Solar PV Power Production, How do we measure and compare?

Monoliths in the Field, and who is allowed in to look at them?

Recently I wrote about Beth Buck Naked, her article about a motorcycle that ran on compressed air, and how the project had made a short list to receive some prestigious award.  Most of the comments that followed her article were made by two distinct groups, those who were awake in eight grade science class, and those who do believe in fairy dust.

At the heart of many of these articles like Beth wrote is the lack of any real measurement regarding  performance you can relate to.  And as you come to the end of the article, you have the feeling that you just read another bait article created to generate  traffic to a point of sale, or promote a product or service.

Is there room here for us to apply some critical thinking? Let’s say you were an operating company who choose to invest in the Hatch Power Plant, would you assume that the power plant had been assembled correctly in Nevada, and then installed correctly? Prior to some ‘hands on experience’ with the power plant, would you forge a durable contract with an entity like El Paso Electric and guarantee the delivery of a specific amount of KWHs through the meter? Would you sign a contract with significant penalties IF you were not able to deliver those Solar PV created KWHs to EPE?

I think we might all question how long any business would be in business assuming so much.  I would imagine the contract between the Power Plant Operator and EPE would have a rather low power production figure until the power plant had proven itself.

With that said, what do we do with the news that the KWH expectation is right on track? It does remind me of the Auto industry.. The salesmen on the Car Dealer’s lot says ” This model fully meets ‘our’ expectations, no doubt it’s the car for you”.

How do we ‘hands on’ DIY types measure performance? I’ll stick with  Amonix as an example, because I think it is prime. Following are twitter exchanges, I find value in Eric’s search for the truth, but I wonder if he has the same need for performance data that allows us to compare one technology against another and >know< the real value? Here’s an old twitter exchange, check the dates.

wesoff-frustration-Amonix

I looked on as Eric made an extreme effort to find out exactly how Hatch was performing.  I thought his Green website was one of the few that attempted to share more than the hype   entities trolling for investors and federal dollars released to bloggers hoping they would paste them and favorably comment.

Here’s my approach, and you may be far too busy, or far too lazy to make your own study.

Put a button on your desktop, visit the El Paso Website, and learn of it quirks, it’s not perfect, and some parts don’t work quite as you’d expect, maybe a browser issue?

Build yourself a little spreadsheet, and note the performance of the Road Runner power plant. I think using a best hour of power production through the meter, and then expressed as a percentage of the MW rating of the power plant IS a figure that carries weight with DIYers. No doubt, there are investors, and politicians who would accept figures based of grams of fairy dust.

I have made several posts about the rather significant difference between the Road Runner power plant, a very simple and cheap technology, and how it seems to ram a rather high percentage of it’s rated capacity though the power meter in comparison to the Hatch power plant. You can make the same comparisons..

But we need add, even a moderately competent mechanic will recognize that the Road Runner is based on KISS technology, a SIMPLE single axis tracker, proven flat panels, no hydraulic pumps, far more power delivered under a significant number of days with high clouds that are not so good for CPV. Furthermore, I have seen the Road Runner deliver 100% of it’s rated output, but by the same measure, Hatch seems to have trouble making 3800KWHs during a best hour of the day. There was a time when Hatch made 4200KWH (best hours), but that was some time back, I can only guess that it’s difficult and or expensive to get hatch back to the power production levels once observed.

Is it dirt and dust on or in the CPV enclosures? Degraded PV cells? Broken trackers, Deformed superstructure bent under the strain of rather significant loads of hail on top ‘stowed’ trackers? CPV demands that we accurately aim ALL of the units on a tracker with some degree of accuracy, what happens when trackers are ‘wracked’ from wind damage, or extremely heavy loads of hail? And if these units can endure these stresses without damage, why do they stow them?

A few hours in the field with a laser and a few blocks, we’d know just how much variation is now built in, and what our ability is to accurately point and train all the modules might be.

At the end of the day, we might ask, what green web site cares about those of us who want just the basic facts? What did your plant do best hour today based as a percentage of the power plant’s rated power production?

Plenty of posts I’ve made, and even some about Martha at the NREL, she is fixated on the efficiency of a solar cell used in CPV, and a lot of mechanics would agree, that’s the easy part, how long the cell lives, and how hard and expensive it is to replace is equally important, and the facts are, you can say it all day long, but the truth is revealed in the field. It’s it curious how few are allowed into the field? I would trust Eric Wesoff to accurately report what he found, but I’m not convinced he’d ask the same questions as those who have grease under their fingernails and hands familiar with the nuts and bolts.

As  per my visits to the El Paso website, I see best hour figures for the Road Runner in the high nineties, and the Hatch power plant performs in the mid seventies.

If you see it  differently, please… please let me know where I’ve gone wrong.  As for your visit to EPE website, the graphs do not always populate for me, it could be my browser.. the hourly power production data is normally available. As part of your study, do consider visiting the underground weather site, and not what happens during the wind gusts I note quite often, when you see the significant holes in the day’s power production at Hatch, you might find an observed wind gust that ‘stowed’ the trackers.

My casual observations cause me to suspect that the weather station nearest to Hatch can see wind gusts as low as 10MPH, WHEN the trackers at Hatch stow, suggesting that the Hatch site sees slightly higher wind speed there.

Of course, it’s all what I think, using my best effort to know the real data.  I am the Student, and like most all who would have read this far, I refuse to bend over and take my lessons in suppository form.

I do reflect on one girl in my grade school class. She was nicer than nice, she had exceptional manners, compassion for every living thing. A good enough student, and I bet she received the highest possible grade in being a good citizen.

She never stared out the window, always paid attention to the teacher, and I never remember her asking a question. Today.. with advanced degrees in the Social Sciences, she makes assessments of the value of green ideas, but I’d wager a paycheck she doesn’t know where the dipstick is in her car, or exactly what a BTU is..

 GB