Critical load panel cost?

DanKegelDanKegel Registered Users Posts: 18 ✭✭
Hi!

California is requiring solar on new houses as of Jan 2020, see https://www.energy.ca.gov/releases/2018_releases/2018-05-09_building_standards_adopted_nr.html so a lot of builders are going to be installing inverters in new construction soon.

California also has a lot of earthquakes.  Power can be out for hours, days, or weeks after an earthquake, for various reasons.

If you're building, say, a new 8 unit apartment building, how much extra would it cost to add a critical load subpanel for each unit, wire a fridge outlet and a bedroom outlet to it, and power them from the building's required solar system during outages?

Comments

  • neutronspinneutronspin Registered Users Posts: 25 ✭✭
    DanKegel said:
    Hi!

    California is requiring solar on new houses as of Jan 2020, see https://www.energy.ca.gov/releases/2018_releases/2018-05-09_building_standards_adopted_nr.html so a lot of builders are going to be installing inverters in new construction soon.

    California also has a lot of earthquakes.  Power can be out for hours, days, or weeks after an earthquake, for various reasons.

    If you're building, say, a new 8 unit apartment building, how much extra would it cost to add a critical load subpanel for each unit, wire a fridge outlet and a bedroom outlet to it, and power them from the building's required solar system during outages?

    If these systems are grid tied systems with no battery backup you will lose power and be in the dark unless you have a generator....
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    SMA does have GT units that support a single 120 VAC @ 10 amps (or so) outlet... So, a protected sub panel is possible.

    https://www.solar-electric.com/sma-sunny-boy-sb3-0-us-grid-tie-inverter.html
    One of the most innovative features found on the Sunny Boy US series is the Secure Power Supply (SPS). SMA has improved upon the US-22 series by increasing the available opportunity power to 2,000 Watts. This means when the utility power goes out, the inverter will provide a dedicated receptacle with power as long as the sun is shining. It’s not as reliable as a battery backup system, but SPS is the next best thing, and much less expensive. 
    https://www.solar-electric.com/lib/wind-sun/SB30-77-1SP-US-40_User_Manual.pdf
    Secure power supply operation
    You can connect an external outlet and a switch to the inverter in order to activate the outlet. In case of a grid failure, the outlet supplies a load with current from the PV system. When the outlet is activated via the switch, the load is supplied with current from the PV system. The inverter automatically regulates the energy supply of the outlet depending on the solar irradiation on the PV system. When the outlet is activated and a load is supplied with current from the PV system, the inverter is disconnected from the utility grid and does not feed into the utility grid.

    Do not connect loads that require a stable electricity supply to the outlet for secure power supply operation

    Secure power supply operation must not be used for loads that require a stable electricity supply. The power available during secure power supply operation depends on the solar irradiation on the PV system. Therefore, power output can fluctuate considerably depending on the weather or may not be available at all.

    • Do not connect loads to the outlet for secure power supply operation if they are dependent on a stable electricity supply for reliable operation.
    I think that most builders (or at least a large number) will take the option to finance a solar array system "elsewhere"--Allowed by the law.

    The reality is that GT Solar will at some point (sooner rather than later) will approach the point where Utility Systems cannot absorb the variable output of all of the new GT Solar power systems (both from the ability to provide steady utility power, and from a point of view of billing subsides to GT Solar power systems).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • neutronspinneutronspin Registered Users Posts: 25 ✭✭
    edited December 2018 #4
    BB. said:
    SMA does have GT units that support a single 120 VAC @ 10 amps (or so) outlet... So, a protected sub panel is possible.

    https://www.solar-electric.com/sma-sunny-boy-sb3-0-us-grid-tie-inverter.html
    One of the most innovative features found on the Sunny Boy US series is the Secure Power Supply (SPS). SMA has improved upon the US-22 series by increasing the available opportunity power to 2,000 Watts. This means when the utility power goes out, the inverter will provide a dedicated receptacle with power as long as the sun is shining. It’s not as reliable as a battery backup system, but SPS is the next best thing, and much less expensive. 
    https://www.solar-electric.com/lib/wind-sun/SB30-77-1SP-US-40_User_Manual.pdf
    Secure power supply operation
    You can connect an external outlet and a switch to the inverter in order to activate the outlet. In case of a grid failure, the outlet supplies a load with current from the PV system. When the outlet is activated via the switch, the load is supplied with current from the PV system. The inverter automatically regulates the energy supply of the outlet depending on the solar irradiation on the PV system. When the outlet is activated and a load is supplied with current from the PV system, the inverter is disconnected from the utility grid and does not feed into the utility grid.

