[RE-wrenches] PV power quality trumps grid power & general observations

[Joel Davidson]

Hello wrenches,

Retrospection is common practice at the end if the year. For me, this year's 
review was triggered by an email. Last week a customer living in Orange, 
California wrote, "Southern California Edison came by yesterday and put a 
tester around each of the 110 volt lines coming into my panel from the grid. 
One had normal voltage the other was low. He cleaned the connections from 
the transformers and - viola - we have normal power!" This is the latest 
chapter in this customer's story. Two weeks ago I got an email from him 
asking, "I have a question about my house current. Can my inverter affect my 
house current? The lights in my house fluctuate from dim to bright during 
the day and night. My neighbors are not having the same fluctuations. Any 
thoughts?" I replied that utility voltage sags can cause grid-tied 
battery-based inverters to sense the brown-out and switch to off-grid mode 
causing lights to brighten and then switch back to grid causing lights to 
dim again, but that I did not know of similar problems with batteryless 
inverter systems. He contacted his utility and they sent a technician which 
got me to thinking.

This customer's story started August 2001 when he found us on the internet 
and emailed for a quotation. After a few emails and phone calls, he bought a 
Xantrex ST2500 and 24 Kyocera KC120 modules in December 2001. In January 
2002, he bought 4 Zomeworks trackers, but did not install his system until 
March 2003 when he finished building his new home. May 2003, the California 
Energy Commission emailed me that they had lost his solar module warranty 
and could not process his rebate check so I fax the warranty info to them. 
August 2003, our customer was concerned about PV power production, heard 
about the ST2500 upgrade, got a new inverter, installed it, but the new 
inverter had problems so he had to send it back, get another new ST2500, and 
re-install it. May 2006, his Kyocera modules' cell interconnections failed 
so he had to remove and return the modules and re-install them which took 
until August 2006. I am sure you all have lots of similar on-going customer 
stories.

Some general observations:
- Poor utility power quality can cause or appear to cause PV system problems 
that are often frustrating and difficult to identify and solve.
- Most utilities say problems are on the customer's side of the meter when 
PV system owners or contractors report a problem.
- More utility companies are getting serious about buying and selling 
renewable energy which means that most Americans will continue to buy 
utility power and not own an RE system.
- Big construction companies will win most of the federally subsidized RE 
projects.
- Big PV contractors will get the biggest share of residential and 
commercial jobs so small companies must differentiate their work like custom 
homebuilders and remodelers do.

- PV and windpower are big businesses that need paid lobbyists in Washington 
and state capitols just like other big businesses.
- Most PV projects will require subsidies so long as non-renewable power is 
subsidized.
- Rebate program bureaucracy, like government, is here to stay and grows 
with population growth.
- Very few people working in the private and public renewable energy sector 
own PV or windpower or solar thermal systems.
- Many PV system contractors and customers are unknowing or unwilling 
equipment beta testers.
- Inverter manufacturers bring new products to market without factoring in 
the extra cost new problems cause contractors and customers.
- 3 major solar module manufacturers had quality problems since 2000 so test 
and commission each system.
- Some customers are less forgiving than others about equipment failures and 
rebate program bureaucratic delays.
- Customers want what you want: quality products, outstanding service, and 
low prices.
- Non-RE plumbers and electricians repair other people's work and don't call 
them "orphan systems."

- The NEC is written in gray ink.
- Staying in tune with local AHJ inspectors requires constant vigilance.
- Good businesses support their customers for life.
- Some good deeds do go unpunished.

Thank you all for working to make the world a better place and best wishes 
for a wonderful new year!

Joel Davidson