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Home Battery versus Generator

pv-magazine-usa.com

13 pointsgnabgib54 comments

After losing power twice for over a week in the depths of winter We installed a transfer switch to allow hooking up a generator. This cost around $200 (my brother-in-law did the electrical for free). We already have a generator built-in in to the truck camper parked in the driveway. The truck camper is setup as an emergency shelter when parked - fully stocked with food, water, and fuel (I live in the PNW and we are expecting the BIG ONE any second).

The transfer switch has multiple switches that allows me to power different sections of the house. I tested everything running the generator - the furnace, the fridges, select lights - it works like a charm. The generator runs off propane and I have 8 bottles of extra in the shed in addition to the large tanks in the camper. Propane is very stable in long-term storage so it is my ideal fuel.

My point being that I don't know where the cost of a home generator is between 7k and 15k. Even if I purchased a separate generator dedicated to house back-up this would be around 2k. The transfer switch would be around 1k for the average consumer. That is 3k. What am I missing about these estimates?

Batteries are fantastic until not and at a very expensive price on top - a generator always works and treated correctly for decades - generators are the way to go for homes.

Batteries are dirt cheap when you take in account the fuel prices over the generators lifespan. These days we can buy like 50Kwh battery's for barely 6000 Euro. That is like 1/10 what this used to cost not even 5 years ago.

And no, not the entire world lives in the US, where people get gasoline/diesel for 1/3 or less, then what we pay in Europe.

I do not understand why solar installations are so expensive in the US, where we get installations often for 1/4 to even 1/6 from the prices i see quoted in the US. There is a reason why seeing solar on every third or forth house is not uncommon here.

A generator (in Europe) is good for those days where you get no solar energy and are totally off-grid living (or do not wamt to use electricity providers anymore with their stupid fixed costs).

>I do not understand why solar installations are so expensive in the US

the Biden administration has recently raised these tariffs, including doubling the tariff rate on solar cells from China to 50%

Tariffs are magic.. they make america so rich!

Looked up the numbers:

Trump initial 25% Tarif (30 down to 25), then Bidden up to 50%, then Trump up to 60% ... It adds up fast.

Europe had import tariffs from 2013 and those expired in September 2023. That is around the same time most countries stopped with subsidies for solar.

The ironic part is, that this flood of cheap Chinese panels, batteries, etc is a major boom to our energy independence as those installations easily last 20+ years. And given our neighbor to the easy issue, energy independence is high on the list.

The US does not have this issue with their gas/oil rich area's (and probably $$$ to politicians).

I love how I'm getting downvoted here :-D

Tariffs DONT make America rich, they make imported products more expensive to buy.

Then if and only if, they get so expensive that its cheaper to make them locally, they start industry to make them locally.

they're still more expensive than the pre tariff price, but they're now cheaper than the imported product.

I'm not arguing against tariffs.. just stating it like it is. and mocking the statement they current leader keeps repeating incorrectly.

A home generator capable of powering an AC system for at least part of a large home is probably going to be several thousand dollars, so that may be the source of some of the estimates that you’re seeing.

That makes sense. Thank you - in Oregon we can live without AC in an emergency.

Seriously .. if you are "expecting the BIG ONE any second" ... maybe you should move?

You could ask this of almost everyone living in California, and I expect their answer would be similar: the apparent benefits outweigh the perceived risk.

Every geographic region in the U.S. has a natural disaster risk factor. In Oregon we are overdue for a large quake, but I've prepared for this. In fact, taken what other regions face - wildfire, tornadoes, hurricanes,flooding - an earthquake sounds down right mild.

My preparation of a truck camper as an emergency shelter makes perfect sense to me. It is mobile, has a built-in generator but is mostly run by solar charging, provides enough space to sleep and live with heat and AC. Few people prep their RV's as an emergency shelter. I'm not sure why. Naturally, I hope my community does not have to face a major earthquake, but I do find it interesting when I get criticism for preparing. Am I coming across as paranoid, or prepared?

Earthquake hazard exists for literally the entire North American west coast.

If you move further east, you start to get other hazards: Hurricanes, tornados, flooding, forest fires. Take your pick, there's always something to worry about.

The important thing is to know what the hazards are for your area and prepare for those.

What is “the BIG ONE” in PNW that could happen without warning any second?

Earthquake or volcano would be my guess, with landslides being a secondary concern. Plate tectonics in that area creates some hidden (or in the case of Tahoma and others in the area, not so hidden) dangers that have struck in the recent history. The Nisqually earthquake comes to mind as well.

https://en.m.wikipedia.org/wiki/2001_Nisqually_earthquake

https://pnsn.org/earthquakes/recent/

Subduction zone earthquake.

