Category: "Energy Storage"

09/30/20

  01:09:00 am, by Sophia   , 323 words  
Categories: Energy Storage

Power Start - Giving Storage Systems a Boost

Ensemble lab

Enphase Ensemble Lab in Petaluma

When you are turning on your AC or other large household appliances, you probably don’t think about how much current these systems require to start-up. Yet many appliances are going to be pulling anywhere from 2 to 2.5 times their regular running current to complete the start-up process. This large change in amperage is what we call a “surge current”.

“Surge current refers to a short-term spike in power demand from a particular appliance to get it started…” For example, when your car battery dies– you have to jump it using another cars battery. “Something similar happens for high load appliances in your home when they are turned on,” suggests Enphase.

With the recent fires and grid blackouts– Californians are coming to grips with the pressing need for solar energy backed by smart storage. The current storage systems on the market have struggled to keep up with surge current loads. This makes it nearly impossible for homes to be independent from the grid. Your system may be able to keep your appliances running, but what happens when they stop? 

According to Enphase, “This inability to handle power-hungry appliances has been a challenge for battery storage systems for years… until now.” 

Into that void now comes the new Power Start™ by Enphase. This technology is designed to help reliably start every appliance in your home during a blackout. Power Start’s unique algorithm detects when a large appliance is trying to start back up and automatically disperses the same amount energy over a fraction of a second. 

This technology can be added onto the Encharge 10 battery systems, which have a continuous power rating of 3.84kWs and a surge power rating of 5.76kWs for 10 seconds.

You can click this link to find common surge current demands within different appliances.

The new Power Start by Enphase is a necessary and vital addition to battery storage systems. This technology will improve reliability and independence from the grid.

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08/30/20

  03:04:00 am, by Sophia   , 381 words  
Categories: Energy Storage

Utility Scale Battery Storage for the Win!

As energy storage becomes increasingly necessary for California residents, solar developers are pushing the bounds of backup battery systems.

Gateway Energy Storage

Gateway Energy Storage Project, San Diego, California.

LS Power has just created one of the largest battery systems in the world! The Gateway Energy Storage project was finalized and unveiled this year on August 19th in San Diego, California.

The 250MW system will enhance California’s grid reliability, according to the California Independent System Operator (CAISO). In addition, the project will greatly reduce energy costs and will contribute to California’s goals to meet clean energy demands. By charging the batteries during off-peak hours, energy can be delivered back to the grid during on-peak demand, which will greatly decrease energy rates for consumers.

Inside Gateway Energy Storage project

LS Power CEO Paul Segal observed: “For more than three decades, LS Power has been at the leading edge of our nation’s transition to cleaner, more innovative energy solutions, and we are powering up Gateway Energy Storage as one more component of this vision.

Through our investments in multiple sectors of the renewables and energy infrastructure space, LS Power is reducing carbon emissions and improving reliability in the markets we serve.”

So, what exactly does this mean for solar integration through the utility?

Grid scale battery storage is a game changer in today’s energy market. According to the National Renewable Energy Laboratory (NREL), battery storage is one of several technology options that can enhance power system flexibility and enable high levels of renewable energy integration. Large energy storage centers, like Gateway, can receive solar production from various sources across the gird network. When the energy comes in from a solar power plant, it can be stored in the batteries and later re-distributed to thousands of businesses and houses.

This is a great way to connect the utility with large-scale solar production. Battery storage centers are opening the door for a renewable energy grid takeover. As we steer further away from fossil fuels, we will see a smoother transition into solar applicability. Powering cities with renewable energy is becoming feasible and inexpensive. Companies like LS power are paving the way for solar technology and accomplishing what we once thought was impossible through back up battery storage.

And to think that some people don’t believe you can run a 21st economy with renewables!

08/20/20

  01:44:00 am, by Jim Jenal - Founder & CEO   , 761 words  
Categories: All About Solar Power, Climate Change, Residential Solar, Energy Storage

Behind the Meter to the Rescue!

