Jul 132013
 
This is a wonderful portable generator, costing only $135 and providing both 12V and 110-120V power.

This is a wonderful portable generator, costing only $135 and providing both 12V and 110-120V power.

We previously wrote a detailed four part series about storing electricity which assumed you wanted to live off-grid, long-term, and needed a high-capacity and very long-lived energy storage solution for such a scenario.

That is of course a valid need, and there’s a lot of good information in that series about all aspects of storing electricity – when time allows, you should read it. 🙂

This article, however, is about one special type of energy storage application – a need to have a short-term emergency supply of power when the mains supply fails.  If the failure is a simple short-term thing such as high winds blowing over power lines, then you just need a little bit of electricity ‘to get by’ until the mains power is restored.  These are Level 1 type situations.

If the failure is caused by a major disruption that will escalate to a Level 2 or 3 scenario, you might need some power for a short while to operate radios to communicate and co-ordinate with other members of your group, prior to bugging out to your retreat location.

There are many different ways you can have an emergency power source always on hand, with many different amounts of electrical storage capacity, complexity, and cost. This article considers two approaches.  There are others, but these two are the simplest, and being the simplest is, for our purposes, an essential consideration – simple things are easier to deploy and less likely to fail.

Portable Generators

For almost any non-trivial amount of electrical power, your best solution will always be a generator.

While they are typically heavy, noisy and expensive, you can also get smaller, lightweight, affordable and very quiet generators that would be suitable for use pretty much anywhere – including for apartment dwellers, too.

For example, here’s a portable generator for only $135 on Amazon (pictured above).  This unit is quiet, lightweight, and runs for 8.5 hours on each 1.2 gallon tank of fuel, providing about 400W – 500W of 120V power during that time.  That’s a great value, and with a five gallon container of fuel and running the generator sparingly rather than 24/7, you’ve enough power for maybe three days.

The above generator is a two-stroke generator.  A similar four-stroke generator generates twice as much power using almost the same amount of fuel (four-stroke engines are more efficient than two-stroke), and is similarly quiet, while weighing an extra 10lbs (54lbs instead of 44 lbs) and being slightly bulkier.  It costs just a hair less than $200.

Amazon has plenty of other portable generators, albeit more expensive than these two, as well. Here’s a listing of some of the nicer modelsthat would be excellent as portable, use anywhere, low-sound type generators.

Four quick comments about generators.

First, no matter what generator you might choose, you must operate it outside, due to all the exhaust gases it produces.

Second, you should run your generator once every few months to be sure it is still in good order and condition, and be sure to stabilize your fuel so it doesn’t ‘go off’ while sitting in the generator or fuel can.  There are several types of fuel stabilizer available, the best is PRI.  Don’t settle for any other brand, use only PRI.

Third, these low power generators are very limited in what they can handle (because of their low power output) and you’ll need to be very careful to match the current drains with the generator capacity.  Using a Kill A Watt meter is an easy way to monitor the power being drawn from the generator, and be very careful of peak loads – when motors first start up, they draw a great deal more current than when they are running at normal speed.   These peak loads can fry your generator if you don’t plan carefully for not just average but also peak loads.

Fourth, keep the cords from the generator to the devices using the power as short as possible, and as heavy-duty as possible.  Short heavy-duty cables will waste less power and provide a better voltage level than would be otherwise the case with lighter and/or longer cables.

Lead-Acid Battery and Trickle Charger

The $135 portable generator we linked to at the start of the previous section is probably the least expensive solution for most people, and when you match that with a single five gallon tank of gas, you’ve got the equivalent of about 15 kWhrs of power, and/or about 35 hours of running time.  If that’s not enough, you can simply store as much extra fuel as you need and are legally allowed to have, and/or get a higher capacity generator.

But if you’re in a situation where either you can’t run a generator – maybe you’re in an apartment with no balcony or outside space to operate the generator, or if you’re in a situation where you need a guaranteed, absolutely-must-work source of power for a short but essential period of time, there’s another solution to consider.

Buy a 12V ‘golf cart’ or other ‘deep cycle’ battery (or two 6V batteries that you’d connect in series).  Note that these are very different to auto starting batteries – do not get a regular car battery.

You also will need a trickle charger to maintain it (them) at full charge.  If the mains power fails, the fully charged battery becomes a source of 12V DC power, and if you connect an inverter, you can get 120V AC power from it too.

