# Renewables in a hurricane



## Easy Livin’ 3000 (Sep 6, 2017)

Curious what would be the effect of sustained category 4 or 5 winds on large solar installations and offshore wind farms.


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## Circus (Sep 6, 2017)

ED 3000 said:


> Curious what would be the effect of sustained category 4 or 5 winds on large solar installations and offshore wind farms.


Probably not much. Turbine pitch can be zero.


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## Doug MacIVER (Sep 6, 2017)

Circus said:


> Probably not much. Turbine pitch can be zero.[/QUO probably not close, but related, up in the air?
> 
> 
> 
> reinforced cell tower, from the islands!


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## peakbagger (Sep 6, 2017)

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).


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## iamlucky13 (Sep 7, 2017)

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.


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## sportbikerider78 (Sep 7, 2017)

Circus said:


> Probably not much. Turbine pitch can be zero.


They still have a massive frontal area that gets hit by wind and absorbs forces.


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## velvetfoot (Sep 7, 2017)

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.


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## begreen (Sep 7, 2017)

Word is that wind turbines in Texas made it through Harvey ok.


velvetfoot said:


> 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.


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.


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## iamlucky13 (Sep 7, 2017)

velvetfoot said:


> 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.



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.


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## begreen (Sep 7, 2017)

Yes, SMA's Sunny Island is what came to mind.


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## peakbagger (Sep 7, 2017)

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.


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## iamlucky13 (Sep 7, 2017)

peakbagger said:


> 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.


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## WoodyIsGoody (Sep 8, 2017)

iamlucky13 said:


> Still, you'd exceed the cost of a decent 2 kW inverter generator without having as much overall versatility.



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.


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## peakbagger (Sep 8, 2017)

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. .


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## woodgeek (Sep 8, 2017)

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.


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## WoodyIsGoody (Sep 8, 2017)

peakbagger said:


> 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.



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.


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## begreen (Sep 8, 2017)

WoodyIsGoody said:


> 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.


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.


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## WoodyIsGoody (Sep 8, 2017)

begreen said:


> 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.



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.


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## begreen (Sep 8, 2017)

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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## Highbeam (Sep 8, 2017)

You've only got to last longer than your neighbors.


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## iamlucky13 (Sep 8, 2017)

WoodyIsGoody said:


> 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.



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.


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## woodgeek (Sep 9, 2017)

WoodyIsGoody said:


> 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.



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?


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## peakbagger (Sep 9, 2017)

No such thing as a 13.5 kW battery, there is such a thing as a 13.5 kW*h* 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.


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## woodgeek (Sep 9, 2017)

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.


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## WoodyIsGoody (Sep 9, 2017)

peakbagger said:


> No such thing as a 13.5 kW battery, there is such a thing as a 13.5 kW*h* battery.



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.



> That is quite small for a PV system battery.



Of course, they are modular. If you have larger power needs than one provides they daisy chain together.



> 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.



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.



> 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.



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. 



> 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.



You should have checked the actual specs before you pronounced it ineffective.



> 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.



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.



> 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.



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 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.



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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## WoodyIsGoody (Sep 9, 2017)

woodgeek said:


> 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.



Not really as negative as you make it sound. The original Powerwall was superseded by Powerwall 2 with more capacity, better battery management and upgraded load capacities. You can bet there will be a Powerwall 3 too. It won't be because the Powerwall 2 didn't do well, it'll be because they have a newer, better version. Why would they leave out-dated and superseded technology on the market? Superseded versions are always withdrawn from the market!

Technology marches on! Exactly when it becomes compelling enough to adopt will vary for each individual and mostly has to do with individuals  standard of living. Poor people in the inner city will be living with power outages for decades to come. They will just do without when there is a disruption or shortage. For somewhat affluent people, the Powerwall 2 already hits the sweet spot of the cost/benefit curve and is improving their lives as we discuss. 

Cheap bastards (like us woodburners) will probably decide to wait for Powerwall 3. Some of us old curmudgeons will swear batteries are no damn good for the rest of our lives as we drive our smoking antique pick-up truck to the gas station and pay $7/gal. to get 5 more gallons to pour into the gas generator under the garage eave. Then we will cuss to find out the gas won't pump because the power is out!


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## peakbagger (Sep 9, 2017)

Thanks for the specs on the Powerwall 2, all previous discussion was on Powerwall (not version 2) which appears to be different beast as it includes the interface electronics I had referred to. Would you care to revise your point to point refutation based on the model we were discussing?  Given your typical condescending approach your reply will be interesting.  

The limited documentation on the Powerwall 2 link refers to some limited specs on the Energy Gateway. Based on the Green Mountain Power experience the equipment started being distributed in July of this year (after months of delay) and it was one of the earliest installs outside of the founders editions.  I was unable to find any companies actually selling Powerwall 2 units. Plenty of references to wait lists. Other sources indicate that it only may work at some point with specific new microinverter based systems that are designed to be compatible with the "energy gateway". Perhaps you would care to post more detailed specs on the energy gateway and what existing PV inverters are compatible with it?

I have no doubt the technology is going to be available at some point in the future but excuse me for not being familiar with what was vaporware until a few months ago. Probably an option for someone thinking of installing a system in the future to go along with their Power Roof with its associated high cost premiums.? I distrust bleeding edge marketing that Tesla uses, generally the marketing is announced long before the actual product is available and frequently the specs change significantly before it actually hits the street. Reportedly both the future Powerwall and Solar Roof vaporware has been used to generate sales leads for high pressure PV installations, apparently the salesmen make some sort of verbal assurance that at some point in the future the equipment installed  will be compatible. Meanwhile someone gets sucked into an overpriced leasing arrangement justifying it with some future capability.

I rarely if ever would recommend someone buy early product with a limited installed base on the street, I let it be on the market for awhile and let the early adopters with money to burn to work the bugs out. Feel free to write the check and tell us how it worked in the long run.