    Do not connect loads that require a stable electricity supply to the outlet for secure power supply operation

    Secure power supply operation must not be used for loads that require a stable electricity supply. The power available during secure power supply operation depends on the solar irradiation on the PV system. Therefore, power output can fluctuate considerably depending on the weather or may not be available at all.

    • Do not connect loads to the outlet for secure power supply operation if they are dependent on a stable electricity supply for reliable operation.
    I think that most builders (or at least a large number) will take the option to finance a solar array system "elsewhere"--Allowed by the law.

    The reality is that GT Solar will at some point (sooner rather than later) will approach the point where Utility Systems cannot absorb the variable output of all of the new GT Solar power systems (both from the ability to provide steady utility power, and from a point of view of billing subsides to GT Solar power systems).

    -Bill
    Just don't plug a toaster or microwave in the outlet...lol....All kidding aside....yes you can get a grid tie inverter to give you a SMALL unreliable outlet but if you are using this for an apartment or public rental building a genset is mandatory if you want power that can be reliable during a long term outage without a battery backup....The SunnyBoy works great during the day but at night when you need to see it will be difficult unless you have candles or a flashlight....
  • AmpsterAmpster Registered Users Posts: 80 ✭✭
    edited December 2018 #5
    DanKegel .......
    If you're building, say, a new 8 unit apartment building, how much extra would it cost to add a critical load subpanel for each unit, wire a fridge outlet and a bedroom outlet to it, and power them from the building's required solar system during outages?

    I know this doesn't answer your question directly but I own a 12 unit apartment building that I built in 1987. Knowing what I know today about trends in California here is what I would do;
    I would provide a 20 or 30 Amp circuit from each unit to that unit's parking space. I would put as much solar on the roof as it would accommodate and connect that to the house meters. Through virtual net metering I would share that solar production with each tenant. You could use that to market your units.
    The probability of a power outage lasting more than a few hours is a lot less than the probability that some of your tenants might want to drive and charge an electric car. In my 12 unit building in Hermosa Beach I have 3 tenants that drive EVs. I provide the power from the house meter on a timer so I only pay $0.13/kWh.  I have begun adding solar to each building to offset that energy cost. The average income of my tenants is over $100,000 and I charge rent consistent with the property values in that town. I believe this strategy has allowed me to differentiate my property. Your mileage may vary based on the demographics of where your proposed property is located. 
  • AmpsterAmpster Registered Users Posts: 80 ✭✭
    BB. said:..........
    I think that most builders (or at least a large number) will take the option to finance a solar array system "elsewhere"--Allowed by the law.

    The reality is that GT Solar will at some point (sooner rather than later) will approach the point where Utility Systems cannot absorb the variable output of all of the new GT Solar power systems (both from the ability to provide steady utility power, and from a point of view of billing subsides to GT Solar power systems).
    I have been involved in the California construction industry for my entire career and your prediction is certainly possible. I do think there may be situations where builders may see an opportunity to differentiate their product by offering onsite solar production. One example may be in the city of Lancaster where the City had aggressive renewable energy goals. They prevailed on Kaufman & Broad Construction to offer solar PV as an option. Surprisingly many customers elected the option. 

    To your second point, my hope is the California Energy Commission is able to address your issue. Certainly the Self Generation Incentive Program has brought a lot of battery systems installations on to the California landscape. If Tesla and Sonnen can network these systems like Sonnen has done in Germany there is some opportunity to provide resiliency to to the grid. Those are supply issues and slow moving beauracracies are slow to respond. 
    There are already programs like OhmConnect which are having some impact on demand issues. 
    California is leading the US in renewable energy implementation but there is much to be learned from the experience in Germany. Hope springs eternal.
  • mike95490mike95490 Solar Expert Posts: 8,069 ✭✭✭✭✭
    The secure power system, I believe requires you to flip a switch to turn the special outlet on.   And any glitch in the sunshine can reset it back to off, since there is no battery.