This is a clean, totally silent and reasonably compact form of electricity generation and storage.  There is almost no maintenance you need to do – you can just set it up and then forget about it for several years before then testing the battery, perhaps once every six months after that, until you note its capacity has diminished to an unacceptable level.

There might be restrictions on how much fuel you can store in an apartment (either from the landlord or the fire department) and there might be restrictions on running a generator, and you might not want to attract attention to yourself and your generator, either; but none of these constraints apply to batteries and battery power.  They don’t need to be stored outside, and modern non-gassing batteries are perfectly fine indoors to store, to charge, and to use as a power source, especially when connected to an intelligent charger.

If you need a lot of standby power, we’d suggest batteries such as these or these.  Other highly respected battery suppliers include Concorde/Lifeline and Rolls/Surrette.

If you don’t need such an expensive high-capacity battery, then a Trojan U1-AGM is a good entry-level battery, probably costing about $125 or thereabouts.  Trojan make other batteries with successively greater capacities, too.

You then need some sort of trickle charger to keep the battery charged.  We consider the NOCO Genius products to be the very best, and you’ll probably find either the G750 or G1100 to be adequate for your needs.  Neither is very expensive, and because your need is more to maintain a charge rather than to recharge the battery, you don’t need a higher current capacity unit.

If you want your battery to run 110-120V appliances, you’ll need an inverter as well.  Get the lowest powered inverter you need, and use it with caution, because any/all 120V appliances will use up your 12V battery very quickly.  We’d suggest you consider getting whatever emergency appliances you need that are designed to operate off 12V DC (and which are designed to be ultra-efficient, too).  That way you don’t ‘waste’ some of your energy by converting it to 120V and then using it in a device that does not have energy efficiency as its main design criteria.  Many appliances designed for sail boats are high-efficiency 12V units, and you can get many different sorts of 12V LED lighting that provide the most energy efficient source of emergency light.

You could also consider getting a set of solar panels to recharge your battery if you were planning for an extended period of needing the battery, but this would likely only give you a very little bit of top up charge each day, unless you had large panels, and then you’re moving beyond the scope of this article (and should read our full four-part series on storing electricity).  Here’s a single panel system that claims to provide 100W of power, and complete with the necessary charge controller unit too; this is about as good a simple choice as possible before needing to move into complicated bulky and fixed installations.  In reality, we expect you’re more likely to get 50W rather than 100W of charging power from the cells, but if you’ve no other way of recharging your battery, this could give you up to as much as 500 W hrs of extra power each day during the period of your power outage.

If you do get a solar panel system like this, you should trial it to understand how it works and how much power to realistically expect, then carefully put it away and not touch it again until you need to start recharging your battery during your power outage.

One more thing to add to your setup.  A 12V to USB charger/connector – a device that will enable you to recharge all your electronic things that can be charged from a USB port.  These devices typically come in the form of a cigarette lighter type adapter for a motor vehicle – they are perfectly good in that form; although you will then either need to solder leads to the adapter or else get a matching socket to connect to your battery.

Make sure that any such USB power supplies are high current (ie more than 2 Amps) so as to be able to recharge tablets as well as phones and other low current devices.

Summary

Many of us have our homes wired up with heavy-duty generators and transfer switches, and many of us have extensive other power storage facilities of various sorts too.

But sometimes these requirements are overkill.  Sometimes we just need a small amount of power, for a short term solution.  Perhaps it is a relatively benign brief power outage, or perhaps it is such a severe event that we’re forced to get out of Dodge just as quickly as we can rendezvous with the other members of our group.

In such cases, a simple small portable generator, or a fully charged golf cart type battery can give us everything we need, and for under $200.

Jun 252013
 
The stunning Tesla S has a best-case range of over 300 miles between battery charges.

The stunning Tesla S has a best-case range of over 300 miles between battery charges.

One of the big problems we all have to consider is what sort of motorized transportation we can use in a Level 2/3 situation.

The problem is that modern-day fuels – gasoline, diesel, liquid propane and compressed natural gas – are all vulnerable to disruptions in supply, processing and distribution such as would occur in any sort of emergency situation, and so we’ll largely be forced to rely on such stored fuel as we may have, and when that runs out, our options become difficult.

Sure, you could look at ways to make your own bio-diesel, and that might become a necessary option.  You could also look at modifying a vehicle to run on wood gas.  And some people, by choice or necessity, will allow themselves to settle for horses or oxen.

But there’s another option worthy of consideration, especially in Level 2 and early Level 3 scenarios.  An electric vehicle that you can recharge from solar or wind power.

