Solar Panels and Inverters, Our First Solar Repair Experience.

In 2012, shortly after moving to electric with our BMW Active E, it became apparent to us that installing a solar array on our roof was going to be beneficial for us to lower the cost of our transportation fuel as well as our consumption of energy at home.  Producing our own fuel coupled with net metering and time of use would provide us with efficiency that would provide for a rather quick payback.

As I understand it, Net Metering allows utility customers with the ability to export the power generated by their devices (in our case, our solar panels) to the utility at the retail rate of energy as a credit against our overall consumption.  Time of Use is a program that provides differing pricing for electricity depending on the time of day and week that energy is consumed by a utility customer.  When we first started on this program, our peak times for energy mapped perfectly with the hours of sunlight.  That is to say, the peak energy times were from Monday to Friday from 10am to 6pm.  This meant that during the the times that we were not at home, our solar panels would produce enough credit to be offset during our primary usage, which is after 6pm and before 10am (in SCE territory, since we installed our panels, this peak time has changed and shifted to 2pm to 8pm).  Under our original assumptions, and armed with a single EV that was capable of an 80-100 mile range, we figured our break-even for this project to be in the approximately six to seven years.  As many long-time readers have found out, it was soon after getting into our BMW Active E that we dedicated ourselves to a primarily EV existence that we went from one EV to three EVs and back down to two EVs.  With the amount of driving that both my wife and I did, this break-even point was reached sometime last year (around the three and a half to four year mark.)

When we first bid out our homes’ solar PV, we shopped it around and ended up with Solar City.  As I’ve documented before, because there was a snag in the age of our roof, we had the opportunity to re-open this to others and ended up with Real Goods Solar (RGS Energy).  We documented all this in some articles on this blog.  I did a follow up that covered the installation.  Because of how things worked out for us, we opted to pre-pay our power purchase agreement with Real Goods Solar for the 20 years of service that we signed up for, if we do this again now, we would buy the system instead, but I didn’t want to have to worry about maintenance and the like.

Which brings us to the subject of inverters.  As I understand it, the inverter is the device that converts the Direct Current (DC) produced by our solar panels into AC (Alternating Current) energy that our appliances and other domestic household devices uses. Every solar company that I spoke to during the bid process basically said that the main thing that would break in a solar installation is the inverter.   Under original solar installation designs, solar installations would have ONE or TWO inverters that connect the whole system to the home and electrical grid. This means that if the inverter failed, the energy produced by the solar panels would not be converted to AC power and be effectively out of service for the whole system until it gets repaired.  We picked Real Goods Solar primarily for financial reasons.  However, at the time, they pitched an interesting system using micro-inverters.  Instead of one (or a primary and backup) inverter situation for the house, each solar panel has its own inverter that converts the energy produced by each panel to AC.  This configuration spread the risk of outage from the whole system to just a single panel at a time.  Being a systems guy and understanding single points of failure versus minimizing this, I appreciated the pitch, but money savings really drove the decision.

One of the technical benefits we got from having the micro-inverter solution is we are able to see the production of our solar system down to the panel level.

So, on a normal day, we can see the panel production on either the website on a browser:

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Or on the mobile app.

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A few months ago, we experienced our first repair under this program.  On the weeks prior to failure, I started receiving alerts regarding AC voltage being out of range and on March 8, I noticed that one of the panels had a hard failure.

This is a screenshot of the email that I received to show the errors in one of the micro-inverters that started to occur.

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It looked minor at first, but as you can see in the graphic of our system, one of the panels is grey.  And this is a good indication of the failure AND the location of the failure in our system.

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I reported this to Real Goods Energy and received a trouble ticket on March 9th. They remotely diagnosed the problem and required me to contact the owners of the system.  Since I am on a Power Purchase Agreement (PPA), I don’t actually own the system on my roof, I effectively buy power from those that do at a predetermined rate when I signed my contract.  Traditional PPA purchasers do this on a monthly basis that have riders that increase the cost per kWh over the years, but we decided to prepay the entire contract at the time that we finalized our deal and therefore fixed our cost per kWh soon after the installation was complete.  Therefore, technically, we don’t own the system on top of our roof.  The owner to the system provided approval and we waited for the repair to be completed.