By the way, this is not a theoretical discussion for me, I designed and installed one of the earlier grid connected PV systems long before it got popular in my state and have done the same with two other systems at home and helped with the design on several successful installs. I also do it for a living on large industrial scale and have over 10  megawatts of installed multimode systems that can run both grid synchronous and isochronous and several more either in the process of being installed or in early stage. If I could justify the need for PV based backup power system I would be the logical person advocating it but the reality is the cost benefit is not there for most, maybe it will be in the future. The reality in my area is extended power outages happen to occur in the winter when we can go days without appreciable solar production. I am far better doing a generator/battery solution with PV contributing what it can. That's readily doable with conventional off grid equipment like Outback which actually publishes detailed specs. Maybe the Energy Gateway will have the capability but I cant tell as I cant find any detailed specs.


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## WoodyIsGoody (Sep 9, 2017)

peakbagger said:


> Thanks for the specs on the Powerwall 2, all previous discussion was on Powerwall (not version 2) which appears to be different beast as it includes the interface electronics I had referred to. Would you care to revise your point to point refutation based on the model we were discussing?  Given your typical condescending approach your reply will be interesting.



Wow, sorry if you feel my approach is "condescending". I found your approach dismissive and condescending. But I can take it. On one hand you brag that you have installed/designed numerous residential PV systems over several years and are currently an active professional in industrial scale PV design or install of many megawatts with numerous projects in the pipeline. On the other hand, you were unaware that the Powerwall 2 was available and had the capacity to power simple things like domestic water pumps and thought the maximum surge capacity was less than half of what it is and that Tesla didn't publish specs for equipment they sold. It's difficult for me to imagine how a professional PV engineer could be so oblivious to what's been going on over the previous 12 months. But I guess when you're surrounded by big commercial installations one might tend to be dismissive of what's going on in residential (even if that was your start into PV systems). Fair enough.

If you want to learn more about what's involved in an AC Powerwall installation this is a good video:



For off grid installs there is the DC Powerwall. And unless you have a huge PV installation, you would want a back-up generator to keep the system charged during unfavorable conditions if you didn't live in a reliably sunny climate. Common sense really. But in an extended outage, a "prepper" would just prioritize energy usage so they always had enough for critical systems. The Powerwall adds significant efficiency to a generator because generators are horribly inefficient when running light loads or idling. You can also run a smaller generator and let the Powerwall take care of peak loads. And you can consume energy during "quiet hours" without the generator running, all significant advantages. Of course this is still in it's infancy and I'm not trying to say it's economic unless you have expendable income and want the kind of security these systems can provide your family. But it is a much better deal than lead-acid batteries which require maintenance and replacement in 3-5 years. The Powerwall is also handles deep discharge better, which is how these systems are used. And 13.5 kWh of lead-acid is not going to give you 7kW of surge power and they are going to weigh tons. 



> Perhaps you would care to post more detailed specs on the energy gateway and what existing PV inverters are compatible with it?



That is beyond my knowledge. But as a commercial PV system engineer, surely you know you can call Tesla and ask them for an authorized distributor list or connect with their own in-house engineers to answer your questions. Oh, I forgot, you don't trust them to give accurate answers...I guess you had better stick with lead acid. If it was good enough for 1920, it's gonna work just fine in 2020!

And please don't take offense at that last comment, it's just light-hearted poking at your anti-Tesla bias. Nothing personal.


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## woodgeek (Sep 9, 2017)

Well, I'm still confused. 

I looked at this tech back when the two Powerwall (1) systems ('solar' and 'backup') were announced.  I had seen the recent Kryten video you posted re Powerwall 2, which at ~20mins in says that the system shuts down completely during a grid outage.  So that is not going to do what you say.  You mention the DC Powerwall 2...so I had to look that up....

https://www.solarquotes.com.au/blog/tesla-kills-off-dc-powerwall-2-ac-version-delayed/

Looks like the DC Powerwall is not for sale outside the US, and the same article says the AC Powerwall 2 can (suitably wired with a disconnect, I assume) provide backup power, but that the battery CANNOT be recharged from the PV or a genny.  This is great for a short outage, but not the same functionality as an islanded PV system OR an off-grid system.

I could not find any usage of the DC Powerwall 2 for islanded PV using The Google. That functionality does not appear to be currently offerred by Tesla....do you know otherwise?

Of course, when I am not shilling for Big Oil, I am 'like'ing Tony Seba videos...so I believe that everything you describe will be available and cheap, and probably from Tesla at that, but that does not seem to be the case YET.  Sometimes with the future the waiting is the hardest part.


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## iamlucky13 (Sep 9, 2017)

WoodyIsGoody said:


> 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.



It really depends what you're trying to accomplish and for solar integration how well your demand aligns with your supply. If you play with the form on Tesla's website, for a 3-bedroom house (they indicate 30 kWh per day average demand, which is in line with figures I've seen from the DOE), and want to be 100% grid independent, they recommend 10 kW of solar and 4 Powerwalls. They don't seem to say what their reference location is. They figure with 2 Powerwalls, you could be 98% independent. I'm guessing those percentage figures indicate days when your supply falls short, and the reference location plainly has fairly consistent sun.

Of course, most off-grid folks focus a lot more on conservation, and would likely be shocked at the thought of trying to go off-grid while using 30 kWh per day.

When I started calculating what it would take in my area (Pacific NW) however, I was floored. The folks who share data on what their solar panels produce were really helpful, and when you see 3-4 days stretches where the production drops by 90% due to heavy overcasts, it really does a number on your panel requirements and your storage requirements. I don't think I saved my calculations to look up again, but it was something like $100,000 for my 3-bedroom, 80's construction house, with a heat pump. And I was using cheaper batteries in my calculations than the Powerwall.

I will note, however, the nominal longevity of high quality, well-managed lithium-ion batteries should bring the long term cost roughly on par with maintenance free lead acid batteries - you pay more up front, but the Powerwall should last longer.


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## WoodyIsGoody (Sep 10, 2017)

woodgeek said:


> I could not find any usage of the DC Powerwall 2 for islanded PV using The Google. That functionality does not appear to be currently offerred by Tesla....do you know otherwise?



Hey, Tom Petty is awesome. But why wait?