Earthquake. The entire North American west coast sits on the boundary of the Pacific tectonic plate, so it's a subduction zone.

Same reason California and Japan are known for large earthquakes.

Why not both?

Even small generators provide a lot of power at once, for a small initial price, but are expensive to run continuously. A battery has low operating cost, but one large enough to run a house off of solar power, year round, is extremely expensive. A battery that is large enough to work 99% of the time is much cheaper, and a generator can fill in that 1%, operating only a few hours a year, at a very low cost.

In my case the answer to why not both was unattended reliability and piece of mind. If it's raining and we lose power we have about four hours before we start to get flooding do to a sump pump not running. Our backup generator will run a self test every week and automatically power the house with a ten second delay when the power goes out. While I suspect solar and a battery backup would keep the sump pump running for a long time it's nice to not need to choose what to run and monitor our power usage during an outage. It's also nice to not worry about power while were on vacation. With solar and a battery backup I'd be concerned about checking it while away from the house. I realize I"m somewhat of a unique situation though in just how quickly we get flooding when power goes out.

You've already got a solution, and often the cheapest solution is the one you already have.

There's no technical reason a generator + battery (and solar?) setup couldn't be configured to run off battery till the battery reaches a preconfigured state of charge then call for the generator.

DO you have commercially available examples of this setup? While I agree there's no technical reason this wouldn't work when doing research for our generator all the hole house generators use a transfer switch so it's either running the entire house completely disconnected from the grid or turned off and running the house from the grid. Solar didn't make sense for us given the costs and our time horizon, but it's always been something I've been interested in. A solar system with a natural gas generator backup to charge the batteries would be nice, especially for shorter outages so we wouldn't need to hear the generator running.

Look for UPS with generator input.

A business that sells solar with battery backup would know the current product range.

I’m only really familiar with industrial kit tupicalled used in data centres.

typically*

This is what I do and it's worked quite well so far -- we haven't had an extended outage to contend with yet.

I have a relatively small battery as these things go (Bluetti AC200 Max w/ extended battery) but it's enough for our essentials. The game changing aspect of it, IMO, is that acts as a buffer for my generator, solar panels and whatever else I may want to use to power it in the future (maybe an EV?).

I do something like that, but a little bigger, and it works great. I put it together after a two-week outage a few years ago (we get multi-day outages almost every year). I have two Bluetti AC300s and four B300 batteries. That gives me ~12 KWh (~24 hours for us) and 240 V so that it can feed the entire house.

The buffer thing you mentioned is key... our average usage is around 400 W, so the generator can be pretty small and the battery system will handle the peaks. We have a hand carryable 2 KW inverter generator. The challenge with this system is that you need 240 V to charge the two Bluetti units (or two 120 V lines on opposite legs of a 240 V feed to ensure the proper phase relationship). I got around this by buying three Mean Well 48 VDC power supplies (meant for large LED installations). Each will do ~500 W. I plug them into the Bluetti units as if they were solar panels. Running the generator through them for 6-8 hours a day is enough to keep the batteries going indefinitely. That's 2-3 gallons of gas per day. And the first day of an outage requires no gas.

In the summer, we have a handful of solar panels I put up in the yard to keep the batteries topped up when not being used for outages (our outages are mostly wind+snow events in winter). Our evaporative cooler, chest freezer, and washer / dryer run off the batteries while the panels are up.

So far I have never seen a system that works as it would need to for that to work. They all have weird fine print which means that despite having both only one is used when backup in needed.

This is the way.

I live in Seattle and I was originally going to go with batteries. However, the half of the year when our power is most likely to go out is also the half of the year where there is very little sun. So for a prolonged outage I’d either need a lot of battery or a generator. For short outages, a battery made sense, but the cost was a lot higher.

I ended up with a 6.5kW portable tri-fuel generator instead. It cost me $1300 and I spent a little more for a plumber to add a gas stub to connect it to. I did my own electrical work which saved some money, but wouldn’t have been much more for an electrician. It can run my whole house indefinitely (obviously with some maintenance - it’s a small engine), except for the A/C which generally isn’t needed most of the year, and with some manual load shedding we can run the hot water too.

I live in the city and shouldn’t need any of this, but Seattle is poorly run so we have lots of outages from trees hitting things. Often a different transformer on the same block because the city will repair them but not take the time to trim the trees near the lines on the same block. I’ve had to throw some food away the last two outages (both in the last 6 months) so this won’t take long to pay for itself!

> an average home battery system costs between $10,000 to $20,000

What size is this? In the UK you can get a 16kWh LFP battery for £2,700. I believe an inverter would be £1,500.

This would cover one day of electricity usage for me if you exclude EV charging, double it to include that too. Note that my heating is gas.

