Generatore for home or solar backup?

[Jim S]

Our power goes out a lot and now the grandchildren live with us.

I'm told even if you have solar panels, they don't run the home even in the day when the power goes out due to some regulation on safety or something.

That means even if you have solar you still need a battery backup for the whole home to last two or three days for when the power goes out.

Or buy a generator but if you hook the generator to the home to automatically kick on and off as needed, then it can't be fueled by gasoline I'm told but by propane (there is no natural gas line here).

My question?

Which is cheaper?

Adding 3 days of battery power to the home or adding the generator and propane tank to run on an average of 3 days to handle power outages?

[hubops]

One other option, depending on whether or not you already own a small tractor - is a PTO driven generator. Adequate fresh fuel would be the limiting factor. The propane powered whole-house auto-start stand-by units are becooming more common in my area but usually the homeowner has propane already. A battery system that is big enough to provide 3 days of normal home power would be pretty big and has maintainence considerations. The off-grid folks who use battey banks tend to have very frugal lifestyle and home energy requirements.

There are so many variables involved, it'a difficult to judge your situation. For over 20 years I have just used a 5 kw portable for storm outages - providing _barely_ enough for essentials. But my outages are not 2 - 3 days and only occur a few times per year. John T.

[Frank]

My brother recently got a Generac propane backup and I believe it cost around $12,000. He does not have natural gas and needed tank for propane.

Cheaper than comparable solar/battery backup:

About 15 years ago I got a gasoline generator and transfer panel which might cost about $2,000 today. Still works fine but does not do whole house and is inconvenient to start up. Power was out an hour and a half just 3 nights ago and knowing it would not be out long we just sat and read by battery powered lamps until restored rather than start up generator.

[Ralph Mowery]

Once you have to ask which is cheaper you probably can not afford it, or do not want to.

At the current prices of fuel you are looking at 2 to 4 dollars an hour for fuel if not more depending on how large of a system you have. It could be as much as 50 to 100 dollars per day for fuel.

As another said a smaller say 5 kw unit and only run it to power up what is actually needed for a few hours per day.

I have a small 3500 watt propane generator for short time outages and a

5000 watt gasolean generator to power more things and maybe easier to get fuel for. My power seldom goes out very long, but I want to be ready. Gasolean does not store too long unless you get the ethanol free gas. I use enough in the summer that I can keep around 15 to 20 gallons around and rotate it in the lawn equipment so it is never very old.

[Scott Lurndal]

There is a quite simple answer.

Solar Panels + whole-house battery.

[Frank]

I find gas with ethanol with added Sta-Bil in full sealed container can last at least two years and even gas in generator tank seems OK.

[Frank]

Solar panels and whole house battery does sound ideal but initial cost is highly expensive. There is a payback period to consider as you can be constantly using solar to power house and not have electric bill and even rebate if fed back to power company. Then there are time and deterioration concerns. Only guy I know with solar had to sue the installer after a few years when it caused his roof to leak and roof had to be replaced. Also batteries cost a bundle and will need replacement in as little as a few years.

As a long time home owner I prefer installation of things that have stood the test of time. I had discussed here years ago getting a new Trex deck which turned out great but had I bought early Trex version I would have problems as it was not yet perfected. That is the way I feel about solar with batteries.

[hubops]

I won't argue over the life-span of gasoline -

- but I will advise to test run the generator every

4 months - 6 months max. - from my experience with the Honda 5000. And run the carb dry when shutting it down for storage. John T.

[hubops]

In my area, the micro solar installations < up to 10 kw > that get the big bucks from green energy subsidy -

- are required to feed into the utility on their own dedicated meter - - ie : it can't feed the homowner's batteries. I can't imagine it being different in other jurisdictions .. John T.

[Scott Lurndal]

It's quite different here. The solar panels reverse feed into the main panel through a branch breaker; the meter runs backward when the solar is producing more than the house consumes, and runs forward otherwise. Called "Net Metering".

The batteries can charge from either source (from the solar normally, but from the utility if necessary using TOU (Time of Use) pricing).

[hubops]

What are the rates for the power that goes out to the grid ? Our original contracts for micro-solar were approx. 6 X the price of buying power ... it would be crazy to use that power even if you could. John T.

