Curious what would be the effect of sustained category 4 or 5 winds on large solar installations and offshore wind farms.
Renewables in a hurricane
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Feeling the Heat
Probably not much. Turbine pitch can be zero.[/QUO probably not close, butrelated, up in the air?
reinforced cell tower, from the islands!
![[Hearth.com] Renewables in a hurricane](https://www.hearth.com/talk/data/attachments/199/199955-8c6c2d295c22d2f831c1d157fa4cc6da.jpg?hash=1343Trlp6W "[Hearth.com] Renewables in a hurricane")
It comes down to what specs the equipment was designed to. My former employer made artic grade wind turbines and they have sold several to areas that have been subject of hurricanes (although not as large as this one).
I think wind turbines get more attention in this regards than solar panels. Solar panels are individually less expensive to replace, and less hazardous to the surroundings if they fail.
sportbikerider78
Minister of Fire
To what extent can residential solar panels be used in a power outage? Even without batteries, I've read of a setup that allows some power to be used by the house when it is sunny out.
Word is that wind turbines in Texas made it through Harvey ok.
Most grid tied inverter systems don't allow the panels to feed the house when there is no grid power sensed. There are some exceptions that allow "islanding" with a battery backup and the solar panels, but they need extra, tested and certified safety systems to guarantee that during the outage no power is backfed into the grid.
SMA offers a feature on some of their inverters called Secure Power Supply. It costs a few hundred dollars more than the equivalent regular inverter, but can provide up to 2 kW through a 120V outlet wired to the inverter. Since that outlet is separate from the rest of your wiring, it appears to me it installation cost should be low and it should avoid a lot of the regulatory issues.
Potentially then, you could do things like run an extension cord to your fridge for a couple hours per day to keep food from spoiling. A sump pump might work, depending how the system handles the startup current. I'm guessing a well pump would be pushing it. Smaller loads like charging a laptop for entertainment in the evening should be a piece of cake.
It would not be as capable as an integrated, "grid-interactive" battery setup, but quite a bit cheaper.
I don't know if other inverter manufacturers have followed suit yet.
I walked a hearth.com member through coming to the conclusion that he couldn't afford not to install solar (his state had incredible incentives), I think he put in two SMA SPS systems. There are significant limitations with the SPS circuits but better than nothing. To really get a useful back up, it requires a battery system, it doesn't need to be huge but it and the required electronics ads far more cost than a generator.
I think you could get something in between for relatively low cost in a sort of redneck fashion with the SPS, using an AC-powered charger, a couple deep cycle batteries, and a separate inverter to use just with the batteries. There'd be a non-trivial efficiency loss doing it this way, but relatively low overall cost compared to a fully integrated storage system. I could do a fair amount with a pair of medium-sized batteries, including run my fireplace insert blower all night long to keep the house cozy.
Still, you'd exceed the cost of a decent 2 kW inverter generator without having as much overall versatility.
WoodyIsGoody
Minister of Fire
Yes, but generators require a large amount of fuel, something that might be hard to replenish during an extended power outage. Solar panels would keep producing for extended periods.
It comes down to how much you want to pay for a backup and what type of backup you want. If its an "end of the world as you know it" scenario the solution is going to be different then a couple of day situation. About 15 to 30 K over the cost of a conventional PV system, plus ongoing battery maintenance and replacement about every 8 to 10 years of 10K (whether you use the system or not) will buy you a very robust system. Spend an extra 5 to 10 K and lot more maintenance and you can upgrade to Nickel Iron batteries (which in theory last 100 years or more).
I do like the Toyota Prius option where the battery is modified to output to a high voltage cable to a commercial UPS that has the appropriate voltage input. The fuel economy when used as a generator is substantially better than a standard generator. I haven't heard of anyone integrating PV into the mix but expect its possible. A PV system with a couple of SMA SPS units would be a nice way to stretch the fuel further. About 20 gallons of fuel will last several days without PV if managed appropriately.
If you want to bet on Tesla actually making a product they announced, they claim that the Solar Roof integrated with a Power Wall will be able to run independent from the grid but given the battery size power management is going to be required to run through periods of no sun. .
I do like the Toyota Prius option where the battery is modified to output to a high voltage cable to a commercial UPS that has the appropriate voltage input. The fuel economy when used as a generator is substantially better than a standard generator. I haven't heard of anyone integrating PV into the mix but expect its possible. A PV system with a couple of SMA SPS units would be a nice way to stretch the fuel further. About 20 gallons of fuel will last several days without PV if managed appropriately.
If you want to bet on Tesla actually making a product they announced, they claim that the Solar Roof integrated with a Power Wall will be able to run independent from the grid but given the battery size power management is going to be required to run through periods of no sun. .
That said, if you already have a battery EV, just getting a biggish, 12V, sine-wave inverter from China is a nice ~$300 backup solution. My puny EV can easily run a 1500W inverter off its 12V system (sized to power all the accessories in the car, including the cabin heater and AC, no acc belt).
