This sounds like what utility scale batteries should solve, stabilizing the grid frequency for short periods of time.
NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
31–40 of 61 posts
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#32Earlier quoted context omitted.
The Enphase IQ8 is now in general release, and is grid-forming. During sun, a site can island with perfect 60Hz AC power from the ASIC-driven IQ8. No battery –– and certainly no grid –– needed.
I spec’d my 21kw system with IQ8+s for this reason. It’s future proofing distributed generation by being software defined (Enphase’s Ensemble system). Highly recommend them to anyone considering residential solar, and go for as big of a system as you can (and your utility will allow, if they limit based on usage history; tell them you’re buying an EV if necessary).
Do you have any battery storage? How well do islanded microinverters handle startup surge on electric motors, or is it the case that you need a 20kw+ array to handle a refrigerator cycling on?
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#33I'm having trouble with the power industry terminology. I /think/ they mean there's going to be more demand, which could overload parts of the distribution grid, causing its overload protections to trip. Is that right? The solar connection is not clear aside from it contributing more power on the grid when it's sunny.
Solar cells generate DC, but this is converted to AC with power electronics: the inverter is the main one. These are all just very high wattage semiconductors, but like all semiconductors, they can be destroyed by a transient event like a lightning strike, or a high fossil-fuel power plant dropping offline. To prevent the power electronics from being destroyed when this happens, they are protected by safety systems w…
A lot of the rules for disconnecting solar were written when solar wasn't expected to be a major part of the grid, so the logic has them trip because that was the sane default.
That's no longer the sane default and the utilities have been slow walking software and hardware updates to fix it.
...and now that might be a problem.
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#34Earlier quoted context omitted.
Perfect comment on the topic. With that said, newer inverters do have “grid fault ride through” capabilities where they will continue to operate during excursions from nominal operating windows, and some regulators are more hip to it than others. https://www.iso-ne.com/static-assets/documents/committees/co... https://www.solarpowerworldonline.com/2019/03/smart-inverter... Grid forming inverters (versus the traditiona…
The Enphase IQ8 is now in general release, and is grid-forming. During sun, a site can island with perfect 60Hz AC power from the ASIC-driven IQ8. No battery –– and certainly no grid –– needed.
This made me think "What about SMA Solar, they are supposed to be a technology leader?"... and yes, they do have all the grid stabilization features (and an island feature in at least some models, not mentioned there):
https://www.sma.de/en/partners/knowledgebase/sma-inverters-a...
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#35Earlier quoted context omitted.
Solar cells generate DC, but this is converted to AC with power electronics: the inverter is the main one. These are all just very high wattage semiconductors, but like all semiconductors, they can be destroyed by a transient event like a lightning strike, or a high fossil-fuel power plant dropping offline. To prevent the power electronics from being destroyed when this happens, they are protected by safety systems w…
A lot of the rules for disconnecting solar were written when solar wasn't expected to be a major part of the grid, so the logic has them trip because that was the sane default. That's no longer the sane default and the utilities have been slow walking software and hardware updates to fix it. ...and now that might be a problem.
Worse still are areas where laws were enacted that _required_ you to get your solar from your utility vs your roof. Or there's a "minimum service fee" even though you don't consume any energy. In the early days you could "sell" your excess energy back to the grid. Now you can't and worse still, they don't know how to handle the infrastructure they have to meet the ever changing climates of the western United States.
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#36Earlier quoted context omitted.
I spec’d my 21kw system with IQ8+s for this reason. It’s future proofing distributed generation by being software defined (Enphase’s Ensemble system). Highly recommend them to anyone considering residential solar, and go for as big of a system as you can (and your utility will allow, if they limit based on usage history; tell them you’re buying an EV if necessary).
Do you have any battery storage? How well do islanded microinverters handle startup surge on electric motors, or is it the case that you need a 20kw+ array to handle a refrigerator cycling on?