It’s hot here in California, fry an egg on the sidewalk style hot, and the grid is feeling the heat.  The California Independent System Operator (CAISO) - the entity responsible for managing the grid - has issued warnings about possible outages, and even our local utility, Pasadena Water & Power, sent out emails to customers warning that cutoffs might be necessary.  The extreme conditions have prompted some extreme reactions, blaming the State’s shift to more and more renewables as the cause of the problem.  But overlooked in all of this is the contribution of local solar power systems, “behind the meter,” that have greatly improved the present situation, and with more aggressive utilization of storage, could do even more.  Here’s our take…

Blame Game

Let’s start by looking at what is causing the present problem. As we all know too well, we are in the middle of a pandemic and conditions in California have been depressingly awful, with a 7-day moving average of new cases at nearly 9,000.  As a result, a lot more people than usual are working from home, driving up electricity loads as we struggle to remain sane, and if possible, cool.  That’s been tough, as the entire state is in the grip of a week-long heat wave, with temperatures soaring above 100 degrees, and in some places, above 110!  All of that has created record demands for electricity and the grid has struggled to meet that need, with spot prices hitting all-time highs.

For those opposed to California’s efforts to “green the grid,” this provides an opportunity to go on offense. Cue Republican Assemblymember, and Vice-Chair of the Committee on Utilities and Energy, Jim Patterson:

You can’t run a 21st century economy that’s the fifth largest on the planet with wind and solar. I have been warning over and over again that the policies coming out of the democrat-controlled legislature and Governors’ office are creating the conditions for blackouts and brownouts and here we are seeing the evidence.

Wow, just how wrong can you be?  Let’s be clear: no 21st-century economy is going to survive the century if we don’t figure out how to do so with solar, wind and other, non-fossil fuel based sources of electricity.  And despite the predictable piling on from climate change deniers, there are multiple paths ahead for getting to an all-green electric grid.

Behind the Meter to the Rescue!

All of the stories about the blackouts, however, ignore the contribution - both present and future - of behind the meter resources, that is, local, rooftop solar.  Our friends over at CALSSA sent out the following graph that helps to make those contributions concrete:

Behind the meter solar and storage contributions to the grid

There’s a lot going on here so let’s break it down.  The brown curve is the actual reported demand data from CAISO on August 14th.  But without the contributions from the million plus behind-the-meter solar installations the actual load would have been significantly greater, as shown by the yellow line.  That is capacity the ratepayers of California did not have to purchase, but still benefited from its production.  Moreover, as the yellow line shows, the peak demand is actually at 3 p.m., but thanks to behind-the-meter installations, the peak on the grid is both lower, and later, a fact not often explained to the public.

The vertical lines mark the period last Friday that was subject to rolling blackouts - from roughly 7 to 10 p.m.  As the merger of the yellow and brown lines around that time indicate, solar production is no longer a factor.  But there is still a role to play as storage begins to be deployed with ever greater frequency.  CALSSA’s policy director, Brad Heavner (who created this illustration), notes:

If California builds 3 GW of additional energy storage systems at customer locations that can be dispatched during grid shortages, it would further trim evening peak needs. This is shown in the figure as the dotted blue line. CALSSA estimates the state can achieve this level of build-out within the next five years with state policies.

This is certainly doable, but it will take ongoing financial support, and preferably a more transparent rebate program than the present, byzantine SGIP program.

Ironically, the utilities are pushing their customers into purchasing more storage, as the public’s patience with grid outages - whether from rolling blackouts, or utility initiated public safety power shutoffs - is at an all-time low. As sophisticated products like the Enphase Energy Ensemble Storage system become available, more and more solar consumers will become storage consumers as well.  Once again, the ratepaying public will benefit from those investments, and hopefully all of us will be able to keep our cool!

08/14/20

  02:55:00 am, by Jim Jenal - Founder & CEO   , 828 words  
Categories: All About Solar Power, Residential Solar, Energy Storage, Solar Repairs

Building on a Legacy: Enphase Opens Ensemble to Earlier Generation Micros!

On Tuesday, August 11, 2020, Enphase sent out a notice to its top installers alerting them that starting in December, the Ensemble Storage System would support earlier generation microinverters and not just the IQ series as had been originally announced.  We contacted Enphase to learn more, and here is our report…

Some Background…

Last November we wrote about the coming Ensemble rollout.  In describing how Ensemble could be incorporated with existing systems we wrote:

First, you need to have IQ microinverters.  At least as of the initial rollout of this system, the older microinverters are not supported.  That means that the M and S-series of microinverters have to be replaced to IQ-series microinverters to work with Ensemble.  (I do not know if this will change in the future, but it is the guidance that we are getting at this time.)  It is possible that there will be some sort of replacement program (like Enphase did with the legacy M-190 customers), but I have not gotten any word about such a plan yet.

