Thoughts on Solar

Readers of this blog know quite well that the long-awaited Enphase IQ8 microinverters are almost here.  (Enphase reports that shipments have started, and our distributor is promising to have them in numbers by next month.)  But there’s one slight catch: in order to commission a PV system with IQ8’s, you have to be certified by going through an online training at Enphase University!

So guess who just got certified?

The training takes you through all of the four use cases for installing IQ8: solar only (no backup or storage components), Sunlight Backup which allows partial backup even without adding any storage components, Partial Home Backup and Full Home Backup. Each of these use cases has different components, and those components need to be properly configured to guarantee that the solar system owner has the best possible experience.

We are excited to be at the forefront of this exciting next step in our partnership with Enphase, and with you, our cherished clients.

Let’s make 2022 one for the record books!

I just returned from two days of hands-on training with the new Ensemble Storage System from Enphase Energy at their HQ in Fremont, California.  Here’s my take…

Ok, to say that I have been somewhat obsessed over the Enphase IQ8 and its incarnation in the Ensemble Storage System over the last year and a half would be an understatement, having written about it here, here, here, here and here!  I’ve attended webinars and conference sessions where Ensemble was discussed and the technology explained.  But like any good installer, what I really wanted to do was get my hands on these devices, wire them up, and get a real feel for what it takes to put these on a client’s wall.  This week I got my chance!

Here is one view from the lab at Fremont.  On the far left is a main service panel and meter. To its right is the Enpower Smart Switch which acts as a Microgrid Interconnect Device (or MID). Next is the Encharge 10, alongside its smaller sibling, the Encharge 3. 

(As this image suggests, Encharge 10 and Encharge 3 can be combined as desired to achieve the combination of energy storage and power output required.) 

Next is the IQ Envoy Combiner (not new, although it now comes with a cellular modem standard).

Finally, there is the simulated array made up of IQ6’s and IQ7’s (both regular and Plus versions).  Out of the field of the picture is a PV array simulator that powers the microinverters.

Oh, and no demo would be complete without some loads, including a light, a microwave, and an electric stove - all of which were powered by this system with the grid disconnected.  (Some people have asked how fast was the switchover - so fast that the light doesn’t blink and the clock on the microwave did not reset.)

Over the course of the two days we spent a lot of time in the classroom - headed by Peter Lum, trainer extaordinaire - focusing on the nitty gritty.  How do you size an Ensemble system, how do you mount these things, how do you wire them up, how do you comply with the electrical code?

Our lab time on the first day was a demo of the system on the wall.  The second day, we were actually mounting these to the wall and wiring them up.

Getting Our Hands Dirty

I’ve already written a lot about the specs of these devices, so I won’t repeat that here.  The point of this post is to discuss the actual installation process.

On the left is the Enpower with its deadfront removed, alongside the Encharge 10 with its cover removed.  (The whitle, L-shaped pieces on top of the Encharge 10 cover are the screw down covers for the Encharge’s wiring compartment.)

Encharge 10

Let’s start with the Encharge 10 - as the photo makes clear, Encharge 10 is actually three Encharge 3’s mounted on a common mounting bracket.  Each Encharge 3 includes four IQ8 microinverters, and they are individually replaceable, so should one ever fail, the others continue to operate and the monitoring will advise the installer of which unit has failed.  All the field technician needs to do is remove the cover, disconnect the failed microinverter, plug in the replacement, and put the cover back on. Moreover, because the micros are on a common bus inside the Encharge 3, if one should happen to fail, you still have 75% of your total power, but 100% of your stored energy!

An Encharge 10 constitutes a 20 Amp branch circuit, and up to two Encharge 10’s can be wired together in series (maximum wire size is #8).  If a larger storage system is required, then the Encharge units need to be landed in a dedicated subpanel.  (The Enpower is rated for up to 80 Amps of storage.)

To the left of the IQ8s is the battery management unit and the battery disconnect switch.  (Not really visible in this picture is a status LED that shows whether the battery is on or not, whether it is idle or charging, and the relative state of charge as it shifts from blue (discharged) to green (charged).

