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On July 18, 2007, our home solar system of nine 170-watt solar panels and a Sunny Boy inverter was fired up.

About one year later, the system has generated a total of 2,130 kilowatt-hours of electricity. Taking away 10 days because of a power outage this winter, that translates to an average of 5.96 kilowatt-hours every day.

We’re very happy with the performance of the system, as it’s generating about 90 percent of our power. We might add more panels in the future to get us to the 100 percent mark, but we’ll probably first take steps to reduce our power consumption more, including adding insulation to our attic. It’s already insulated up there, but it probably could use more.

Since climate control is our big power-sucker, especially in the summertime, it only makes sense to cocoon the house from the outside elements.

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Recently, something happened that we’d always dreamed of when we first installed our solar-power system in July 2007 — we generated more power than we used.

I had a hunch it might happen in April or May. Those were the days in which we saw a lot of intense sun but mild temperatures — perfect conditions for solar-power generation. In fact, one day in early May, we generated an all-time high of 10.02 kilowatt-hours of electricity, and there were several other days of 9 KWH and higher.

According to our AEP-PSO bill, the meter reading on April 25 was 89377. On May 27, the meter reading was 89354. (Remember, this is the utility doing the reading, not us.) That meant the solar array was generating so much juice that month that the meter turned backwards to the tune of 23 KWH.

I always wondered what that would do to utility bill. The residential service total was $13.95, but the actual amount due was $12.64. AEP-PSO credited us $1.31 for the power the power we provided to them.

After seeing their KWH totals go lower instead of higher, it wouldn’t surprise me if AEP-PSO repairmen come out for a third time to replace the meter. It’s not like that hasn’t happened before.

Spring has arrived, and with it is a significant jump in our solar array’s production.

From Feb. 19 to March 19, our solar panels produced 158.3 kilowatt hours of electricity. So that means in 29 days (remember, February is a short month), the solar-power system produced an average of 5.46 KWH per day.

It’s apparent to me that some of the best production days are not in the summer, but in the spring and fall when temperatures are mild but the sunshine is intense. Hot temperatures depress solar panels’ efficiency 5-15 percent. But in the milder months, it’s not uncommon to see days of 8 KWH or higher. Just yesterday, I saw the inverter read 8.12 KWH with several hours of sunshine remaining.

This morning, I was working in my office when I heard a scraping sound on the side of the house. I went outside, and there was an AEP-PSO repairman, taking the cover off my electrical meter box.

“Hi,” he said. “We got word that there must be something wrong with the meter … that it’s going backwards.”

Not again, I thought.

“Well, the meter is going backwards, and I’ll show you why,” I said. “Take a look on the roof.”

He stepped back a few feet and saw the solar panels.

“Well, I’ll be,” he said.

He turned out to be a nice guy. He peppered me with questions about the system … how much it cost, how much power I was getting from it, etc. He thought it was cool that we were getting so much power from it.
He shook his head a bit.

“I think we need some training on this,” he said sheepishly. “We just don’t see hardly any systems like this. There’s one other one I know about, and he has the same problem — the power company’s always checking to see why the meter’s running backwards.

That sounds familiar, I thought.

He started to walk down the driveway. “Well, sorry to bother you. I’ll try to explain to them what’s going on so we don’t keep coming out here,” he said.

****

On a semi-related note, the system generated 134 kilowatt-hours of electricity from Jan. 20 to Feb. 20. That’s an average of 4.32 per day.

We’re really starting to generate juice now. The cool temperatures, combined with lengthening daylight, and we’re seeing days of 7 KWH and higher.

I’m a bit behind on my usual reports, but I did collect the data.

From Dec. 19 to Jan. 20, we collected 4.53 kilowatt hours per day. With our current electric bill from PSO, we used just 10 KWH of power from the utility during the entire month. So we were getting well over 90 percent of our power from the solar array.

In the six month since the solar-power system was placed online, it has generated 971 KWH of electricity. Divided by 175 days (I took off seven days because of the ice-storm power outage), that’s 5.54 KWH per day.

The past month has been a strange one at the House of the Lifted Lorax.

I usually check the solar array’s performance of a 31- or 32-day intervals. But in early December, Oklahoma was ravaged by a historic ice storm that downed trees and power lines all over the place. At one point, more than 600,000 customers were without power in the Sooner State. More than 10 days after the storm, there are still tens of thousands in the state without power.

Even though we get much of our power from the sun, the solar array is a grid-tie system. So we were in the dark along with thousands of other Tulsans. Our house had no power for a total of eight days. We did fine in the meantime — we had heat from a wood stove, hot showers from our gas water heater, and a number of LED lights to read and see by at night.

From Nov. 19 to Dec. 19, the solar array generated 70.1 kilowatt-hours of electricity. I lopped off eight days for the power outage, the average was 3.04 KWH per day. Given the fact these are the among the shortest days of the year, along with a long spate of cloudy days, the solar array did quite well.