As we were told by Enphase CEO, Badri Kothandaraman, at SPI last year, it was important for Enphase to focus on a successful launch of Ensemble, and the way to do that was to concentrate on pairing it with the more capable IQ series of microinverters.  It had been disappointing news, but understandable given the challenges of bringing a product as technically sophisticated as Ensemble to market.

So I was more than a bit surprised when I saw the announcement from David Ranhoff, Chief Commercial Officer at Enphase, that Ensemble would be able to support M215 and M250-based systems as of December!  Of course this raised nearly as many questions as it answered, so I reached out to Enphase for more details.  

What We Know Now

I was able to speak with Utsav Ghosh, Senior Product Manager, about the details behind the announcement.

Our first question was: What about the S280’s?  They are more capable than the M-series, so are they included?  Sadly, no, not at this time.  Given that the M215’s and M250’s are the largest segment of the non-IQ installed base, they generated the greatest number of inquiries, and so they got the staffing attention.

I remarked that given the relatively short window between when Ensemble was available for the IQ micros and when it will be available for the M-series, why not just say that they would be supported.  The answer, it seems, is that in refining Ensemble, they realized that it would be easier than previously thought to fold in the M215/250’s.  This, of course, gives me hope that the S280’s won’t be far down the line.  Squeak, squeak!

Enphase M215 microinverter will now work with Ensemble Storage System  Enphase M250 microinverter will now work with Ensemble Storage System 
Enphase M215 Microinverter is Eligible…  As is the M250 to work with the Ensemble Storage System! 
Alas, the S280 is out of the picture, for now! 
Envoy S

Our next question concerned communications - the M-series micros communicate via Power Line Communications (PLC) via the neutral and hot conductors.  The IQ-series does not bring a neutral to the roof, so it communicates PLC from hot to hot.  How does this get resolved?  

Turns out quite easily, assuming you have an Envoy-S, like the one on the right.  So how do the IQ8 microinverters in Ensemble communicate with the Envoy?  As it turns out, the same way that they do in an IQ system - via the add on Comm Kit that adds Zigbee capability to the Envoy-S.  The even better news is that Comm Kit is part of every Ensemble Storage System, so there is no additional cost for M-series systems over IQ systems!  Yay!  (The Envoy-S will need a new software version, but that is a free download.)

Our next concern had to do with speed issues: the M-series micros just aren’t anywhere near as computationally powerful as their IQ cousins.  Would the seamless backup functionality promised with the IQ series still apply?  Yes, we were assured.  Cool!

Which brought us to our final question: What ratio of legacy inverters to IQ8 inverters will be needed to allow the microgrid to operate?  Recall that with the IQ series we are presently being told that the ratio is 1.5:1, that is, an Encharge 10, that has 12 IQ8 micros inside, can support up to 18 IQ 6 or 7 micros on the roof.  (While we are hoping to see some movement on that front, that is the present design guidance.)  So what will the ratio be for the M-series?

Great question - no precise answer as of yet, other than “it will be more restrictive."  There is testing ongoing to establish precisely what those limits are, which is why the availability is being cited for December and not now.  Obviously we will be following this closely and will update you when we know more, watch this space!

I want to thank Utsav Ghosh for being so responsive and generous with his time.

And I especially want to thank Enphase for responding to the cries of their clients in getting this much-needed functionality addressed.  Great job, folks!

Now about those S280’s…

05/12/20

  06:41:00 am, by Jim Jenal - Founder & CEO   , 949 words  
Categories: All About Solar Power, Residential Solar, Energy Storage

New Rule in SCE Territory Makes Solar + Storage More Valuable

We just learned from our friends at Energy Toolbase that Southern California Edison has just changed a rule about how solar PV systems with Energy Storage can operate, and the result - amazingly enough - results in greater savings for our clients!  Imagine that?!?  Here’s our take…

It used to be in SCE territory that when you added a storage system to your PV array, you could not export energy from the storage system to the grid and receive net metering credit.  That meant that when the storage system was discharging, it could not exceed what the home’s loads were demanding.  If your usage in the evening was low, or say you were out of town, your fully charged battery could not discharge at all - a poor utilization of that expensive storage system.