Here's an example of how the Powerwall 2 can be used for power failure (or entirely off-grid). Tesla has made it so it's not rocket science:


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## WoodyIsGoody (Sep 10, 2017)

iamlucky13 said:


> It really depends what you're trying to accomplish and for solar integration how well your demand aligns with your supply. If you play with the form on Tesla's website, for a 3-bedroom house (they indicate 30 kWh per day average demand, which is in line with figures I've seen from the DOE), and want to be 100% grid independent, they recommend 10 kW of solar and 4 Powerwalls. They don't seem to say what their reference location is. They figure with 2 Powerwalls, you could be 98% independent. I'm guessing those percentage figures indicate days when your supply falls short, and the reference location plainly has fairly consistent sun.
> 
> Of course, most off-grid folks focus a lot more on conservation, and would likely be shocked at the thought of trying to go off-grid while using 30 kWh per day.



Exactly! We are very wasteful of electricity and conservation is an important part of being willing to go off-grid unless you have money to burn. Even then, going off-grid is not to save money, it's for other reasons. Some people like they are not participating in the consumption of electricity generated in a "dirty" manner with regard to AGW and human health. Others like the security of providing their own and never having a power outage. And some remain connected to the grid but only draw during slack demand.



> When I started calculating what it would take in my area (Pacific NW) however, I was floored. The folks who share data on what their solar panels produce were really helpful, and when you see 3-4 days stretches where the production drops by 90% due to heavy overcasts, it really does a number on your panel requirements and your storage requirements. I don't think I saved my calculations to look up again, but it was something like $100,000 for my 3-bedroom, 80's construction house, with a heat pump. And I was using cheaper batteries in my calculations than the Powerwall.



Yeah, off grid systems typically don't try to heat big loads using electricity! Because heating loads peak when solar energy is at a minimum. So wood heat makes the most sense.



> I will note, however, the nominal longevity of high quality, well-managed lithium-ion batteries should bring the long term cost roughly on par with maintenance free lead acid batteries - you pay more up front, but the Powerwall should last longer.



Yes, a lot longer.


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## woodgeek (Sep 10, 2017)

WoodyIsGoody said:


> Hey, Tom Petty is awesome. But why wait?
> 
> Here's an example of how the Powerwall 2 can be used for power failure (or entirely off-grid). Tesla has made it so it's not rocket science:



Digging into the comments, I learned that the 'energy gateway' that does the switching and isolation is a separate Tesla product (not sold in a spiffy LED illuminated box).

I think the lack of consumer support here is b/c each system is intended to be engineered and installed by a local tech, in a manner that varies with the users current wiring/solar setup.  It would not be possible to come up with a 'one size fits all' system, given the broad range, age and complexity of different retrofit and new solar installs possible....not to mention sizing and use cases.

The BIG question is availability of US installers....we have seen videos from the UK and OZ, but none from the US yet...what gives?


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## WoodyIsGoody (Sep 10, 2017)

woodgeek said:


> The BIG question is availability of US installers....we have seen videos from the UK and OZ, but none from the US yet...what gives?



My best guess is that the US has the most negative (and inexplicable) distrust and bias against solar power of any country I'm familiar with. When a company is releasing a new product they spent millions developing, they want to make sure the initial users have realistic expectations that are matched to published product capabilities. All other countries tend to have residents that are more energy conscious, more conservation orientated and more informed than Americans. If Tesla released it first in the US, I can think of some negative consequences (from the companies perspective):

Ignorant consumers bitching that the battery couldn't make it through the middle of the night whether it was due to the electrical heat tape covering all their exposed plumbing, an electric water heater feeding a dripping faucet or the block heater keeping their diesel truck from freezing during a Minnesota winter or the electric space heater keeping their uninsulated garage at 55F or a combination of little boneheaded energy "blunders". Some people just don't understand supply and demand very well, they want everything to be unlimited and, when they fall short, they will blame the product. I'm an American myself but I have to call it how I see it, on average, Americans have this "entitlement" attitude when it comes to energy that is not well grounded in facts and that most people around the globe do not share.

The US has a very loud and vocal support of the fossil fuel industry compared to other countries like those in the UK, EU and AUS. Many Americans have been brainwashed to believe that cheap energy and wasting energy is somehow a very good and powerful thing, very American, very patriotic. When releasing a new product, a product that assumes the user understands it's published limitations, this can create very negative (if unwarranted) publicity. When a new product has more demand than supply, it is simply good business to release the early units into the markets that will put your product in the best light.

The above is just my speculation but I do know that Tesla is run by very bright, very aware and forward thinking people. It would be odd if they didn't take the dynamics of these regional differences into account when releasing new products that are production constrained. It is not true that all publicity is good publicity.


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## woodgeek (Sep 10, 2017)

I think we'll have to agree to disagree.  

The US rooftop PV penetration is not as high as in OZ, but total PV (rooftop and utility) capacity is large and growing quickly.  Also Tesla has a whole subsidiary (formerly SolarCity) that does complete PV installs from the ground up, in many markets across the country.  I guess I could buy your argument for some states that are outright hostile to solar....but Tesla finds the legal/political environment too anti-solar or the customer base too small in say, California, to sell this product there??  When grid failures are more common in the US than in almost any developed country?


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## georgepds (Sep 10, 2017)

For those of us in the dark about OZ:

When *Aus* or Aussie, the short form for an Australian, is pronounced for fun with a hissing sound at the end, it sounds as though the word being pronounced has the spelling *Oz*. The word Australia when referred to informally with its first three letters becomes *Aus*.


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## WoodyIsGoody (Sep 10, 2017)

woodgeek said:


> I guess I could buy your argument for some states that are outright hostile to solar....but Tesla finds the legal/political environment too anti-solar or the customer base too small in say, California, to sell this product there??



Uh, no. Please re-read what I wrote.

I didn't say Tesla WOULDN'T sell the Powerwall in the U.S., I simply supplied logical reasons why they might send initial production to areas that are more solar friendly first.


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## begreen (Sep 10, 2017)

Are they able to keep up with demand or are these units on backorder? Just wondering how they can produce enough to keep up with their industrial demands and production requirement of the Tesla 3.


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## georgepds (Sep 10, 2017)

Not to mention that big battery in OZ


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## begreen (Sep 10, 2017)

georgepds said:


> Not to mention that big battery in OZ


That was one of the industrial projects I had in mind.


