A recent post to another thread caused me to do some thinking and wondering if there is a "better" alternative to a StandBy Whole Home Generator. Here's the post:
Generator? Batteries? or Both?
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I was talking to my neighbor just the other day when he was thinking about how to hook up the portable generator he got from a friend. He's seriously thinking about getting battery backup now. We had a storm a couple years back that caused a 3 day outage, and while the generator worked fine...it did make me think what I would do about a really long outage or prolonged grid down event and for me battery backup made sense. With the cost being the main con, the pros are numerous:
1. Redundancy
2. Quiet (run on battery at night)
3. Security (store the gen in the garage at night)
4. Efficiency (all of the gen power goes into batteries, where you then use only the energy you need)
5. Option to expand with solar as another power source
6. Maintenance (gen gets far less use)
7. Power spikes (can't run large loads like my HVAC with the gen...even with a soft starter)
8. For short outages, just flip the interlock and the on button. No hauling out and connecting the gen.
9. 30% Federal tax credit on entire battery/inverter purchase.
1. Redundancy
2. Quiet (run on battery at night)
3. Security (store the gen in the garage at night)
4. Efficiency (all of the gen power goes into batteries, where you then use only the energy you need)
5. Option to expand with solar as another power source
6. Maintenance (gen gets far less use)
7. Power spikes (can't run large loads like my HVAC with the gen...even with a soft starter)
8. For short outages, just flip the interlock and the on button. No hauling out and connecting the gen.
9. 30% Federal tax credit on entire battery/inverter purchase.
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You will need a robust inverter and the batteries to support that to run the HVAC. Why when I chose between grid tired solar and powerwall with no HVAC or solar offline and generator, I picked the latter. 6000 cheeper and I get to run the HVAC. To keep my house alive over night I figured 400W for 10 hours with possible peaks to 3KW. No HVAC. So 5kwh of batteries and a 3-4kw inverter/charger.
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The standby generator is a strange market concept ... the grid is down, short to long duration outage, frequency of a few times per year to a bunch.
Such outage/frequency market is well-served by the standby gen if you have a very dependable water-cooled (diesel) standby generator, all correctly sized/installed/serviced by a nearby authorized dealer. I'll go out on a limb and assume this starts at $10k to 15k, and goes up from there.
This same market is not as well-served if your standby gen is air-cooled (whatever fuel). This might be because the air-cooled range of gens are very problematic, and this and other forums abound with problems and outright failures. Here, I think the pricing basically starts at $5k to 10k, all correctly sized/installed/serviced by a nearby authorized dealer. It doesn't matter that it is half the cost of water-cooled, because odds are, it won't last, especially if you "choose poorly" on the manufacturer.
I think that there is a 3rd & 4th "alternative" solution:
Depending on your AHJ, both alternative solutions might require extra headache (inspections, extra parts, etc.), but then, so might the standby gens.
The water-cooled solution and the alternative solutions totally cut out the pucker factor from the air-cooled standby gen market ... that is, total catastrophic failure of the air-cooled gen (doing something unnatural, like trying to run for more than an hour or so), with manufacturer running away from the problem.
IMHO, you just can't go the air-cooled route ... even though this is the route chosen for most "subdivision/tract" homes, where the air-cooled gen manufacturers target those homes.
Such outage/frequency market is well-served by the standby gen if you have a very dependable water-cooled (diesel) standby generator, all correctly sized/installed/serviced by a nearby authorized dealer. I'll go out on a limb and assume this starts at $10k to 15k, and goes up from there.
This same market is not as well-served if your standby gen is air-cooled (whatever fuel). This might be because the air-cooled range of gens are very problematic, and this and other forums abound with problems and outright failures. Here, I think the pricing basically starts at $5k to 10k, all correctly sized/installed/serviced by a nearby authorized dealer. It doesn't matter that it is half the cost of water-cooled, because odds are, it won't last, especially if you "choose poorly" on the manufacturer.
I think that there is a 3rd & 4th "alternative" solution:
- replace standby gen with a highly durable/portable inverter-gen, like the honda 7000 line ... as others point out above. sizing/installation needed. starts at $5k (diy, installation extra). This will work, and rarely will you have a catastrophic failure. Solution runs 24hrs/day (per vendor guidelines) during extended outages.
- replace standby gen with inverter/battery-bank/charger, and $1k or so portable gen. Sizing/installation needed, starts at about $8k, including $1k open-frame portable gen (diy, installation extra). Many might combine this with an inverter-gen, for a higher portable gen price; solution might get closer to $10k. Solution runs 24 hrs/day, and gen only runs 4 hrs/day or thereabouts.