This is of course not a cheap option, because the first thing you need to do is buy an electric vehicle.  But if you have the budget to consider such things, and depending on the amount of surplus renewable electricity you expect to be generating each day, it might be your best option.

How Much Electricity Does an Electric Vehicle Use

Just as with any other powered vehicle, the range you get depends on your speed, driving style, and the terrain.

There are some major differences in how battery mileage is tested in the US, Japan and Europe, so we’re generally using US EPA quoted figures, which may or may not be exactly realistic, but which tend to give the lowest claimed ranges, so they are probably better than the other tested range claims.  If you are evaluating electric car ranges, make sure you understand how the range figure was established – the latest US EPA test is a ‘five cycle’ test and more complete than its earlier two-cycle testing.

Their range also depends on how much of the battery’s full charge is used.  Generally it seems to be considered best practice not to 100% deplete the batteries.

  •  A Tesla Model S has either 60 kWhr or 85 kWhr batteries, and can get you 350 miles or more on a single charge in optimum conditions.  We are not certain how much of the total stored charge is used.
  • A 2013 Chevrolet Volt has a 16.5 kWhr battery and a 38 mile range, during the course of which it depletes 10.3 kWhr of its total battery capacity.
  • A Nissan Leaf with a 24 kWhr battery gets 84 miles on a full battery charge, or 75 miles on an unstated lesser amount of charge.
  • AA Ford Focus Electric with a 23 kWhr battery gets 76 miles per EPA figures.

Looking at these and other numbers, it seems fair to say that each mile driven in an electric vehicle takes somewhere in the order of 250 – 300 Whr of electric energy.

To translate that to other terms, you could run a 20 watt LED/CFL lightbulb for 12 – 15 hours with the same amount of power required for an electric vehicle to drive one mile.  You could run a 1600 watt heater for 10 minutes with the same power that takes the electric vehicle one mile.

More Electricity is Required to Charge the Car

Say you have a solar panel setup that gives you 5000 W of power when the sun is shining on them.  You might think that you can connect the solar panels up to your electric vehicle, and if the vehicle has, say, a 20 Whr battery, then a simple calculation suggests that you just need to charge it for four hours and you’ve put 20 kWhrs of charge into it.

Unfortunately, that’s an over-simplification.  You need to adjust for the various inefficiencies and conversion losses you’ll experience from when the power comes out of the solar panels until when it ends up stored in the vehicle battery.  You should figure on as much as 30% of the power from your solar cells being lost in the process of taking them from the original low voltage DC solar cell output to a high voltage input (often in AC) to the charger unit for the vehicle, and through that and in to the batteries themselves.

It would probably be prudent for you to talk to the car manufacturer about a direct DC input to the vehicle’s charging system.  If you can go straight from DC to DC, this might give you a considerable improvement in efficiency, but depending on the vehicle and its DC charge voltage (which could be very high), this might not be feasible.

There is another electricity need as well.  You can’t leave a car with a dead battery.  You need to keep the battery with a certain minimum amount of charge, and because the batteries self-discharge at a slow rate, you need to be topping the vehicle up every week or so whether you are using it or not.

One more thing to consider is that charging your vehicle will probably take considerable time.  If you can provide, say, 5 kW of power, then you’re looking at probably a full sunny day of solar power for a Leaf or Focus to be charged, and two or three days of this to charge a large capacity battery (but longer range) Tesla.

And if you thought you’d pack a portable solar kit in the back of the vehicle and charge it at your destination prior to returning home, that is probably impractical.  If you had a 200 W solar array (uncommon, but here’s a site selling 150 W and 300 W portable panels), then it would take about two hours of charging for each mile of range added to the car.  If there were 8 – 10 hours of sun in a day, that would give you 4 – 5 miles of extra range.

What is the Service Life of a Battery Powered Car

Unlike the lead-acid starter battery in a regular vehicle which works until, one day, it no longer works; electric vehicle batteries don’t usually catastrophically fail.  Instead, they slowly but surely degrade, meaning they hold less and less charge with each successive discharge/recharge cycle.

Their rate of deterioration depends on various things, with the two major issues being the simple passing of time, and the number of cycles of charge/discharge they experience.

Chevrolet warrant their Volt batteries for 100,000 miles or 8 years and estimate that the battery will have lost 20% of its ability to hold a charge by the end of that time.  Its battery warranty is a slightly complex consideration though because the vehicle is dual-fuel; it will be running on its gasoline engine for an unknown percentage of the warranty period, as well as sometimes off its batteries.