The finned area is the actual LFP batteries themselves.  All cooling is passive, no fans are involved.  The unit needs to be mounted a minimum of one foot from the ground, and if you have more than one row, at least six inches (vertically) between rows.

The mounting bracket is secured to the wall with sufficient hardware and into sufficient structure to support the total weight of 346 pounds.  (Enphase will be releasing a white paper on best mounting practices - a must read to be sure!)  Each individual Encharge 3 is then lifted onto the bracket.  Given that these are over 100 pounds, this is a two-person lift to be sure!  My colleague Greg and I struggled a bit with the lift, mostly because I wasn’t really pulling my weight - so to speak.  (My value add isn’t really in lift strength!)  But the younger guys that were in the training with us managed the task with ease - ah youth!

The Encharge 3’s are then daisy-chained together in a wiring compartment at the top of the units, as you can see in the picture on the left.  Each terminal block can hold two wires, one coming in, one going out.  The last unit just has the incoming connection and no other termination is required.

Note the black piece connecting to the two units.  That is a plastic, snap in conduit section that is added after the units are mounted.  The last unit in the chain has a rubber plug in that opening to keep the wiring compartment watertight. 

(Note, the section with the microinverters is not watertight as the IQ8’s are NEMA 6x, which means that they can - and are tested to prove it - operate under water!)

Once the wiring between the Encharge units is complete, the unit closest to the Enpower is then wired to it, and then the tops can be screwed on, and the cover added.

Enpower

Which brings us to the Enpower - which is both a MID and an interconnection center.  Note, however, that Enpower is not a general purpose panelboard, but rather, a specially listed UL device and as such, the 120% rule does not apply.  As a result, the Enpower will accommodate up to 80 Amps of PV input (i.e., a fully populated IQ Combiner) and 80 Amps of storage input (i.e., four Encharge 10’s.)

In the picture above, the input from the meter (if serving as a whole-home backup system) or the the main service panel (in a partial-home backup) comes in on the right hand side.  In the picture there is an Eaton main service, bolt-down breaker installed.  If this were intended for a partial-home backup with a breaker in the main service panel, the Eaton breaker could be omitted and the input conductors would land on the existing lugs.

Directly above that main breaker is the isolation relay, which trips when the grid fails and isolates the system for creating a microgrid.  Above and to the center is the neutral forming transformer that allows the system to power 120 VAC loads.  Below that on the left is the common bus that holds (going counterclockwise from the top left) the breaker for the PV, the breaker for Encharge, a breaker for a generator (but not yet), and the breaker for the neutral forming transformer.  

You can see the conductors for all of those connections pre-wired in the photo, waiting to be attached to the appropriately sized breaker.  The actual connections for both the PV and Encharge are made on lugs at the very bottom.

The output to the loads is at the base of the common bus where an appropriate Eaton breaker is added.  Fun fact - the Eaton service rated breakers actually swap L1 and L2 from one side of the breaker to the other!  This means that installers need to pay attention to their phasing so that the consumption and production CTs are reading the proper values - a topic we discussed in some detail in the classroom, and then verified in the lab - damn, isn’t hands-on training the best!

The Enpower switch, the Encharge units, and the IQ Envoy Combiner all communicate directly via Zigbee.  In fact, each unit has two radios, one at 2.4 GHz and the other at 900 MHz and the units switch automatically between channels and frequencies as necessary to provide the clearest signal.  Moreover, if the Combiner box is remote from the Enpower but closer to Encharge, the Encharge unit (or vice versa) can serve as a repeater to get signals to the other devices.  Pretty clever.

Providing Feedback…

Of course, there are two purposes to a training like this during a beta period: to get the initial installers up to speed with the product, and for the installers to provide Enphase with feedback.  Along the way we discovered a diagram that was wrong (nice pickup, Greg!), and a couple of places where esthetics got in the way of utility.  Those are easy things to correct, and Enphase’s CEO himself came into our classroom to hear our feedback directly!  That is a level of dedication to hearing what the long tail has to say that just isn’t happening with other solar companies.

