Saturday and banked about 18 kWh for the day. Sunday morning had me wishing I had shut down the inverter the night before, though, as its antics woke me up.

I was snoozing in bed around 6:52 AM when I awoke to a loud popping sound from my clock radio. Since this was about the same time the other inverter issues took place, I suspected the inverter had gone offline again.

Before I went outside, I checked the eGauge power graph. It showed power was being generated but, more than that, it showed a very strange anomaly at the time I heard my clock radio pop. All power to the house had been interrupted at that moment: it seems the inverter had malfunctioned yet again.

I let it run the full day yesterday as it seems fine once the sun gets going. I did, however, shut it down overnight last night, and noted no power anomalies.

I’m thinking now that the problem is with the inverter, specifically when the panels produce enough energy for the first time of the day to cause the inverter to resync with the grid. I wondered if the inverter isn’t syncing properly, sending a power surge through the wiring instead. At the time of Sunday’s blip, the panels were up to a mere 100 watts, which is basically nothing.

I’ll leave the inverter shut off until the Southern Energy techs can give it a good going-over. My electronics are at stake here, you know.

Power failure

Solar PV deck

Solar PV deck


Tomorrow will be two weeks since our solar panels were installed by Southern Energy Management. When we first got them, I jokingly complained on Facebook how the panels only lasted 12 hours and then quit working. Some of my friends caught on to my joke (it was nighttime) right away while others scratched their heads.

Unfortunately, it’s no longer a joke. Twice over the last week the inverter has failed with a ground fault error, indicating a wiring problem in the panel side of system. What’s more, last week the main breaker tripped, indicating a problem with the grid side of the system. A tech came out on Tuesday and wrapped tape around a nick in the AC cable’s insulation which fixed the breaker issue but the panels are still down until the ground fault gets fixed.

For anyone considering getting a solar PV system, the best advice I can provide you is to be patient. It is a long wait until anything even gets put on your roof. Then the install itself can take a couple of weeks, depending on the difficulty, weather, crew availability, and other potential setbacks. Finally, even if all the parts are supposedly in place, there still might be work to do in ironing out the kinks, as we have found out this week.

Inverter ground fault

Inverter no workie

On several days I made arrangements to work from home during this process, taking time away from the office that would have been very beneficial to me in my new position. The same work could have been accomplished in half the time had the communication and coordination been better. I don’t think my time was considered as valuable as it probably should have been.

Communication was also a problem. We got handed off to various crews who evidently don’t talk to each other. The first technician who came out to scope out the project needs didn’t tell the next technician (who ran conduit) what the plans were. The conduit guy had to start from scratch. He did a very good job, mind you, with what he had to work with but ran the conduit to the wrong place relative to the future panels. The team installing the panels replaced half the conduit and moved it further up the roof.

We were handed off to a project coordinator, which would ordinarily be a wise move and cut down on confusion but in our case was of little help. Day one of the panel install I was assured the team would only be there for “a few hours and gone by lunch.” Um, no. It took multiple days to complete the roof deck installation.

Once the gear was in place, the project coordinator scheduled an electrical inspection, which (understandably, this time) required me to be home. We needed two inspections, however: electrical and building, and a city building inspector showed up a few hours later thinking he would be doing the final on the project. By that time the SEM tech was long gone, and the inspection had to be rescheduled for this morning. The inspector required the consulting engineer to seal his building plans before the inspector would sign off on the project. I was told by SEM this was highly unusual.

Then the ground fault issue hit us last week. I let our project coordinator know about it and asked for a tech to be sent out to fix it. The tech who arrived knew nothing of the problem and had to be told by Kelly what the issue was.

Yesterday morning, I wrote the project coordinator about the latest ground fault and asked that a tech look at it today. The coordinator came out this morning for the final building inspection and, after the inspector had departed, asked to see the inverter, declared it needed fixing and that a crew would be out on Tuesday, and then left. I essentially wasted a day I could’ve spent in the office for something I could’ve accomplished with my smartphone’s camera. It was very frustrating.

Oh, and our project coordinator was not aware that our “certificate of completion” had been sent this week to the power company. If you’re the project coordinator and you don’t even know when a project you’re supposedly coordinating is complete, you might not be doing your job right.

