Solace in Solar
RF test engineer Joe Cahak, owner of Sunshine Design Engineering Services, recently had a photovoltaic panel
system installed on his southern California home. After much research and running through return on investment (RoI)
calculations, he made the decision to invest in a state-of-the-art system by Semper Solaris in San Diego. If you
have not looked into modern PV technology, you might be surprised - as was I - to learn that rather than all the
panels feeding their DC outputs into a common AC inverter that handles phasing issues with the street service, instead
each panel has its own inverter and phase matching circuit so everything simply feeds into a 2-pole circuit breaker.
Doing so eliminates single point failures and allows graceful degradation if necessary rather than taking down the
entire system. Joe has provided a very nicely done write-up on the system and its installation.
Solace in Solar
By Joseph L. Cahak
Copyright 2013 Sunshine Design Engineering Services
I consider myself a conservative investor and also a practical environmentalist. I have watched alternative
energy and especially solar for many years and closely looked at the technology, the lifetime, the efficiency and
the economics of various incarnations of solar systems. I also looked at methane and wind power as possibilities.
None quite fit the bill as easy and low maintenance, until now.
I finally made the decision to purchase a
system after many years of looking. We decided to go with a company called Semper Solaris in San Diego, CA. They
serve the entire Southern California area. So why did I purchase a solar system now and what did I get? Why did
I go with the vendor I did?
In order for me to give a bit of perspective on the solar topic, please bear
with a quasi-historical review. In the early days it was 12 or 48VDC lead acid batteries and single inverters and
high DC losses between the solar cells and the batteries. The batteries were expensive, heavy, dangerous and prone
to failure with regular replacement costs. The systems were OK for small scale and/or emergency use, but not cost
effective for total home power systems. The solar panel glazing and solar cells did not hold up well in the sun.
The solar cells also suffered high temperature power output loss. The DC line losses are very prohibitive as is
the battery losses and expense.
Another reason working against the solar system cost and maintenance was
the competing lower cost of the grid. In California the cost of power was already very high. The last few years
we have had power deregulation and other stupid politics and energy gaming schemes with the big energy and power
companies colluding to set high prices. The rates are due to go up a minimum of 6-8% per year for many years to
come. In addition, recently Edison Electric and SDG&E decided to shut down San Onofrae nuclear reactor. They
are working to try to make us rate payers pay for the failed generator. So rates will really jump. Estimates range
from 30-40% in addition to the 6-8%/ year projected increases. This makes solar very attractive for southern California
and Arizona. In addition the minimum electric price is $5 per month and SDG&E is expected to raise it to either
$10/month or $50/month. We are waiting to find out. Reviewing my SDG&E bill I see they now charge me $65 for
electric generation, $3.48 DWR bond charge, $65.81 distribution and $1.88 Competition Transition Charge. I find
it interesting that they want so much more for distribution. These charges sound excessive to me.
we live in central San Diego County it gets very hot in the summer and Air Conditioning is critical. We minimize
it as much as we can, but with tiered rates, we pay a minimum of $0.17/KWh. We can pay of $0.35/KWh when using more
than 597 KWh. This coincides with the high heat of summer. This adds up to steep costs very quickly. Now the AC
will run the most while we produce the most solar power mid day summer. The panels are have an aspect ratio sized
for maximum output when the heat load on the house is highest through the spring, summer and fall. In addition the
tax incentives for Solar power are lapsing after Dec. 31st this year. Even with this loss on credit, solar will
still be a viable electric rate investment given the increases coming.
The Solar Cells in the early years
were only about 6-8% efficient at best and they did not hold up well under heat and intense sun. The contacts also
did not always adhere well. They also were prone to corrosion around the contacts. The newer solar cells are larger,
have good heat resistance and lifetime. The single crystal cells have higher efficiency than the cheap poly-silicon
cells so prevalent in the market today. The efficiency of our panels is 14.8%. The implant and surface finish holds
up to the heat and sun better than previously and has a highly rated lifetime warranty. They also have better grids
and interconnects for longer life. Solar World encapsulates the cells and contacts in a moisture proof hermetic
Many solar panels are not built well and can have the glazing cloud and crack after time; some of them
get moisture inside easily and fail to shed it well to keep the panels working best. Some panels are not built to
last for the long haul. The Solar Panels we got are from Solar World. They are US made and of the highest quality
and have a 25 year warranty. They are solidly built of all aluminum frame and solid corners. The panels are clear
covered with a moisture and environmental seal and backed with a white solar resistant material and then the glazing
sits on the panels to help with heat transfer and lower reflective loss, all very lightweight and strong. I was
told I could stand on the panels even in the center.
Figure 1 - Solar World Panel
Figure 2 - Solar Panel Grid and Corner
Figure 3 - Solar Panel Rear Electric Connection
A few years ago, Enphase Energy developed what is now
known as the micro inverter. The Micro Inverters have changed the alternate energy market completely. With the micro
inverters, the DC from the solar panel is converted in small inverters at the solar panel to AC for feed into the
home AC entry panel. All that was needed was some Quad20Amp breakers to the 240/208 VAC AC feed panel.
solar system uses Enphase Micro Inverters model M215 and has one inverter for each panel. This has several advantages.
