Tags: enphase


  09:46:00 am, by Jim Jenal - Founder & CEO   , 2125 words  
Categories: Solar Economics, Residential Solar

I've got solar; why is my bill so high?

Shocking electric billsEvery now and then we get a call from someone who has solar installed at their home but they’re not happy.  Typically this occurs when they get their “true-up” bill at the end of the year, and are shocked to see that the amount that they owe is way more than they expected!  In many cases this leads them to believe that the system simply isn’t working, and now they want a third-party (like Run on Sun) to come out and evaluate the performance of their system. 

Here are the three leading reasons why that bill is so high…

Your system just isn’t working!

Although this tends to be the number one suspected reason for why the bill is so high, generally it isn’t the actual cause.  Most systems are installed properly and are in operation.  But every now and then we come across a system that simply isn’t working at all.  That was the case with one man who was convinced that his system had never worked and that the company that installed it was simply out to cheat him.  We didn’t see signs of that—the system had been installed and the overall workmanship was acceptable on the surface, so it wasn’t like someone just slapped the panels on the roof and ran away.  But here’s the thing—this was an Enphase system so there should have been monitoring in place to answer the question of how well the system was working.  Except that the installer had never bothered to complete the setup of the monitoring system!

When we came out we were able to access the Envoy directly, and while it could see the microinverters, it was clear that they had never produced any power—in over a year!

So how can a solar system owner prevent this?  Simple—when your system goes live, make sure that the installer walks you through the operation of the system so that you can see with your own two eyes that the system is actually producing power.  (This could be a readout on the inverter/monitoring system, or a spinning performance meter, or an indication that utility meter is going backwards.)  Better yet, ask them up-front how will you be able to know that your system is working, and then when it goes live, make them prove it to you!

Your system is working, but…

This second case is actually far more likely: the system is performing, but it is not meeting your savings expectations.  In our experience there are two main reasons for this: hype and over use.

Beware the hype

One reason for this disconnect is that a dishonest sales person over-hyped the savings to be had from the system installed.  For example, we have seen “savings” projections based just on the size of the system, without regard for how shaded the system was, or its orientation - to say nothing of the actual rate structure that is being used by the utility. 

Shaded systems produce less energy.  Systems aligned away from South will produce less energy.  A utility customer on a time-of-use rate structure may well save less than one on a tiered rate structure (depending on how those rates are designed).

The point is to beware of overly simplistic savings projections.  A proper analysis will factor in all of these issues to provide the best possible estimate of savings.

Solar is not a silver bullet

Even the best savings projection is predicated on future energy usage being consistent with the historical data that the solar company was given (unless increases are specifically discussed and included).  While many people with solar power systems become vigilant about reducing their overall energy consumption, others go in exactly the opposite direction.  Indeed, it is not uncommon to hear people say that part of why they want to “go solar” is so they can afford to run their air conditioning “more” during the summer. 

Solar power systems are finite resources—they can only produce so much energy consistent with the size of the system, and most utilities limit system size to the historical energy usage average at the site.  If you install solar, but then triple how much energy you use during the year, you shouldn’t be surprised if you are not saving any money!

What we have here is a failure to communicate!

Which leads us to the most likely culprit—there has been a failure to communicate between installer and consumer.  At the root of this is Net Metering and the complexities of most energy bills.  (A big part of the blame here goes to the utilities who seem determined to make their bills as complicated as possible!)  Let’s provide an overview of this issue and then illustrate with a specific example.

How Net Metering Works

Solar system owners - at least here in SoCal - operate under utility rules known as Net Energy Metering, or just Net Metering for short.  Here is how this works: on the day when your solar power system is given “Permission to Operate” (or PTO) by the utility, your billing will shift to Net Metering (often the utility will change your meter to allow for that switch).  Every day, as your system operates, you will either be exporting (selling) energy back onto the grid, or importing (purchasing) energy from the grid. 

Think of it this way: you get up at 6 a.m. and it’s dark outside.  You turn on some lights, the radio, coffee maker, etc.  Your solar system isn’t producing anything (it’s dark outside, remember?) so you are purchasing energy from the grid.  You go off to work as the sun comes up, and your system turns on.  All day long, your solar system is producing energy, but there is no one there to use it—the A/C is off, the TV is off, the house is dark—so all of that excess energy is sold back to the utility.  Your fancy new meter keeps track of all of that energy coming and going.