No battery storage. 1:1 net metering with my utility. 21kw array is about 30% over what we’d need for annual consumption, but (Q Cell) panels were the smallest component of total system cost and they help keep the attic 5 degrees F cooler. Also, I’m required to carry $1M in liability insurance for anything over 10kw. Even if I have credits forever I want to maximize production to offset utility natural gas generation during daylight hours. Not needed but installed a soft start on the 4 ton AC condensing unit for longevity and to reduce start surge. I will likely add battery storage in the future when it declines in cost for outages.
The system is not yet configured to support solar only utility disconnected operation due to supply chain issues (additional components, rush to PTO), so I cannot speak to surge start capability of the IQ8+ micros in island mode.
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#37Earlier quoted context omitted.
The Enphase IQ8 is now in general release, and is grid-forming. During sun, a site can island with perfect 60Hz AC power from the ASIC-driven IQ8. No battery –– and certainly no grid –– needed.
I spec’d my 21kw system with IQ8+s for this reason. It’s future proofing distributed generation by being software defined (Enphase’s Ensemble system). Highly recommend them to anyone considering residential solar, and go for as big of a system as you can (and your utility will allow, if they limit based on usage history; tell them you’re buying an EV if necessary).
We ended up with 16kW and solar edge stack. 16kw was about all we could fit on the roof. Was a nightmare getting Xcel to approve it. Took them 2 months. We have 20 kWh of battery to buffer and back us up in the case of extended outages. It is a nice system. Anything over 10k in Colorado requires a lengthier approval process.
We also moved the house entirely to heatpumps. They practically sip energy for cooling.
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#38Earlier quoted context omitted.
Because photovoltaic got so good & cheap, with no moving parts. In most locales it’s now more cost effective to heat your water with photovoltaic panels & an electric water heater.
Specifically, a heat pump water heater.
That usually is true if your electricity is generated by natural gas too and you're comparing it against a gas HWH
Rough math is
NG -> Electricty is 50% efficient thermally.
A heat pump can have a COP of 4.2.
100 * .5 * 4.2 = 210% efficient, thermally
A hot water heater powered directly by gas is ~100% efficient thermally.
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#39Why is solar thermal so rare?
Because photovoltaic got so good & cheap, with no moving parts. In most locales it’s now more cost effective to heat your water with photovoltaic panels & an electric water heater.
Not at industry scale, I don't think. At least according to these guys: https://www.absolicon.com/
Re: NERC sounds alarm on solar tripping in ‘sobering’ summer reliability report
#40> But the biggest long-term risk may be the unexpected tripping of solar resources during grid disturbances, This is entirely the electricity grids own doing. They told everyone who wanted solar that they must use inverters that are super safe and self disconnect if anything unexpected happens. The regulations were written super tight, with frequency limits, harmonic limits, reactive power limits, rate of change of f…
Last year, I had the opportunity to talk to some PG&E-associated contractors [0] who were replacing the distribution transformer serving me. I asked them whether they trusted the anti-islanding protection in everyone’s inverters and whether they would like me to turn off my main breaker. They laughed and said that they couldn’t care less. They were going to intentionally short the secondary circuit if they were doing…
> I’m genuinely unsure what purpose anti-islanding actually serves.
Scroll up to read about the HNer required to carrying $1M in insurance for having more than 10kW in solar on their roof, which is just...insane. Solar is mired in bullshit to make it seem dangerous, make it look ugly, make it as complex and expensive to install as possible. That's how you end up with regulations requiring what looks like an electrical substation on the side of your home, covered in neon-colored labels. Gotta make sure someone knows the system is "RAPID SHUTDOWN EQUIPPED" from 100 feet away!
Electrical grid operators want you to buy electricity, not make it for them. Their nightmare is becoming "just" a grid.
Their biggest nightmare, however, is you realizing that you no longer need them at all. Lots and lots of people, especially those out in suburban or rural areas, could easily go off-grid these days. Homes are better insulated, heatpumps are quite common, solar costs a fraction of what it used to, lithium ion battery prices are crashing and LiFePo batteries are getting commonplace, etc. So what's a utility to do? Push microinverters that require a grid connection and so on.