Tesla warrant their batteries for eight years and unlimited miles, and will replace them if their capacity diminishes by 30% during that time.

So it seems that we can expect probably ten or more useful years from a battery pack, no matter how much we do or do not use it.  That’s both good and bad – what say TEOTWAWKI occurs just a month or two before you were planning on (needing to) replace your battery pack?  As long as you have a reasonably new battery pack, you’re good for up to ten more years of battery life, but otherwise, you’re going to have a much shorter useful remaining life, and because the batteries slowly decay even if sitting unused, you couldn’t keep a supply of spare batteries to extend the total life of the vehicle.

Needless to say, there’s no way you’ll be able to build your own high-tech lithium ion battery.  Once the one in the car is no longer functional, that’s it until – if/when – the high-tech world we luxuriate in  is restored again.

Uses For an Electric Car

So why would you even want to consider an electric car in a Level 2/3 situation?  After all (at least per our standard definitions) a Level 2 situation is all about living off stored resources until such time as normalcy returns, and a Level 3 situation assumes normalcy won’t return any time in the foreseeable future and requires you to fully transform to a sustainable ongoing lifestyle.

In a Level 2 situation, you’d simply run normal vehicles off stored fuel.  In a Level 3 situation, you’d be reliant on animal power or a low tech type of wood gas burning car – maybe even a steam-powered car.  (Yes, we’ll write about both these concepts in future articles.)

But there may still be room for an alternate technology in both situations.  An electric car reduces your reliance on stored fuel while you still have any (a Chevrolet Volt type solution – a vehicle that will run on either battery or gasoline would be ideal), and in a Level 3 situation, an electric car gives you additional capabilities that animals don’t have – the ability to travel an extended distance at speed, at least for as long as there are passable roads, and to the limit of your battery range.

Unless you spend a lot of money on a Tesla, the present selection of electric vehicles all have limited range – about 30 – 70 miles, depending on driving conditions.  There’ll be no recharging stations for you en route WTSHTF but if your retreat is within 10 or so miles of a local community, making roundtrips between retreat and community possible on a single charge, then in a future Level 2/3 situation, the electric vehicle can be useful.

Clearly, it is not an essential item that you must have as part of your basic core prepping supplies, but if budget and circumstance allows, it might be a valuable additional option.

A Warning Note About Range Claims

It goes without saying that ‘your mileage may vary’ in terms of the actual range you get out of your vehicle.

In addition to all the usual range-affecting factors that you are familiar with when driving a regular gas-powered vehicle, an electric vehicle’s range also varies significantly if you need to use its heater or a/c unit (headlights don’t make such a big difference).

But there’s another factor to also keep in mind.  Every time you discharge and recharge the lithium ion batteries, their capacity diminishes slightly – maybe by less than one tenth of one percent, which sounds like nothing until you think forward to what happens after the 100th or 1000th charging cycle and then all those tiny reductions in storage capacity have become significant.

The chances are that the useful life of your vehicle’s battery system will be determined not by its sudden complete failure, but by its gradual reduction in driving range below the point that you need.  For example, if your retreat is 12 miles from the nearest town, and you have a vehicle with a 35 mile range, you start off, with a brand new battery, needing to drive 24 miles with a 35 mile charge.  That’s easy.

But after some years, the batteries have lost 20% of their storage capacity and you now have to drive 24 miles on a battery that holds a 28 mile charge.  That’s getting to be ‘touch and go’, isn’t it.

Then, in another year or two or three, the batteries reduce down to having the same range as you need to drive, and what happens then?  Remember where we commented, above, that recharging the vehicle away from a heavy-duty high current source of power will take almost literally forever.  In other words, the vehicle has essentially become functionally useless, unless you can arrange for some source of recharging in the local township you make your roundtrip visits to.

Our points here are three-fold.

First, take all range claims with a grain of salt.  They’re probably not as inaccurate as some of the claims made for regular vehicles that you drive ‘normally’, and in the future, you’ll almost definitely drive an electric vehicle as super-economically as possible, but even so, allow yourself a margin of error between the claimed range and the actual range you might get.

Second, if your typical roundtrip distance will be close to the claimed range capability of the electric vehicle when new, you’ll only have a limited life before the vehicle’s range has reduced below that you need.

Third, because the effective life of the vehicle will most likely be limited by its gradually reducing range, the longer the range it has when new, the longer its effective life will be before that range has diminished down to useless.