Every billing cycle the utility will look at those readings—how much energy did you sell compared to how much did you purchase—and “net” out the difference.  If you were a net seller of energy, you will have a credit.  If you were a net purchaser of energy you will have a balance due.  But here is where some people get confused—your bill won’t ask you to pay for the energy you used that month.  Typically you  will only be charged for whatever “customer charge” there may be along with taxes and other fees.  The bill for your energy usage (or credit, if you are so lucky) is carried forward to the next billing cycle, and the next, and the next, until you get to the anniversary of your PTO date.  Now your usage will be “trued up” and you will either get a bill to pay (assuming that for the year you were a net energy purchaser) or a check (assuming you were a net energy seller, but don’t get too excited because that payment is really tiny).

Here’s the thing, depending on how much of a net energy purchaser you were, that bill could be pretty significant, in some cases well over a thousand dollars or more!

Of course, you would have been receiving bills every cycle that showed what you were accumulating (either a balance due or a credit) but since there is no related payment required, it is easy for some to overlook those bills, and if this process has never been explained—or even if it was but the consumer simply didn’t “get it” at the time—this can lead to a nasty surprise.

Bottom line - solar companies need to do a better job here in explaining how this works.  (Hence this post!)

A real-life example

Consider a hypothetical solar system owner, let’s call him Bob.  Now Bob is a smart guy, but this is the first solar power system he has ever owned.  His installer explained everything to him when the system went live, but Bob was distracted by the excitement of a potentially zero bill.  His system has Enphase microinverters so he has been receiving energy production emails from Enphase every month, and that looked cool, but he never attempted to reconcile his Enphase report with his utility bill (Bob’s not so big on balancing his checkbook, either).  But to be fair to Bob, the Enphase report that he receives is for each calendar month, but his billing is every two months, and they aren’t calendar months; rather, they run from meter read date to meter read date (e.g., 7/28/2016 to 9/26/2016).

The good news is that Enphase has a reporting feature that allows you to enter any two dates since the system went live and receive day-by-day energy production, with the total at the end.  Let’s see what we can learn when we put Bob’s billing data next to his production data from the Enphase reporting feature:

Usage versus production data

Ten months of Bob’s usage versus production

The first two columns show the start and end dates for each meter reading/billing cycle.  The bought column is the amount of energy that Bob purchased from his utility.  (Whoa, what happened during the latest billing cycle???)  The sold column is the amount of energy that Bob sold back to his utility during that period, as reported by the utility.  The next column is the amount of energy that Bob’s system produced during the dates in the billing cycle, according to the Enphase website.  But wait, how can this be?  In that first period, the utility says that Bob only sold 774 kWh of energy, but Enphase says his system produced nearly twice as much, 1,338 kWh!

How do we make sense of this disparity?  The answer is simple: local consumption.  It is important to remember that the utility has no idea how much energy Bob’s system is producing, all they see is how much energy Bob is selling back to them.  So both Enphase and the utility are correct, they are just measuring different things.  Enphase measures total energy produced.  The utility measures energy sold to them—the difference is energy used to power Bob’s house that didn’t come from the utility; rather, it came from the solar system!  In that first billing cycle, Bob’s system produced 1,338 kWh and of that, 774 kWh were sold back to the utility, meaning 564 kWh of that production were used to power his house.  And that means that Bob’s total consumption for the month is the amount that he bought from his utility, 1,402 kWh, plus the solar production that was consumed locally, 564 kWh, for a total consumption of 1,966 kWh.  Applying that reasoning to the rest of the data shows that Bob’s overall consumption has increased in every billing cycle except one, with a whopper over the holidays!  (Maybe too many holiday lights?)

The production data shows that Bob’s system has been performing appropriately - increasing over the summer months, decreasing over the winter months.  Here’s a graph that puts that all into perspective:

Bob's usage versus production

Bob’s solar power system: Lifetime energy production versus expected.