Finally, a point of personal privilege: some years ago we did a video about our installation at Westridge School for Girls here in Pasadena (you can find it here.)  Well what do you know but that video is part of a loop that is playing in the Enphase lobby!  One of the engineers actually came up to me and exclaimed, “You’re the guy in the video!"  Fun way to end our two days at Enphase HQ. 

Bring on the Beta!

Our friends over at Enphase have posted a video to YouTube explaining in non-technical terms what the IQ8 will do for solar consumers, both in the developing world, and here at home.  Here’s the video and some quick thoughts about it.

To quote the video, “Isn’t it cool?"  Well yes, as we’ve been saying for quite some time here, this is waaaay cool.  But here are some other takeaways from the video:

• Strong endorsement for interoperability with the IQ6’s and IQ7’s that we have been installing for the past year and a half.  But no word about how this will work with earlier versions.
• The Enpower switch - which is needed to legally isolate you from the grid - is pictured, but still no details.
• A hint at pricing would be nice!

As far as I’m aware, this is the first, general-public-facing details about the IQ8 and Ensemble that Enphase has released.  It went live on May 28, and three days later is sitting on just under 15,000 views, with 154 up-votes to 6 down-votes.  (What is there to down vote?  Gee, SEDG, troll much?)

This will be very cool technology for our clients, but it will truly be life-changing for folks in the developing world or any place where the grid is unreliable.

Watch this space.

UPDATE - We got a message back from Enphase about a viable approach to the whole-house connection issue discussed below.  

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The end of March found me in San Diego attending the annual NABCEP Continuing Education Conference.  As part of being NABCEP certified, I am required to recertify every three years, and my third recertification occurs this year.  The Conference is a convenient way to earn the credit hours needed as part of the recertification process. 

While much of that is bone dry (such as a full day talking about the most recent changes to the National Electrical Code, made tolerable only by the wit of the presenter, Ryan Mayfield), or surprisingly cool (such as our discovery of Scanifly), nothing was more anticipated than our chance to attend a talk presented by Enphase titled, “Design and Specification of Grid-Agnostic Enphase Ensemble™ based Systems."  (Enphase describes the Ensemble system as being “grid-agnostic” because it is intended to switch seamlessly between grid connected and grid isolated operation.) Here is our take…

The room for this talk, as was the case with a number of talks, was way too small for the number of interested participants.  I arrived early and was rewarded with a seat.  Late arrivals were SRO.  The talk was presented by Peter Lum, with an assist from Field Applications Engineer, Nathan Charles. 

Key Takeaways

For folks looking for just the highlights, here are some (in no particular order):

1. Initial rollout of the IQ8 in the U.S. will be as part of the Encharge energy storage system
2. Encharge will come in two basic flavors, a 3.3 kWh, 1.28 kW unit, and a 10 kWh, 3.8 kW - both with a peak surge output of 150% rated power for one second
3. The 3.3 kWh unit will be 24″ high, 13″ wide, and 12″ deep, weighing 88 lbs, mountable either on the floor or the wall, and it can be mounted outdoors
4. Cells are LFP, cooling is passive, and comms are - surprise - Zigbee
5. The 3.3 kWh unit has four IQ8 microinverters inside, that are field replaceable should one fail
6. The battery cells are not tied to any one microinverter; if a microinverter fails the storage capacity is unaffected, but peak output power is diminished
7. Warranty will be for 4,000 cycles (100% DoD) or 10 years, whichever comes first
8. For a microgrid to form, there must be roughly the same amount of IQ8 power as there is IQ6 or IQ7 power in the system
9. Not compatible with M-series microinverters, “at launch”
10. No word yet on pricing, anticipated deliveries to begin Q4

A Little More Depth

So those are some highlights, let’s talk about some details. The smarts inside the IQ8 is an Application Specific Integrated Circuit (ASIC) with some 5 million gates. As a result, the IQ8 is able to update its control vectors every 20 ns.  Thus, the individual IQ8 provides the primary control over the microgrid, and there is no master/slave relationship.  However, the IQ6 and IQ7 do not have that level of independent control functionality, and so they rely on secondary control, via the Envoy, to stay in sync with the microgrid.

