SolarEdge has gotten a fair amount of buzz this week thanks to their IPO, but it made us think that maybe it was time to revisit the question—who really has the edge: DC-to-DC “optimizers” like SolarEdge or Enphase microinverters?
|Which would you choose?|
|Enphase Microinverter||SolarEdge Optimizer|
In our view this is a bit of a “no-brainer” and it really comes down to the following three reasons:
Reason #3 - Integrated Grounding — In every solar array, all metal surfaces have to be grounded for safety. Enphase microinverters now feature integrated grounding, which eliminates the need for a separate equipment grounding conductor. SolarEdge does not have this feature and, depending on the jurisdiction, may require the use of a dedicated copper conductor to be run from one unit to the next. This increases both labor costs as well as part costs (copper is expensive these days!). Far better to have that grounding built-in at the factory than assembled on the roof.
Reason #2 - Easier Installation — Beyond the need for that equipment grounding conductor, the SolarEdge system requires the installer to not only mount the optimizers on the roof beneath each panel, but it also requires the installer to mount one or more heavy (51 to 88 pound) inverter(s) on the wall. In contrast, Enphase combines everything into one unit, so there are no heavy inverters to mount to the side of the client’s house.
Reason #1 - Greater Reliability —The number one reason for us at Run on Sun is the greater reliability you get from using Enphase. Frankly, the SolarEdge approach combines the worst of both alternative approaches (i.e., string inverters versus microinverters). You are still putting power electronics in the demanding environment of a roof, AND you have combined that with a single point of failure with the inverter back on the ground! When you use Enphase microinverters you eliminate that single point of failure and you are going with the industry leader in creating reliable, roof-mounted power systems.
Put all of that together, and we think Enphase microinverters provide the greatest value to our clients, which is why we feature them in all of our solar power systems, despite the occassional “buzz” other approaches might generate.
Ever since a fire chief in New Jersey let a warehouse burn for days because of his concerns about dealing with the solar power system on the roof, we are seeing a spate of these stories now migrated to concerns about residential solar as well. We think the risk is greatly overstated, but it turns out that allaying a firefighter’s fear of solar is one more argument for using Enphase microinverters.
We wrote about the New Jersey issue back in September and the fire chief was quoted as saying, “with all that power and energy up there, I can’t jeopardize a guy’s life for that.” Now no one wants to see anyone injured because of a fire, and certainly not because solar was on the structure that was burning. (The cause of the fire has not yet been disclosed.) But was that really the only option—avoid the roof and let the fire burn for days?
Worse still, now we are starting to see a steady drumbeat of similar stories with a residential slant.
Take this story that aired on a local news outlet with the scary title: Firefighters Warn Solar Panels Could Prevent Homes from Being Saved in Blaze. While the homeowner is thrilled to be saving money, he is unaware of the danger he is facing until it is presented to him—by the reporter. But how great is that danger, and what can be done to minimize it?
For one thing, here in California there are already State Fire Marshall guidelines that require set-asides on the roof to allow firefighters access and space to vent the roof as needed, without having to cut into areas covered by solar.
As for the concern about turning the system off so that dangerous amounts of power aren’t present on the roof, well, that is where the benefit of microinverters, such as those that we use from Enphase Energy, comes into play. When you shut off the power at the ground-based AC disconnect switch, the entire array is powered down. The solar conduits coming down from the roof are rendered inert, harmless, with no power present at all. This is the safest possible environment for firefighters with solar and the fire inspectors that we have dealt with readily understand, and appreciate, the difference.
So, should a homeowner pick a solar power system based on avoiding fire danger? Perhaps not; but if you are the sort that worries about such things, you should know that microinverters give you one more benefit—firefighter safety—over older designs. To maximize that benefit, we just need a generally accepted sign to mount on our systems that will let firefighters know what sort of solar system they are facing.
Our friends over at Enphase Energy had a significant announcement a week or so ago, touting how their tried-and-true M215 microinverter had just been improved by redesigning it to feature integrated grounding, just like its bigger sibling, the new M250’s. We wrote about the value of integrated grounding last year when the M250’s were introduced, and it is a really great development, cutting install time, reducing hazards on the roof, and making the installed system safer for everyone. Enphase has even created a dedicated webpage to explain the benefits of integrated grounding. What’s not to love?
Unless, that is, you are the City of Los Angeles. You see, the Building and Safety department of Los Angeles is a universe unto itself, a universe where good news goes to die. To LA, it doesn’t matter that the M250 and the new M215 have been independently tested and found compliant with all of the relevant standards for inverters. No, LA doesn’t care—they insist that these products be submitted to LA for its own testing.
Now just who does this help? Well, presumably the folks who work in LA’s lab get to stay employed but somehow the permitting process shouldn’t be a jobs program. No, all this does is add cost (directly to Enphase who has to jump through these hoops, indirectly to everyone else) and delay into the process. We have sold projects that are delayed in LA while we wait for this nonsense to get resolved. Indeed, it is just this sort of abuse of the process that causes us to have a 7 kW threshold for projects in LA—anything smaller is just not worth the agitation.
To be clear, it doesn’t have to be this way. We have already installed projects in Pasadena and surrounding cities without difficulty using integrated grounding. No one else has had a problem—the units are appropriately listed so you are good to go. But not so in LA.
Everyone talks about how reducing “soft costs” is the key to making solar viable in a post-subsidy world. If so, here’s a prime example of a soft cost that offers zero value to the process and needs to be eliminated—but it is far from an isolated example.