The blue represents the actual energy produced each day.  The gray line is the predicted system production (in this case modeled using the CSI calculator). Over the lifetime of the system, the maximum amount of energy produced in a day was 29.7 kWh (42% above what was predicted for that day) and on the day when this graph was created, the system produced 15.7 kWh.

Generally, the performance peaks well above what is expected (particularly in the late June through early November period).  But once we get into mid-November things deteriorate—not because of a fault in the system, but because of abnormally wet weather here in SoCal (as we head into a 1″/hour rain storm today!).  For much of the past two months, actual production has fallen well below what was predicted, with just 77% of predicted being realized so far this month.  And yet, despite all of that, overall the system has still produced 99% of its estimated lifetime production.

This points out a couple of key things to me: First, you just gotta love the data that is available through the Enphase monitoring system.  It allows system owners and installers alike to have near-real time access to system performance, as well as to review long-term data to discern trends and uncover patterns.  Priceless!

Second, we as solar professionals need to do a much better job of informing our clients so that they know what to expect.  (I’m leaving out the hype-sters who couldn’t care less what the consumer knows as long as they make a sale.) 

We live with this stuff every day but for most of our clients, this is all brand new, and confusing.  We need to take the time to explain how this works so that they can understand the actual value of their investment.


  04:49:00 pm, by Jim Jenal - Founder & CEO   , 1451 words  
Categories: All About Solar Power, Solar Economics, Residential Solar, Ranting, Energy Storage

Elon Musk's 3-Biggest Powerwall Whoppers

Elon Musk is a visionary and a showman, but occasionally his enthusiasm for his vision gets way out ahead of reality.  Nowhere was that disconnect more on display than this past week when he made his much talked about announcement of the Tesla Powerwall battery storage system.  While we share the vision for the potential of battery systems (such as the one Enphase Energy is set to release later this year, albeit in a far more understated fashion), when 38,000 people go online to order a product that doesn’t yet exist, it is time to debunk some of the more exorbitant claims made by Musk. 

Here are the three biggest whoppers that Musk made during his Powerwall presentation (video below).

Whopper #3 - Power for an ice storm or other significant grid failure event

Musk touted the “peace of mind” that would come from having the Powerwall, and said, “if there’s a cut in the utilities you’re always gonna have power, particularly if you’re in a place that’s very cold, now you don’t have to worry about being out of power if there’s an ice storm.” (See video at 8:35.)

The Powerwall unit that Musk was talking about that was designed for “daily cycling” was a 7 kWh unit that is priced at $3,000.  The average home in the Run on Sun service area uses 25 kWh/day.  So a single Powerwall unit provides roughly one quarter of the energy demand of an average home.  If your desire for “peace of mind” means running your home for a full day in normal fashion, you will need to purchase 4 Powerwall units (assuming you have the wall space to mount them) and that will cost you $12,000.

Of course, many outages last longer than a day.  The longer you want to stay powered, the more units you will need.

Whopper #2 - Powerwall will work with existing solar systems

Musk insisted that Powerwall has been designed to work with solar systems, “right out of the box."  (See video at 8:25.)

Except… that the Powerwall is designed to fit between existing solar panels and the DC-AC inverter(s) in the system (i.e., on the DC side of the system).  But here’s the thing - the vast majority of inverters are what are known as “grid-tied,” which means if the grid goes down, the inverter shuts off, and stays off until the grid comes back.  If the Powerwall is on the DC side, there is no way for it to “mimic” the grid (which, of course, is on the AC side), and so the inverter will shut off.  While the inverter could certainly be replaced with a hybrid inverter (that can work both independently and tied to the grid) such a replacement is a pricey undertaking and certainly not a plug-and-play installation.

But Musk, like the true showman that he is, saved his biggest Whopper for the end…

Whopper #1 - You can go off grid… for $3,500!

Warming to his subject, Musk really brought down the house with his most outrageous claim of all:

You could actually go, if you want, completely off-grid.  You can take your solar panels, charge the battery packs and that’s all you use.  So it gives you safety, security, and it gives you a complete and affordable solution.  And the cost of this is $3,500."  [Gasps and applause from audience.] (Video at 8:55.)

No.  No you cannot.

