Off Grid Building

mikeames

Senior Member
Location
Germantown MD
Occupation
Teacher - Master Electrician - 2017 NEC
Simple is my vote. I could not follow past the second level of transfer switches in the first setup.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Occupation
Field coordinator/ technical support
Yes, exactly. I'm wondering if this is "supposed" to be Green?

If that's not the reason, then why?
Green is probably what’s growing in there, that’s the only kind of warehouse that could produce enough profit to do that! LOL! With California’s rolling blackouts, loss of crop could justify it. LOL!
 

Joe.B

Member
Location
Arcata Ca
Occupation
Building Inspector
Obviously slightly off-topic, but thought I'd share anyways.

There was a house recently built in my area that is 2 minutes from downtown, but was an undeveloped lot. PG&E was going to charge him $50,000 to get power to his place. He purchased a solar setup with 16 panels, inverter, battery, and generator for $20,000. It's a small house and he has a propane tank for cooking, hot water, and secondary heat, wood burning stove for primary heat. He also installed the solar himself which helped keep the cost down. He's got enough juice to top off his battery within one hour of sun hitting the panels and he can run power tools all day long as long as the sun is shining. Battery has never gone below 60% overnight, even in the winter. Off grid, pretty cool setup.
 

junkhound

Senior Member
Location
Renton, WA
Occupation
EE, power electronics specialty
Cabin in WA with microhydro, About 4 kHz 3 phase generator for best use of hydro with flow and head I have.
Cabin 800 feet from generator.

all custom one of a kind dc-dc converters to get 400 Vdc to cabin and then and more custom dc-dc converters for lighting and other cutom loads (e.g bypass rect stage in electronic and go straight to internal dc bus, etc) - a few small (50 W) off the shelf dc-ac for small 60 Hz loads not worth bothering with customizing.

selected 400 V as best fit for buying FETS with ratings sufficient to last for 100,000 hours, all ferrite transformers, etc.
nothing simple about any of it.

Back in 1979, even with the cost and state of solar at that time, for the MX racetrack basing scheme solar was a toss up in life cycle cost with building a new power plant and installing the distribution system (4600 sites running 24/7 at 30 kW) in southern Nevada and Utah. Biggest solar advantage was that over the 1950 to 1978 time frame, the longest stretch of continuous overcast was 3 days.
 

mbrooke

Batteries Not Included
Location
United States
Occupation
Electricity
Cabin in WA with microhydro, About 4 kHz 3 phase generator for best use of hydro with flow and head I have.
Cabin 800 feet from generator.

all custom one of a kind dc-dc converters to get 400 Vdc to cabin and then and more custom dc-dc converters for lighting and other cutom loads (e.g bypass rect stage in electronic and go straight to internal dc bus, etc) - a few small (50 W) off the shelf dc-ac for small 60 Hz loads not worth bothering with customizing.

selected 400 V as best fit for buying FETS with ratings sufficient to last for 100,000 hours, all ferrite transformers, etc.
nothing simple about any of it.

Back in 1979, even with the cost and state of solar at that time, for the MX racetrack basing scheme solar was a toss up in life cycle cost with building a new power plant and installing the distribution system (4600 sites running 24/7 at 30 kW) in southern Nevada and Utah. Biggest solar advantage was that over the 1950 to 1978 time frame, the longest stretch of continuous overcast was 3 days.

Here is a bit of a hybrid approach.

100% loading of the 1000kw gensets with (50% of the general lighting load plus 100% of the emergency load)


 

steve66

Senior Member
Location
Illinois
Occupation
Engineer
Lots of things to consider here that are maybe even more important than the one-line.

You don't want the typical standby generators, they should be continuous duty. Maintaining the generators while they are running is another consideration (can filters be changed without shutting the generator off?)

What about transfers? They probably aren't going to be very happy if there is a short blackout on every transfer.

I'd also consider paralleling generators.
 

d0nut

Senior Member
Location
Omaha, NE
I'd also consider paralleling generators.
If it was me, that is what I would do as well. I would get rid of most (if not all) of the transfer switches and handle my redundancy at the generator level. You could also build in some battery UPS or large flywheels to minimize potential switching transients.
 

romex jockey

Senior Member
Location
Vermont
'off grid' / 'grid tie' , by way of how we see the niche industry growing, is probably going to work it's way into our infrastructure......this 'ol dog might even learn some new tricks! 🤫 ~RJ~
 

mbrooke

Batteries Not Included
Location
United States
Occupation
Electricity
Lots of things to consider here that are maybe even more important than the one-line.

You don't want the typical standby generators, they should be continuous duty. Maintaining the generators while they are running is another consideration (can filters be changed without shutting the generator off?)

What about transfers? They probably aren't going to be very happy if there is a short blackout on every transfer.

I'd also consider paralleling generators.

I've read that typical 1,800 rpm engines come in prime and continuous ratings. Any input on this?
 

mbrooke

Batteries Not Included
Location
United States
Occupation
Electricity
If it was me, that is what I would do as well. I would get rid of most (if not all) of the transfer switches and handle my redundancy at the generator level. You could also build in some battery UPS or large flywheels to minimize potential switching transients.

The thing is money spent on paralleling can go into more gensets or larger ones. In the end the cost ends up being about the same. Yes the pro is better control with fewer blinks, but at the same time the complexity and common mode failure is a huge disadvantage.


You can find techs who are experienced in stand alone genenrators and ATSs, but parelleling gear is a niche specialty.
 
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