In the meantime, I’ve been collecting downed tree limbs to become next year’s firewood. We probably already have enough wood for next winter.

A few weeks ago, I said “nearly 90 percent” of the power we consumed came from our solar panels.

I had a hunch it was higher, but wanted to be conservative in the estimates. The power meter fiasco a few weeks ago skewed the numbers, so getting a fix on what was being generated and consumed was difficult.

A few days ago, we received our AEP-PSO bill. According to the the utility’s actual meter reading, we used 12 kilowatt hours of electricity from Oct. 26 to Nov. 26.

No, that’s not a typo.

Twelve.

That’s barely one-third of a KWH per day.

I don’t have the solar-power numbers from that exact period, but they’re close enough — from Oct. 19 to Nov. 19. In that time, the solar array generated 158.5 kilowatt hours of electricity. And weather conditions between AEP-PSO’s billing period and the period that I track were similar.

So … 93 percent of all the power we used came from the sun.

Remarkable.

By far the biggest power drain we have is the air conditioner during summer. The solar array’s portion of electricity we use drops to as low as 50 percent during particularly sweltering months.

But the central A/C unit is well over a decade old; we plan to replace it during the spring for more energy savings. We’ll keep you posted on how that goes.

The days grow shorter, but in the past 31 days the solar array has generated 158.5 kilowatt hours of electricity. That’s 5.11 KWH per day, which is about equal to the previous month.

That’s all attributable to good weather. It’s been remarkably sunny and pleasant, with almost no rain at all. At one point, during a three-week period, we used just 24 KWH from the electric company. Nearly 90 percent of our electricity came from the sun.

And, yes, the new electric meter is still going backwards on clear days.

So I was surfing the Internet on a cloudy Friday morning when the doorbell rang.

It was a serviceman from American Electric Power-Public Service Company of Oklahoma, aka AEP-PSO.

“I’m here to replace your power meter,” he said. He warned me that if I had any computers running, I should shut them down and let him know when it was OK to begin his work.

The visit wasn’t unexpected. When we’d installed our solar panels in July, an AEP-PSO representative said it was likely that our power meter would be replaced with a digital model. When nothing happened for months, I figured it was simply the slowly turning wheels of AEP-PSO’s bureaucracy. No big deal — our solar array would work fine, new power meter or not.

After taking care of the computers, I went into the back yard to let him know he could proceed.

“So,” I said, “are you putting in a digital meter?”

“No,” he said, “we’re replacing it with the same model. We’ve been told your meter’s running backwards, and we’re putting one on that should work correctly.”

After a stunned pause, I said: “No, the meter’s fine. The reason it’s running backwards is because I have solar panels on the roof.”

The serviceman stepped back a few feet, gazed up at the roofline where the nine Sharp photovoltaic panels were lined in a row, and half-grinned. “Oh, that explains it.”

I realized what had happened. About three weeks ago, I’d received an AEP-PSO bill nearly triple of what it should have been. That’s because it was estimated, based on data from our home’s electricity usage since taking occupancy in 2004. (AEP-PSO conducts actual readings every other month.) But the estimate failed to consider our drastically decreased utility usage since the solar panels were installed in July.

I immediately checked the actual numbers on the meter and called AEP-PSO’s customer service line. I explained that we’d installed solar panels during the summer and that the estimated usage needed to be lowered. I briefly mentioned that the meter even ran backwards on sunny days. He seemed to understand, and said a revised bill would be mailed.

Weeks later, the revised bill had not arrived, and here was an AEP-PSO serviceman, thinking the meter was malfunctioning. The customer-service rep that I talked to obviously had filed an erroneous report.

The serviceman, even after seeing the solar array, was still determined to replace the meter. “It shouldn’t run backwards,” he said. “The solar panels should slow the turning, but it shouldn’t run backwards.”

I explained that this was a grid-tied system. When the sun was out and electrical use in our house was low, the meter would turn backwards. When the sun went down, the meter would resume its normal pace.

He nodded, but insisted the meter shouldn’t go backwards. I shrugged and let him swap out the device. It wasn’t like it was going to cost anything.

He also was startled when I told him that even before installing a solar array, our electric bill was as low as $32 a month.

Apparently AEP-PSO personnel have little experience with home-owned alternative energy.

He installed the meter and went on his way, convinced the problem was solved.

A few minutes later, I saw the sun peeking slightly through the clouds. I went outside to check the new meter.

It was running backwards.

So much for the so-called “repairs.”

… So the amount of power generated by our solar panel array is dropping.

However, in the past 33 days (with a lot of rainy periods), it has generated 173 kilowatt-hours of electricity. That’s a respectable 5.2 per day.

And because we’re using the air conditioner much less, the sun is still generating a big percentage of our total power consumption.