Hypothetical question - emergency preparedness/response

bill von novak

To follow up in a discussion in another forum -

After Hurricane Sandy, several friends/relatives in NY went without power for quite some time. I got a few questions about solar power for backup purposes but there's not much I could do for them from 3000 miles away.

But what if I had been there? Could I have done anything?

So here's the hypothetical question. Your small neighborhood (say two blocks, 24 houses total) experiences a disaster. Nearby fires, an earthquake, a hurricane, something like that. The grid is out and will be for a long time - they estimate a month but could be longer. Fortunately no one in your neighborhood is seriously hurt, and their homes are intact. Many roads are out but a few trucks are able to get through via intact secondary streets, and local businesses are able to continue basic retail services. Food is available. Water is available nearby but no one's well pumps are working. Gasoline is marginally available - the truck can make deliveries but most gas pumps are out, so it's somewhat scarce. It is mid-Fall so people's homes are cold but the pipes aren't freezing yet.

In your block of 24 houses most people try to stay in their homes, and the neighborhood comes together; everyone pitches in to help out. This is a small community; your furthest neighbor is only about 500 feet away on the next block.

People's needs for power are:
Two people with oxygen concentrators (400 watts each.) They have tanks for backup but they'll have to be evacuated if power is out for a while.
One couple with an at-risk infant who needs heat and a humidifier.
A few lights at night (no more than about 100 watts per house.)
Power to charge laptops, radios and flashlights
Power to run some refrigerators. People are willing to "share" refrigerators to reduce total need.
Power to run well pumps for at least 15 minutes a day to fill toilets, bathtubs and pots
Power to run sump pumps for a little while each day to pump out floodwaters, keep basements relatively dry etc

Neighborhood resources are:
Three ancient gasoline powered 5500 watt 240VAC generators. Two will start at all. One is quickly melted down by everyone trying to plug into it.
One more modern Honda EU1000i inverter generator
Four grid tied solar power installations, 5KW a piece, each about 5 years old. Three string and one microinverter system.
A few Priuses

The neighbors with generators try the usual extension-cords-and-two-ended-plugs to get power to neighbors. This starts one small fire (see above) and one generator is trashed. After that people are more cautious.

You have whatever solar power system you have now. Your resources are what you have in your house plus whatever is at the local hardware store and Radio Shack. People come by and ask them if you can help them restore a little power for the month or so before utility power can be restored. They are willing to pay for any local materials you need.

What could you do?

mike95490

Re: Hypothetical question - emergency preparedness/response

what a can of worms !


Do the priuses have a 120V outlet in them ?

First pass is to form a pool of the neighbors, and see who is going to be "king".
Cant get 24 familys to get to consensus on anything.

Send the 2 needing Oxygen to the local Fire station, no help for them in your commune, not enough power.

Grid Tie inverters are totally useless. You can wire 2 or 3 panels to a car battery to run an inverter for daytime loads (fridge, etc...) but have to shut down at night. also have to use a meter to decide when to disconnect PV to prevent overcharge of battery.

Flashlights for house lighting. make those batteries last.

Generators will have to be reserved to pump water, can't expect fuel to last much longer, or the gear to hold up - when was their oil changed last ?

Food , cooking. on your own

solar_dave

Re: Hypothetical question - emergency preparedness/response

Pool the gasoline and fill a pickup truck up and drive it one tank of gas away(perhaps with a trailer), then buy a huge generator(s), the biggest one you can get and all the 5 gallon cans you can fit. Fill the truck back up and all the cans and take the generator(s) back to the neighborhood. Be prepared to save some fuel to reload the truck for another fuel run.

Another options is to take a vehicle and drive out and get some 12V inverters with wiring and a load of fuel.

bill von novak

Re: Hypothetical question - emergency preparedness/response

mike95490 wrote: »

what a can of worms ! Do the priuses have a 120V outlet in them ?

No, but it is relatively easy to tap into their HV systems. You get between 125 and 300 volts depending on state of charge and engine state at about 10kW. Converting that to useful power is, of course, the challenge.

Alternatively you can get about 700 watts from their 12V battery if you have the wire and the inverter to do it.

First pass is to form a pool of the neighbors, and see who is going to be "king".

What does the "king" do?

Grid Tie inverters are totally useless. You can wire 2 or 3 panels to a car battery to run an inverter for daytime loads (fridge, etc...) but have to shut down at night. also have to use a meter to decide when to disconnect PV to prevent overcharge of battery.

So you take apart your RE system and divvy up the panels to everyone?

Generators will have to be reserved to pump water, can't expect fuel to last much longer, or the gear to hold up - when was their oil changed last ?