Benefits of an Electric Car

An electric car offers several benefits compared to regular gasoline powered vehicles.

The first benefit is that, as surprising as it may seem, an electric car should be more reliable than a regular internal combustion engine powered vehicle.  It has many fewer moving parts, and many fewer stressed parts.  With the local dealership no longer being available to fix your vehicle any time it develops a problem, a reliable vehicle becomes much more essential.

The second benefit is that electricity is an easier fuel source to create and replenish than petrol.  This might also seem counter-intuitive, but the chances are your retreat will have multiple ways of generating electricity but no ways of making petrol.  At a stretch, you could come up with a bio-diesel or a wood gas type system, but complexity issues start to increase in such cases.

The third benefit is that it is quite likely you will simultaneously be desperately short of energy in general, but also have occasional surpluses of electricity.  An electric car provides a way for you to store and use any surplus electricity you are generating, rather than have it go to waste.

What About the Prius and Other Hybrid Vehicles?

Do not buy a Prius or other hybrid electric vehicle.  These cars essentially have no ‘stand alone’ or independent electric power capacity.  They are designed to recover, store, and re-use power from the vehicle when it brakes, so their batteries have very limited capacity and their electric motors are primarily boost or assist motors, capable of powering the vehicle only at low speeds.

These are great cars, for sure, but they are best thought of as super-efficient gasoline powered cars.  Without available petrol, they are useless; indeed, most of them have no provision for external charging.  They also have very low capacity batteries – a typical Prius has about a 1 kWhr battery, of which only about half is available for use in powering the vehicle.  This is a perfectly sensible design for its prime purpose – recovering and reusing energy that would otherwise be lost every time the vehicle brakes, but it is clearly totally insufficient to allow for fully electric-powered travel for more than a mile or so.

The plug-in version of the Prius has a larger battery – 4.4 kWhr – which gives it about an 11 mile range.  This is great when you have gasoline in the tank to fall back on as soon as the 11 mile range has been used up, but not so great as a purely electric vehicle in a future scenario where gas is no longer available.

Electric Car Models

There are quite a few different models of electric cars out there, although most sell at best only a few thousand units each year, so you’re not likely to find one on the local used car lot any time soon.

Furthermore, it is our sense that the technology is steadily evolving, and with the batteries having a finite life, there are definite costs associated with buying a second-hand electric vehicle.  It is good to delay buying an electric vehicle as long as possible – but if you decide you can afford one and can justify one, be careful of this strategy.  You might find you leave it too late!

Rather than list the vehicles currently available – a list which risks being incomplete and quickly going out of date, we suggest you look at these two Wikipedia pages – a list of electric cars currently available and a list of production battery electric vehicles, to see whatever is currently out there.

Most of the electric vehicles are solely electrically powered.  But there are a few (most notably the Volt) which combined both a regular petrol engine with a battery/electric motor, and while these might have shorter electric ranges, they open up an interesting possibility for the future.

First, their shorter range (ie about 35 miles for a Volt) might be sufficient for short runs between your retreat and the nearest township.  And, second, you might be able to modify the petrol powered engine to run on wood gas.

This would require considerable effort on your part, of course, but by making a hybrid electric/wood gas vehicle, that would seem to give you the best of both worlds for the future.

Summary

In our wonderful modern world, with gasoline prices amazingly low (even $4.50 a gallon is ‘low’ compared to the true replacement/alternate technology costs of energy) and petrol freely available at gas stations open 24/7 just about everywhere in the country, electric cars make no sense for most of us.

While it is true you save money in per mile fuel costs when running on electricity; overall, and for most of us, the up-front extra cost of the electric car outweighs the per mile savings.  Even if there is an eventual saving to be had, the inconvenience of the range limitations of electric vehicles, and the time it takes to recharge them, reduces the use of electric cars to essentially around-town runabouts.

But in the future, when gas disappears from the gas stations, and other liquid fuel replacements become massively more expensive than petrol even at its highest current prices, electric cars may become much more useful for shorter range transportation.  Most of us will find it easier to generate electricity (to power a vehicle) than to create petrol or diesel.

Jun 042013
 
When the grid goes down, we will not only need to generate our own electricity but we'll need to store it too.

When the grid goes down, we will not only need to generate our own electricity but we’ll need to store it too.

In our amazing modern life, we seldom pause to consider all the ‘behind the scenes’ miracles that are being worked for our benefit – all the things which could fail, might fail, and probably will fail in a Level 2/3 scenario.

