Running generators in parallel

[3930dave]

In my area, we allowed trees to be trimmed near wires and poles. We neer lost power. In the Tree Hugger areas, power was out for the longest times.

Up here, so far, the Darwin Award wannabes don't get to tell the utilities if they get to trim on their right-of-way. Long private lines on rural property, I'd say that you are pretty much on your own wherever you are - as it should be.

Cities have concentrated services, but that only works quickly up to a certain level of damage. Out in the middle of nowhere, for a first-pass work-around, you could run a dozer down many rural roads and just push debris to the side for the time being, and open a road fairly quickly. In many city environments there isn't space to do that temporarily on a road, and cleaning up line damage in residential areas with mature tree canopies can be really time consuming - you are dealing with many fallen trees jammed in amongst relatively (compared to rural spaces) tightly packed houses - hard for heavy equipment to move fast.

I don't personally panic if the power is out for a couple of hours. I view the medium term limit as about 8 hours, with Winter obviously being the critical factor - beyond that in most households you better start planning for draining pipes in the dead of our Winter if you have no grid-independent source of heat.....

I remember a cbc news item on a multi-day power outage in Toronto. The news crew was walking down the road near High Park (old, now expensive, large homes, amongst old urban tree canopy) and found one guy helping out half a dozen neighbours. It took a guy from the Yukon visiting his in-laws to go out and buy a Honda EU2000, some wire and plugs, and wire up those half a dozen gas furnaces - he just kept rotating the little EU from house to house, keeping them heated. A little Honda suitcase gen was perfect for that application - plenty of power to keep the heat running short-term, quiet for 24hour operation (and not attracting attention), and easy for one person to move.....

On topic, that outage scenario is a good example of the utility of being able to split up 2 generators when desired....

When I think of disaster recovery, skilled people, equipment, and fuel are some of the first things I think of. The limiting factor I see coming into play more often locally (though, I'm sure it's wider spread than that...) is financial. You may have men, equipment, and fuel in place, but more often once they hit 44 hours (or whatever your regional limit is....) , the CFO dictates "Down Tools, until the next pay cycle starts.....". You need to know somebody inside that environment to hear that story; obviously they don't release it publicly....

If you live in the middle-of-nowhere, last on a long rural power line, it's fairly intuitive to expect being out for a while after a major event. In contrast, I've seen enough major urban events in the last 20 years or so to know that living in a high-density urban area does not guarantee fast grid recovery. Many cities are under much more financial pressure than they were 50, or even 20 years ago.....

Rgds, D.

 

[Garandman]

As a coastal dweller (most of the time) this is what got me planning for an extended power outage in Boston, even though the longest power outage we've had in the last 20 years is one 90 minute period.

FEMA updated the Boston flood maps in 2013 and again in 2016. We happen to live in a neighborhood that is the oldest settled part of mainland Boston, and it has never flooded, but huge areas of the coast would be flooded in a Hurricane Sandy magnitude storm. Looked at an interactive flood map and while we won't flood, we'll effectively be living on an island for 12 hours a day.

Spending $800 for a generator plug and line power disconnect, and buying a couple of portable generators I can use for all kinds of other projects seems prudent. The cost to store 15 gallons of fuel for the winter is ridiculously small compared to the misery that would ensue without it. I'm expecting we'd be hosting some elderly neighbors and families with young children as well. To the point of this thread, we chose a parallel setup for all the reasons already named by others:

Portability for unexpected needs
Reliability: "Two is one, one is none."
Lowest possible fuel consumption
Electronics-safe power that inverters generate

The downsides are:

Low output wattage for the money
Limited run time with internal tank

By contrast in our NH neighborhood easily one third the houses have installed whole house gensets, and many others have a portable hookup.

 

[IslandTractor]

Taking a step back, it is interesting to ponder just how folks in the 1950/60s and earlier handled these types of power outages. Surely there were not nearly as many portable generators around, that phenomenon seems to have started in the 70s/80s and whole house emergency power systems are really a 21st century development. People are spending big bucks to solve this "problem" today and I wonder whether the risks are being exaggerated for marketing purposes.