[Ralph Mowery]

I won't get into the gas storage either. I just do not see the point of running the generator every 4 to 6 months. For the last 10 years I ran my tiller dry and it sits a year and has always started on one or two pulls.

I can see starting the engines if they have gas in them

[Jim S]

You are correct.

I wouldn't be asking which is cheaper if I had the money.

But it's still a useful question to ask for WHEN I have the money.

[Jim S]

Good questions. Good answers. More questions. More answers.

Out here I think they use "wholesale" prices for what you generate which are (I'm told) much lower than their retail prices for what you use.

Like someone said, they have a net trueup once a year, where if you own them money then you pay them, otherwise any credit gets dumped I'm told.

You still have to pay for the basic service but it's a nominal fee. Most people have from 10KW to 20KW generators from what I'm told.

I'm going to agree with someone who said fifty to a hundred dollars a day depending greatly on the cost of the generator fuel.

For a battery backup, it makes no sense unless you "generate" the electricity to feed that battery from "somewhere", the least expensive in terms of cost per kilowatt hour used being solar but then you have to already have the solar panels (which I don't have).

If I added solar (which I can't afford just now), that would have the payback period someone suggested of, what? Maybe 10 years?

What's the replacement period for solar panels & whole house batteries?

[Frank]

I'll have gas in tank but have shut off valve and run dry. Mad the mistake with snow thrower a few years ago and it would not start. Do not understand why all small engine manufacturers do not include shut off valve. I have to drain snow thrower tank then run dry.

[Scott Lurndal]

Generally unfavorable to the homeowner. Although some communities would kick in a bit extra to get closer to the wholesale energy market price. Without that supplement, the utility pays about 0.03/kwh for energy supplied to the grid from the solar array where the retail price is closer to 0.30/kwh.

Arrays are generally designed to be sufficiently designed to offset the typical consumption of the house on an annual basis, plus or minus a few percentage points.

It's not common to have an excess at the end of the year true-up for most net metering solar home installations, so the rate is somewhat moot (the smart meters measure consumption/production continuously and track production and consumption in each time-of-use period - energy produced during each time-of-use period by the array minus any consumption on the premises is used for billing).

[Scott Lurndal]

Sometimes. I got a $400 check last year due to excess production (the house had been vacant for renovations most of the year, so the excess was pretty large). The municipality offering the rebate has reduced the per-kwh value by a factor of eight this year, sadly.

[micky]

For any who get solar panels on the roof of their house, make sure the installers do a nice job.

A house near hear has an ugly galvanized conduit running down the front. The house used to be cute.

Another one is farther away and looks better, but I'm not sure. Another runs the cable down the side, that not many look at.

I would want to run the conduit through the roof into the attic, down through the stack to the basement, but most of my n'bors don't know there is a stack. And it has a floor between the first and second floor, which is hard to reach to drill through, but I did it with a 6' foot drill bit, a one foot extension, and a long arm, and so can a contractor..

Or maybe through closets.

[trader_4]

There is a lot there to unpack. First, a battery that's capable of powering the house for 2 to 3 days is likely going to require a lot of batteries and that in turn is expensive. How much capacity you need depends on what loads you intend to power. It could be practical if all it is are some LED lighting, charging PCs, cell phones, etc. Since you have solar, the ideal solution would be a solar system that supports batteries, in which case you would be able to use solar/battery with the grid down. But that's expensive, the solar converter you have would have to be replaced and the batteries aren't cheap.

A generator can be fueled by gasoline, unless you live in California, where they are now illegal for new purchase. It's just that if you have natural gas, it's a much better solution for obvious reasons. You talk about the generator being connected automatically, again this is a more expensive solution and it's called an automatic standby generator, they typically start at ~$2500 plus installation. For under $1000 you can get a 5KW portable generator that runs on nat gas. Then you can use that with just extension cords or you can probably have a lockout installed on your panel with an inlet. When power goes out, you plug the generator into the inlet and disconnect the main breaker via the lockout. With that you can power anything in the house, subject to managing the various loads so you stay under 5KW. If you expect to run a big load, eg whole house AC, you'll need a larger generator.