MicroInverters ready for the big time

solar1Andalay solar, a subisidiary of AKeena solar has recently partneredwith Westinghouse and is preparing for a big push into the residentialmarkets.

Akeena is a large installer of PV systems in California and in 2007they partnered with Enphase to design a module with a prewired inverterattached. They then took the Enphase inverter and the module and ran it through the UL testing. The resulting product is UL listed andproduced AC power directly from the panel. What they have done isbasically combined two steps in the process (therefore simplifying theinstallation process).

They have been having pretty good success and have actually startedselling some of their panels at Lowes and Home Depot.

This latest announcement by Andalay that they will be changing andusing the name of Westinhouse is a marketing move to try to capturelarge market share. They already have an innovative, game changingproduct, and now they will be recognized as one of the oldest andrespected names in appliances and electricity.

We are excited to see how this partnership will play itself out.This product in the mainstream does have the ability to radicallysimplify solar installations and begin to drive down the price.

At SimpleEnergyWorks we are Andalay dealers (we can install/sell) and will soon be selling Westinghouse (they officially change their nameover this summer).

An interesting development in the microinverter market that willaffect solar implementation by the average DIY homeowner and ACelectricians.



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Video: 3 Types of PV systems (and their advantages)

Just released a new video dealing with the 3 primary types of PVsystems.

Watch this video for an introduction to PV systems.
Why grid tied systems are over 90% of all installed (in past 5 years)
Which system prepares you for the apocalypse?
How to decide between the three types.


Keep on learning!


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Review: Here Comes The Sun

Excellent overview of the “solar Miracle” that has occurred inGermany over the past 10 years. Included is an interview of thearchitect of the solar revolution in Germany. Very insightful andencouraging. They deal with issues as they currently stand (2010) andlook at the near future for “grid parity.”

I normally do not like documentaries, but this one held my interestfor the whole time. Solar is coming, whether the big utilities want itor not. And when it comes there will be “unlimited fuel” for all PVsystem owners. Once the technology is paid for- the fuel is free.There is no “gatekeeper” to pay for the fuel. With Coal, Oil andNuclear we are constantly paying for the “fuel” and the “power plants.” Once solar has traction the utilities days are limited. Why elsewould they be dragging their feet?

Enjoy this documentary!


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Enphase System Installers Survey

EnphaseInstaller_Survey_ChartEnphase recently tabulated the results of their first survey. Thissurvey went out to installers who have installed at least one Enphasesystem.

Newcomers and Veterans Agree on Enphase. Enphase has proven valuableto both solar first-timers and solar old-timers. According to thesurvey, our largest customer group did their first solar installation in 2009 and the second largest Enphase customer group has been doing solar installations for more than five years. Most see significant energy harvest gains (click on chart above). Ofthe installers tracking energy production, 90% observed an increase ofmore than 5% with Enphase, and 12% of installers noticed an increase ofmore than 20%.

There are many reasons to consider Enphase. 100% of installers saidenergy harvest played a role in their choice to use Enphase, butinstallers had a number of other reasons for choosing Enphase, with ease of design/installation and ease of monitoring ranking high on the list.

Check out the graph below to see how much of an energy increase these installers experienced with Enphase microinverters:


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How to Find a Local Electrician for PV Installation

FindLocalElectrician I have puttogether a mindmap which goes through the process of finding a localelectrician.

It is very specific on the steps that you need to cover as youcontact electricians and what you must say to them as you getcompetitive bids (from at least 3 of them). There are many hungry electricians who are anxious to work.  Many are willing to work for less than the “going wage” if you contact them andexplain exactly what you are interested in doing.  Many will even workfor Free (to get a foot in the door by installing a PV system).

Now, I do not recommend that you use an electrician for free. Because someone is hungry is no reason to pay them “slave wages.”  Onthe other hand, a fair price negotiated beforehand will be a win win for both you and the electrician!

Now, we are constantly working with electricians, so we are prettyfamiliar with the pay rates and how to find good electricians.  I hopeyou find the .pdf file useful and helpful as you go about getting yourPV system installed.

Now remember, an electrician does not need to install the PV system,but they do need to connect things to your breaker box, and they alsoneed to sign off on the system and connect it to the grid (depending onyour utility companies inter-connection policies).  You will need tofind out any regulations from your local electrical inspector AND fromyour utility company.  Once you figure out what those inspectors aregoing to require then you can go about talking with potentialelectricians.

Refer to the image below for the first few branches in the process. I have made the whole process available for  you to download for free.  Enjoy!   Download and Print Here: FindElectrician.pdf

You will need to print it out as I had to save it in “landscape”format in order to fit it all on one page. You will notice in the image below that there are circles at the end of each line. Well thosecircles mean that there are more categories of explanation out beyondthose branches.

Keep on Learning!


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Another MicroInverter Installation!

This one was installed by professionals, but they used the enphase microinvertersand were able to simplify the installation (he could have done ithimself!).


Keep Learning!


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How Much Energy Wiill This System Produce?

National_PV_Map_Letter2Brilliantquestion. And one which requires a careful answer… It all depends!