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## WoodyIsGoody (Sep 10, 2017)

begreen said:


> Are they able to keep up with demand or are these units on backorder? Just wondering how they can produce enough to keep up with their industrial demands and production requirement of the Tesla 3.



That's a good point, the Powerwall, the utility grade Powerpack and the Model 3 all compete for the same cells. Tesla has already done big, utility scale battery installs in Kauai and California (and perhaps others I haven't heard about). One project in CA has enough batteries to power 15,000 homes over the 4 hour peak demand period.

Today I visited Tesla Chat Help to inquire about availability of Powerwall 2 in the US. Unfortunately, they don't have certified installers available in my zipcode (until this October) but they did confirm they are installing them in other areas of the US and that they can be used for back-up power when the grid is down.

This is a huge ramp-up and it takes time to get all the teams trained and put into place. But I do think they are making cells as fast as their production facilities allow and are production constrained. I don't think their Gigafactory is anywhere near it's planned production capacity. They have got the entire machine turning, just a matter of steadily increasing output and building up sales/installation networks (not to mention supply chains, etc).


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## begreen (Sep 10, 2017)

The planned growth and size of the gigafactory is staggering. Musk thinks big, very big. Reno must love him.


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## iamlucky13 (Sep 12, 2017)

georgepds said:


> Not to mention that big battery in OZ



It used a net capacity of cells roughly equivalent to the Model X production last month, and if I remember right, they're using a different chemistry for stationary power applications, so it shouldn't directly impact cell availability for EV's.

What was most interesting about that is the delivery timeline, which suggests to me they were probably already stockpiling the modular units in anticipation of upcoming sales.



begreen said:


> The planned growth and size of the gigafactory is staggering. Musk thinks big, very big. Reno must love him.



The size committed to at the moment is roughly proportional to their planned production ramp-up so far, and they want to grow in other markets, too, including stationary power.

If EV's really do track towards sales volume parity with ICE's by a 2040-2050 timeline, a huge amount more capacity will be needed.

He's definitely put a lot of money at risk, but I assume they're also holding a lot back until they see how fast the market actually grows, as well as to preserve their capital and credit for the challenge of their ongoing production rampup.


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## WoodyIsGoody (Sep 13, 2017)

iamlucky13 said:


> It used a net capacity of cells roughly equivalent to the Model X production last month, and if I remember right, they're using a different chemistry for stationary power applications, so it shouldn't directly impact cell availability for EV's.



As I mentioned in my previous message, the exact same cells are used in the Model 3, Powerwall 2 and Powerpack 2.



> If EV's really do track towards sales volume parity with ICE's by a 2040-2050 timeline, a huge amount more capacity will be needed.



EV's at volume parity with ICE vehicles by 2040-2050? LOL! We'll see but I think you're likely to be about 10-20 years late!


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## woodgeek (Sep 13, 2017)

I too recall hearing that the cells in the 'AUS' array were not from the Gigafactory.


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## WoodyIsGoody (Sep 13, 2017)

woodgeek said:


> I too recall hearing that the cells in the 'AUS' array were not from the Gigafactory.



Being production constrained and due to the size of the install down under, maybe Tesla sourced cells elsewhere as a stopgap measure. But the Powerpack 2 and Powerwall 2 are Tesla's primary stationary storage solutions and both are outfitted with the same cells found in the Model 3.


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## Seasoned Oak (Sep 13, 2017)

We do have a member from southern florida (Where2)with lots of solar panels ,anyone heard from him???????????????


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## WoodyIsGoody (Sep 13, 2017)

Seasoned Oak said:


> We do have a member from southern florida (Where2)with lots of solar panels ,anyone heard from him???????????????



I haven't, I hope they're ok! 

Here's a fairly comprehensive answer to the original question (at least with respect to PV in hurricanes):

https://solarpowerrocks.com/solar-questions/happens-solar-panels-hurricane/


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## Where2 (Sep 15, 2017)

Seasoned Oak said:


> We do have a member from southern florida (Where2) with lots of solar panels ,anyone heard from him???????????????


No, you haven't heard from me. Probably because I was off dealing with Hurricane Irma, 60 hours without grid power, cleaning up my yard for two days, and processing avocados.

Technically, I have one of the smaller arrays at only 4.4kW (twenty 220W panels). For backup power, I have a 5,500W (big box store) gas generator.

When the power eventually went out (Sunday at 4:40PM), we quickly dumped the food from the side-by-side freezer and fridge into the Engel MT-60 and MT-27 refrigerated chest coolers respectively. Both units were pre-chilled on 120V power, until the grid dropped out. Prior to the storm, our neighbor offered us an outlet for an extension cord (12AWG) off the inverter he was running from his Ford Powerstroke parked in front of his garage. My kill-a-watt said the output was a square wave inverter, but the conversion system in the Engel refrigerators didn't seem to care. The two Engel units were drawing a peak combined of under 150W. The neighbor's quiet backup system lasted until one of the leads to the battery off the neighbor's truck came loose in the middle of the storm, which was sometime in the middle of the first night. Monday morning, I pulled out our trusty 5.5kW generator (bought after Hurricane Frances in 2004) that I had last used after Hurricane Wilma in 2005. I started by disassembling the carburetor after sitting for 12 years. There was minor varnish in the float bowl (it was drained of fuel and run until it stalled out, prior to leaving it sit in the garage for 12 years), so I carried the carburetor over to my father's house to use his compressor to blow the tar out of the passages. (Dad's got an Onan in his Winnebago, so he had power for tools, you just had to pick what you wanted to run) My 5.5kW generator spent a good portion (75%) of the next 48 hours running a consistent 1.8kW-2.2kW load. That load was the main side-by-side fridge, the two Engel refrigerated coolers, a 12,000Btu roll around single hose A/C unit, and an occasional load of laundry through the Samsung front load washer. I used my TED 5000 to keep track of current/wattage drawn off the generator.

Just a few hours prior to losing power, I had turned up the hot water heater, and it was up to 137°F when the grid failed. It was only 117° when the grid returned 60 hours later... That was after a few showers from the wife and I. At close to 2kW load, the gas generator burns ~0.5 gallons per hour. Our neighbors across the street had power restored Monday morning. Other people on their side of the block still didn't have power when I got home from work tonight (Friday night). It took 10 days after hurricane Frances to get power back on our side of the street, so I am familiar with how brutal it can be to live without it.