I’ve considered getting a setup like this just to charge it at night at 7p/kWh and use it during the day to save paying 30p/kWh but the ROI of saving £100/month is slightly too long. If prices come down further I’ll probably bite.

By your numbers the payback period would be about 3.5 years. A bit more for a transfer switch and some wiring and other accessories.

That seems like reasonable investment.

Is that Fogstar? Because looking at non-niche brands like Growatt, Goodwe, Givenergy, Solax, Huawei, LG Chem, etc., it looks to be more like the rest of Western Europe at ~€800-1000 per kWh (which is highway robbery to a depressing degree), or am I missing something like some green tax deductions?

[Edited to use € instead of £ because it turns out I wasn't up-to-speed with current exchange rates]

Take a look here (titansolar DOT de) or ( etronixcenter DOT com) or ( secondsol DOT com)...

If you look around, you can go as low as 50kwh for 6000 Euro. So around 120 Euro / Kwh on the low point. For the newer models with build in fire suppression, its around 150 Euro / Kwh.

Ofcourse, self installation. Its those "professional" installation jobs that are so overpriced and where you pay a premium. Think my dad payed like 3.5K euro for a 5K battery a few years ago (Huawei). And he passive regretted not just doing a second installation himself with a 20k battery (at that time was around 3.5k).

Prices have collapsed. Bifu (double side) Panels are now like 70 Euro, even 62 Euro (32 panel packs).

Note: German prices in the above stores, aka no tax on solar as its tax free in Germany.

Yes, fogstar: https://www.fogstar.co.uk/collections/solar-battery-storage/...

I’m no expert - is there any issue with fogstar?

Had never heard of them before, that's all. Only familiar with the usual players. They look interesting for sure. I've been so depressed with prices of home batteries compared to prices on naked prismatic LFP cells that I've semi-seriously considered DIY-ing one, but time is also money.

Here in Seattle, I've had 2 outages that lasted 4 days, and one that lasted 2 weeks. A battery won't last that long. I get a couple outages a year, from 4 hours to a day.

Sick of all this, I finally bought a generator. It is hooked up to the natural gas pipe, so I don't need to store fuel (something I really don't care to do) and the supply is infinite.

Nearly all the outages are trees falling on the wires. The power company refuses to bury them, even when the road is trenched for other reasons.

The potential energies are massively different. A 16kw battery can run a 2hp motor for about 10 hours. A 16kw gas generator with 300 gallons of fuel will run it for maybe 1,200 hours. If you're planning for just short disasters batteries make a lot more sense. I'm planning on multi-week ice-storm outages and multi-day wildfire fighting, so I recently got a propane standby generator.

But both of those together will run things a lot longer.

Best would be to match up max efficiency of the generator with the charging speed of the batteries though.

(this is about outages, the article seems to talk about offgrid?)

nope, once you decide on a genset, then investment in / maintenance on a battery just makes zero sense.

If you decide on battery and then decide on a generator, you can get a lot more bang for the buck. Most of the time you don't need the full output from the generator and running it just burns fuel to keep minimal power delivery. Replace that with just charging batteries as needed and you will have the best of both worlds and ... it's quieter.

Take in account, you may be speaking to a American, and there the whole solar/battery vs Generator can be extreme different.

Solar prices are still extreme expensive in the US (from my perspective), same with batteries, while gasoline is like 1/3 the price of Europe. So from that US point of view, its one or the other but both is more expensive.

Here going big with solar is way easier, and just a small backup generator is the norm for off-grid or grid-disconnected homes. People going 50, 70 ... battery Kwh installations is not uncommon anymore for the off-grid/grid disconnected homes. Especially when the batteries cost you barely 6k Euro.

I balk at seeing the US prices and that may be because of the much higher import taxes on Chinese panels/batteries (that and some extreme scrupulous installers).

Now to be honest, what people also ignore is that fuel prices are going to go only one way, and that is up. While a fix solar installation has only one cost, the few times you need to run a jenny. Batteries, especially large setups, easily do 20 year before they hit 80%.

Another US caveat, is that US households use way more electricity then Europeans. That is also a factor...

> (from my perspective)

In california, where electricity routinely reaches 50c/kwh (and rising) with PG&E, the economics are upside down.

That said, a battery + generator system allows a smaller quieter generator (maybe even DC), and possibly fewer batteris, so could be very efficient in other ways too.

We've discussed getting backup power periodically since moving (most of our neighbors have something). After the big bomb cyclone that hit the NPW this became a priority and I did a very similar tradeoff matrix.

Here were some of my consideration points against a generator (I had a list for batteries too):

1. the previous owners electrified the house so having a tank just for a generator didn't make sense

2. per 1, a small tank wouldn't last very long and if we're out of power for multiple days gas delivery is unlikely to be happening anyway.