    If you want power all night, you have to install a battery, and that will greatly add to the cost.  The other problem is for the power company to use your battery to stabilize the Grid, YOU pay for the battery, and they get to use up it's cycle life for peak surges
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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  • littleharbor2littleharbor2 Solar Expert Posts: 1,134 ✭✭✭✭
    edited December 2018 #8
    mike95490 said:
    The secure power system, I believe requires you to flip a switch to turn the special outlet on.   And any glitch in the sunshine can reset it back to off, since there is no battery.

    And you will need to manually switch it off before your inverter will sync back up to the grid. When grid power is restored your inverter is dead in the water till this is done.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

  • EstragonEstragon Registered Users Posts: 3,127 ✭✭✭✭✭
    I also have some residential rental business experience, and I think there may be some merit to using solar for self-consumption offset as a product differentiator.

    Trying to use it as a critical load supply, with or without battery, strikes me as a bad idea though.  The cost of the panel will likely end up as small beer compared to the cost and hassle when the food spoils because the tenants' definitions of "critical" include adding an octopus to run the space heater, microwave, hair dryer, etc., which of course they'll deny having used after the fact.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • AmpsterAmpster Registered Users Posts: 80 ✭✭
    edited December 2018 #10

    Estragon said:
    ..........
    Trying to use it as a critical load supply, with or without battery, strikes me as a bad idea though.  The cost of the panel will likely end up as small beer compared to the cost and hassle when the food spoils because the tenants' definitions of "critical" include adding an octop
    Yes, the complexity of providing battery backup to multiple critical loads panels plus the dynamics of tenant relations cannot be over emphasized.
  • AmpsterAmpster Registered Users Posts: 80 ✭✭
    mike95490 said:............  The other problem is for the power company to use your battery to stabilize the Grid, YOU pay for the battery, and they get to use up it's cycle life for peak surges
    I agree with you. I have no desire to help support the grid more than I already am by shifting load to off peak hours. Since that load shifting makes more of my Grid Tied solar available for purchase at full On Peak rates I am getting compensated. 
    Here is an example from Australia where Tesla's commercial battery system actually got paid for providing frequency support to the grid:
    https://electrek.co/2018/01/23/tesla-giant-battery-australia-1-million/

    Sorry about the hijack. This is an interesting subject to me, especially in California where the grid is changing rapidly as more solar and wind are installed.
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    Ampster, I too am very interested in grid stabilization... And at good battery+inverter-charger system could be very useful. Probably better than the flywheel systems of "yesterday" that were tried (original post started in 2008).

    https://forum.solar-electric.com/discussion/2124/flywheel-based-electrical-storage

    However, they make money because:
    What we are seeing here is the Powerpack system enabling Neoen to sell electricity at up to $14,000 AUD per MWh and charging itself at almost no cost during overproduction.
    That is $140.00 AUSD per kWH wholesale costs. What is wholesale $/kWH costs in normal times--Something less than $0.10 per kWH?

    Reminds me very much of what happened in California in 2000-2001 when we had our crazy de-re-regulations/Eron/etc... Just absolutely insane prices for peak power (too many loads, too few generators, too many folks playing games by with-holding energy until "market prices" peaked.

    If they had "normal" fossil (or nuclear) fueled base load plants, they would be paying 1/1,000 as much for power and that plant would have "made" less than AUSD $1,000.00 --- Not a million bucks.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • AmpsterAmpster Registered Users Posts: 80 ✭✭
    edited December 2018 #13
    The problem seems to be the grid in Australia. I hope there are lessons to be learned so we don't have to repeat them, or worse get into another Enron like energy crisis. In California we are still paying for that on our bills. It shows up as  DWP Bond Charge.