If you're wondering about the Engel refrigerated coolers: my thought was I could run them off 12V deep cycle batteries out of one of our boats for extended periods of time if necessary, and recharge the batteries off the generator. As it turned out, it was so incredibly hot and humid the two days and nights that we were without power that my wife spent most of the time parked in front of the roll around A/C unit which only managed to get the room it was operating in down to 80°F at best. Monday night, we both slept on the terrazzo floor (without A/C) to keep cool. The 12V 0.45A PC muffin fans run off a 7Ah battery for several hours... 

Thoughts in retrospect: 400W of PV panels coupled to a MPPT charge controller and a 12V battery would run the two refrigerated Engel coolers indefinitely. Making your own 120V power runs around $0.85/kWh. The 48 LED (5050 chip) panels I bought off eBay generate an incredible amount of light, if only my house had a centralized 12V wiring system to accommodate running some 12V items like fans and lights. At some point, I need to build an integrated power monitoring system into the generator or the house power inlet. And finally, I need to devise a 9V (dc) backup system for the Davis Weather Wizard III to keep track of the winds.

In the end, we are safe with NO damage to the house, despite dropping a large royal palm frond directly on the PV array in the midst of the storm. Mostly minor damage to our 5 avocado trees in the yard. We did harvest our entire crop of >100 large Luna avocados on the day before the storm. Despite giving away dozens of avocados, I now have 10+ quart sized bags of frozen avocado paste in the freezer to make guacamole for months to come. The fruit keep for weeks on the tree, but ripen within 3-5 days of being picked off the tree. This morning, my wife spent 3+ hours processing ripe avocados into frozen paste. At some points in the forecast cones it looked like we might be getting the brunt of a Cat 4 or Cat 5 storm. In the end, it came in the west coast as a Cat 3 (we are on the East Coast), and we really didn't test the 170mph wind rating on my array's attachment to the second floor roof.


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## Seasoned Oak (Sep 16, 2017)

Good to know your all safe  W2 ,i figured you were busy and would give us a heads up when you had a chance. Iv got family in Coco ,power stayed on for them. They got lucky .


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## jatoxico (Sep 16, 2017)

Where2 said:


> At close to 2kW load, the gas generator burns ~0.5 gallons per hour.


Glad to hear you got thru OK.

I get about about the same "mileage" on my 5500 W unit. Having dealt w/ several extended outages in the last few years I can say fuel consumption using a conventional unit is a major difficulty. Especially painful when you're running w/ low load demand.

I've been optimizing my setup and decided to buy a 2000 W inverter generator as a second unit. Will run 10 hrs on a gallon @ 25% load and is whisper quiet. Of course having made the purchase I've insured no outages for at least a few years.


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## begreen (Sep 19, 2017)

Some thoughts coming out of rebuilding and decentralizing the infrastructure after the devastation left by Irma. 
https://www.greenbiz.com/article/rebuilding-resilient-renewable-caribbean


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## Seasoned Oak (Sep 19, 2017)

begreen said:


> Some thoughts coming out of rebuilding and decentralizing the infrastructure after the devastation left by Irma.
> https://www.greenbiz.com/article/rebuilding-resilient-renewable-caribbean


They wont have much choice . If they want to keep living in the path of hurricanes. Will be very difficult to build the same old way ,unless you plan to NOT have insurance.  Im sure the insurance companies will demand new building codes in order to be insured at all.  The whole gulf coast is probably in for a big price increase for insurance.


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## peakbagger (Sep 19, 2017)

Post Andrew, there was a lot of forensic engineering of damaged structures. Florida's codes were updated and building inspectors actually started inspecting. To date I haven't seen any real analysis of how newer built to code buildings stood up compared to older buildings. Down in the keys there were a lot of older homes especially mobile homes that were grandfathered. They were cheap to live in but once they get wiped out they can not be replaced.  I expect there were also a lot of older structures along the gulf who got hammered. Developers look at storms like these as its the opportunity to find new properties to buy to redevelop.


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## begreen (Sep 19, 2017)

Sounds like the Virgin Islands and Puerto Rico are about to get hammered again tomorrow. By the time these storms finish there won't be much to rebuild or the funds to do it. I hope they get folks evacuated in time.


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## peakbagger (Sep 20, 2017)

For some reason, the cable shows where they show three houses at the ocean  or on a tropical island seem to have switched to showing places in Alaska of late. . 

I would be really interested on how the "beachfront deals" homes are making it out.


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## Seasoned Oak (Sep 20, 2017)

For the Keys even a structure that can withstand 200MPH winds would still be susceptible to the storm surge . Pretty hard to make it waterproof. Perhaps most new structures will be on stilts  open  underneath. For higher elevations you still got to deal with a foot or 2 of rain on top of the wind.


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## peakbagger (Sep 20, 2017)

The standard approach is the house goes up on engineered "stilts" with wall panels that are loosely attached on the ground floor , if there is a surge, the panels blow out and the water runs under the structure. The area can be used for a garage and accessory space but flood insurance doesn't pay a dime for anything in that space. Many folks put in bootleg guest rooms or apartments in those spaces and take their chances. Of course add in the winds with an elevated structure and that makes a pretty beefy set of stilts. New construction in many areas reportedly require steel reinforcements straps that run from the foundation, up over the plates and then continuing up the wall and then wrapping over the roof rafters. I think they also use a lot more reinforcing clips in place of nailing and a lot of construction adhesives. There is a lot of attention paid on holes in walls like where windows used to be after a projectile hit it. What happens is the wind get inside the house and blows out the roof or walls from the inside. I think hurricane shutters are pretty well mandatory now in high wind areas.

Buildings usually fail due to bad details, details cost money so builders tend to skip over them unless the inspector is watching. Florida reportedly had very weak local building codes with weak enforcement pre Andrew as much of the expansion was into rural areas that didn't have the governments they needed to make sure it was done right and its that older stock of homes and buildings that probably bore the brunt. Most folks would rather pay for granite counters then pay a bit more for better building so that's what the builders do. The builders know they are long gone before the next hurricane, so all the need to do is hope the inspector doesn't tag them on shortcuts.  

