Solar Panels by JimboPalmer posted Mar 19, 2020 at 3:15 PM I have 8 240v outlets in my garage. 2 of them are 3 phase. I have a solar system from Generac making 7 kwhs. I have a 20 kW natural gas generator, just in case the power fails. And I do not own an electric car. https://www.generac.com/generaccorporate/media/library/content/all-products/clean-energy/pwrcell_inverter_apke00014_apke00013_sellsheet_v3.pdf?ext=.pdf If I got electricity in MS from a private company or co-operative, I could get net metering. Unfortunately i have a municipal electric service which is not regulated by the Public Service Commission. They will not even take my excess electricity for free.
They are trying to modernize their interconnect agreement. My understanding is that they are tryinng to get a meter that can read how much extra I produce. They are so new at this they are worried I might electrocute their linemen when working on a 'dead' line. I want to see how reasonable they become before I piss them off too much. Worst comes to worst I power up Christmas lights year round.
Or charge up a couple Tesla Powerwalls, or similar? That could sharply reduce any net metering 'problems'.
The only other person to go solar in town spent $13,000 on batteries so she could avoid the problem, she makes 85% of her own power and uses it into the night. I am hoping not to spend that much. Generac makes this, if the city proves intractable. https://www.generac.com/generaccorporate/media/library/content/all-products/clean-energy/pwrcell_battery_specsheet.pdf?ext=.pdf So far they seem willing, but reluctant. I can store electricity like nuts if I have to.
We do not have a backup battery system on my parents' system. It does shut off when there is a power outage, although the logistics of how that happens bewilders me. I've been searching for a "NEM electric meter" and came up with something from a company that sells solar and runs an alternative energy forum I have been a member of: Focus kWh Meter for 240 Volt Service | Northern Arizona Wind & Sun Reading up on specs of two different models I've looked at it's not clear whether they "spin backwards". This one implies it should because they sell solar. The solution might be "as simple as" replacing the meter, or adding a sub-meter. I quote "as simple as" because in all honesty I'm not sure how difficult that job is. I've been painfully electrocuted replacing various lights around the house..... moto g(7) power ?
Grid-tie systems are required to shut down during power outages, for the safety of people working on the grid. And also for local (in your own home) electrical safety. This is accomplished by using a control scheme that can only follow the grid, never lead it. And it follows only when the grid is operating within a narrow voltage and frequency window, tripping off whenever the apparent grid falls out of spec. It won't follow most home generators. It is possible for grid-tie systems to also have an off-grid mode, but that requires a separate outlet, special hardware, and extra $$. The off-grid power cannot be allowed to back-feed into the grid. The old style mechanical meters here should run backwards, though may no longer be certified for utility-required accuracy: Hialeah Meter I use several for sub-metering. One was on my PV system for the first month while waiting for the official production meter (required here) provided by my utility, though I had it wired in forward mode, not reverse. Mechanical meters can be locked to not spin backwards, so it is a matter of digging into the supplier's specs as to how the meter is configured. Or directly asking them. For digital meters, it is a matter of internal programming. When my utility switched me to digital meters last year (PV customers were switched last), they were programmed to not spin backwards, but instead to have two separate readings, one for each direction. And the backwards direction is not currently displayed. And the promised website where we could check up on the daily or hourly automatic reports is years behind schedule. And of course, none of this was disclosed prior to the meter replacement. I got comfortable enough to work in my electric service panel while it was still live, adding and changing breakers and moving wires. If you have been zapped by changing light bulbs, then definitely don't do this yourself.
Mains>> Backup Generator >> household When I lose power, my generator kicks in in 10 seconds, via an Automatic Transfer Switch. You are saying the Solar will cut off for the same 10 seconds, then when the generator provides a Sine wave, Solar can assist it? Or Solar cannot assist the generator, only the Mains? I know they are installing a manual disconnect so that Linemen will safe from my solar generating voltage upstream. I get the feeling my contractor was just agreeing because it was cheap, not because it was safer.
The new RAV4 plug-in might give you the cargo space you need but I gather that is going to be higher end.
This will depend on the system architecture. Normal grid-tie PV equipment will also require the generator to have fairly tight voltage and frequency accuracy, otherwise it won't connect to assist. Or may cut out when large loads try to turn on. Many small home generators simply won't be good enough. I don't know about the large ones. A manual disconnect is required for responding firefights to shut down the solar system with a single switch pull. And it needs to be close to the main electric service entrance / meter.
Here is the spec sheet for the generator. https://www.generac.com/generaccorporate/media/library/content/all-products/generators/home-generators/guardian-series/16kw-7036/20-and-22kw-spec-sheet-generac_1.pdf
Thanks fuzzy1 for the explanation. Our current meter does spin backwards, got a year end true up of -$54.xx. I was looking for a possible solution for Jimbo.
I don't have actual direct experience here, so can talk only generalities from what I've heard about, filtered through some engineering experience on semi-related topics. The 1% voltage regulation spec is plenty good enough for steady state operation. Actual in-home voltages have a fairly wide range, due to power distribution line resistance and impedance drops and changing load currents. The only voltage issue here might be the generator's transient regulation when larger appliances turn on and off. Unfortunately, that datasheet doesn't really have a meaningful figure for frequency regulation. I don't recall the frequency tolerance allowance on my microinverters, but seem to remember it being narrow. Narrow enough that they had to provide a special firmware version for Hawaii with a wider tolerance window. Average or long term frequency can relatively easily be controlled to being dead-nuts-on, the issue again is transient response. And most of that response will be in the throttle control of that 2 cylinder 1 liter ICE driving the generator. It seems that common appliances switching on and off, microwave oven magnetrons cycling, and other variations could be very frequently causing transients that trip off the PV inverters before the ICE throttle can respond. And even the PV inverters themselves cutting in may cause large enough transients to immediately trip themselves off. And once tripped, they are slow to re-connect after the power source stabilizes. You'll need advice from folks with much closer experience to this topic.