    I will have to dig deeper to understand the difference between frequency support and peaker generation in that situation. I agree that is a lot to spend. I don't know how that compares to the cost of paying a base load plant as a spinning reserve. By spinning reserve I don't mean flywheels but the concept of having the boilers heated up and turbines idling ready to ramp up. There are a lot of complexities in keeping the grid stable.
    Again apologies to the OP for the hijack. If there is enough interest this might be a topic for further discussion. I realize the audience here is global but these issues are similar as the percentage of intermittent renewables continues to grow around the globe.
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    edited December 2018 #14
    Directly, "brownouts" happened when the voltage is slowly ramped down--When there is more load than current available from the utility.

    In the olden days (40-50+ years ago), our utility would let the voltage sag during problem times. And this was causing refrigerator compressors to fail (stalled compressor, not enough voltage/current, would sit and cook to failure).

    Brownouts were a simple solution to a complex problem. Things like filament lamps would use less current if the voltage dropped (P=V*I). However, constant power devices (typically refrigerator compressors, and today--electronic power supplies for computers and stuff) have the nasty habit of drawing more current if the voltage falls (P=V*I, voltage falls, I must increase to keep constant power). So brownouts would have limited usefulness in shedding power. USSR decades ago (as I recall) found this out when they would brownout during power emergencies--And found out that they burned out many of their motors.

    Later, after the (our) utility was held responsible for brownout failures of appliances, they instead simply cut the power instead.

    So, the second method used was dropping frequency a bit. Normally, utilities have very tight control over their line frequency.

    https://en.wikipedia.org/wiki/Utility_frequency

    Normally it is 60 Hz +/- 0.5 Hz... If it goes out of that range, the utility will cut power. In a 24 hour period, the utility will slow a bit below 60 Hz during heavy usage, and run a bit faster than 60 Hz during periods of light usage--So that your clocks, on average, are exactly accurate (although, they could be fast or slow by a few seconds during the day).

    So frequency regulation is just a method of adjusting loads and generator supply on the utility network.

    A base load plant (thermal plant like coal or nuclear) needs to be fired up/hot/at pressure regardless of the loads... So they work great for "base loads". Using a base load plant without loads, they still consume a lot of fuel (don't know, but a simple gasoline genset at home consumes almost 50% of fuel flow at anything between 50% an 0% output).

    Gas Turbine, hydro power plants, etc. are great for peakers--They are quick to bring up to speed and shutdown/throttled back when not needed.

    Solar and wind turbines can be throttled back (in most cases)... However, the people running them generally do not want to do that (will not answer phone calls from power managers in some cases) because they get a whole bunch of money (high base rates, production subsidies) that they do not want to cut back output when the wind is blowing. That is pure lost revenue (turn off a peak plant, and the fuel costs drop to near zero until it is needed again).

    I believe that newer GT inverters (I read about this first being done in Germany) can be programmed to vary their output based on utility line frequency (SMA does this for their SunnyIsland off grid products). At line frequency and below, produce 100% of available power. At +0.5 Hz, zero output (and vary from 100% to 0% in between). That is probably one way that California (and others) will manage the widespread use of GT Solar power systems and to keep the grid stable. (SMA and other off grid micro AC systems vary their frequency +/- 0.X Hz around center frequency to keep clocks accurate).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • DanKegelDanKegel Registered Users Posts: 18 ✭✭
    Thanks for the interesting replies.

    Not exposing any 110v outlets to the apartment user sounds like a must.

    So what could one offer without that?
    USB ports for phone charging, and a couple hardwired overhead LED lights, maybe.
    I hear some buildings are providing wifi as a service, and that could be done without exposing a 110v outlet, too.
    The total wattage would be tiny, probably wouldn't even need a per-unit critical load panel.

    I agree, from what I've heard, you would almost certainly need a battery to handle the startup surge of refrigerators, inverters can't do it alone.  
  • EstragonEstragon Registered Users Posts: 3,127 ✭✭✭✭✭
    If I was going to do it, I'd look at grid-tied solar as a partial offset to consumption.  This would be set up such that solar power is used if and to the extent available, and the balance of loads powered by grid.  This would be mainly a PR exercise, and may save a few bucks on utility bills.

    I'd handle emergency planning separately by using a backup generator, maybe wired to supply fridge(s) etc in a common party or guest suite.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    GT Solar and Utility contracts are only good as long as the parties are able to support those agreements...