Let’s unpack his statement.  There’s two major claims here, neither of which is true.  The first is that you could go completely off-grid, and the second is that it would cost you $3,500.  So let’s start with the easy one to disprove, indeed, we already did above: this won’t cost $3,500.  The Powerwall provides 7 kWh of storage.  The average house uses 25 kWh/day.  If the battery has to run your house for just one day, you would need 4 Powerwall units at a cost of $12,000.  (The 7 kWh unit is the one designed for daily cycling - what you need to go off-grid, and it costs $3,000 - if you could actually purchase one, which you can’t.)

So that’s easy to debunk.  But what about the second, more fundamental question.  Can I use this Powerwall system to go off-grid without changing my middle-class, suburban lifestyle?  For most folks the answer is simply, no.  Here’s why.  When you go off-grid you need to be able to meet all of your energy needs all the time without assistance from your local utility.  To do that, you need a battery system large enough to last you during the longest typical shortfall of available energy (i.e., how many stormy/cloudy days in a row will you see), plus a solar array large enough to charge that battery on sunny days while meeting the household needs.  Turns out, that is quite a lot of both.

Folks who design off-grid systems (very few of which are found in areas like Pasadena), typically design for three (or more) days of self-sufficiency (or autonomy, as they put it).  For our typical, 25 kWh/day home, that would require storage of a minimum of 75 kWh.  But according to Tesla, you can only stack a maximum of nine Powerwall units, which limits you to 63 kWh.  Sometime around noon on that third day without sun, your house will shut down.  Oh, and that much storage will cost you $27,000.

What about the solar array side of the equation?  Let’s start by asking how big an array can you fit on an average house?  House sizes have trended bigger in the past couple of decades, so more recently built houses are an overstatement of the average house out there.  Still, to have a starting point (and to give Musk the benefit of the doubt), let’s assume that our average house is 2,400 square feet (a fair estimate based on US Census data), and that it is optimally designed to maximize solar production: a near perfect square with a true south face, pitched at latitude (34° here in Pasadena), with no shading.  Of course, we still have to give the Fire Marshall the desired setoffs so that gets us to 1,115 square feet of roof space (math available upon request), enough for 62 LG 305 solar modules, but because we need to use a hybrid inverter with fixed string sizes, we will drop that down to 60 solar modules. That yields an 18.3 kW system which at $3.50/Watt would cost a cool $64,000 - and be bigger than our biggest ever residential installation. 

So the Sixty-four Thousand Dollar question becomes: How well will that do on meeting our needs?  Per the CSI calculator, this maximal system will produce roughly 29,000 kWh in Year 1, or an average daily output of 79.5 kWh.  (Less in the winter, of course, when you are most likely to see those cloudy days.)  After providing for my daily needs of 25 kWh, I have 54.5 kWh to spare, not quite enough to fully charge my batteries (which require 63 kWh).  A scenario where I have two cloudy days, followed by one partly sunny day, followed by two more cloudy days could easily leave you in the lurch.  And for this you paid a total of $91,000!  If you live somewhere with poorer weather than what we find in the Run on Sun service area (i.e., pretty much the entire rest of the country!) your performance will be even more dismal.

The true value of storage

The sad part of this whole thing is that battery storage combined with solar is going to be huge, but not for the reasons Musk alluded to in his speech.  The future of utility rates is the shift to time-of-use rate structures - a fact already well and painfully known by our clients in SCE territory, and soon to be seen by everyone.  Time-of-use rates, where utility customers pay more for energy during the peak part of the day, are the only way to match utility costs with customer charges.  (It is the head of the Duck in the famous Duck Curve below.)

The famous duck curve

That “overgeneration” that drives down demand at noon is presently fed back to the grid, where the grid operator has to modify the power mix to accommodate it - in essence, it is wasted.  (Although presently, net metering customers get full retail credit for it - something, that in all likelihood, will soon go away.)

But add storage to the mix, and you shift that overgeneration from the middle of the day, to the evening peak hours, benefiting the time-of-use customer as well as the utility.  It is the way to bring about a peaceful end to the utility-solar wars, and it is the true benefit of storage to solar customers - without oversizing either your solar array or your storage system.