Depending on your AHJ, both alternative solutions might require extra headache (inspections, extra parts, etc.), but then, so might the standby gens.
The water-cooled solution and the alternative solutions totally cut out the pucker factor from the air-cooled standby gen market ... that is, total catastrophic failure of the air-cooled gen (doing something unnatural, like trying to run for more than an hour or so), with manufacturer running away from the problem.
IMHO, you just can't go the air-cooled route ... even though this is the route chosen for most "subdivision/tract" homes, where the air-cooled gen manufacturers target those homes.
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I have 30kWh of batteries, and a 4kW dual fuel generator. In the event of an extended outtage without much sun, I can run the generator to keep up the battery. I have a few 20# propane tanks. Each tank provides about 15kWh of power.
Thought about tri-fuel, but not worth the cost of installing a natural gas port to hook up the generator. Cheaper to buy a few 20# propane tanks.
I can use the small generator for other needs. A 7kWh would be better, but weighs 200 lbs, and overkill for me needs 99% of the time.
Thought about tri-fuel, but not worth the cost of installing a natural gas port to hook up the generator. Cheaper to buy a few 20# propane tanks.
I can use the small generator for other needs. A 7kWh would be better, but weighs 200 lbs, and overkill for me needs 99% of the time.
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If you had deep pockets you could use a battery generator at night while sleeping and a engine driven generator in the day.
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just keep in mind that batteries are a 5-10 year life time.
it all depends on the setup and the charger maintainers.
BIG batteries like they used in the telco systems last longer.
but it takes a pro to keep them going.
a power wall setup is something to look at.
but i would rather do that in a separated from the house and garage setup just in case.
think concrete bunker style gen shack.
and if you are building that proper clad the outside with tin for the faraday cage.
a good battery system runs $1000.00 and up depending on the power needed and days of reserve.
best advice is to make sure the inverters for the battery section are able to run in parallel.
and be able to switch battery blocks in and out.
then you could scale it up or down just like the honda inverter gens.
i use up to 4 of the eu2200i gens in parallel for summer cooling.
pm if you need a link for the build on that setup.
start small and buy it a bit at a time and in a few years you have a good solid back up system.
unless you have the bucks now to swing $10-30k for a mid sized battery system.
also think water storage as well.
it is hard to live with out good clean water.
Quoting you, but this is for the OP:
At least a 10yr old generator will still work if you maintain it. Batteries degrade whether you use them or not, so unless you have a LOT of outages, or devise a way of using that power more often, it's a supreme waste of money. It would be no different than buying a $50K Tesla and never driving it.
In other words, batteries have better ROI if you can use them for other purposes than sitting around waiting for an outage.
Besides the cost of a battery solution being more (much more) expensive than a generator, this is one aspect frequently overlooked. Use them or lose them.
At least a 10yr old generator will still work if you maintain it. Batteries degrade whether you use them or not, so unless you have a LOT of outages, or devise a way of using that power more often, it's a supreme waste of money. It would be no different than buying a $50K Tesla and never driving it.
In other words, batteries have better ROI if you can use them for other purposes than sitting around waiting for an outage.
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This is true to an extent, though my understanding is that LIFEPO4 batteries are expected to retain the majority of their output power for 20+ years and 7k cycles. If you want to go the cheapest route, get two inverter generators that can be paralleled. Use one for the majority of the work and have a second as a backup and for situations when more power is required. Just make sure you have a reliable fuel source.
You also have to power the batteries, or constantly top of them off. I'm not sure what that rate of parasitic drain is, but it isn't free. This is where having a complete solution that involves solar panels becomes practical, although for more upfront $$ of course. Technically "free" sun power is keeping those batteries charged, so your electric company isn't doing it.
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Absolutely. Adding some panels would be best, but due to my lack of decent solar exposure and very tough local permitting restrictions, it's not in the cards right now. I'm looking at the batteries as an extra layer of insurance in the event of a major grid down event. Considering our current paradigm, I don't want to the guy who's only generator just failed and says "****, I was thinking about some redundancy but never went through with the purchase."
Lithium batteries deteriorate both from cycle aging and from calendar aging. Depth of discharge, C-rate (how fast the battery is charged or discharged, relative to its size), and the state of charge it lives at also significantly influence how long they will last. And they cannot be charged when temperatures approach freezing or they will damaged through a process called lithium plating. You can get around that by having a battery management system that actively heats the battery via some external mechanism, prior to charging, but of course that takes a lot of power in and of itself.
