Tag: "storage"


  03:15:00 am, by Jim Jenal - Founder & CEO   , 1210 words  
Categories: All About Solar Power, Residential Solar, Energy Storage

What I Saw at Enphase - Mind Blown!

Enphase hqLast month during Intersolar, I (along with colleagues Sara and Victoria) was lucky enough to get invited to see a microgrid demonstration featuring the Enphase next-gen IQ8 at their headquarters in Petaluma, California.  As I had to sign an NDA as the price of admission, I was unable to write about what I had seen until today, when Enphase hosted their annual Analyst’s Day.  But I am no longer bound by that agreement, and can now tell you about what I saw. 

To say that I was impressed would be a gross understatement - quite simply, it was the most astonishing thing I have ever seen in the solar industry.  Settle in and let me tell you what I saw…

What Happens Today

Before I launch into describing the demo, let me remind you of what happens today.  All of the systems that we have installed are what is referred to as “grid-tied” which means that if the grid goes down, the PV system that is capable of back-feeding the grid also goes down, and remains down until the grid comes back.  (This is to prevent your house from being an island of energy, feeding the grid, and potentially injuring a worker trying to restore grid service.  As a result, this feature is known as “anti-islanding” and it is required of all inverter systems that are connected to the grid.)

Normally this is not a problem, but last month, when it got super hot out here (think 115° F hot!), both SCE and LADWP suffered dozens of outages, taking down PV systems across large swathes of LA County, and leaving frustrated PV owners without power, or A/C, just like their PV-less brethren.  Not good.

What I Saw in the Lab

Which brings us to what I saw at Enphase last month.

The lab looked like an ordinary industrial space, but with a series of household appliances and tools at one side.  There was a simulated array feeding a bank of IQ8 inverters, and a display that showed the output of the array (i.e., PV production), the total consumption from the loads, and any power being exported or imported to support those loads.  At the start of the demo the only load was a single red lamp, and the display indicated that it was drawing roughly 90 Watts.  The PV array was producing roughly 1.9 kWs, so the excess 1,800 Watts was being exported to the grid.  All super normal stuff.

But then things got interesting…

One of the engineers switched off the breaker that connected the PV array to the grid… and nothing happened!  Well, actually, a lot happened, but what didn’t happen was that the red light did not go off.  It didn’t even flicker to the extent that we could detect it.  But then when you looked at the display you noticed something amazing.  Not only had the microinverters created a grid on their own in fractions of a second, but they had throttled the output down so that now the production of the PV array exactly matched the load of the red light!  And here’s the kicker - there were no batteries attached to this system!!!

But what fun is just having a light on?  How about some toast?  So they switched on a toaster, and it lit up, and the total load jumped by about 1,000 Watts, making the total load now around 1.1 kW, and the PV array scaled up to meet it!  Still no batteries.  And how about this - there was no central controller, no master-slave relationship between the microinverters.  Rather, this was the “hive mind” at work, as the micros sensed the demand and scaled up or down as necessary to meet that load!

But wait, there’s more!

The next load to be added was a grinder like you might find on your workbench in the garage.  All by itself, that device drew roughly 1,200 Watts, bring our total load to roughly 2.3 kW - more than the maximum output of our simulated array.  What would happen when that was added to the mix?  Surprisingly little.  The grinder spun normally, but the red light dimmed slightly.  What was going on?  The system’s “hive mind” had lowered the voltage slightly (a microgrid equivalent of a brown out) to meet the amperage demand of the new load mix!  So slightly slower than normal, cooler than normal, dimmer than normal, but all operating.

Of course, all good things must come to an end.  Our already overloaded microgrid faced one more challenge - a vacuum cleaner with a significant in-rush current, far in excess of what the grid could sustain.  Indeed, as soon as they switched the vacuum cleaner to “on", everything shut off.  Nothing was damaged, the microinverters just shut off to protect themselves.

Turning on the vacuum cleaner served as the “ah-ha” moment for the potential homeowner - I guess I can’t run everything in grid outage mode.  So what do you do when something you just did produced an undesired result?  Well if you can, you undo it!  Turning the vacuum cleaner off, immediately restored the microgrid to its previous state of operation!  No delay.  No human intervention - just turn off that latest (over)load, and the system recovers on its own!

How cool is that?  Pretty damn cool, if you ask me!

Batteries Please?

So what about batteries, how do they play with this new system?  Just exactly as you would want.

The engineers added a bank of batteries to the mix, each with an IQ8 installed.  Now the display also indicated the battery’s overall state of charge, and whether they were charging or discharging.  Reset the demo to just the red light as a load and the batteries at 30% state of charge.  The PV array output jumped back to its maximum, with the surplus energy being used to charge the batteries.  As more loads were added, the PV array remained at maximum output, and as needed, drew power from the batteries.  Should the batteries reach full capacity and the PV output is greater than the loads, the microinverters will once again throttle down.


What’s Next?

I hope you agree that this was an amazing demo, and the IQ8 (or Ensemble, as Enphase refers to the overall system) has tremendous potential, both for Enphase as a company, and for so many nascent markets.  Think of how this product could have helped out in Puerto Rico, or in parts of Africa which have never, ever seen a grid!  Makes me want to book a trip to bring power to a village somewhere - hey Laurel, what do you say?

For our own clients, this has the potential to be the answer we have been seeking ever since Elon’s whoppers got people thinking about storage for the first time ever.