That's the question. They would likely best be used sporadically (once a day for an hour) to charge batteries and run heavy loads like pumps.

BB.

Re: Hypothetical question - emergency preparedness/response

In California and many other states--We have natural disasters that can make a home unlivable.

• Earthquakes
  • foundation bolts
  • cripple wall re-enforcing
  • shear walls with plywood (especially multi-story homes)
  • bolting water heaters so they don't get knocked over
  • flexible gas/water lines to home
  • gas line excessive flow/ground motion shutoffs
• Flooding
  • pumps with and without grid power
  • lift home above flood plane
  • move electrical service above flood level
• Fire
  • clear area of brush/fuel around home
  • issues of vinyl siding vs stucco in heat
  • wood shake roof vs other non-flammable materials
  • smoke alarms
  • sprinklers
• Storms/Winds
  • fastening roof rafters to walls/foundation
  • wind rated roofing materials
  • wind rated windows/skylights

Etc., etc., etc...

And many times there are natural hazards that we may not even be aware of... In California, we are all aware of earthquakes... But it turns out the eastern US is also highly vulnerable--In some ways worse.

In California, the base rock tends to be newer and softer. Quake energy dissipates relatively quickly from the epicenter. Plus, many older areas have either already lost masonry structures (fell over) and/or stricter building codes have addressed the major weaknesses.

Out east, you have new Madrid which can shake a major portion of the eastern US. Older buildings, pre-earthquake codes, etc. Or Not...

http://www.lanereport.com/21524/2013/05/new-madrid-earthquake-threat-is-overstated-kentucky-geological-survey-says/

So--if you have your home (and nearby roads/infrastructure) secured from natural/events that are possible in your area... Then you can use my suggestion:

• 3 minutes without air
• 3 hours without shelter (during inclement weather)
• 3 days without water
• 3 weeks without food

So--I more or less, look at it like camping. Water+Food+fuel+shelter. Others have suggested not to forget soap/cleaning aids.

Water heaters are good for 30-50 gallons of water (homes, apartments may not). Flashlights/headlamps (LED for long battery life, AA batteries 5+ years, CR123 batteries for 10 year storage). Choose common batteries (such as AA for flashlight, radio, UV water purifier, etc.).

So--Back to the list. Well? Stored water. Trash cans that you can fill before water/power fails. Chlorine...

Area to safely get rid of trash/waste (if plumbing/water not available).

Fuel to use for genset plus stove (that can burn multi-fuels). Plus can use in car/truck to bug out if needed.

Refrigeration for medicine / special foods (milk for the baby).. Etc.

Generally, if you can survive for 3+ days without outside help--After that length of time, either help will finally reach you--Or you will have to decide if you can stay or should leave.

In some cities, they have cut municipal water because of lack of power for sewage pumping stations. Others have cut electricity and/or natural gas because of wide spread infrastructure disruption (such as after hurricane Sandy).

Having a centralized cached of water/fuel/food/equipment/tools/repair supplies for a group--Always an issue of how to share with a group (ongoing maintenance/restocking and how to distribute in an emergency).

So much depends on the area (city/country), available storage space, etc... I don't know that there is a good generic answer for everyone.

-Bill

ggunn

Re: Hypothetical question - emergency preparedness/response

The problem as I see it is this:

Just who will be affected by such a disaster is impossible to predict, and for everyone to equip themselves to be able to generate their own electrical power would be very very expensive.

NorthGuy

Re: Hypothetical question - emergency preparedness/response

IMHO, the most important characteric of the backup power is that it is available exaxtly when you need it. Solar power is anything but that - it is only available when the sun shines.

A battery based backup or a generator will work much better.

ggunn

Re: Hypothetical question - emergency preparedness/response

NorthGuy wrote: »

IMHO, the most important characteric of the backup power is that it is available exaxtly when you need it. Solar power is anything but that - it is only available when the sun shines.

A battery based backup or a generator will work much better.

I think the point was that neither a generator nor battery backup alone is a sustainable solution in the face of a widespread and lengthy power outage.

Sometimes you are just screwed; there is no such thing as being 100% prepared for anything and everything that could happen. You can be 90% prepared, or 99% prepared, or 99.9% prepared... How many nines would you like to buy?

NorthGuy

Re: Hypothetical question - emergency preparedness/response

ggunn wrote: »

I think the point was that neither a generator nor battery backup alone is a sustainable solution in the face of a widespread and lengthy power outage.

