Jack Ricard on UL-1741 and utility tapering, thoughts?

[941all-electric]

Back in 2019, Jack Rickard argued that UL-1741 Supplemental Annex Phase 2 allowed utilities to use frequency modulation to taper the amount of homeowners' rooftop solar the grid absorbed. This was ostensibly to deal with the duck curve issue. But homeowners would have no idea this was happening. Utilities could treat rooftop solar as discretionary peaker plants. See starting at the 48min mark here, and stay with it after the cut 1-2 mins in:

Has anyone else looked into this? Would love for Will's take.

FWIW, people's perspectives on that will guide my purchasing decision:

Where I live, I still have 1:1 net metering (albeit with a $25 min bill), but outages are also an issue so a battery is a big part of the draw.

I'm quoted $35k-$40k for a grid-tie with a single Tesla Powerwall 3 (14kWh NMC chemistry!).

But for $20k, I could buy a 10kW split-phase victron system, 28kWh EG4 battery, 240V-200A Victron MPPT, and still have $15k-$20k left over for installation costs. Albeit, no ability to sell back to the grid.

 

[1201]

if you have 1:1 net metering take advantage of it. Lock it in before it goes away. get yourself connected with an inexpensive grid tie system, and then add your backup system inexpensively later.

yes, the grid can control inverter outputs. but @Hedges mentioned its not something they would do lightly. it has repercussions

 

[Solar Guppy]

Your $20k would not be able to be built legally with permits as the Victron components do not have UL listings, not an apples to apples comparison.

 

[941all-electric]

if you have 1:1 net metering take advantage of it. Lock it in before it goes away. get yourself connected with an inexpensive grid tie system, and then add your backup system inexpensively later.

yes, the grid can control inverter outputs. but @Hedges mentioned its not something they would do lightly. it has repercussions

Thanks, this is my gut feeling too. Do you have recommendations on grid tie system, within the framework of what installers typically offer?

I gather I should avoid Solar Edge microinverters (shading isn't an issue) at a minimum, correct? Ideally I want all the PV's DC flowing to a central point, where I could access it with a backup inverter?

EDIT: would also appreciate any links to @Hedges content too!

 

[mciholas]

Back in 2019, Jack Rickard argued that UL-1741 Supplemental Annex Phase 2 allowed utilities to use frequency modulation to taper the amount of homeowners' rooftop solar the grid absorbed.

This is tin foil hat talk.

The utility grid frequency is VERY tightly controlled. The utility is not going to shift it for some solar inverters. That would screw up people's clocks and the phasing of all the utilities power sources, including the interconnection of other grids across a wide area.

The synchronous grid:

Wide area synchronous grid - Wikipedia

en.wikipedia.org

The utility is not gong to screw with that to play with your inverters.

Mike C.

 

[Philip53]

if you have 1:1 net metering take advantage of it. Lock it in before it goes away. get yourself connected with an inexpensive grid tie system, and then add your backup system inexpensively later.

The idea to lock in the 1:1 net metering, and then add on later may not be a perfect solution. Twelve years ago I installed a PV system on my home in Louisisana, at the 1:1 net metering - great plan. Now, I have read recently on this forum that the metering regulations now require the homeowner to accept the most current metering plan, which is not 1:1, if they change their original PV system in a 'substantive' way. So, if you had the original metering plan, but later have a significant change in your system, you will be under the then current, less homeowner advantageous rules.

 

[Danke]

The idea to lock in the 1:1 net metering, and then add on later may not be a perfect solution. Twelve years ago I installed a PV system on my home in Louisisana, at the 1:1 net metering - great plan. Now, I have read recently on this forum that the metering regulations now require the homeowner to accept the most current metering plan, which is not 1:1, if they change their original PV system in a 'substantive' way. So, if you had the original metering plan, but later have a significant change in your system, you will be under the then current, less homeowner advantageous rules.

Self reporting?

 

[Solar Guppy]

Do you have recommendations on grid tie system, within the framework of what installers typically offer?

I gather I should avoid Solar Edge microinverters (shading isn't an issue) at a minimum, correct? Ideally I want all the PV's DC flowing to a central point, where I could access it with a backup inverter?

Every system is unique for each location and the option are near endless. For GT only, the turn-key systems are usually micro-inverter based as they have the simplest wiring, is well known and easy to permit, Enphase by far is the choice with this option.