A point we raised with Enphase management is the need to have a reasonable upgrade path for existing clients.  Indeed, I have a call with Enphase tomorrow to discuss that very topic.  We know that current Enphase IQ products (the 6+ and 7+ we have been installing this year) will be compatible with Ensemble.  We expect to be able to work with older systems, though there may be a higher retrofit cost.  When we have that information, we will surely let you know!  The IQ8 is expected to be available in 1H2019… watch this space!

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  09:15:00 am, by Jim Jenal - Founder & CEO   , 1086 words  
Categories: Solar Events, Ranting, Energy Storage, Intersolar 2013

Intersolar 2013 - The Storage Debate: Poseurs and a Player

We went to Intersolar (IS) wanting to suss out who actually was on track to bring a useful solar energy storage system to market.  We found lots of poseurs and one real player.  Here’s our take.

Only Pretend

You would think that if you worked for a major manufacturer in the solar space as a director of product development you would have an idea of what your product was, and what the target market for it might be.  But when it comes to product developers in the solar storage space that just doesn’t seem to be true.  Or at least that was the impression we were left with after talking to some of the folks in the Storage corner of IS.

Solar Battery

Solar Battery booth at ISTake these guys.  Solar Battery - or Sonnen Batterie as it appeared on CTO Torsten Stiefenhofer’s business card - had the largest booth, and the biggest box (allegedly a product) in the Storage corner.  They also had the strangest attitude of any of the storage folks that we spoke to at the show.

Keep in mind that I approached Herr Stiefenhofer from the perspective of someone who really, really wants to buy his product for my clients.  And he insisted he had an actual working product - over 1,000 sold! - but only in Germany.  Well, when was he bringing a product to the U.S.?  No idea - that was why they were at the show, to get a sense of the potential U.S. market.

Ok, fair enough, but then the conversation turned strange.  Rather than discussing his product’s benefits and features, he was actively hostile about the question of selling here.  It was almost like he had been ordered to be at IS, but clearly thought the whole idea of selling a product in the States was a giant waste of time.  Certainly there are significant logistical issues in bringing a complicated product to market here, and once introduced it has to be supported.  But all of that is apparent - so why the attitude?  Somehow I doubt that we will be purchasing a product from “Solar Battery” any time soon.

Which brings us to KACO.

KACO New Energy

KACO's faux storageKACO has been talking about bringing a solar storage product to market for a long time.  In fact, we wrote about this impressive looking box after Intersolar last year. A year later and there was no product on display, and apparently, still no product coming to these shores.  My conversation with Bill Reaugh, Senior Director of Product Management, left me scratching my head as he seemed to have very little sense of what market he should be targeting or how to get his hands on data to allow him to do so.

He initially suggested that the market was the residential space - and seemed surprised when I pushed back and insisted that the small commercial market was a more realistic segment.  After all, folks in GS-2 that could shift their peak demand so as to get into GS-1 where the full value of a solar power system could be realized would save a bundle using such a system.

“But how big would such a device need to be and how big of a market could that actually be,” he demanded.

Ok, so now I’m supposed to be doing his job for him?  Fine, I’ll play along.

How about this, I suggested.  Contact the California Public Utilities Commission and make a public records act request.  Ask them to give you data about the number of customers that each of the IOUs have on GS-2 (or the equivalent, demand-driven rate structure in PG&E and SDG&E territories)  and their average peak demands.  Analyzing that data would give you some ideas about both product design and market size.

“Interesting,” he said, turning to his colleague in the booth, “Research that.”

You’re welcome.

On Point

By this time I was pretty thoroughly frustrated.  These folks just didn’t seem like they were serious about bringing a product to market anytime soon.  What we need is a U.S. company that actually gets the market and has an intelligent, focused strategy for serving it.  Enter Stem.


We had come across Stem before when they announced a partnership with SMUD but we had never spoken with anyone from the company. My first hint that things might be different at the Stem booth was the pleasant discovery that the very capable Leesa Lee - formerly of another clever company, Enphase - was there as Stem’s Senior Director of Marketing.  A company that could lure Leesa away from Enphase must be on to something.

Stem data analysisThen Leesa launched into her pitch describing the company’s focus and it was as if she had been listening to my prior conversations.  Stem is all about the commercial space, and the ability to intelligently offset peak demand to maximize the benefit of local power generation.

Here’s how they frame it on their  impressive website:


Our vision is to bring energy consumption into the 21st century through distributed storage technology. We are an energy technology company that enables businesses to control their electricity expenses and helps the electrical grid to be more efficient in managing peak usage. Our mission is to provide energy customers and providers with a powerful optimization service that responds to their unique consumption and distribution needs.

About Stem

Stem is leading the way to a brighter, more cost-effective energy future. Since 2009, Stem has been analyzing how various types of businesses use electricity and how they are charged for it. We’ve used this information to design a solution that protects companies from unnecessarily high electricity costs without requiring any changes to the way they run their businesses.

In other words, Stem has taken the time to analyze the market and develop a product directed at the needs of that market!  What a concept!

According to Leesa, Stem should be shipping products before the end of the year.  And as further evidence of their understanding of the market, they are putting on a webinar next week on “Using storage to optimize value of PV installations."  Yeah, I think these folks get it.

Of course, there is a difference between having a clear view of your market niche and being able to fill that niche, and the jury is still out on Stem.  But it is awfully refreshing to talk with people who actually seem to understand what it is they are trying to do.  We are looking forward to seeing Stem succeed - oh, and did I mention that they are a U.S. company?  Even better.


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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