The only bright side to this is how quickly Duke Energy Progress came out and installed our new bidirectional meter. My fellow solar PV owner, Jason Hibbets, said it took Progress Energy eight weeks to put in his meter. Ours came well within a week of filing our completion papers. That’s the way to underpromise and overdeliver!

So, what would we do differently?

Better project management. I chose Southern Energy thinking they would provide us with expert service. I’m not sure what we got was expert service. Too many pieces seemed to fall through the cracks, so to speak, to give me confidence in them. Having a real project manager would have made all the difference in this regard. There are other solar installers out there, so find one that also excels at customer service.

Better contract terms. We paid the full price near the front end of the project. The SEM salesperson told us they needed the 12-months same as cash loan signed over at the start yet the bank providing the loan stressed to pay it only at project completion. Thus our “12 months same as cash” was whittled down by two months. Also, we wrote our last check at the completion of the “material installation” stage but in hindsight should have insisted that the last payment occur only once we were fully satisfied and all inspections had been completed and passed. Dumb, dumb, dumb. You should treat getting solar PV system like closing on a house: only when you’re completely satisfied with the work should the bill get paid in full.

Overall, we’re pleased to be joining the solar revolution. We’re the envy of the neighborhood, with many neighbors contemplating their own moves to solar. No matter what promise our panels bring us, though, they’re just very expensive roof ornaments if they’re not creating electricity. The thrill of going solar will start flowing as soon as the electrons do.

Turner Power Station approved

Solar panels

Solar panels


We got this email in today from Duke Energy Progress. We got our bidirectional meter on Tuesday and are officially authorized to generate electricity!

We have received the Certificate of Completion verifying the installation of your solar PV system, and your residential meter has been exchanged with a bi-directional meter. You are fully enrolled in the Duke Energy Progress SunSense Solar PV Program effective June 2013. This 60-month commitment requires your participation on our Schedule R-TOUD, Net Meter and SSR riders in order to receive a monthly SunSense bill credit. Here’s what to expect:

Your next Duke Energy Progress bill statement will reflect your previous rate structure (i.e. Residential rate or TOU rate if previously enrolled) from the time you placed your system in service until your next meter read date. Any excess solar production will be tracked for net-metering purposes, and will be displayed as “Energy Received by Duke Energy Progress” on a bill insert.
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Solar system

Solar panels

Solar panels


Last week we got our own solar system: a solar PV system installed by Southern Energy Management. Friday morning, I flipped the breaker that officially “tied” it to the power grid. The rooftop panels then began feeding electricity to both our home and the neighborhood.

It’s been a long journey to get here and we’re not done yet. It was two years ago that we first considered getting solar panels. We got the roof surveyed and a quote generated but didn’t feel the need to jump on it yet. Then in February, the rapid rise of stupidity in our state legislature made me wonder if the many incentives now in place to encourage solar adoption might soon vanish with the setting sun. I also knew the price of solar had dropped considerably in that time so it was wise to revisit the decision.
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Time of Use electric rates

With a few days of eGauge power tracking under my belt, I began to look into the other half of our solar equation: the Time of Use electric billing. Duke Energy (formerly Progress Energy) be installing a new meter for us after our solar panels get installed. We’ll be billed at a much, much different rate once that happens.

Power companies offer optional Time Of Use (TOU) rates for customers who would like to shift their power consumption to off-peak times. This benefits the power company because it doesn’t have to spin up new power plants to handle the peak demand. Demand-generated electricity is very expensive compared to a plant that’s already online, so power companies obviously want to avoid it.
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Tracking the sun (and more) with eGauge

The eGuage (upper right) installed in our electrical panel.

The eGuage (upper right) installed in our electrical panel.


I found out this morning that Southern Energy will be installing our solar panels on Monday! After a perfect, sun-filled afternoon today I was daydreaming of how our home’s electric meter might soon be spinning backwards!

As part of our installation we’ve purchased a power meter to track our electricity generation and consumption. It’s called eGauge and has become surprisingly addictive since I turned it on this afternoon, providing instantly-updated data through a web browser. Our solar panels aren’t installed yet but once they are, I’ll be able to see a ream of information on our electricity use.
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