As with its other IQ cousins, the IQ8 is a bi-directional inverter, meaning the same device that can be in an array, converting DC to AC, can be in the battery, converting AC to DC to charge the cells.

Keying off the 2017 NEC (which California will adopt come January), we were introduced to a new acronym: MID - which stands for Microgrid Interconnect Device, and is defined as, “A device that allows a microgrid system to separate from and reconnect to a primary power source.” (705.2)  The Enphase MID is referred to as Enpower, and it essentially has three components: an automatic transfer switch, a neutral forming transformer (recall that the IQ series just uses the two hots, L1 and L2, so the NFT is necessary to power 120 volt loads when off grid), and a control device.  Comms are - you guessed it - Zigbee.

Use Cases

There are two primary use cases for the new Encharge component, Energy Optimization, and Storage with Backup.  Let’s look at each one in turn.

Energy Optimization

Energy optimization, or more to the point, Time-of-Use arbitrage, involves storing energy during the peak production portion of the day (instead of exporting it to the grid) and using it later in the day for local consumption.  This becomes important as utilities - think SCE - switch to TOU rates where energy in the middle of the day is significantly cheaper than energy during the peak TOU period (more and more, something like 4-9 p.m.). 

Our friends over at Energy Toolbase just blogged about, “A Historic Moment for Residential Energy Storage Economics: California’s new Time-of-Use Rates,” noting that for the first time it was possible to model a more economically advantageous system adding storage, than just solar alone.  Which means that the Energy Optimization use case may pencil out on its own - though that is hard to say for sure until we have some actual pricing!

Enphase provided the following illustration (sorry for the lousy images, taken from the side with my phone!). You can click on the image to see a larger version.  

On the far left is the Encharge 3.3 kWh storage system showing the four IQ8’s.  To the right is an array built on an equal number of IQ7 microinverters - but note well, this is not a microgrid configuration.  Why?   Because it doesn’t have a MID, and per the 2017 NEC, you can’t have a grid-agnostic microgrid without a MID. 

In the middle is the latest version of the IQ combiner box.  (We just installed one of these and frankly, I’m not a big fan.  The wiring for consumption CTs requires you to cross reference an unmarked connection block to the lid for the wiring diagram.  This is going to be error prone, IMHO.  Also the Envoy has been reduced to just a circuit board w/out its own case.  Ok, it’s in a NEMA 4 box so the case is probably not needed, but if you are trying to operate it with the deadfront off (say during testing), you need to watch where you put your fingers!  A false economy here, I’d say.)  

Note the green boxes which denote updated software both in the cloud and in the Envoy.  Also, the Envoy picks up a Zigbee device (to communicate with Encharge) to be attached to one of the two USB ports on the Envoy.  (As we noted before, Zigbee is built into Encharge, though not called out on this slide.

This is super easy to set up as the Encharge just lands on one of the breakers in the IQ combiner.  And while it may - assuming our friends at ET are correct - pencil out, it isn’t what all the buzz has been about, so let’s turn to that use case, shall we?

Storage with Backup

Ever since I made my pilgrimage to Petaluma last summer, the amazing microgrid has been the feature that everyone is eager to see.  The good news is, we are closer!  The bad news is, this isn’t going to be as easy as we had hoped.  So here is the key diagram from last week:

There is really only one change from the prior diagram and that is in the upper right hand corner, where the Enphase MID - dubbed the Enpower 200G, has been added.  The switch is rated at 200 A (that is the significance of the 200, G stands for grid), and in theory could be an all home setup.  In a grid outage, the Enpower ATF switches and the microgrid forms - automagically.  Depending on the actual array and storage configuration deployed, will determine how much of the house loads could actually be powered here. 