We suspect that the Garcetti Administration could make this go away tomorrow—so why don’t they? Given the Mayor’s claim to green cred, why not call a meeting with appropriate stakeholders: installers (including small installers), manufacturers, and department heads and lets cut through this unnecessary nonsense and make it easier to install rooftop solar in the biggest city in the biggest solar market in the country. It’s about time.
Continuing its (in our view unfortunate) three-year odyssey away from California, SPI 2013 is in Chicago this year for the first time ever. Wait, what? Chicago?
This isn’t a wind-turbine convention - you know, Chicago, the “windy city” - this is the show for Solar. What is it doing in Chicago? (Hey - no knock on Chi-town, we’ve had some great times there and the people are terrific, but when you think of solar you do not think of Chicago.)
So the question is - will this sortie into the Midwest help or hurt attendance? We are guessing the latter, but it will be interesting to see what the numbers say. (And you know that we love us some data!)
Given the location, and the recent trend of some bigger players taking a pass on big booths, who will be the notable “no-shows” at this year’s event (besides us, that is). Enphase won’t have a booth, but their presence will be felt as they host a plethora of parties and other events during the show. Interestingly, rumor has it that SMA will also not have a booth - hard to picture the SMA folks partying like their rivals at Enphase but I suppose it could happen. (Pictures, please!)
But who else gives the exhibit floor a pass? And better question - why?
Buzz is sorta the point of having a booth and LG Electronics - poised to have the first shipments of its long-awaited 300-Watt modules hit U.S. shores in the weeks immediately following the show (and yes, we are in that queue, thank you Focused Energy) is going to have a major booth. Will they capture the buzz?
With neither SMA nor Enphase fronting a booth, who will capture attention in the inverter space? At Intersolar the robots seemed to have gotten a lot of interest - will they be prowling the floor?
What about on the racking front - always lots of products and manufacturers out there - but not much buzz. (Except, perhaps, when a major product is phased out.) Can anyone break through the noise and clutter to make an impression worthy of the booth fees?
And what about the storage sector - will we see more folks now getting it, like Stem? Or will it be more of the same fumbling to find a rationale for their product offering that has been typical in the past?
One of solar’s best kept secrets is that there are lots of intelligent, professional women in the industry - will they finally be seen as the force that they need to be at SPI? We know that our friends Raina Russo and Glenna Wiseman will be there promoting their survey of women’s attitudes about solar marketing. What other events will feature women prominently in ways that capitalize on their intellectual contributions to the industry?
After Intersolar’s debacle with RECOM and its ilk demonstrating that they had no sense beyond that of inebriated frat boys, tremendous pressure was put on the management of SPI to crack down on unseemly displays on the exhibit floor. How well will that be enforced? And how will RECOM’s recent effort to recast itself play with the women at the show? (Interestingly, as to that last point, comments we have received from women are supportive and grateful for our taking a stand whereas those from men are more along the lines of “why are you talking about this?")
So that’s it - a few things to keep in mind as you pack your bags for Chicago - have a swell time and think about us slaving away back home!
We spent yesterday with the great group of folks from Team USC working to re-install their solar PV system. Here’s our update.
Although the Team had the house entirely complete for the Send-off Celebration, it had to be deconstructed into its three component pieces for the trip down to Irvine. That meant cutting open drywall and unbolting sections from each other before the three sections could be loaded onto trucks. But it also meant that the solar array, which actually consists of four branch circuits, had to be partially disassembled since three of the four cross section boundaries. Yesterday’s task was to restore those connections in a manner that was up to code - since these houses need to pass a rigorous inspection process before being hooked up to the local “micro-grid” - and help the Team stay on track.
While next weekend the Irvine competition site will be a solar village, right now it is very much a construction zone with massive cranes in all directions manipulating the different homes into place. Here was the view to the North from atop fluxHome:
The view to the South featured a similar display of activity - and the Great Park’s trademark orange sphere is there in the background:
With all of that activity going on, the competition organizers were taking no chances with safety - everyone entering the competition area was required to wear hard hats, eye protection and proper foot protection. When working on the roof - where I spent the most of my day - harnesses and fall protection gear were mandatory. In fact, if a team member is spotted without proper safety gear, the team is docked competition points. A powerful incentive to follow the rules and maximize safety - always a good lesson to learn.
This image shows us fully decked out in all of our safety gear, working on restoring one of the branch circuit connections:
As you can probably tell, it was a beautiful day to be working on a solar project, particularly an inspiring gig like USC’s fluxHome. Here’s a view of the roof yesterday:
In the foreground you see the massive, automated skylight that forms the aperture for the “solar chimney” that is an integral part of the home’s systems. Behind the skylight is a portion of the solar array.
It is a privilege to be a part of the Solar Decathlon - but for the teams involved it is also a massive fund raising project and success, or failure, can be tied to that aspect as much as a great design. In fact we learned yesterday that one of the teams from Virginia had to drop out of the contest because they couldn’t raise enough money to complete their design and then ship it to California. So sad to think that two years worth of hard work went down the drain because they fell short on their fund raising. (As they said in The Right Stuff, “No bucks, no Buck Rogers.")
While Team USC has not suffered such a depressing fate, they could still use your support. So if you would be interested in contributing to the team, you can jump over to their Support page and make a donation.
Finally, while we were taking a break on the ground, we came across a film team that was documenting the Team’s progress and they told us about this video that was shot while we were doing the initial installation. The entire video is well worth watching as it documents the efforts of the four teams from California that are competing this year. But we have to admit, we are partial to the section that begins around the 35 minute mark - and stick around for the happy conclusion after the break!
Best of luck to all the schools competing, and especially to Team USC - Fight On!