Each panel puts out it individual maximum output to the inverter which converts to 240V AC and is synchronously
feed back into the utility grid. This gives the lowest line losses to the AC Line Power. Batteries are no longer
used, as the power grid becomes the backup system. You are merely adding power back and getting credit up to the
amount of electricity you use over the year above what you produced. You typically will not make money from the
utility in California. The power companies have strong agreements and regulations in their favor. So the strategy
is to make enough power to almost cover your maximum average total power. Our system should produce > 95% of
or Electric use today. One final feature of the micro inverters is that if one or more panels lose some or all power
due to shade, the loss only affects the shaded panels. All other panels will still produce all that they can or
not. The synchronous inverter detects the frequency and phase of the grid electric feed and synchronously inverts
and steps up the VDC input to the 240VAC output to match the line characteristics and the added phase needed to
produce instead of use power.
Figure 4 - Enphase Micro Inverter Top
Figure 5 - Enphase Micro Inverter Bottom
The Enphase units each report to an Envoy Communications Gateway.
We log in through a web portal and can monitor our panels’ output, status and contact support when needed.
The Solar power feeds into most 200 AMP home panels. They just feed in thru breakers. This saves a huge amount
on panel replacement.
Figure 6 - Quad Pak Panel Breaker
Figure 7 - Electric Panel Labeling
When the installation crew worked the roof for the installation mounts,
they discovered a bit of roof damage and the old roofing paper was dried to powder. So we had to add about $2400
for a section of roof repair. They fixed two leaks in the process. We weren’t thrilled about the added cost, but
Final System looks great and has a low profile that is not visible from the front of the house.
Figure 8 - Complete Solar Installation
Figure 9 - Side View with Gap Above Roof Tiles
Figure 10 - Solar Panel Close-Up
Figure 11 - Solar Panels After Tree Trimming
We have talked to and looked
at many of the solar systems and finance agreements over the years, but just never saw one that had all I was looking
for. Then I gave a call to Semper Solaris after seeing an ad in the paper. Semper Solaris is a local company and
one of the founders was a marine. We met Mike, one of the salesmen and he explained the system and I liked all the
features and warranty. The finance terms are all fine for many people in different income situations. I was just
getting back to work, but had some saving to invest in the right things. So I asked about cash discount and got
an 8% savings on the total for paying with cash. This investment of $21K would "earn" me about $170-300 a month
for the next 25 years. Sounds like a good retirement investment to me. Certainly better return than I was getting
One note on leased solar system is that is may impact your ability to sell or the sale-ability
of your home. Some of the leases and systems may not be attractive to prospective buyers and it may greatly limit
your range of buyers.
20 panels rated at 245 watts each for a total
full power ~3.5-5kWh for about 600-1000kWh/month or an annual average of 740kWh/month. The panels have a rated module
efficiency of 14.8%.
We are using about 742kWh/month annual average presently. Our house is about 1800 Sq
Ft and we live in central San Diego County. So our highest cost utilities are the water well pump, the freezer,
refrigerator and the Air Conditioner/Furnace. The solar system was estimated generate about >96% of our total
As I write this, on a sunny November day, 6 weeks from solar minimum, we are getting 26 kWh/Day
from the system. With some quick estimates for the solar min and max output, one can approximate of 20-35 kWh/day
for a monthly output range of 600-1000 kWh. At this day’s output of 26KWh, if we had a full 30 days of sun, would
equate to 770 kWh/month output. This output in fall at the beginning of November sun season is a very good sign
to start with. We’ll be watching to see how things stack up when the days get cloudy as well to see the impact to
the overall total collected. The overage also accommodates the cloudy days to keep the average at better than 700kWh/month.
The roof has an aspect angle of 30 degrees. The sun ranges here in San Diego County between 33.5 and 80.5 degrees.
So a 30 slope means it is perpendicular to a 60 degree sun. This puts sun max collected in the spring (~April 15th)
and fall (~Sept 15th). Our hottest days are in July-October so the aspect is well suited for this.
them a cleaning after 3 weeks. We have horses and live in a dry, windy and dusty area, so they build up dust in
the dew laden mornings. I used some light dish soap and a half cup of white vinegar to cut mineral deposits with
city water. I found a great 16 ft variable length rod and brush/squeegee and wide bucket to the cleaning and wiping
dry. Home Depot had pretty good deals on them. I saw about a 200-300 Watt bump in power output after the cleaning.
The total system cost was $21,200 after 8% off for cash discount with $2400
roof repair and $6500 tax credits yields $17,100 net cost
Return on Investment
Notes on Permits
- The ROI for 17,100 at today’s electric rate is $2500 for a payback period of 6.8 years.
- The ROI for 17,100 at next year’s rate is $3500 for a payback period of 4.8 years.
- The earning after the system is paid off is $3500 per year. So the income from the loss offset is between
14.8 to 20.5% annually or about $208-$290/month. Not too bad an investment.
- Not to be forgotten is the property value increase with an owned system on the house. I figure the house value
could have increased by at least $30K.
- San Diego County Building Permit was obtained after the system was drafted and documented.
- San Diego County then performed an on-site inspection to approve the building changes.
- SDG&E Permit To Operate - for solar power hook up and right to operate
We give Semper Solaris a 5 star rating. They were professional in
the sales and explanations of the deals and system. Mike was real upfront about everything and provided me with
follow up materials to share with this article. I was told the serve the entire Southern California area: San Diego,
Temecula and Murrieta. If this interests you, call them and ask for Mike Barnett, tell them Joe sent you.
Mike has given me his word of special deals for all referrals. Semper Solaris
CA licensed General Building Contractor: #B978152
1637 Tierra Montanosa
Alpine, CA 91901
Sunshine Design Engineering
23517 Carmena Rd
Ramona, CA 92065
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Sunshine Design Engineering Services is located in
the sunny San Vicente Valley near San Diego, CA, gateway to the mountains and skies. Are you looking for new things
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Posted November 5, 2013