There is one fly in the ointment in this illustration.  In many parts of the country, the utility meter is mounted outdoors and the distribution panel - the Main Load Center in the slide - is located indoors.  In such a scenario, the Enpower MID could be wired in between those two components with minimal disruption or cost.

Alas, in California, at least in Southern California, that is not how we do things.  99.9% of the services that I have ever looked at consisted of a combination meter and load center “all-in-one".  The rub here is that there is no easy way to physically interconnect the Enpower device between the meter and the load center.  When pressed on that issue, Enphase - accurately, if not helpfully - pointed out that we would have the same problem with any such storage solution and the combo meter/load centers.  True enough, but we have been talking about this product for a long time now, and you would like to think that they would have a clean solution in mind as to how to make this work by now.

UPDATE: I spoke with Enphase Field Applications Engineer Nick Dadikozian about the following possible solution.  Assuming that the utility and the AHJ go along, you could add a separate meter socket and wire the line side to the service, with the load side of the socket connecting to the line side of the Enpower MID, and the load side of the MID to the load side of the meter socket in the combo panel, or if no way to do that, wire to the line side of the combo meter socket and install appropriately rated jumpers in lieu of the relocated meter. 

Of course, another approach is to have a critical loads subpanel, with a breaker on the main panel and the Enpower in between.  That, I suspect, will be the approach most commonly taken.

So there you have it – all that I could absorb from our relatively short session, and some follow-on conversations with Peter over the next couple of days.  (My thanks to him for his patience in dealing with my myriad questions.)

Eager to hear your thoughts on how you will be using this system.

In the highly competitive solar marketplace, some companies are thriving while others are withering on the vine.  It’s the age old question: Who’s Hot and Who’s Not?  In Part 2 of our series on the State of SoCal Solar, we will answer that question, and more!

In Part 1 of this Series we explained our methodology and looked at some overall trends in the data.  To identify the players in the SoCal solar marketplace, we extracted the solar panel and inverter data from our CSI data set.  (Unfortunately, the CSI data does not include any information regarding racking equipment used on a project.) While the CSI data allows for multiple different panels and inverters to be identified with each project, in reality the overwhelming majority of projects report only one panel or inverter choice.  As a result, we will continue our practice from last year and only look at the first choice reported for both solar panels and inverters.

Top Solar Panels

There are two statistics that are meaningful - the total number of panels utilized and the number of projects on which those panels were employed.  We excluded “delisted” projects from our analysis and we will further divide the universe of projects by residential or commercial.

Residential Trends

In the residential space, there are 97 different panel manufacturers listed, but only 15 of them accounted for more than 1% of the total sales volume of 228,372 panels.

Here are our results for the residential market:

From this analysis it is clear that SunPower and Yingli rule the residential marketplace, combining for 37% of all sales and a comparable share of all projects.  New kid on the block, South Korea’s LG Electronics, has jumped out to a very strong start, coming in fifth place behind venerable contenders, Suntech Power and Sharp.  Also notable is that Sanyo - a long-time leader thanks to its great efficiency and thermal properties - has nearly fallen off this chart altogether. (Sanyo accounted for just barely 1% of total sales on just 0.8% of all projects.)

Those are the results for the residential market overall, but does it make a difference if you distinguish leased projects from cash purchase?  Indeed it does, with only three companies having more than 5% market share in both market segments: SunPower (22.8% purchased, 18% leased), Sharp (16% and 5.3%) and Canadian Solar (9.5% and 6%).  LG Electronics sold almost all of its product into the leased systems segment with a market share of 10.7% compared to less than one-half a percent in the purchased segment.  Altogether, the purchased market segment accounted for 65,841 panels sold whereas the leased segment dwarfed its older sister with 162,531 panels sold.

The top-five most popular residential solar panel models were: Yingli YL235P (21,098 units), LG Electronics 255S1C (15,970), SunPower 327NE (12,273), Suntech Power 190S (11,488) and SunPower 230E (9,069).