    PG&E, Northern California's major gas and electric utility is probably going to file Chapter 11 bankruptcy by the end of this month (January 2019):

    https://www.reuters.com/article/us-pg-e-us-bankruptcy-idUSKCN1P815B

    Regarding setting up GT Solar for rentals... Longer term, contracting with the utility for a percentage of a solar farm removes a lot of potential costs and responsibilities for the complex owner.

    Backup genset for a few lights and refrigerator... I can just see renters plugging in an electric heater if the power fails during the cold... And/or starts plugging in power strips if they figure out that the Refrigerator circuit has "free power" (if power comes in from House Power+Genset transfer panel). Running an emergency circuit that has 10 refrigerators, and a significant number of them may try to "restart" when the power fails and the 10 seconds for the genset to start an pickup loads. Now, you are looking at a system that needs to support a large VA (Watts) startup surge of >600 VA, but only need to run ~100 Watts during normal operation (and then there is the >500 Watts for defrost cycle).

    I can see that the complex owner is trying to be helpful for the residents... But this is also setting up for lots of possible liabilities... Genset fails to start, runs out of fuel, transfer switch fails (even when utility power is good), stored fuel (diesel) needs to be "refreshed every couple years, inspections, etc.--And everyone's food goes bad, and somebody has $1,000 of medication in one unit that needs refrigeration....

    The KISS principle---Keep it Simple....

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EstragonEstragon Registered Users Posts: 3,127 ✭✭✭✭✭
    The PG&E thing is a bit interesting in that the common equity still had material market value after the notice filing.  With an impending bankruptcy highly likely, you'd expect the common to trade near zero. 

    Maybe short covering is keeping it up some (bears make money, pigs get slaughtered)? 

    Putting the critical loads in a party room allows some control in an emergency, but yeah, may still be more trouble than it's worth.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
  • BB.BB. Super Moderators, Administrators Posts: 28,315 admin
    While I have no love for PG&E. Bad brush and forest land management, as well as city planning, etc. all helped lead us to Inferno California.

    I believe it is the fear that lawsuits over these recent fires will empty the company's coffers... So this is more of a "defensive" Chapter 11 filing.

    https://en.wikipedia.org/wiki/Chapter_11,_Title_11,_United_States_Code

    When a business is unable to service its debt or pay its creditors, the business or its creditors can file with a federal bankruptcy court for protection under either Chapter 7 or Chapter 11.

    In Chapter 7, the business ceases operations, a trustee sells all of its assets, and then distributes the proceeds to its creditors. Any residual amount is returned to the owners of the company.[citation needed]

    In Chapter 11, in most instances the debtor remains in control of its business operations as a debtor in possession, and is subject to the oversight and jurisdiction of the court.[2]

    https://247wallst.com/infrastructure/2019/01/14/pge-chaos-ceo-departs-bankruptcy-looms-tens-of-billions-in-liabilities/

    I guess, basically give PG&E to the banks/creditors, and let them work with the state of California to float more State Bonds to cover the 2018 losses. But the PUC (public utility commission) is playing hardball to prevent 2018 fire losses being bonded until the 2017 costs are resolved.

    Stock was at ~$55 to $65 prior to 2017 fires... Now at $6 and change -- At the moment. Was at ~$5.20 as "somebody" was bailing earlier in the day.

    https://www.nasdaq.com/symbol/pcg/interactive-chart

    Whatever it is is, it will be very messy. No longer a "Widow-and-orphan stock" (typically utilities with low risks and pay steady dividends).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • EstragonEstragon Registered Users Posts: 3,127 ✭✭✭✭✭
    Hmmm, sounds like everyone's playing chicken, as often happens even in a typical bankruptcy.  Common typically gets wiped out, but sometimes owning common can give leverage to someone with a larger position up the capital structure (eg senior secured vs junior debt).  State backed bonds are another wrinkle.

    Hard to tell from sat pics, but it does look like a lot of cut lines are badly maintained or apparently not done at all.  Makes me wonder if a politically motivated rate setting board didn't leave room for proper maintenance.  Deferred maintenance is one of those costs that doesn't matter until it does.

    Sad to see it go from a widows and orphan stock to a stock that makes widows and orphans.
    Off-grid.  
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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