This Old House long ago had a show on raising ranch homes after Hurricane Andrew and did a more recent version on one of their Sandy rebuilds.

Structures can be built to survive high winds. There is a small complex of buildings on Mt Washington NH and some of them survived what at the time was the highest wind speed recorded on Earth (231 MPH) it subsequently become the second windiest place on earth after a higher reading in the middle of tropical cyclone. Some of the older buildings are literally chained to the ground with chains running up over the tops of the sidewalls while the newest building is massive concrete structure. If you go on their webcam you can see the roof https://www.mountwashington.org/premium-content/webcam-videos/observation-deck.aspx (looks rainy today). There are several above tree line mountain "huts" in the same area also that have been around for decades that probably get exposed to similar winds. No storm surge but several feet of snow and they rarely have issues   There currently is highly controversial hotel proposed near the summit of Mt Washington that is going to have to build for high wind speeds like Florida. Generally the building codes are quiet on zones like these and the local authorities require a PE to sign off on the design and the assumptions and that stamp doesn't come cheap.


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## begreen (Sep 26, 2017)

Back to the original question. It looks like when you have 155mph winds sitting over your country for hours that renewables won't help much if they are grid connected. Puerto Rico's power infrastructure has been devastated. Large solar installations took a hit, but even if they didn't, the transmission network is down over most of the island. This is like the state of Connecticut losing power - for months. Those people that had small local solar systems may make out for at least having lighting, but overall there is not much power on the island unless you have a generator and fuel is running out. That means no water for many areas, no sewer, no refrigeration, no communications, and in some places the roads and bridges are destroyed too.

I can't recall a greater disaster to ever have hit in the US. Unlike stateside, PR can not connect to a neighboring grid or bring in crews from neighboring states. Repairs to major transmission system parts may require flying them out to the states, then flying them back. The US Virgin Islands are not fairing much better. In the case of PR however, with the power structure bankrupt, there aren't the funds to rebuild.


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## WoodyIsGoody (Sep 26, 2017)

begreen said:


> I can't recall a greater disaster to ever have hit in the US. Unlike stateside, PR can not connect to a neighboring grid or bring in crews from neighboring states. Repairs to major transmission system parts may require flying them out to the states, then flying them back. The US Virgin Islands are not fairing much better. In the case of PR however, with the power structure bankrupt, there aren't the funds to rebuild.



Yes, it's a real travesty. And many American's don't even know that Puerto Rico is part of the United States of America, Puerto Ricans are full American citizens who pay their US taxes, they just don't have statehood. 

Yes, power crews CAN be sent from other states but the logistics are certainly more difficult because everything has to travel by boat or airplane. And then there are the logistics of where to house and feed the crews imported from stateside. They sent an aircraft carrier to the Keys  but I think Puerto Rico needs a lot more help than that.


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## begreen (Sep 26, 2017)

WoodyIsGoody said:


> Yes, it's a real travesty. And many American's don't even know that Puerto Rico is part of the United States of America, Puerto Ricans are full American citizens who pay their US taxes, they just don't have statehood.
> 
> Yes, power crews CAN be sent from other states but the logistics are certainly more difficult because everything has to travel by boat or airplane. And then there are the logistics of where to house and feed the crews imported from stateside. They sent an aircraft carrier to the Keys  but I think Puerto Rico needs a lot more help than that.


A carrier might be a good idea. Lots of helicopters are going to be needed to deliver food, water, materials and medicine.


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## Seasoned Oak (Sep 26, 2017)

I think its time for the National Guard and the Army Corp of engineers to get involved there in a big way!


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## begreen (Sep 26, 2017)

Indeed. A Navy hospital ship would also help.


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## Seasoned Oak (Sep 27, 2017)

Seems like our massive military industrial complex is only used for the benefit of other nations . Like building power plants, schools and sewer plants in Iraq.  Being such a huge part of our budget,it can be dual use at the least . May justify its enormous cost to some extent.  Here is that big infrastructure project i keep hearing about, hand delivered and shovel ready.   Houston ,Florida and PR for starters.


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## begreen (Sep 27, 2017)

You can be sure giant contracts are going out to the usual suspects - Halliburton, Blackwater,Fluor, etc..
Building materials too like Weyerhaeuser, Louisiana-Pacific and USG — to road aggregates — Martin Marietta Materials' wheelhouse — to roofing — the specialty of Owens Corning and Beacon Roofing will benefit for the next year.


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## Seasoned Oak (Sep 27, 2017)

Since 50% of working age males were not working there before the storm it may be a good chance to start a jobs program there.  Get some economic activity going and turn it into something positive.


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## WoodyIsGoody (Sep 27, 2017)

Seasoned Oak said:


> Since 50% of working age males were not working there before the storm it may be a good chance to start a jobs program there.  Get some economic activity going and turn it into something positive.



I'm curious where you found that Puerto Rican unemployment statistic?


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## WoodyIsGoody (Sep 27, 2017)

Puerto Rico is having trouble getting fuel and oil they desperately need after the hurricane and the current administration hasn't given them the waivers they need:

https://a.msn.com/r/2/AAswO69?m=en-us


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## Seasoned Oak (Sep 27, 2017)

WoodyIsGoody said:


> Puerto Rico is having trouble getting fuel and oil they desperately need after the hurricane and the current administration hasn't given them the waivers they need:
> 
> https://a.msn.com/r/2/AAswO69?m=en-us


Seems the trouble is the roads are not passable yet ,the fuel is there ,just cant get to those far away stations over land.


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## Seasoned Oak (Sep 27, 2017)

WoodyIsGoody said:


> I'm curious where you found that Puerto Rican unemployment statistic?


Was in a news article about the island being deep in debt, and the sorry state its been governed for a long time.  Regardless they need emergency services same as florida and Texas .  Perfect place and time for a 30 s era jobs corp. Im sure a good number of homes and business were insured so , no excuse for that kind of unemployment rate going forward ,rebuilding means jobs ,lots of em.