Commercial Trends

On the commercial side, there are 60 manufacturers listed, of which only 13 accounted for more than 1% of the total sales volume of 350,360 panels.  Here are our results from the commercial side:

Suntech has taken over from SunPower the top spot in the rankings, accounting for nearly 21% of the panels installed and it did it with only 7% of the total projects.  In contrast, second place finisher, Yingli, had more than twice as many projects - 14.4% of the total - but its market share was only 16.2%.  While this select group were the only manufacturers to crack 1% of sales, the remaining manufacturers captured a whopping 28% of all projects.

The top-five most popular commercial solar panel models were: Yingli 230P (43,064 units), Suntech Power 280-24/Vd and /Vb-1 (65,475 - two variants), SunPower 327NE, Trina Solar 230PA05 (21,590) and Trina Solar 225PA05 (17,950).

Top Inverter Manufacturers

Analyzing inverter sales is a bit different since many projects have more than one inverter, and in the case of micro-inverters installations, there is one inverter for each solar panel.  For our analysis, we will just look at the number of projects with the manufacturer’s product listed as inverter number one.

Residential Trends

The CSI data reveals 24 different inverter manufacturers in the residential space, but only 8 of them cracked the 1% market share threshold.  Here are our results for the residential market:

SMA is still the leader, with 31% market share but it is losing ground to our favorite inverter manufacturer, Enphase Energy which now finds itself at 21% of the overall residential market.  When just leased systems are considered, Enphase falls to number four with just 12.7%, trailing SMA (32.4%), Power-One (21.7%) and SunPower (16.3%).

Buried amidst the 1% that is “other” are some very well known names that appear to have fallen out of favor, such as: Outback Power Systems and Xantrex, as well as newcomers SolarBridge and Enecsys.

Commercial Trends

When we shift our focus to the commercial segment the number of players drops to just 13, with only 11 cracking the 1% barrier.  Here are those results:

This is a very different graph.  SatCon Technology has a clear market lead, despite being dogged by rumors of its imminent demise.  SMA is second, but most of that is driven by sales of the same, small-scale string inverters that constitute its products in the residential sector.  Enphase weighs in at 3.5%, not a bad number considering that large-scale commercial sales are not its forte (although that may be changing).

Popular Pairings

While our CSI data set potentially allows for more than 2,300 different pairings of inverter and solar panel manufacturers, in reality the number of actual pairings is far smaller, with just five pairings accounting for nearly 48% of all projects.  Here are the top five pairs:

SunPower - with its 19% market share pairings - clearly demonstrates the joy of vertical integration and a strong improvement over last year when that combination accounted for just 12.4%.  The Enphase-Sharp combination comes in at number 2, but at 8.5% the combination has fallen from 10.3% last year.  (Given that the overall market share for Enphase improved from last year, this “decline” really reflects a broader base of installation combinations.)  Yingli is well represented as is SMA (which, of course, is the dominant driver behind “SunPower” inverters which are mostly SMA inverters re-branded).  Nowhere to be seen in the top five is inverter manufacturer Fronius which last year accounted for two of the top five entries but this year did not exceed 4% in any pairing.  Likewise, last year’s panel leader, Suntech, failed to reach the top five this year and Kyocera was also pushed off stage with no pairing exceeding 2%.

Who’s Hot and Who’s Not?

Next, as we did last year, we decided to take a look at what pairings are the most, and least, costly, efficient, and ultimately, cost effective.  As we noted last year, choosing a second-tier (or third-tier for that matter) solar panel by no means assures you of getting the lowest system cost.  In fact, when we looked at the top ten solar panel manufacturers by average cost per CSI AC watt, the results are a bit startling:

None of these are top-tier panels, but they surely are commanding top prices!  Keep in mind that our overall average price across all systems (excluding delisted) is just $6.23/Watt and you can see that some seriously overpriced systems were built using these panels.