So let’s all get excited over solar with storage, but for the right, and much more cost-effective reasons - and not the nonsensical hype being spewed by that super showman, Elon Musk.


  07:13:00 am, by Jim Jenal - Founder & CEO   , 741 words  
Categories: Solar Economics, Residential Solar, Ranting

How can love survive?

In the stage version of The Sound of Music, there is a song about the perils of romance among the affluent titled, “How Can Love Survive” – sadly it was cut for the movie. But I’ve always liked that song and I was reminded of it while reading a piece over at greentechsolar that debated the question: Will smaller solar installers survive? Lest you have any doubt where we come out in this debate, the answer is simple: heck yeah! But let’s see why…

The debate was held last week at the U.S. Solar Market Insight event in San Diego and was reported on by the always interesting Herman Trabish in a piece titled, “GTM Debate: Will Smaller Installers Survive in Tomorrow’s Solar Market?” (H/T solarwakeup.com)  The debate featured Vivint Solar’s VP Thomas Plagemann squaring off against SunPower’s Residential Solar VP/General Manager Martin DeBono.

Plagemann’s comments reflect all of the arrogance and self-importance we have come to expect from such major players:

“In this business, we have to take three essential steps,” Plagemann said. “Find and acquire customers, design and install systems, and finance the systems.”

Financing has to come first, he explained. “A typical equity finance fund of $50 million, at $2.50 per watt and 5 kilowatts per system, means 4,000 systems. Using small installers to get that scale cedes control.”

Vivint has installed home security systems nationally for twenty years and keeps that control. “We acquire customers. That’s what we do. We took that customer acquisition engine and applied it to solar. Our success in the last twelve months is the answer to this debate.”

(Emphasis added.)

We note that Vivint has mostly done its work outside of the California market, so that $2.50/Watt number is not reflective of their presence in our fair state.  Indeed, when we last looked at CSI data for the first half of 2013, Vivint did not even crack our list of the top 16 installers. Here’s that graph:

Top 16 solar installers first half of 2013But even if they aren’t (yet) big in CA, is there any doubt that you could have gotten the same response from someone at SolarCity?  Their goal is to make solar a commodity with a standard set of offerings - if your roof fits into that model (and your FICO score is high enough) - you are golden.  Just don’t look for any real care and attention to detail.

Speaking for the little guy was DeBono from SunPower (with just a little irony given the size of SunPower).  He noted that:

“Small business is the second most popular institution in the U.S., after the military,” he said. People want to buy from small businesses.” In the home building industry, 40 percent of new homes are built by large national builders, but 60 percent are built by small local builders. Solar installation will break out the same way, he said.

“Large solar installers can leverage the advantage of scale as long as everything is uniform,” he argued, “but variance is the rule in solar, and variance is anathema to scale. For customers that don’t fit into a box, local installers are the answer. Variance will cap the rise of national installers.”

DeBono went on to note that forming a partnership with SunPower provides installers with leverage and a national brand.

We agree that establishing partnerships is essential, though we might question the degree to which SunPower is a national brand in the way that matters most - consumer consciousness.  Toward that end, we believe that partnering with a company like LG Electronics - which truly is a national brand and has the ad budget to prove it - makes more sense for small installers.  But how do you get access to the other essentials of the business?

Run on Sun has been exceptionally fortunate to have partnered with Focused Energy, who is much more than a premier distributor.  They have not only been our primary supplier since we first connected a few years ago, but they have offered us support, flexibility and insight that has made them an essential part of our success.  If you run a small solar business and you haven’t connected with them yet, we would encourage you to check them out.

As we have said many times, solar has to be more than just another business.  We have to be better.  At the end of the day, that is why the small installers will survive: because we care more, and that translates into greater value for our clients.

Bonus for sticking around to the end:


  09:24:00 am, by Jim Jenal - Founder & CEO   , 820 words  
Categories: All About Solar Power, Solar News, Commercial Solar, Safety

Fire! Is Solar a Threat?