Seems there are critical (electric dependent heat in the north), semi critical (air cond in deep south, well pumps), economic (freezer and refrig losses) and convenience (TV and cell phone chargers) issues that have driven us to invest in generators and their maintenance. Considering the costs associated with generators ($300 for a HF 3000w up to-$15,000 for whole house) it does make you wonder if a major investment is worthwhile. I'd assume that any generator will be less than reliable after ten years so all of those costs are best thought of as amortized over 10 years. Having a cheapish (less than $1000) generator in the garage seems pretty reasonable if just for convenience sake so long as you are willing to invest the time in keeping it reliable. I can see that some might like the flexibility of the new suitcase sized carryable Honda/Yamaha type inverter gens too as they have multiple potential uses. What I have a harder time understanding is spending big bucks on a permanent whole house system. Convenient? Sure. But does the cost/benefit calculation make sense. Most of us would be a greatest risk of just losing the contents of the refrigerator and freezer with a power outage of more than 24hrs. The single most critical electric dependent function of a home is probably heat in mid winter in the north where a house may not stay above freezing for more than 24 hrs after power failure. Even there you have 24hrs to get an alternative temporary heat source just to keep pipes from freezing or alternatively to drain the pipes. A single 20lb tank of propane with a $15 heater will pump out enough BTUs in 24hrs to keep a house from freezing. Even a gas stove with all burners lit will put out plenty of heat to keep the house from freezing in most places. Nobody freezes to death in power outages and there are other community resources to prevent loss of life so it really does come down to a combination of convenience and mid winter heat along with the variable of refrig/freezer content loss. There are a few individuals who have medical needs dependent on electricity but realistically they should have alternative bug out plans anyways.

It does seem to me that the costs of installing and maintaining and periodically replacing a full house generation system are pretty high when compared to the risks and costs associated with occasional >24 loss of power. Not sure a $1000 plus per year "insurance" policy on loss of refrigerator contents makes sense. And, in the north, you probably need a back up to the back up anyways for winter heat so why not just keep five or six propane tanks and a couple of tank top heaters handy. Of course you could look at it another way and say that $1000/yr is worth it to insure that you have full charged cell phones and don't miss the super bowl on TV but I think our rough and tumble forefathers would get a laugh out of that.

 

[3930dave]

I was impressed by what my ancestors coped with, and accomplished, given the time they lived in. They were a tough and resourceful bunch - lessons I try to carry with me today.

I grew up with a rotary-dial phone - if the grid was down, that phone would be supported by the CO for something like a week. Most cell phones today don't last much more than 24 hours w/o recharging, and the 10 of us that still have landlines often rely on cordless phones. In this respect, I consider voice technology less reliable today.

I grew up in a city, so storm-drains took care of ground water for me back then. Now I prefer, and choose, to live outside of city-limits. With standard construction and topology here, if you don't have a way to back up your sump pump, you risk having a flooded basement.

Reasons for having standby power (and how much money one wants to spend) will vary, as we all have different needs, priorities and budgets.....

Rgds, D.

 

[MossRoad]

The worst-case scenario here in Boston is a Northeaster with full moon. Large accumulations of heavy snow, high winds, and coastal flooding.

So we are most concerned with heating the house. We have natural gas, which is "off grid." If we lost that, it's pretty much over.

One thing we do from sailing. If we expect a bad storm, we freeze two or three milk jugs of water. If we loose power we put daily access items in a cooler, and keep those ice jugs in the fridge.

We are fortunate in that we have enough dry/canned food and bottled liquids to last a couple months, if pressed. We have well water. Even if the generator failed, our well is shallow enough I could remove the cap and dip water out with a cup on a string if pressed. We heat our house with wood. Really, in the big picture here, when weighing survival VS comfort, the generator is only a convenience to keep our freezer food from spoiling.