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## Where2 (Sep 27, 2017)

peakbagger said:


> New construction in many areas reportedly require steel reinforcements straps that run from the foundation, up over the plates and then continuing up the wall and then wrapping over the roof rafters. I think they also use a lot more reinforcing clips in place of nailing and a lot of construction adhesives. There is a lot of attention paid on holes in walls like where windows used to be after a projectile hit it. What happens is the wind get inside the house and blows out the roof or walls from the inside. I think hurricane shutters are pretty well mandatory now in high wind areas.
> 
> Buildings usually fail due to bad details, details cost money so builders tend to skip over them unless the inspector is watching. Florida reportedly had very weak local building codes with weak enforcement pre Andrew as much of the expansion was into rural areas that didn't have the governments they needed to make sure it was done right and its that older stock of homes and buildings that probably bore the brunt. Most folks would rather pay for granite counters then pay a bit more for better building so that's what the builders do. The builders know they are long gone before the next hurricane, so all the need to do is hope the inspector doesn't tag them on shortcuts.
> 
> Structures *can* be built to survive high winds.



Yes, they can. Many old homes in FL can also be retrofit, if you can find an older structural PE who understands high wind zones and is willing to work with you. After Hurricanes Frances, Jeanne, and Wilma, my wife and I were able to work with a PE to retrofit our 1962 two story, combination concrete block and wood frame home. You definitely want some form of steel providing a connection from the foundation on up, and clips securing the rafters to the top plate. For my house, a retrofit meant unwrapping the entire second floor (all the sheathing off) so threaded rods could be epoxied into the poured top beam on the concrete block first story. Those threaded rods go up through the walls with nuts on top of the top plate of the wood framed walls. The rods are capped with hurricane washers and nuts "finger tight", not torqued. The hurricane clips tie the rafters to the top plate, and rest assured the inspectors count nails. Inspectors in my little town have always been sticklers, but post Andrew was a whole new level of attention to detail.

As I listen to the daily news reports of Puerto Rico, I can't help but think: America has the technology to fix this. Electric can be run underground just as water and sewer are. It's not rocket science. We may need to develop a whole new foundation system for ground mounted transformers, to give them some level of flood resistance, but that is not too problematic. (right now, a ground mounted power transformer to feed a neighborhood typically uses a slab on grade foundation). Do you really need to put some of the infrastructure back? Is there a reason to put wire based phones back at all? If you're replacing cabling for internet and television, put fiber in, and put it underground.

The real question becomes, whether distributed renewable energy systems become more economical to reattach the outlying communities than burying the grid to get power back to them? I know where our second home is, in Northern Maine, outlying properties can have very steep connection costs to bring the grid to them, and that is with overhead wiring. Every major hurricane points out the issue with overhead wiring in wind prone areas. A large enough force (high wind) pressing on an old wooden lever arm (power pole), tends to snap them off. Throw in wind borne debris, and survival gets very tough on any utility wiring overhead.

As for technology to make hurricane damaged areas habitable in the short term, I see opportunities for people making competition for SunDanzer refrigerators. Low power consumption refrigeration cooling systems capable of running off a combination of solar and stored battery power exist.


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## Seasoned Oak (Sep 28, 2017)

Probably a good % of those homes in rural areas will never be rebuilt.  Will cost a lot of $ to build it storm proof and off grid those $ are just not there in PR.  Even the cash to rebuild the public grid will be hard to come by unless its a grant cuz ,i think PR has been borrowed out to the max for some time.


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## WoodyIsGoody (Sep 28, 2017)

Seasoned Oak said:


> Seems the trouble is the roads are not passable yet ,the fuel is there ,just cant get to those far away stations over land.



Better late than never:

https://a.msn.com/r/2/AAsztuE?m=en-us

It looks like the administration finally realized you don't play crony capitalism with Americans who are suffering.


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## begreen (Oct 1, 2017)

The solar industry is starting to assess what it will take to rewire PR with an alternative to a centralized grid. Same for the US Virgin Islands. 
https://www.greentechmedia.com/articles/read/the-solar-industry-wants-to-help-puerto-rico#gs.dBc2MvU


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## Seasoned Oak (Oct 2, 2017)

WoodyIsGoody said:


> It looks like the administration finally realized you don't play crony capitalism with Americans who are suffering.


More about optics than need. It just makes one less thing to blame on the US govt for PRs  internal problems with distribution. Im betting lifting the rule will make zero difference since the port is already clogged with goods.


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## Seasoned Oak (Oct 2, 2017)

begreen said:


> The solar industry is starting to assess what it will take to rewire PR with an alternative to a centralized grid. Same for the US Virgin Islands.
> https://www.greentechmedia.com/articles/read/the-solar-industry-wants-to-help-puerto-rico#gs.dBc2MvU


In many ways this is a "good news " story. What got destroyed was barely adequate to begin with.  Doing the whole island over the way it was will only last till the next big storm. Before the storm ,no one was in a hurry to loan any more money to PR ,now they will get lots of grants to do it right , i hope.  Whatever goes in will have to be storm proof to some extent. More small rainwater cisterns would be nice too.


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## WoodyIsGoody (Oct 2, 2017)

Seasoned Oak said:


> More about optics than need. It just makes one less thing to blame on the US govt for PRs  internal problems with distribution. Im betting lifting the rule will make zero difference since the port is already clogged with goods.



Yes, at the very least it was extremely poor optics for a President to say "“We have a lot of shippers and a lot of people and a lot of people that work in the shipping industry that don’t want the Jones Act lifted." To protect peoples profit interests in the face of desperate and dying people is unconscionable. But it was his first instinct. 

The goal in a crisis such as this is to get the needed equipment and supplies on site clearing roads, bringing food, fuel and water as soon as possible. You don't want to prevent that road grader sitting on a ship in nearby Grenada from helping to clear the roads simply because the vessel it's sitting on happens to be registered in Greece (or wherever). The goods couldn't even get to the desperate people because the roads needed clearing. 

How much of a difference lifting the Jones Act sooner would have made, I don't know. But that's not the kind of decision that requires hesitation.


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## Seasoned Oak (Oct 2, 2017)

Woody , im leaving politics  out of the discussion ,and for good reason . Both sides think the other side is destroying the country  and to a certain degree ,both sides are right .