Storage based systems are easily 10x the cost in hardware, mostly the battery, but even the inverters are 4X or more in purchase cost and the permitting a very complex.

I've built and was legally permitted in Florida numerous time for my own homes and it is possible to build for about 1/10th the cost of turn-key, but one has to learn about all the codes, what is needed code wise and where to purchase all the parts. I can be done, but you basically have to learn all the skills and what services to use for permit packages that the turn-key contractors do every day.

 

[Philip53]

Oh, I doubt that! The utility could easily monitor your usage and sell-back to generate reports for closer scrutiny. And with these newer smart, reporting meters, they can get very detailed reports on what is changing with your PV system.

Self reporting?

 

[SparkyJJO]

Oh, I doubt that! The utility could easily monitor your usage and sell-back to generate reports for closer scrutiny. And with these newer smart, reporting meters, they can get very detailed reports on what is changing with your PV system.

But if you didn't change your PV side, just added storage, that shouldn't affect it any.

 

[Danke]

Oh, I doubt that! The utility could easily monitor your usage and sell-back to generate reports for closer scrutiny. And with these newer smart, reporting meters, they can get very detailed reports on what is changing with your PV system.

Besides seeing your sell back is less and/or consumption is more during the day, plus usage possibly being less at night compared to previous times, what else can they see?

 

[hwy17]

How the grid gonna frequency modulate lol. Yes it's possible with VFT's but not practical. Export might as well just be banned, it would simplify things for everyone. It's only sustainable at very low penetration, Hawaii already had to stop it.

 

[Philip53]

My monthly statement shows the amount I sell back to the utility, as well as what I purchase from them. If they see a signifacant change in reduced usage and/or increased sell-back compared to historical data, that would trigger a closer look to see what is happening. While I don't imagine they care one whit about battery storage, they would be interested in a change in PV production rate or quantity - larger inverter or more PV panels. That would enable them to change your 1:1 metering to the current plan & rates.

 

[1201]

Thanks, this is my gut feeling too. Do you have recommendations on grid tie system, within the framework of what installers typically offer?

I gather I should avoid Solar Edge microinverters (shading isn't an issue) at a minimum, correct? Ideally I want all the PV's DC flowing to a central point, where I could access it with a backup inverter?

EDIT: would also appreciate any links to @Hedges content too!

you need something that you can ac couple with later. an inexpensive grid tie inverter (growatt, solis, goodwe) etc
later you can add batteries by yourself, inexpensively. for example my poco requires notification if you add panels but they dont require notification if you add batteries or add components.

 

[1201]

The idea to lock in the 1:1 net metering, and then add on later may not be a perfect solution. Twelve years ago I installed a PV system on my home in Louisisana, at the 1:1 net metering - great plan. Now, I have read recently on this forum that the metering regulations now require the homeowner to accept the most current metering plan, which is not 1:1, if they change their original PV system in a 'substantive' way. So, if you had the original metering plan, but later have a significant change in your system, you will be under the then current, less homeowner advantageous rules.

there are two ways he could do it. Crazy we are talking about an installed system on a diy forum, but he could
1. have an installer do a full grid tie system with no battery involved
2. have installer do a very small system, like 2kw, get the interconnect agreement and then add the rest of the system diy. That would depend on requirements of poco and ahj

 

[Hedges]

In California, April 14th 2023 was last chance to get net metering, with backfeed credit same as charge to consume power.
Although grandfathered for 20 years (they say), changes like $100 +/- flat monthly rate and reduced kWh charge are in discussion.

In California, we are allowed to add battery inverters while keeping our net metering plan

Frequency shift of the grid would be the entire Western half of the US, or the entire Eastern half. Could be useful if GT PV in some portion exceeds what they can use and export elsewhere. So far, California utilities have objected that the last kWh from PV exceeded California consumption and they had to pay money to Arizona to take the surplus power (Arizona simply curtailed their own utility-scale PV to accept the money.) Frequency shifting could happen, but grid-wide affects areas that need more power as well as those that need less.

The newer inverters allowed to grid-tie are required to have have SunSpec (or similar?) communication which can control their output via Ethernet, but our inverters aren't on the network.