A big problem for anyone contemplating using them for emergency power backup is that when kept "topped off" at a near 100% state of charge, they degrade significantly faster.
The benefits of lithium batteries are many, starting with their much higher energy density than most other chemistries. And unlike sealed lead acid, they can be discharged to nearly zero percent state of charge without damage. But they are expensive and require a bit more care and understanding. I like them quite a lot - I have a number of larger (12-20 Ah) lithium batteries I use in my ham radio hobby, and I have an 82 kWH lithium pack underneath my Tesla Model 3. But a 20-year battery they are not. Alas.
To the OP's question... I think generators provide the most flexibility for backup power. And they're reasonably affordable. If I won the lottery I'd have a solar array large enough to meet all my electrical needs, a lithium battery setup as part of that (acknowledging that those batteries are expensive and will need replacing every some years), and several generators as my backup to that.
And not that it ought to count in anyone's decision... but generators are just plain cool!
A big problem for anyone contemplating using them for emergency power backup is that when kept "topped off" at a near 100% state of charge, they degrade significantly faster.
The benefits of lithium batteries are many, starting with their much higher energy density than most other chemistries. And unlike sealed lead acid, they can be discharged to nearly zero percent state of charge without damage. But they are expensive and require a bit more care and understanding. I like them quite a lot - I have a number of larger (12-20 Ah) lithium batteries I use in my ham radio hobby, and I have an 82 kWH lithium pack underneath my Tesla Model 3. But a 20-year battery they are not. Alas.
To the OP's question... I think generators provide the most flexibility for backup power. And they're reasonably affordable. If I won the lottery I'd have a solar array large enough to meet all my electrical needs, a lithium battery setup as part of that (acknowledging that those batteries are expensive and will need replacing every some years), and several generators as my backup to that.
And not that it ought to count in anyone's decision... but generators are just plain cool!
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LiFePO4 sel discharge about 2% per month. They have expected life of 15 years. Do not have the fire issue of earlier generation of lithium batteries. Qualify for a federal tax credit of 30%. Some areas, like CT, have state tax credits, and grid support performance credits that pay for most of the cost of the battery over 10 years. When combined with solar, you have significant grid backup capabilities and can use a cheap portable generator for backup to the backup capabilities. The portable generator only has to charge at a steady rate (75% of load) and not have a large capacity to handle max loads.
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can you use the solar shingles deweb?
some areas the HO groups allow those as long as they are colored to match the roof system.
they are pricy at best.
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The only southern facing part of my roof is a small area that is mostly shaded from my neighbor's trees. I have a fence line on the opposite side of the yard that could potentially accept a ground mount, but I don't want to deal with the permitting since we are likely moving in a year or two. It would likely only accept a small 3kw array, so the cost wouldn't be worth it for such a small timeframe. Assuming we could average 10kWh useable per day, at 25 cents per kwh the utility saving would only be $2 per day.
I could get a few portable panels for a prolonged grid down event, but it's easier and faster to just use my Honda for recharging.
Once we have a new property under consideration, I will get to work on a serious plan for solar. I'd like some acreage to get away from the noise and people, but getting a good water supply and natural gas is going to be tough since those are usually available only in larger towns and cities. I could theoretically do without natural gas (cooking, heat, laundry, generator) if my solar setup was large enough.
One more year until retirement, then the grand search to find our forever home commences...
Yes, Battery's are like Automobiles: if you don't run them, they won't last. My power company charges "Premium" rates for electricity from 4p-9p. What if a Battery system is scheduled to run your home during that Premium rate period? You'd be running the battery system, saving money, and possibly even re-charge from the Grid during off-rate hours (i.e. Midnight-5am?).
Would propane work @Browse Deweb ? I, too, am looking at properties with some acreage (among other things, being able to shoot in my back yard is one of my requirements). Natural gas is pretty much missing from all those rural properties I've looked at, but big propane tanks are pretty common.
I'm hoping that solar comes down in price as more and more people move to it.
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My issue with propane is risk (of supply issues) and cost. Under normal circumstances, supply isn't a problem...but I can see it becoming one if things get bad. Not sure if that would be the case with NG, but I like not having to rely on deliveries. I suppose one could have a large amount of propane storage, but that could get really expensive. Tough call.
If your generator is a Duel-Fuel model, at least it gives you another option (gasoline or propane). Yeah, I have the same concern. That's why a Battery system that can be charged from multiple sources (Solar, Grid, Generator) is attractive. Unfortunately, I can only mount 13 solar panels on my roofs unless I cut down a small grove of Redwood trees.
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