The size of the natural gas line feeding your house is a critical cost dtiver. In our case, we could squeeze in an 8 Kw standby generator with our existing gas service, to cover (roughly) half the house, including heat, some lights, fridge and DW's medical equipment. But to go up to the next size, 12KW, would have required installing a larger feed pipe from the main gas line to the house--an estimated 8-10 K dollar increase alone over the 5K$ for the (fully installed) 8KW model. Not someting that was worth it for us. (Better use for 8-10K $).

So, IMO, cover the critical circuits first. Then, size your generator for that. You would be surpised how much power you can do without and be just fine. Most lighting circuits are, IMO, a luxury. Heat is not. Medical devices are not.

12Kw and 15Kw backup generators.


Large Panel LED TV - 120W
Laptop - 60W
LED lighting per room - 40-50W
Hi-Fi - 50W
Chest freezer 0.47 Kwhr per day
Fridge - 0.3 KwHr per day
Washing machine - 2.5 Kwhr per load
Microwave Oven - 850 W - 0.425 Kwhr for 30 minutes use per day.

Running a generator from LPG to turn the energy into electricity to heat an electric hotplate, oven or electrical central heating and water heaters (cold environments) is throwing away money $4 out of $5 spent on useful energy. (or to put it another way, if you had planned for 1 week off grid that would become 4-5 weeks off grid capability)

For hot environments where electrical cooling is required will usually mean there is plenty of free sunshine to turn in electricity.

How do they run those natural gas lines to properties - I don't think that they run up in the air over poles along with the electricity and comms cables.

Rather than spend $XX,XXX on a backup, can I ask why there is no movement to call for an actual modernisation and improve programme for the delivery of the electrical grid supply by the Operator Companies or even call for an investigation into their monopolistic activities and market rigging whilst the companies repair the lines only to be blown over once again come the next wet and windy inclement weather event. The Silence appears to be deafening.

modernisation and improve programme for the delivery of the electrical grid supply by the Operator Companies or even call for an investigation into their monopolistic activities and market rigging whilst the companies repair the lines only to be blown over once again come the next wet and windy inclement weather event. The Silence appears to be deafening.
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Shoot,it took years and years and years just to get cable up here,believe it would be prohibitively expensive to take the utilities underground for the small population here.

Agreed,using generator power for heating is horribly inefficient.

8KW would be overload power here,very cool!Long term might be real nice to have,so far we have managed easily with 2kw genny,small solar and battery storage/inverters keeping us with lights,TV,computer and freezer/fridge,we arent big power users.In winter freezer contents can just be transferred to porch,its freezing there after all.Worst for us was an ice storm that took out power for 2 weeks.

In fact,only danger area for us is in pipe freezings,thats not a pleasant thing at all,pricey!But taking out freezer and transferring that power to heated insulated pipe (yup,learned that lesson the hard way) might be doable.Typical hard outage is 2-3 days here 1-2 times per winter.

SIL in Denver area (McMansion style) was just asking Mrs about house generators yesterday,they lost power and had no heat,gas furnace wouldnt run.

The replies are much appreciated as I will pass the info along.

Most entrepreneurial companies would form local power companies to provide localised power and heat systems, they are even more efficient than the National grid system overall. Even in the remote islands of the Scottish Hebrides they can do it.

http://www.youtube.com/watch?v=l3n-6YHquno

In all honesty, the electrical grid is one of the most up to date of our overall infrastructure, along with cable/internet lines. It's one of the few utilities around here that I see constant improvement. As an example, recently the majority of our local telephone poles had solar panels installed, essentially creating a town-wide solar grid. They're also leasing space on cell towers and water towers for solar panels (they even approached us about putting them on the roofs of our buildings).

Now our sewers, water pipes, bridges, levees, certain highways....a lot of this stuff was put in by the Corp of Engineers around WWII and hasn't seen any major maintenance since. Much of it is in dire need of replacement and updating; and I should know since I'm a fourth generation contractor working in the underground utilities trade. I would rather see a lot of that stuff overhauled first. I mean, if I loose power for a few days, no big deal. If a large water main, gas main, or parts of a bridge let go, it can be catastrophic.

