alt Hacker NewsMy biggest problem with batteries for grid outages is that the only outages I am actually concerned with would drain them to zero before the outage is resolved. For short term, smaller/portable batteries are fantastic at bridging a few hours. Plug the wifi & fridge in and you can sometimes go for 2-3 days.
I am not aware of any economically feasible way to run my 5+ ton HVAC system full-time on batteries after a hurricane just reset all the infrastructure, and you do need to run it full time because of the insane humidity and latent heat that follows a tropical system. Doing the math, I'd need something approaching 800kWh of storage to ride through this kind of event (7+ days). This is approaching half a million dollars in batteries. I can install an extremely nice 1800 RPM generator for ~15% of this cost, which would also include a year's worth of propane buried on the property.
I think a simple generator on an ATS remains undefeated from an engineering perspective. If you have an air cooled unit, the maintenance is not much more complicated than with a lawnmower. You just have one extra spark plug to deal with, and sometimes the oil pressure sensor needs replacing. I can get my stubborn Honda generator to start with all kinds of weird tricks. If my Ecoflow battery starts to act weird, I have very little recourse by comparison.
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You can run your hvac fan and an oversized dehumidifier for a while off batteries. You don't need the whole hvac system.
I’ve been looking into a smaller scale option to run limited items medium term on part time hours…
Best option so far involves a mix of batteries that are charged from the mains when available and topped up from a mix of solar and a LPG/multi-fuel generator.
But unless you want to go very large on the solar and generator size it’s unlikely to cover everything full time.
Assuming you have enough solar, how about running your 5+ ton HVAC system only when there is enough production? And properly insulating your home, of course, using it as a thermal battery of sorts.
If there is a grid outage, surely one can shift consumption to solar production hours while using the battery for the always-on systems (fridge, lights, some computing...).
Yeah it's hard for batteries alone to compete with generators, unless we put a lot of weight on things like noise, or are just focused on small loads like fridges.
I think the more interesting comparison is generators vs solar, though it depends on the local weather etc.
Oil generators have an “artificially” low price because there’s a lot of demand for oil for other things. If the other sources of demand go away, the price may become unfavorable even if gas generators make a lot more sense from a redundancy perspective.
>I think a simple generator on an ATS remains undefeated from an engineering perspective.
Let me just inject a bit of nuance here to avoid what I think is an unintentional sleight if hand...
For the small sliver of the population that lives under threat of a large area week long blackout in a hot humid climate, I think a simple generator on an ATS remains undefeated from an engineering perspective.
For the vast majority of the population, it's incredibly rare to lose power for that long, and need AC 24/7 afterwards. It basically only happens in the gulf.
How about reducing energy use? In general, but then especially after a grid-destroying event that keeps you offline for a week? You surely don't need to have everything HVAC running on full blast in the whole house during that time. And your laundry and next oven long cook can probably also wait until the grid power is back.
If you then add some solar into the mix, it doesn't sound as dramatic anymore.
There is something in between flashlights and a grid scale battery that van power your full electric home.
I just have a plugin battery that I can run the lights, fridges, phone chargers off of for 24 hrs. That is good enough for me, and I think most people. Anything shorter, and it's not necessary to run the rest, much longer, there also isn't because apparently shit hit the fan and we're not necessarily assuming the power comes back on in the next weeks or ever.
I have 18kw of solar and 30kwh of batteries with a 5ton ac it will run it will run indefinitely assuming the sun comes out, if it doesn’t I have a chargeverter that can keep the batteries charged off my RV’s diesel generator or gas portable.
My solar system generates excess power daily and has zero maintenance, the generators are pure money sinks for backup power and require regular maintenance.
Options are nice.
Also heat pump water heater and dryer help reduce load along with efficient variable speed hvac and good insulation.
Fuel is a problem during a storm too and a buried large propane tank is a good way to go but very expensive on top of installation.
An electric car with bi directional charging would add to flexibility either charging from home system or being able to go find power and bring it home.
Ideally I would like a gasoline hybrid with power out like a F150 power boost and a fully electric with large battery and V2L any Tesla would do now as they all have 2400w out I believe Cybertruck can do more. My chargeverter can take 120v or 240v
Batteries alone are not suitable for long duration outages, but solar+batteries, designed correctly, can not only supply enough power during long outages, it can get you to be off-grid entirely in the first place at a dramatically more cost effective number than your $500k quoted - perhaps 1/5 or less for a system suitable for your needs of 115kWh per day. So while the system might be more expensive than a generator alone, it can still beat on value because it provides power all year round.
You also do an unfair comparison here - you are OK with portable batteries providing only fridge & WiFi for a couple hours, but expect whole-hole batteries to last a week. Many people use whole-home batteries to bridge typical outages that last <24 hours, and do so without ever having to notice any change of use of their home - powering their full heating/cooling etc.
Batteries and generators are also not mutually exclusive. You can install a solar+battery system because it makes economic sense and pays for itself while providing zero-downtime backup for most outages, while also backing that up with a generator for longer term edge case outages eg long extended outages during the winter or where there is an unusually long “solar drought” - it really depends on how much resilience you are designing for.