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## WoodyIsGoody (Oct 3, 2017)

Seasoned Oak said:


> Woody , im leaving politics  out of the discussion ,and for good reason . Both sides think the other side is destroying the country  and to a certain degree ,both sides are right .



That's a very political statement because it tries to excuse what happened by claiming both sides are equally bad. I prefer to not deal in broad sweeping generalities but I can understand why you don't want to discuss specifics in this case.


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## begreen (Oct 3, 2017)

Hospitals have be badly hit if not totally devastated in both PR and the Virgin Islands. As they are rebuilt, this seems like a good first place to employ rooftop solar with tesla powerwalls in addition to generator backup.


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## Seasoned Oak (Oct 3, 2017)

begreen said:


> Hospitals have be badly hit if not totally devastated in both PR and the Virgin Islands. As they are rebuilt, this seems like a good first place to employ rooftop solar with tesla powerwalls in addition to generator backup.


Have to figure out a way to keep the roof on in a cat 5 storm  so the solar panels stay put as well.  Or make them easy to disconnect to take em down if a big storm is approaching. Its not that often a cat 5 storm does a direct hit.


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## begreen (Oct 3, 2017)

Yes, they'd need a reinforced mounting system which is more practical than a hospital taking in 20+ panels.


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## Seasoned Oak (Oct 3, 2017)

begreen said:


> Yes, they'd need a reinforced mounting system which is more practical than a hospital taking in 20+ panels.


May get smashed by coconuts flying by at 150MPH .


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## begreen (Oct 3, 2017)

Yes, it would be good to have a few spare panels inside and keep tall palm trees away from the building.


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## Seasoned Oak (Oct 3, 2017)

WoodyIsGoody said:


> That's a very political statement because it tries to excuse what happened by claiming both sides are equally bad. I prefer to not deal in broad sweeping generalities but I can understand why you don't want to discuss specifics in this case.


Not sure if yur around long enough to remember woody but spouting political opinions is the quickest way to get a thread shut down here on hearth ,no matter which side yur on. We used to have something called the ash can but even that got too "heated"  so it was just relegated to the history bin as a lost cause.  With good reason because debating politics like religion is a sure way to bring conflict between friends.  Helps us remain friends here.


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## Where2 (Oct 3, 2017)

begreen said:


> Yes, they'd need a reinforced mounting system which is more practical than a hospital taking in 20+ panels.



A reinforced mounting system on a commercial building is not all that complicated, just hire a Structural PE, and pay them for their work product. My array has stamped engineering plans with a design uplift and down force calculations to survive a 3 second gust of 170mph. If you want an array to survive 185mph or 200mph gusts, all it takes is $$$ to design the appropriate rack system to support the array.


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## Seasoned Oak (Oct 4, 2017)

As important as it is to keep the panels in place i can just just imaging what is being carried in the wind that will smash just about any panel if its traveling at 100+ MPH.   For this particular storm i think taking them down would have been the only option to preserve them.


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## WoodyIsGoody (Oct 4, 2017)

Seasoned Oak said:


> Have to figure out a way to keep the roof on in a cat 5 storm  so the solar panels stay put as well.  Or make them easy to disconnect to take em down if a big storm is approaching. Its not that often a cat 5 storm does a direct hit.



Not much survives a direct hit from a powerful cat 5 storm, even the non-solar electrical infrastructure (including fossil fuel generation) was taken out by the recent direct hit. I would make the case that direct hits are rare enough and cover a narrow enough swath that it's uneconomic to design buildings and infrastructure to handle the worst kind of direct hit. Everything would end up looking like military bunkers!


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## WoodyIsGoody (Oct 4, 2017)

Seasoned Oak said:


> As important as it is to keep the panels in place i can just just imaging what is being carried in the wind that will smash just about any panel if its traveling at 100+ MPH.   For this particular storm i think taking them down would have been the only option to preserve them.



Tesla has demonstrated that their solar roof shingles can withstand direct hits from large hail stones traveling in excess of 100 mph. That's enough to total a vehicle so the glass shingles are pretty tough.


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## Seasoned Oak (Oct 4, 2017)

WoodyIsGoody said:


> I would make the case that direct hits are rare enough and cover a narrow enough swath that it's uneconomic to design buildings and infrastructure to handle the worst kind of direct hit. Everything would end up looking like military bunkers!


 About 30 yrs i think since they had the last one . Certainly you want any residential or business structure would have an expected life span of 50 to 100 yrs certainly longer than 30 yrs . Plus factor in what the GW people are saying an they may be a lot more frequent and stronger.


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## Seasoned Oak (Oct 4, 2017)

If that Tony Seba video is correct it may be a big waste of time and money to rebuild PR eLectrical grid outside.the capitol city.


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## WoodyIsGoody (Oct 4, 2017)

Seasoned Oak said:


> About 30 yrs i think since they had the last one



Nope. In recorded history there has only been one other Cat. 5 hurricane in PR. That was in 1928, almost 90 years ago. I believe it's wise to design and build for extreme weather but not for direct hits of category 5 hurricanes.  That would not be cost effective to do in all hurricane regions.


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## begreen (Oct 6, 2017)

More information on Puerto Rico's power grid issues. While some solar installations were devastated, one survived intact. It was engineered and built to withstand a cat 5 storm and it did. 
https://earther.com/puerto-rico-has-a-once-in-a-lifetime-opportunity-to-ret-1819143446
Musk believes Tesla can be part of the solution
http://www.bbc.com/news/world-us-canada-41524220


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## Seasoned Oak (Oct 6, 2017)

There you go ,even though they dont get cat 5 hurricanes that often there's nothing preventing another one next year or any year. building the same old way is a waste. No mater who pays for it.


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## Zack R (Oct 18, 2017)

Commercial scale wind turbines are built to survive hurricane force winds. Each model has a "survival cutout" speed where the blades pitch to feather and the machine rides out the storm. Once the wind drops back into the operating range for a pre determined amount of time it will adjust the blade pitch and resume power production.

http://www.businessinsider.com/texa...-dodged-a-bullet-with-hurricane-harvey-2017-9

Source: I have 10+ years experience in the wind energy field and have visited wind farms in southern Texas.


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