Some of the biggest confusion comes from Solar Installersoverpromising on the energy production that a system will be able toproduce. We want to be very careful to consider all of the factors sothat you will know exactly how much energy your system will produce. We will assume that you will be installing 5 X 200 watt solar modules for a total of 1000 watts. That is a 1 KiloWatt system. We normallysell 230 watt modules, but for ease of math we will be using a 1 kWsystem. The first (and most important) factor in how much energy your systemwill produce is the size of the system (ie. the number of watts total). This will always be the starting number from with we do the rest of our calculations.

The second factor is where are youinstalling the system? For example what is the exact location (latitude and longitude) of the installation. Each location has a recordedweather history (of approximately 40 years) which will be used toaverage how much sunlight you can expect per day.

The above map will give you a pretty good idea of how many hours ofgood quality sunlight (1000 watts per square meter) you will get at your specific location. If you want more specific data (for example monthly data, or exact location data) you can visit the NREL PVwatts calculator at:

Once you know how many watts and how many hours of good sunlight youget per day you need a few more bits of information including theazimuth, the roof slope, and how much shade you get at the locationwhere you will be installing the system.

The azimuth refers to whether the panels are facing due south (whichis best). Due south is 180 degrees. If your panels are facing 175degrees then there will be a minor (but measurable energy productionreduction). To figure out the azimuth you may need to take out anactual compass and find true north.

In our example we are assuming that we have a 4/12 roof pitch. Toconvert the pitch of a roof to an angle use the following table:

Roof pitch ratio/Roof pitch angle
1:12=4.5 degrees
2:12=9.5 degrees
3:12=14 degrees
4:12=18.5 degrees
5:12=22.5 degrees
6:12=26.5 degrees
7:12=30.5 degrees
8:12=33.5 degrees
9:12=37 degrees
10:12=40 degrees
11:12=42.5 degrees
12:12=45 degrees

An ideal angle is equal to your latitude. For instance, if you areat 35 degrees latitude then a 35 degree slope would be maximal formounting your solar modules. Any variation from that will decrease your annual energy production (a little). (The reason latitude works as ageneral guide is because at the equator the sun is shining directlyperpendicular, as you move up to latitude 35 degrees you will simplyneed to slope your modules up to that 35 degree angle to approximateperpendicular sun).

The final factor affecting solar pv energy production is how muchshade you get at the site. Pick a shadeless site if at all possible.Shade is the enemy of any PV system. For a site to be worthwhile youreally want good sunlight from 9am until 3pm. If you don’t have goodsunlight for those hours you may want to consider a different site(possibly even a ground mount solution).

Anyway, to get the exact amount of shade on a specific site you canjust use your eyes and approximate how much sun a site gets. You willneed to know which way is south and also be familiar with the path ofthe sun. If you need specific data you will need to get a hold of aSolar Pathfinder. This tool will give you a full year’s data on aspecific site shading. It allows you to analyze when shade will hit aspecific location for each month of the year. (It’s a very handy toolto have). Either order one (or have a solar installation company comeout and give an evaluation).

A chainsaw is a tool of last resort, but one which may come in handyas you are dealing with shade issues.

Once you have all of the above information (watts, location, azimuth, slope, shade %) then you can go to PVwatts and put the information into it’s “Derate” worksheet and it willautomatically give you an annual production estimate.

Lets run through an example using a 1000 watt (1kW) system withEnphase microinverters from SimpleEnergyWorks.    We will assume thatthe installation is in Knoxville, TN.  We put in some of our information on the first page:

We put a 1 into the DC rating (1 kW).

We use a “fixed tilt” (because we are not using a mechanical suntracker).

We put 30.5 degrees in as the “Array Tilt” or slope (because the roof has a 7:12 pitch).

We put in 180 for azimuth because the roof faces due south.

Now we push the “Derate Help” button to figure out how much we will“Derate” the system.  (Derating is simply taking all of the factors that will lower production and account for them indiviudally, then addingthem together so that you can see the real efficiency of the system)

Now you change the numbers underthe “component derate values” to those for your system:

The Yingli modules we use have a fluctuation rate of 3% (so insert.97 in the first field).

The Enphase Inverters have an efficiency rating of 95%, (so insert.95 in the second field).

Using Microinverters mismatch does not affect the system, so put in.995 (99.5%).

“Diodes and connections” also does not affect microinverter systemsso insert (.997)

Bump DC wiring up to 99% (so insert .99) because there is no DCwiring.

Bump “System Availability” up to 99.5% (.995) because microinvertersincrease it.

This is where you would put in a % of shading (if any).  (Leave at 1for now)

Push the recalculate button at the bottom and it will give you aDerate factor of .846.

So…. insert this .846 into the previous page where it asks for derate factor.

PVWatts will then calculate how much that system will produce overthe next 12 months.  It will look like the following:

So a 1 kW system in knoxville, TN with the before mentionedassumptions will produce 1333 kWh of energy over the next year.

If you are installing a 4.2 kW system simply multiply that 1 kWnumber by 4.2 and we find that the larger system will produce 5598 kWover the next 12 months.

I hope you enjoy running through these steps to figure out potentialsystem production.

This complex formula is the reason why it is hard to just give asimple answer of “how much will it produce?”  Estimates are easy, but to know exactly what it will produce you need to follow the steps!

Enjoy, and keep on learning.



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