But now SCE - along with the other IOU’s, PG&E and SDG&E - have changed their rules to allow storage systems to discharge back to the grid and receive full net metering credit for that energy, as long as the storage system is solely charged by the PV array.  When you combine that rule change with electricity rates that favor storage, such as SCE’s TOU-D-Prime rate, the change in the rule can account for significant savings.

To get a handle on how big a change this will be, we went back to the data that we have for a client who we will be installing a small PV array and a 10 kWh Ensemble storage system soon.  (All of our data analysis and visualizations you see here were done using Energy Toolbase, simply the best presentation tool on the market.)

Solar PV & Storage - No Net Metering Discharge

Our client with the small, 4.6 kW, PV system and 10 kWh Ensemble storage system has a system payback of 11.4 years.  (Larger systems would have a faster payback.)  For this analysis, we imported his SCE interval usage data (provided by UtilityAPI) into Energy Toolbase.  ET then takes the performance output from the PV system, the charge and discharge parameters of the storage system, and overlays that on the existing usage - doing that calculation over every fifteen minute interval for a year.

The graph below shows one day, July 8th, as a representative sample.  Let’s break this down:

Solar PV + Storage - no net metering discharge

There’s a lot going on in this image (click on it for a larger version).  The dark gray is the historical usage demand based on the SCE data.  The value is shown at the top as “Current Demand” and at the moment we have focused on - July 8 at 4:15 p.m. - the historical demand was 1.94 kW. 

The green curve shows the modeled PV array output, using the specific parameters for this site - azimuth, tilt, shading, historical weather, specific equipment being used - as determined by NREL’s PVWatts tool (version 5).  Right now it is at 1.17 kW. 

The red line shows the percentage state of charge for the storage system, at this moment it is 83%.  Net Demand is what is being imported (positive number) or exported (negative number) to the grid.  Finally, Battery Power is how much power is being pulled from the storage system which at this moment is 1.94 kW.  At the bottom is the cost parameters for this rate schedule.  Under the pre-solar Domestic rate (which is a tiered rate) the cost of energy is 18.7 cents/kWh, whereas under the new rate structure it is more than twice that at 38.3 cents during the peak, 4-9 p.m. period.

 So… earlier in the day, as the output from the PV increases, and energy charges are cheap, the solar charges the battery for use later when the rates are high. As we cross over into the peak rate period at 4:00, the storage system begins to discharge and its output is exactly the same as the demand, meaning that all of the power from the PV system can be exported to the grid. 

But note that the battery power is only 1.94 kW, even though its continuous peak output is roughly twice that, 3.84 kW.  Under the old rules though, the storage system cannot output more than that, since it is barred from exporting to the grid.  As a result, when the peak rate period ends at 9:00 p.m. the storage system shuts off, even though it is still partially charged (nearly 40% capacity remains in this example).

That’s leaving money on the table!

Solar PV & Storage - Net Metering Discharge Allowed

Consider the same day, only now we can export the full output of the storage system as desired to maximize our time-of-use arbitrage.

Solar PV + Storage - no net metering discharge

Everything is essentially the same until we get to 4:00 p.m. and then things get very different!  Look at the difference in the output from the battery system, it is now putting out it’s maximum sustained power of 3.84 kW, resulting in more than 3 kW being exported during the peak price period

More importantly from an arbitrage perspective, the storage system is completely cycled.  Meaning that we have gotten full utilization from our storage system investment.  

What does that mean overall economically?  Payback is reduced from 11.4 to 10.7 years, a 6.1% improvement.  Gee, thanks, SCE!

So why are they doing this?  Simple: grid support. Having storage systems maximizing their output during the peak demand period (remember the Duck Curve?) helps the utility to manage its load, and reduce the need for expensive peaker capacity. Everybody benefits: our client (with faster payback), the utility (with better grid load management), and even non-solar/storage rate payers (as they don’t have to pay for that additional production capacity.  Win, win, win!

Of course, these economic benefits don’t really apply to a tiered rate structure, such as is used for residential rates in PWP territory.  But if you are in SCE territory, adding smart storage, like the Enphase Ensemble system, just became a lot more lucrative.

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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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