EG4 18kpv and PowerPro are a UL listed pair. Apparently some units shipped without UL sticker, not acceptable to some AHJ, but paperwork alone is good enough for others, YMMV.

That's hybrid. Separate GT PV inverter AC coupled to battery inverter is another way to go. Consider prices and surge capability to start motors. Also reputation for quality.

SolArk is another UL listed AIO, don't know if there is battery for it making listed ESS yet. I think it can be installed batteryless, getting permit and PTO, add battery later.

Nice thing about hybrid is you can put on excess PV, with AC export remaining within whatever wattage limit (e.g. 7.7kW for 40A breaker limit of some panels under 120% rule) and the extra goes to battery.

 

[SparkyJJO]

My monthly statement shows the amount I sell back to the utility, as well as what I purchase from them. If they see a signifacant change in reduced usage and/or increased sell-back compared to historical data, that would trigger a closer look to see what is happening. While I don't imagine they care one whit about battery storage, they would be interested in a change in PV production rate or quantity - larger inverter or more PV panels. That would enable them to change your 1:1 metering to the current plan & rates.

Adding storage will not increase sellback. Besides, as long as you do not increase your PV that's what they would care about. My sell back varies a fair bit based on my usage changes and weather.

 

[Ampster]

Utilities could treat rooftop solar as discretionary peaker plants.

The problem with that logic is that when peaker plants are needed in the neck of the duck curve, solar production is declining. Jack's videos were fun to watch but he had opinions that were sometimes controversial. For a long time he did not believe in BMSs until he bought a Tesla and saw what a well designed BMS could actually do.
Actually Tesla has allowed Powerwall users to voluntarily aggregate into a Virtual Power Plant and sell into the spot market at Peaker Plant rates. Tesla, not the utility, controls that system and users are seeing occasional rates as high as $3/kWh for some short periods.

 

[1201]

The problem with that logic is that when peaker plants are needed in the neck of the duck curve, solar production is declining. Jack's videos were fun to watch but he had opinions that were sometimes controversial. For a long time he did not believe in BMSs until he bought a Tesla and saw what a well designed BMS could actually do.
Actually Tesla has allowed Powerwall users to voluntarily aggregate into a Virtual Power Plant and sell into the spot market at Peaker Plant rates. Tesla, not the utility, controls that system and users are seeing occasional rates as high as $3/kWh for some short periods.

Must be nice.

In texas Tesla has the ader program where you sell from battery to the grid at regular crappy rates, but they give you $10 a month per powerwall. Worst "deal" I've ever heard of in my life

https://www.tesla.com/support/energy/virtual-power-plant/tesla-electric

 

[Hedges]

The utility does care that you don't recharge batteries with lower rate off-peak, discharge batteries to backfeed grid on-peak.
That function is done somewhere, but they don't want you to do it at retail rates.

The duck's back is where peak consumer demand for electricity occurs. Time of use rates used to be highest then.
It is just that so much PV has been installed that demand from generators other than (rooftop?) PV now takes a dip in the middle of the afternoon.

"Duck's back curve" is a lie. It is not demand for electricity. It is demand from electricity minus what is supplied by (rooftop?) PV. It doesn't show that rooftop PV isn't useful to the grid, it shows the benefit rooftop PV has provided (including offsetting consumption of fossil fuel.) We are getting to the point where more rooftop PV isn't beneficial on the best of days.

The utility could make similar curves showing how useless peaker plants are in early evening (duck's head). That curve would show high amount of power consumed middle of the afternoon, largely from (rooftop?) PV. Very little power consumed early evening from sources other than peaker plants, because peaker plants are supplying that consumption. See?! Peaker plants are bad, they only produce power when less consumption comes from other sources.

I call that the Elephant's back curve.

What ought to be published is total consumption. Not total consumption minus one particular generation source (rooftop?) PV. Total consumption peaks in the afternoon with AC in commercial buildings working harder.

Of course utilities are deploying PV, or signing contracts to purchase power from PV. Something they would not do if PV produced power when not needed.

It is all a lie, to achieve regulations/pricing that boost utility revenue and profit. The California Corporate Utilities Commission doesn't serve the public.

(yes, net metering is an unfair deal for utilities, but presently the pendulum has swung too far toward favoring utilities to the detriment of environmental and fossil fuel depletion concerns.)