With load management (and poor eff associated with turning the HVDC to 12V and then to 120VAC), I can still run my 300W average 120V loads for a couple days, with enough surge power to run an espresso machine, microwave or a sump pump.
My next EV with a bigger battery will probably make that 4 days.
No sun required.
With load management (and poor eff associated with turning the HVDC to 12V and then to 120VAC), I can still run my 300W average 120V loads for a couple days, with enough surge power to run an espresso machine, microwave or a sump pump.
My next EV with a bigger battery will probably make that 4 days.
No sun required.
WoodyIsGoody
Minister of Fire
The Tesla Powerwall is fully guaranteed to last 10 years with daily discharge/recharge. If used only as a power back-up for outages it will last much longer than 10 years. Useable capacity is 13.5 kW for $5500.
Not much in the NW during late fall to early spring. It's why we have a small, efficient propane generator and a big reserve tank.
WoodyIsGoody
Minister of Fire
I know and that's a good way to bridge typical power outages. But when a gas/propane generator runs out of fuel, and you can't get more, a small supply of solar electricity is much better than a generator with no fuel. I'm not so worried about little 5-7 day outages, but the kind that would happen after the big one hits. You need enough electricity to fire up a laptop, run a few LED lights, keep a refrigerator going, run a radio, etc.
Refrigeration is our main concern. With a small efficient generator we have about a month's running storage. More if I tap into the propane stovetop supply. Radio's battery recharges when running refrig cycle. Light can be made from a potato battery.
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Building on what peakbagger said, yes it is another useful option, and if you already have solar and want to be able to deal with an extended outage with minimal compromises, a very good one, I think.
For a more basic level of coverage, especially for shorter outages, it's hard to beat the cost-effectiveness of a small generator unless you also need to power 240V appliances. An EU2000i can provide in the ballpark of 3 kWh per gallon of fuel.
If you don't have solar, $5500 is a lot to pay for single-discharge capability. Actually, I was just trying to remind myself of a couple details about the Powerwall's specs and I see Tesla actually lists it as $6000 including the installation kit they don't seem to let you buy it without.
My understanding was that the first generation Powerwall had two versions....a solar version and a backup power solution. I think for Powerwall 2, the backup solution was discontinued....now they just do solar buffering. But I think the Powerwall 2 solar battery system does NOT do islanding in case of power outage....although they have promised to provide that as a 'future upgrade' to existing users.
N'est-ce pas?
No such thing as a 13.5 kW battery, there is such a thing as a 13.5 kWh battery. That is quite small for a PV system battery. I believe the Powerwall is rated for 2 KW output rate. One major annoyance is Tesla doesnt readilly publish any spec sheets. I couldnt quickly find a charge rate but generally a safe assumption is the charge rate is roughly its output capacity so a standard Powerwall would be able to handle a 2kW PV array. This is great to run lights and small portable appliances but not so great for things like well pumps and AC units which have surge loads. I would suggest a minimum would be two 13.5kWh batteries. Over the years in the northeast, I see most folks running 6 kW generators during extended blackouts to cover their well and refrigeration needs, some folks get away with 4 kW with load management and most permanent household generators installed are a minimum of 10KW. This would imply that 3 or 4 Powerwall batteries may be needed unless load management is put in place.
The devil is definitely in the details on the output side, there probably is some surge capacity in output on the battery but rarely does it match a typical start surge of an electric motor which is usually 3 times nameplate. I have seen a surge output rate of 3.3 kW for a Powerwall so two batteries might be able to handle the surge load from starting a 15 amp 240 volt across the line well pump. If the homeowner has a more modern well pump with variable speed drive with current limiting they may be able to squeak by with a single battery. .A Powerwall doesnt include a output inverter, using a 3.3 kW surge for one battery I would expect a known brand 3500 KW inverter with surge rating would be needed to keep it from kicking out. Of course if someone is trying to run a well pump at 240 volts they would be unable to run standard lighting and small appliance circuits without a step down transformer or some other circuity.
The off grid folks have already figured this out in great detail as they live constantly with a blackout since there is no grid. To date I see very few off grid systems with Powerwalls and the vast majority of the systems use lead acid chemistry with a very small minority using Nickel Iron. Batteries are a constant PITA for an off gridder and a big ongoing investment. I expect that if a Powerwall solution would be an advantage they would be buying them.
There are folks experimenting with LI batteries but they are home brewing battery packs and running into issues that lithium Ion batteries require very extensive battery management systems down to the cell level.
I have seen in the past, a category of "blackout busters" These typically are for homes that are in areas with poor power availability, usually rural areas where power may go down often enough that they want short term power, the systems dont run that often and are intended to ride through a couple of hours, basically a big UPS. In this case a Powerwall based solution may have some value but given the surge rating limitations I expect that there is standby generator and the fuel to run it in the background.