One measure of panel performance (and the only one that can be teased out of the CSI data) is the ratio of PTC panel rating (meant to more closely reflect real-world conditions) divided by the nameplate panel rating (in STC watts), the higher the ratio the better.

The Sun Energy Engineering panels have a dismal 79.25% rating and the average across all of the panels listed here is under 85%.  By contrast, Sanyo panels have an average ratio greater than 89%, ten percent higher than third-tier panels from Sun Energy, yet the systems installed with Sanyo panels averaged $6.84/Watt!  (We note with dismay that the entry for Sun Energy panels represents only one system, installed in Malibu - perhaps this was an example of zip-code pricing?)

How do our top pairings rank in terms of dollar per watt?  Their numbers are all lower than what we see here, ranging from a high of $8.79/Watt for the average of combinations using REC panels to a low of $6.84/Watt for systems using Yingli panels.

What about efficiency?  Which equipment pairings produced the highest and lowest efficiency ratings (as measured by the ratio of CSI Rating divided by Nameplate)?  This is a more involved number, since it is not simply a function of efficient equipment (although panel PTC/STC rating and inverter conversion efficiency are both included) but also the specifics of the site - azimuth, tilt, shading and geographic location.  Nevertheless, good equipment certainly helps so let’s see where the numbers fall.  One additional restriction is required - we will limit this to the residential sector.  Why?  Because larger commercial projects often using tracking mounts that can have efficiencies greater than 100% and would skew our results away from the panel-inverter pairing.

So with that limitation in mind,the highest combination of panels and inverters in terms of efficiency is First Solar panels (thin film) combined with a Fronius inverter for a 90.51% efficiency score (thanks in part to the thin film panels great PTC to STC rating) while the lowest end is a depressingly low of 68.45% derived from MAGE Solar panels and inverters from SolarEdge.  (Not clear if even “power optimizers” can rescue a site with such dismal design characteristics.)

What about our most popular panel-inverter combinations - how did they fare on the efficiency scale?  Not surprisingly, the SunPower-SunPower combination is the winner at 84.38%, but four of our five favorite pairs are closely bunched: Yingli-SMA (83.28%), Sharp-Enphase (82.43%), and Yingli-Power-One (82.35%). The lone outlier was REC-SMA which came in at a relatively low 80.11%.

Who Uses What?

Finally, as we pivot from a pure equipment analysis to one more focused on the practices of the solar installation companies, we wanted to see what the biggest players are using and how does that affect their pricing?  Last year we looked at the top five players, but to give us a broader picture this time around we are looking at everyone with 100 or more projects (excluding projects that are delisted).  Here are our results:

First a comment or two on who made the top five in this list - SolarCity and Verengo have swapped places, Galkos remains at number three (despite our observations about them last year) but REC Solar and Real Goods have been driven down the chart (to numbers six and twelve respectively) to be replaced by previously uncharted Elite Electric and American Solar Direct.  (We will have more to say about all of these folks in Part 3.)

Last year Kyocera was the panel of choice for two of the top five; this year Kyocera did not crack the top fifteen, although it was the second choice for SolarCity.  LG Electronics found a niche with Petersen-Dean (and was the second choice for Verengo), while Chinese panel manufacturers dominated the list, capturing five of the fifteen slots.  Indeed, the big winner on this list would have to be Yingli, increasing its share of SolarCity’s business from 48% last year to 66% now and pushing aside its countrymate, Suntech, to become the number one choice at Verengo.  It will be interesting to see how the ongoing trade dispute and imposed tariffs change these rankings next year.

Power-One gets the big boost this year in terms of inverter choices - elbowing past SMA for the top spot with overall leader, Verengo.  But if you want to talk brand loyalty, Enphase is the clear winner - when it cracks the list it is used more than 97% of the time!

Collectively, these fifteen installation companies accounted for two thirds of all the solar projects in our CSI data set - but did that translate into lower prices for their customers?  To answer that question - and a whole bunch more - in Part 3 we will turn our attention to Outliers and Oddities to discover the good, the bad and the ugly amongst solar companies.  You won’t want to miss it!