We saw a piece today about a fire on a distribution warehouse in New Jersey that was gutted in part because the local fire department was afraid to interact with the solar power system on the warehouse roof.  As solar makes greater inroads on commercial buildings, what can we as an industry do to address this concern? (H/T SolarWakeup.com)

The distribution center, owned by Dietz & Watson, was a refrigerated warehouse that supported over 7,000 solar modules according to news reports.  From Google we get this image of the center in happier days:

Dietz & Watson distribution center, new jerseyThis is a very large commercial array by any measure - even if those are 200 Watt modules you are looking at a 1.4 MW install on the roof, to say nothing of the additional capacity installed in the carports to the west.

It is also a very nicely designed array with clear access paths throughout the roof and plenty of potential areas that could be broken open to allow for venting (although I’m sure from a fire fighter’s perspective, they would always want more).

Sadly, this is how it looked during the fire:

warehouse on fire

Here is the view of the blaze taken from the raw video recorded by local TV station NBC10:

Fire on warehouseThis image makes clear that the NE quadrant of the building has been extensively damaged - the black area is where the solar panels have been completely destroyed.

The image also makes clear that the fire department chose to fight this fire from the ground, spraying water and foam onto the roof as opposed to going on to the roof itself.  (There was no explanation given as to the cause of the fire.)

The local reporting indicated that the fire crews were concerned about possible collapse of the roof due to the amount of water being poured onto the fire.  But they also mentioned the concern over possible electrocution:

Firefighters had to pull back at some points because the fully-charged solar panels posed the risk of electrocution.

“With all that power and energy up there, I can’t jeopardize a guy’s life for that,” said [Delanco Fire Chief Ron] Holt.

So what to make of all of this?

There can be no doubt that solar installations have the potential to make the already dangerous business of fighting a fire more hazardous.  Strings of solar panels can produce as much as 600 Volts DC and as a general rule, there is no way to shut them off from the ground.  While a DC disconnect on the ground could isolate the array from a ground mounted inverter, there is still potential in the conductors leading from the roof to the inverter.  If those conductors are shorted together - due to either a fireman’s actions or the fire itself - there is the potential for significant arcing and possibly even electrocution.

Of course, one way to reduce that risk is through the use of microinverters or AC modules.  With a microinverter, the only conductor runs are AC which can be safely switched off from the ground meaning that any conductors coming from the roof to the ground will be safe.  The individual solar modules can still produce power, but there are no strings to slice into or suddenly short to create a dangerous condition on the roof.  While microinverter systems are not generally considered on systems of this size, Enphase recently announced the use of their products on a 2.3 MW commercial array - possibly larger than this one.

Which begs the question - would that have mattered here?  Maybe, maybe not.  The question really is a function of how well would the local fire department understand the difference?  When we talk with local fire inspectors, they are always appreciative of the added safety to be found with microinverter systems but how well does the inspector’s understanding extend to the fire crews reporting to that fire?  Would they have trusted that the claimed safety was real and moved more aggressively to fight the fire on the roof?  Or would they have elected to play it safe?

The solar industry can work to develop safer products - which microinverters surely are - but that won’t matter if local fire crews aren’t educated as to how best to fight these fires.  Interestingly, while local codes require solar installers to provide all sorts of largely useless signage on our arrays - for example, specifying the nominal AC voltage and current as if that would make the least difference to anyone - there is no requirement to indicate whether the type of inverter being used.  Absent such signage, how would a local fire crew know what they were facing?

Maybe our friends at Enphase can design a placard to attach to our AC disconnect switches that advises the local fire department that throwing that one switch renders the conductors coming down from the roof safe.

So much of what we must do in the solar industry is education - this is perhaps one area where we need to improve our efforts.


  07:04:00 am, by Jim Jenal - Founder & CEO   , 908 words  
Categories: PWP Rebates, Commercial Solar, Non-profit solar, Westridge PAC Project

Westridge Case Study: Part 2 - Run on Sun Gets it Done!

In Part One of this three-part Case Study we learned how Westridge School chose Run on Sun as their solar contractor.  Here in Part Two we focus on the actual process of the installation as seen from the client’s perspective.

Run on Sun Gets it Done

With the paperwork filed and the rebate secured, Run on Sun had a very tight window —  less than two weeks in April 2012 — in which to install and connect all 209 solar modules and get the monitoring software up and running. The goal was for the project to be completed and operational by the time Westridge students returned from Spring break, so time was of the essence.