The devil is definitely in the details on the output side, there probably is some surge capacity in output on the battery but rarely does it match a typical start surge of an electric motor which is usually 3 times nameplate. I have seen a surge output rate of 3.3 kW for a Powerwall so two batteries might be able to handle the surge load from starting a 15 amp 240 volt across the line well pump. If the homeowner has a more modern well pump with variable speed drive with current limiting they may be able to squeak by with a single battery. .A Powerwall doesnt include a output inverter, using a 3.3 kW surge for one battery I would expect a known brand 3500 KW inverter with surge rating would be needed to keep it from kicking out. Of course if someone is trying to run a well pump at 240 volts they would be unable to run standard lighting and small appliance circuits without a step down transformer or some other circuity.
The off grid folks have already figured this out in great detail as they live constantly with a blackout since there is no grid. To date I see very few off grid systems with Powerwalls and the vast majority of the systems use lead acid chemistry with a very small minority using Nickel Iron. Batteries are a constant PITA for an off gridder and a big ongoing investment. I expect that if a Powerwall solution would be an advantage they would be buying them.
There are folks experimenting with LI batteries but they are home brewing battery packs and running into issues that lithium Ion batteries require very extensive battery management systems down to the cell level.
I have seen in the past, a category of "blackout busters" These typically are for homes that are in areas with poor power availability, usually rural areas where power may go down often enough that they want short term power, the systems dont run that often and are intended to ride through a couple of hours, basically a big UPS. In this case a Powerwall based solution may have some value but given the surge rating limitations I expect that there is standby generator and the fuel to run it in the background.
Agree with your cogent analysis @peakbagger. I think this is why the Powerwall version for backups was withdrawn from the market...it did not do well. Now they only sell "Powerwall 2" which is for solar buffering (and 2x the capacity of the Powerwall 1 for solar) if you do not have flat net metering, or wish not minimize your volume of grid exchange.
That said, its still early days. Lithium is just going to rapidly get cheaper until the price/capacity of these systems make it stupid not to do them, and where they eat all the other off-grid storage tech you mentioned. Also, given the finicky balancing circuits required by Lithium, it is not clear how much of a low-tech DIY-able solution it is.
It might just be that somebody sells you a spiffy, no maintenance box at a compelling price and with a nice warranty. In other words, the Tesla model, but a factor of several better in capacity and lower in price.
In like 3-4 years.
That said, its still early days. Lithium is just going to rapidly get cheaper until the price/capacity of these systems make it stupid not to do them, and where they eat all the other off-grid storage tech you mentioned. Also, given the finicky balancing circuits required by Lithium, it is not clear how much of a low-tech DIY-able solution it is.
It might just be that somebody sells you a spiffy, no maintenance box at a compelling price and with a nice warranty. In other words, the Tesla model, but a factor of several better in capacity and lower in price.
In like 3-4 years.
WoodyIsGoody
Minister of Fire
Yeah, I saw I left the "h" off as soon as I posted it. I almost went back to edit it and then I thought, nah, not going to waste my time. Anybody who knows anything will know what it means.
Of course, they are modular. If you have larger power needs than one provides they daisy chain together.
Did you check the Powerwall 2 Data Sheet Tesla released months ago?
http://provisionsolar.com/wp-content/uploads/2016/12/Powerwall-2_AC_Backup_Datasheet_English.pdf
Total (useable) capacity is 13.5 kWh. Actual continuous power (both for charging and discharging) is 5kW with a 10 sec. surge capability of 7kW. That is more than enough to handle typical domestic well pumps and even modern air conditioners. But yeah, if you have a McMansion in Arizona with a huge cooling load, you're probably not gonna be running it on batteries. You could do it by daisy chaining a bunch of them together but that's going to get somewhat expensive and they were not intended to be utility scale electric. Don't try to charge your electric car with one or smelt aluminum either. They are for running fridge/freezers, computer networks, furnace control systems and blowers, water heater controls, garage doors, lights, etc.
Tesla sized the Powerwall 2 for reasonable single family residence needs. If you have a huge family or special needs you might need two or, God forbid, 3 of them. But one would suffice for normal residences designed to not be electrical hogs.
You should have checked the actual specs before you pronounced it ineffective.
Not long ago there were 0 Powerwall sales. If you're going to write it off because there are still so many lead-acid battery installs humming away, you can similarly write off electric cars because most people use gasoline. The electrics must not be any good!
And, yes, batteries have been a constant PIA and big on-going investment. But the Powerwall is lowering the cost curve dramatically, far lower than existing lead acid installs. And they will only get cheaper for the foreseeable future. As to the on-going replacement cost, it is nothing compared lead acid batteries (or the gasoline a generator uses). Of course a generator will still be cheaper to get you through those couple days a year when you don't have electricity. But a "prepper" would be better off in most locals with a Powerwall and rooftop solar to charge it (because that system can provide continuous power for months). The higher your electrical consumption, the more expensive the system. That's why good design is important. You don't want to be running a 1980's vintage air conditioner off batteries. And it would make even less sense to run it off a gas generator.
The Powerwall 2 is an integrated and engineered system. You shouldn't expect a homebrew system to be cheaper or more reliable. That's strictly for hobbyists who want to play around.
I'm not sure why you are so intent on talking down the system without even having the facts present. You are completely misrepresenting the capabilities of the Powerwall. I've included a link to the actual specs above. So dismissive, so biased. Sad.
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