It took about a month for the full repair to be completed and I estimate that we lost about 40kWh of production from having one panel out that entire month.  To put this into perspective, the whole system produces 40kWh on a Summer day, so even though the panels were missing one of the 28 panels on the roof from producing, my outage was only equivalent to one day’s outage with a more traditional set up.

So, what does a micro-inverter look like?  Well.  Here are a few photos.

Here is the broken one getting put back in the box.

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Here it is on the roof.

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And here it is installed and in-place.

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In writing this article, I was looking for pictures of larger inverters and came across this picture of a commercial solar installation from Brightergy.com.

Solar Inverters at Cross Midwest’s solar-power installation

The picture is from an article “How Solar Inverters Work” from February 6, 2013 on the brightergy website. It also covers inverters.

Here is the picture of a more common inverter from Wikipedia’s article on Solar Inverters.

Solar Inverter from Wikipedia
Solar Inverter from Wikipedia

Why would I not want to use micro-inverters. In moderate climate, like California, it works great. However, someone in Arizona has mentioned to me that it is too hot in their climate. I don’t know if this is true, but it has been reported by one person to me.

Consider going solar, use our referral code here.   If you wish to have a longer discussion, I have access to other installers as well.  Send me a tweet and we can get that process started interactively.

Tesla Solar EVent

On Friday, October 28, 2016, approximately a year and a half since the original Tesla Energy launch EVent on April 30, 2015, Tesla improved upon the PowerWall and PowerPack, Tesla revisited Tesla Energy with the launch of the Tesla/Solar City product launch for the Solar Shingles.

Tesla Energy 2015 Launch

I did a bunch of tweets during the original Tesla Energy, PowerWall and PowerPack launch event from April 30, 2015…

(Here’s a link to the Flickr album from the Tesla Energy event.)

Tesla PowerWall

Some selected tweets from the original Tesla Energy Event:

 

 

 

 

Tesla Solar Event

The focus of the event held by Tesla this past Friday, October 28, 2016, at Universal Studios Hollywood was on the newly unveiled Solar Roofing products that were developed in conjunction with Solar City.  As impressive as this product line is, the Solar Roof is definitely not a financial fit in our current configuration.  Many who follow this blog will note that we just achieved our break-even point this past year (the fourth year of our twenty year agreement for Solar power) and paid less than $20 for all of the fourth year of energy (not counting taxes.)

One could say that neither the PowerWall nor its succeeding product, the PowerWall2 really makes economic sense for our use case either.  With net-metering still in effect in California, the economics of the PowerWall2 is not the reason to go ahead and purchase one.  However, coupled with time-of-use, and the whole-house backup capabilities of the PowerWall2, it looks like a great solution for a whole-house backup system.  With our summer peaks generating power at 40 kWh, two units may be all we’ll ever need.  I intend to recharge the system during the super off-peak time of day and get more bang for our buck by feeding back our solar production to the grid at a higher rate. Southern California is known to be very seismically active, and a whole-house backup system might just be something that would be really cool to have.

I was involved in tweeting out details for the event this past Friday through both my own account and my friends at Teslarati’s as well.  The guys at Teslarati had family commitments to attend to during the event and I was approached to see if I could possibly cover their Twitter feed for them, so I embed those tweets that I sent out here.  Hope those of you that follow Teslarati and my Twitter accounts enjoyed the coverage.

 

 

 

 

 

 

 

 

 

 

 

 

Since I committed to cover the event for Teslarati, I figured that we should arrive a little early.  No press pass for me, but covering it as an owner was fine for them.

The valet at this event provided sent us a text with a mobile website to handle the request and retrieval of our vehicle, it’s a lot more greeen than handing us a paper voucher.  I don’t remember whether they had this system at the last event we drove in for. It’s been a while that we valet parked a vehicle at a Tesla EVent since the last Tesla event for us was the Gigafactory Party that was the subject of our Long Way Round Round trip.  However, we took a loaner to the event. So, I photographed the vehicle and key to ensure that I know what I’m looking for.  Just in case this SMS ticket method were to fail.

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We were among the first ten cars through the valet and had been asked to wait in a lounge area to the right of the check in desk until they opened the “neighborhood” area.