3. tank + generator didn't have a practical placement location for us

4. smaller portable generators didn't make sense from a maintenance perspective since they didn't auto test.

5. what happens if it fails a self test right before a storm?

6. we get intermittent power cuts / fluctuations / outages throughout the year and the generator + ATS wouldn't protect sensitive electronics well

Edit: ATS + batteries can play nice together then I might look at doing a small portable as aux backup

> the previous owners electrified the house so having a tank just for a generator didn't make sense

The PNW has been on a campaign of hate against natural gas lately and unfortunately that delusion has spread to its residents. One of the most reliable low-maintenance appliances you could own is a direct vent natural gas fired water heater. Requires no external power source and quietly delivers hot water. The previous administration outlawed them but I understand that ridiculous law has now been reversed. You were trading a shred of efficiency for much lower reliability and resiliency. I would hear a lot of whataboutism that natural gas delivery requires electricity for the pumps but have never seen or heard of a single example of that happening, certainly not your typical PNW windstorm.

That leaves the essentials:

* Fridge/Freezer

* Heat

With an Energy Star fridge and a high efficiency natural gas fired furnace you could easily power this off a Costco-grade portable generator and have enough power left over to power the phone chargers and Internet (assuming that isn't out too).

The PNW's environmental crusading hate-boner against natural gas is going to end very poorly for its residents. Before forcing everyone onto heat pumps and electric everything they need to figure out how to keep the lights on more consistently than Puerto Rico.

Y'all have natural gas lines run to the home but use electric to heat it? That seems so backwards.

I didn't see anything about load shifting in the article - are there any sites that help calculate the ROI on a battery system that is used to power the house during the day and recharges overnight?

For example, here in Ontario Canada, we have the option of an "Ultra Low Overnight" rate where the energy price is 2.8c/kWh between 11pm and 7am, while the tiered rates start at 9.3c/kWh; given the 6.5c/kWh delta, how many days' worth of use would be needed in order to pay off a given battery system? How would adding a solar system affect that calculation?

Rate references: https://www.oeb.ca/consumer-information-and-protection/elect...

I saw an Xcel Energy promotion for a Powerwall system with rebates taking the cost down from $13.5K to $3.5K, in Denver CO USA. I would have been very tempted by that except I don't have Xcel for electric in my area.

edit: Check to see if you have rebates in your area.

So far we are buying electricity based on the supply-demand price. When will availability be factored into the price? It find it untenable to have that floating, just for the sake of allowing volatile solar and wind on the grid at the cost of baseload providers.

In my second-hand experience, 2 out of 3 times, when the generator is needed, it doesn't work, due to the long time since it last ran. Or requires ~weekly reruns to make sure it is in working order.

Just from that PoV, I'd personally favour batteries.

That is much less of a concern with a propane generator, due to fewer issues with longer term fuel storage and carburation than gasoline generators. Batteries still require maintenance, and regular starting, fuel and oil checks are all a good idea, regardless.

[flagged]

Sorry to rub salt in the wound, but a power cut every month seems very high for a rich area in a rich country. Having lived decades across different cities across western Europe I've experienced power cuts maybe two or three times - and otherwise only on vacation in developing countries.

Our services here all have more or less publicly owned infrastructure with private providers handing the contracts and energy supply. I guess that must be a happy middle ground, and having a private corporation handling infrastructure seems a bad idea all around.

Oh hell yes, I know it is. I moved from the UK 20 years ago. In thirty-odd years of living in the UK prior to that, I had a power cut precisely once - in the great storm of 1987 [1].

I’m leaving the US and going back to the UK in a few months - just waiting until the end of the school year for the kid’s sake. I don’t like what the USA has become, and I can retire nicely now, so it seems like a good time. I’m looking forward to not needing power-walls in the future, as well as 4 actual seasons :)

1: https://en.wikipedia.org/wiki/Great_storm_of_1987

[editing this post because apparently I can't edit my previous one, and it's been "flagged". I assume this is because I'm saying some not-nice things about Mr. Musk and someone got their knickers in a twist over it because the comment about generators seems fairly innocuous. Snowflakes. Maybe he wouldn't be called out (worldwide) as a nazi if he didn't do nazi salutes in public...]

Re: noise complaints, I'd suspect that most neighbors wouldn't mind if you had a generator running during a power outage - especially if you offer to share to keep their fridge cool.

Yeah.. I tried that argument... I spent quite some time talking to the (very nice, but immovable) city people.

The response was that the ordinance is there for a reason, and even if I were to keep to that offer, and even if my neighbors were happy with that, if the house is sold or new neighbors move in, things might deteriorate and they'd have problems trying to have the generator removed.

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