If you want to design a backup system, which is guaranteed to provide a power for an arbitrary long outage, you need a sollar array substantially bigger than for a comparable off-grid system, because off-grid systems can and do relay on generators. If you do install a solar array of that size, there's no need for grid connection any more and you can go off-grid.

That is true that some people regard off-grid living as the best backup solution, but this is rather uncommon point of few. Conventional battery/generator backup arrangement is a fraction of the cost of such system, and does provide backup for nearly all kinds of outages. Moreover, the conventional system will fare better than generator-less off-grid system in all scenarios where you get long periods of no sun.

techntrek

Re: Hypothetical question - emergency preparedness/response

bill von novak wrote: »

No, but it is relatively easy to tap into their HV systems. You get between 125 and 300 volts depending on state of charge and engine state at about 10kW. Converting that to useful power is, of course, the challenge.
Alternatively you can get about 700 watts from their 12V battery if you have the wire and the inverter to do it.

Only plan on getting 3-4 kw continuous due to thermal issues, 10 kw is fine for surge loads. On the 12 volt side you can go up to 1 kw. See the link in my sig.

They would likely best be used sporadically (once a day for an hour) to charge batteries and run heavy loads like pumps.

Save a lot of gas and only use the big guys for 5 minutes a day to get water - be ready to fill everything at once with all hands on deck. Then use the Honda inverter genset or Prius to charge batteries. Even if you plug in all the phones laptops in the subdivision you'll only need a thousand watts max, better to match the size of the genset to the size of the load.

ggunn

Re: Hypothetical question - emergency preparedness/response

NorthGuy wrote: »

If you want to design a backup system, which is guaranteed to provide a power for an arbitrary long outage, you need a sollar array substantially bigger than for a comparable off-grid system, because off-grid systems can and do relay on generators. If you do install a solar array of that size, there's no need for grid connection any more and you can go off-grid.

OTOH, what people are willing to live with during an emergency can be (or should be, anyway) significantly less than what they would want in a permanent living situation.

westbranch

Re: Hypothetical question - emergency preparedness/response

If the outage is for a month or longer, I would doubt that the cell towers would have power either... so IMHO forget about charging the cell phones. And food gathering will be a problem too in addition to gas...

bill von novak

Re: Hypothetical question - emergency preparedness/response

ggunn wrote: »

OTOH, what people are willing to live with during an emergency can be (or should be, anyway) significantly less than what they would want in a permanent living situation.

Agreed, and that was what I was thinking. Things are easiest with 24kW available from a 100 amp utility service. But if that's not available you are way better off with 500 watts than you are with nothing.

NorthGuy

Re: Hypothetical question - emergency preparedness/response

bill von novak wrote: »

But if that's not available you are way better off with 500 watts than you are with nothing.

Ok. What size solar array do you need to get 500W continuous even in a cloudy weather? 10kW perhaps?

bill von novak

Re: Hypothetical question - emergency preparedness/response

NorthGuy wrote: »

Ok. What size solar array do you need to get 500W continuous even in a cloudy weather? 10kW perhaps?

I wasn't talking continuous. I'm talking a service that gives you 500W peak and a few kwhr a day.

What's going to let someone continue living somewhere?

-Occasional ability to run a furnace to keep pipes from freezing
-Occasional use of a sump pump to keep areas dry
-Occasional use of a well pump to fill bathtubs and toilets
-Enough light to see by (call it 4 15W compact fluorescents)
-Refrigeration (perhaps shared)

This is seasonally dependent of course. In the dry season sump pumps aren't as needed. In winter refrigeration loads are less; in summer furnace operation isn't needed.

NorthGuy

Re: Hypothetical question - emergency preparedness/response

bill von novak wrote: »

What's going to let someone continue living somewhere?

100 years ago most people lived without electricity. And for millions of years before that there was no electric power at all. So, the answer of this question is definitely zero.

In practical terms, it depends on what you want to have in case of emergency. Whatever it is, small or large, it is much cheaper and more reliable to serve these needs with a generator than with solar panels.

The only "hypotethical" case where the solar would be ahead of generator is highly unlikely. There must be a very long outage, you must run out of your existing gasoline supply (which could be made to last for months), there must be no external supply of gasoline for generator, there must be mostly sunny, the neighbours must be very kind not to take over your power source and house, and at the same time there must be some compelling reason for you to stay in your house instead of leaving the affected disaster area. I don't think that such conditions may ever exist.

Solar power depends on the insolation. If you want it to be used on demand, without generator support, you must oversize it considerably and provide consderable battery storage. If you already have a large GT array and a battery backup, it's a good idea to make provisions for charging batteries from solar. But buying these things for backup purposes? Not at all practical.