Even with the standby generator, I'm not going to rely 100% on the natural gas lines. While it's proven to be reliable for us in the past major storms, I'm planning on it possibly going out at any time. Hence I'm going to install the gas feed in such a way that I can easily switch over to a propane tank. I've already spoken with my welding gas supplier about getting a stock of 100lb propane tanks. I'm also keeping my diesel generator as a backup to that.

While powering a whole house on a standby generator might not be the most efficient system, I really don't care right now as long as it means I've got my entire house powered for a week or two in an emergency, hopefully with little or no work on my part (other than paying a gas bill).

Now, if I choose to spend the money on making it more efficient and more 'off-grid worthy' later, we could integrate it with a solar system. For now though, it beats the heck out of putting fuel or gas in a bunch of generators every 6 hours. Especially if I'm not home to do it, I was incapacitated and couldn't do it, or I can't get to the homes of elderly family members to do it for them.

Here in the UK I have installed a number of domestic sized backup generators.
One or two have been whole house units, typicly 20KVA or more.
Most are much smaller. In most homes I would connect all the lighting to the generator, provided that low energy lamps are used, then the installed load is unlikely to exceed 400 watts, and the average consumption would probably be nearer 100 watts for lighting.
With a smallish generator of say 5KVA, that allows effectively unlimited use of all low loading appliances, plus just one large appliance at a time.
For example normal use of lighting, TV, PC, refrigeration, gas central heating,and the like, plus the washing machine OR the kettle, OR the toaster, Or the microwave, but only one such appliance at a time.

Local electrical codes can come into play and complicate the planning for your automatic generator. We ran into this.

Although we identified all of the critical items, the way the code requires the installation is for each electrical panel circuit that item was on to be routed to the generator sub-panel in its entirety, and must pass inspection by the County inspectors (both electrical and gas, 2 different guys). So, if, for example, the stair lift was on one 15 amp circut, that whole circuit had to go to the sub-panel. We could not pick and choose what plug outlets where routed to the subpanel. Nor does the County electrical inspector give you any grace if you argue "But sir, there is only one thing on this 15 amp circuit, and it doesn't draw 15 amps." The inspectors assume that when the power is out, every live circuit will be plugged into up to the max. They simply will not approve a sub-panel that draws anything more than the generator is able to output.

This caused us to max out the 8KW before we maxed out all our needs, but only because of the numerous under used circuits that were routed into the sub-panel. We were able to make do by doing just what the inspectors expected---running an extension cord into one of the live circuits via a neaby wall plug that was not normally used, but included in one of the sub-panel circuits.

I asked about the possibility of re-wiring the house circuits to pick up just the critical items. My electrical contractor said it was theoretically possible, but in an already built house, would be way too expensive.

So, although I had been using a 5KW generator with heavy duty extension cords to cover everything we needed, an 8KW automatic standby generator was only adequate with a bit of fudging with a single short extension cord. My best estimate is that if everything is running at once (unlikely), we would sill be drawing just under 5KW.

Re: electrical inspectors and generators

There are specific ways that loads are to be calculated according to the NEC. You have to use a NEC approved way when you install a generator.

In neither case are you required to consider every circuit that has a 15A outlet on it as a 15A load. If I recall correctly, they are generally calculated at 180VA per receptacle. Some of them don't have to be counted at all, while those dedicated to a specific purpose have to be considered at full load.

The calculations are fairly straightforward if you are used to them but are often daunting for the uninitiated.

No doubt.

I wonder if these calculations require actually looking at what is on each circuit?

Our inspector came in, looked at: 1) the amps of each of the circuits going to the sub-panel, 2) the size of the breaker sending the power to the sub-panel, 3) the sub-panel, and 4) the size of the generator.

I'm happy we passed.

I've often found that, in theory, theory and practice are the same, but that in practice, they are not.

Great write-up Paul. I was lucky enough to be in a part of Brooklyn that was unaffected. The only thing I would add to the discussion is that people should consider getting an amateur radio license. With about 10 hours study time, and the $15 fee for the test, you have access to a communication system that is reliable after all else fails.

There are UHF/VHF repeaters all over the NY/NJ area, so those who were without power and comms were able to communicate with those of us who were still up and running to arrange supply drops, phone out to family members etc.

If nothing else, it provided a degree of comfort to some pretty shell-shocked folks in the immediate aftermath.