Enphase display of Westridge projectFor the rooftop display Run on Sun used a microinverter system supplied by Enphase Energy, which allows customers and solar installers to track the output of the modules, individually or collectively, from the convenience of their computers, iPads or smartphones. This software was a selling point for the school, because it would make the technology accessible to students and allow teachers to creatively incorporate aspects of the solar system’s performance into classroom instruction.

The modules were grouped into three sub-arrays that formed a larger circuit. Under each module, a microinverter was installed to convert DC energy gathered from the module into AC power, which could be combined and fed back into the school’s electrical service. The 1:1 ratio of microinverters to modules allows for a more detailed readout that lets users know the output of each module and gives an easy-to-read display should anything ever go amiss, from a connection issue to dirt on the module’s surface.

Throughout the installation Williams remained on hand to oversee the work, though there were no delays and no change orders requesting funds beyond what had been originally estimated. Within the assigned two-week period, Run on Sun had completed the project on time, and everything was in working order.

Westridge project complete

A Picture-Perfect Roof, Perfected

“I’ve worked with a lot of contractors, and I can honestly say, in this situation, this was one of the most seamless projects we’ve ever completed,” Williams recalls. “They were here early on the first day and, boom, they got it. It was done on schedule, at the price they said and signed off by the city. I wouldn’t hesitate to do a project like that again.”

A Truly Happy Anniversary

April 2013 marked the one-year anniversary of Westridge School’s solar installation, and Williams reports the system is running smoothly. The Enphase software makes it easy for officials, teachers and students to monitor the activity of all 209 modules, but Run on Sun also keeps a close eye on the operations and reaches out if and when an anomaly is detected. In the event that an outage or a decline in energy production should occur, the company promptly notifies the school.

For example, when one of the modules stopped reporting and apparently needed to be replaced, Run on Sun immediately contacted Williams to schedule a visit. The rest of the modules were still in full working order, and upon close inspection it was revealed that a connection had come loose. Still, to ensure maximum performance, the company replaced the microinverter at no cost to the school.

Another time Williams received a notification email from Run on Sun after the campus Internet connection had been temporarily cut during some service upgrades. And when the energy dipped from its norm of exceeding system predictions to 98 percent of anticipated, a call came in with a recommendation to check the array for accumulated dirt. After a brief spray with a hose, the system was back to producing at maximum capacity.

At the one-year mark, the school became eligible to receive its first annual rebate from Pasadena Water and Power. This is the first of five annual rebates it will receive, the dollar amounts directly correlated to the system’s actual production.

When a technician came from the city to assess the energy output of the system, the school was excited to learn the results. The city’s readings gave some very welcome news, indeed — the energy generated by the installation was above and beyond the original estimate provided to PWP, and it looked like the first rebate would be larger than anticipated.

“He said, ‘You’re over your estimate,’ and that’s all we could ask for,” says a thoroughly pleased Williams. “To date, everything that was promised to us was delivered — plus.”

In terms of the amount of energy generated, the rooftop system has continued to outpace expectations. The school expected to see a return on its investment in seven years, but it’s shaping up to come in as few as six. Because of the installation, Westridge is using 30 percent fewer kilowatt hours and is seeing its bills reduced by thousands of dollars each month, in addition to the rebate. The overall savings is far greater than the cost of running the air-conditioner in the gym, the initial impetus for bringing solar to campus. To Williams, making the decision to go solar was a “no-brainer.”

“The neat thing about this is it runs itself. If somebody walks onto campus, they don’t know we have a 52 kilowatt solar system on campus,” he adds. “They don’t see it. It doesn’t impact anything. All you do is save money.”

We will conclude this three-part Case Study with Part Three - Advice for the Solar Reluctant.

The preceding is an excerpt from Jim Jenal’s upcoming book, Commercial Solar: Step-by-Step, due out this summer.

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Jim Jenal is the Founder & CEO of Run on Sun, Pasadena's premier installer and integrator of top-of-the-line solar power installations.
Run on Sun also offers solar consulting services, working with consumers, utilities, and municipalities to help them make solar power affordable and reliable.

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