 

[David_Kb7uns]

Numerous places on the internet on synchronizing and paralleling normal non inverter generators to a common bus. Never had a chance to try it but roughly you need generators of the same, type, size and frequency. You rig up a light where it is connected to the hot wire of each generator and watch the light. If the light is illuminated the generators are out of phase, adjustments are made to the governor until you get the lights so they are flashing at the slowest rate possible. Once you get a slow flash the breaker for the common bus is closed when the light is off and the generators will be synchronized and run as one. If they are combined when out of phase as they say bad things will happen and you will have large masses trying to correct and things will fly.

Video shows the concept.
Synchronizing AC generators -- Part 1 (introduction and sync lamps) - YouTube

David

 

[3930dave]

We are fortunate in that we have enough dry/canned food and bottled liquids to last a couple months, if pressed. We have well water. Even if the generator failed, our well is shallow enough I could remove the cap and dip water out with a cup on a string if pressed. We heat our house with wood. Really, in the big picture here, when weighing survival VS comfort, the generator is only a convenience to keep our freezer food from spoiling.

No ground-water/sump pump issues ?

Agreeing that for many things, generators are Nice To Have..... just curious about construction norms down your way....

Rgds, D.

 

[3930dave]

Numerous places on the internet on synchronizing and paralleling normal non inverter generators to a common bus. Never had a chance to try it but roughly you need generators of the same, type, size and frequency. You rig up a light where it is connected to the hot wire of each generator and watch the light. If the light is illuminated the generators are out of phase, adjustments are made to the governor until you get the lights so they are flashing at the slowest rate possible. Once you get a slow flash the breaker for the common bus is closed when the light is off and the generators will be synchronized and run as one. If they are combined when out of phase as they say bad things will happen and you will have large masses trying to correct and things will fly.

Video shows the concept.
Synchronizing AC generators -- Part 1 (introduction and sync lamps) - YouTube

David

Interesting.

If you are adept at building RF transmitters, perhaps not a big deal. Given the extent I see most people struggle with basic 12v wiring, not for the average Homer though....

Rgds, D.

 

[buckeyefarmer]

Numerous places on the internet on synchronizing and paralleling normal non inverter generators to a common bus. Never had a chance to try it but roughly you need generators of the same, type, size and frequency. You rig up a light where it is connected to the hot wire of each generator and watch the light. If the light is illuminated the generators are out of phase, adjustments are made to the governor until you get the lights so they are flashing at the slowest rate possible. Once you get a slow flash the breaker for the common bus is closed when the light is off and the generators will be synchronized and run as one. If they are combined when out of phase as they say bad things will happen and you will have large masses trying to correct and things will fly.

Video shows the concept.
Synchronizing AC generators -- Part 1 (introduction and sync lamps) - YouTube

David

Yep, how we paralleled them in school. But you gotta be able to control the field to get them in sync.

 

[MossRoad]

No ground-water/sump pump issues ?

Agreeing that for many things, generators are Nice To Have..... just curious about construction norms down your way....

Rgds, D.

We are fortunate that where we live, there's about a foot of really nice top soil above about 100' of sand. Water table is about 40' down. No one in my neighborhood has a sump pump for ground /rain water. There are NO groundwater issues in the basements in our area. The houses were built in the late 20's through 50's. There's no perimeter foundation drains on any of them. No need. If you have the landscaping sloped properly, all rainwater drains away from the houses to the streets. Some people with laundry or bathroom in the basements have a sump pump to pump a couple feet up to their sewage discharge pipe level, but we don't. Our washing machine pumps up about 3' then through a pipe in the wall and out to a drainage field.

New construction requires perimeter drain tiles that come into the house to a sump pit that would pump any water back outside. Most of those pits are dry as a bone. Never needed on this side of the county. In other areas of our county, there are more clay-like soils, high water issues, septic issues, poor drainage issues, etc.... and the need for sump pumps.