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I think that the folks were unprepared for the number of people forced to wait in this area. It was standing room only.

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Luckily, the wait was not too long before the “neighborhood” was opened for us to enjoy. Fans of the old “Desperate Housewives” set will recognize the set as “Wisteria Lane.”

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Tesla’s catering services were the best that we’ve had in the various parties that we’ve attended. The neighborhood setting had enough seating, the food and drink was plentiful and did not run out as they have in the past.  There was a mix of self-serve sections as well as server provided locations.

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The bar lines were manageable and had a good selection of wine and other drinks.

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A few panoramics of the first neighborhood, before the section with the four remodeled houses was opened for the presentation.

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And right around 5:30pm, they let us into the neighborhood with the new Solar Tiles.

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Here’s the stage with the sun shining brightly on it.

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I was able to take one panoramic shot of the stage and the two closest houses to it.  On the left side of the stage is the house that the Model 3 prototype will emerge from later in the presentation.  I didn’t actually notice it emerge as I was closer to the right side of the stage.

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Here’s a closer shot of the house with the Model 3 in the garage before it emerged during Elon’s presentation.

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The house on the right’s shingles was more obviously solar shingles.  However, aesthetically they were quite pleasing.

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While waiting for the event to start, we were looking at the two houses on our left and were wondering whether they were solar shingles.  Something that Elon revealed as fact during the presentation.  The Tuscan Solar Tile, as this model was revealed later, is ideal for many homes in Southern California.

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I even tweeted my suspicions just prior to Elon’s talk.

 

The Presentation

Since the presentation was a joint Solar City/Tesla Event, it started off with a few minutes with Lyndon Rive, Solar City’s CEO and Elon Musk’s first cousin.

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Afterwards, Elon spoke.

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Here’s Tesla’s official YouTube video of the event:

Needless to say… The Solar Tiles are impressive. However, as I previously mentioned, we recently re-roofed when we installed our Solar Panels four years ago. So, that’s just not going to happen. We paid less than $20 for last year’s power and have recently hit our break-even point for our solar panels.

We did take a few good close ups, but a lot of the pictures can be seen on our Flickr Album of the event.

Tesla Solar Roof

Here are some of the pictures on the album above.

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Even though we’re probably not going with the cool solar tiles, the whole house backup thing though is VERY tempting. So tempting that we put in a deposit for a few of them.

How many you may ask? Probably more than we needed… But here’s a hint.

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Especially since the new version can be more efficiently mounted and stacked this way.

The original PowerWall had to be installed side by side and mounted on the wall.

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Looks really cool, but I think it’s probably more efficient to install it stacked.

One other thing about that Powerwall… It’s capacity is doubled in the same amount of space at less than double the price, considering the fact that the AC-DC Inverters are included. I also did the iPhone 4 width test that I did with PowerWall 1 with PowerWall 2.

PowerWall 1 compared to an iPhone 4.

The Home solution is slightly wider than an iPhone 4s #TEatTesla

PowerWall 2 compared to an iPhone 4.

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Color me impressed.

Model 3

The surprise for me was the appearance of the Prototype Model 3 at such close proximity.

The album for the event has a lot more pictures of the Model 3, but here are a few more shots.

It’s bigger than I had hoped.  It is smaller than the Model S, but bigger than the Active E. We got a few great shots in before security cordoned off the vehicle from closer inspection.

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Still a great shot that the better half took of me with the Model 3 in the background.

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We didn’t get any good interior shots, but this was the best shot of the Model 3 interior… Security was starting to cordon off and was kicking us out.

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It may be bigger than what I expected, but I still like the Model 3.

A multi-Tesla neighborhood… Sounds like a nice, clean environment.

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There was also a nice, blue Roadster there.

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There were a few Xs there, but just didn’t take pictures. There’s just so many of them around now. 😉

It was a fun event. The food and drink was the best service of the ones that I’ve been to. The valet had a wait, but I think that it was better than previous events that I used valet in. Take that last sentiment with a “grain of salt” since I used the bus at the Gigafactory Party, and I found that to be the most relaxing way in and out of a Tesla Party. The party may have been free to attend, but I walked away with a very expensive deposit for some batteries for the house. We’ll have to see how long before we get these installed.