Of all these blessings that we take for granted, perhaps none is greater than the miracle of electricity.  For most of us, nearly all the time, we can plug anything into any wall socket in our house and it will operate, and we can turn on any or all of our appliances and enjoy their normal operation, at any hour of the day or night.

Electricity from our local utility company is always available and amazingly inexpensive and probably has been the greatest lifestyle enhancer of the last 100 years.

You mightn’t think electricity to be amazingly inexpensive when seeing your monthly bill, but try going without electricity for a week or two then ask yourself ‘how much would I pay to get my electricity back?’ and then you’ll appreciate its value.  Or cost out other ways of creating the electricity – for example, electricity from a high-efficiency diesel generator will probably cost 40c per kWhr, compared to a typical cost of about 10c for mains provided electricity.

When the grid goes down and you have to generate your own electricity, you’ll quickly build an even greater appreciation of how amazing our present electricity supply is.  No part of generating electricity in the future will be easy, and because you’ll be using a different way of generating much/most/all of your electricity, one issue deserves particular mention – something you’ve never needed to think about in normal life (although in actuality, it is something the utility companies are very sensitive to).

The chances are you’ll make use of photo-voltaic cells – PV cells or solar cells – for at least some of your energy needs.  Maybe you might use of wind power, too.  These are great energy sources, but there’s an associated problem.  This is the start of a four-part series of articles that considers this problem, and offers ways to optimize your work-arounds and solutions.

The Need to Match Electricity Demand to Electricity Supply

The problem relates to a major limitation of both your likely future energy sources.  In the case of PV cells, you know they only work when there’s reasonably bright sunlight.  So, you never get any power at night, and on short winter days that are overcast, you get very little power even in the middle of the day.

In the case of wind power, the wind turbine only generates power when there is ‘good’ wind – nice steady smooth wind blowing in a reasonably consistent direction at a reasonably consistent speed (wind gusts can destroy a turbine) that is neither too fast (at high speeds, turbines stop working to prevent damage) nor too slow (turbines have a minimum speed below which they no longer generate useful amounts of power).

The problem with both PV cells and wind turbines is that you can’t match their power generation to meet your requirements.  A diesel generator simply starts working harder (and burning more fuel) when its load increases, and if you have a micro-hydro station, you can vary the amount of water driving the turbine, but there’s no way you can make the wind blow more strongly or the sun shine more brightly.

The typical solution is to have a PV/wind system that provides enough power during a realistic typical sort of day of working to both cover your power needs during the period of operation, plus surplus power which can be transferred into some sort of electricity storage system.  Then, when the power being generated becomes insufficient to meet your requirements, you can switch to the stored power and use that until such time as the primary power source can start meeting your needs again.

Hence the need to store electricity.

Storing Electricity is Not Always the Best Solution

In addition to whatever method of storing electricity you might choose to match with your renewable electricity generation program, there is another way of storing electricity which has a huge plus but also a huge minus.

We are talking about simply keeping a large supply of diesel or propane for a generator.  Each gallon of diesel can give you about 10 kWhrs of electricity, and with a typical house using about 1000 kWhr of electricity a month (depending on design, size, and climate of course) at present (with plentiful energy, low-cost, and no need to fanatically conserve energy) this suggests a diesel generator would consume about 100 gallons of diesel a month to give you all the electricity you need.  A few tweaks to your retreat design, some more insulation, and some alternative heat and energy supplements, and you could easily halve this to 500 kWhr of supplementary electricity per month – a mere 50 gallons.

If you have 1,000 of diesel stored, that could see you through 20 months of power needs, which would cover all Level 1 and most Level 2 scenarios.  Those 1,000 gallons of diesel represent something well under $10,000 to purchase, to stabilize with fuel stabilizer for many years, and to store in good quality long life tanks.

As a comparison, if you wanted to have a battery based electricity storage capacity of say 75 kWhr, you’re looking at an investment in batteries and control circuitry of $20,000 or more, and you’ll want to significantly expand the power output of your solar or wind setup so it has sufficient extra capacity not just to meet your regular needs but also to charge up the storage banks – maybe something like an extra 5 kW – 10 kW of power generating capacity – figure on another $10,000 or so for that.

So for solutions extending out a year, two, maybe even three or four, you might decide not to overcomplicate things (and add to the cost as well) and have a system that provides renewable energy during the day and relies on a diesel generator at night.

But, having said that, a key part of preparing includes planning not just for Level 2 situations, but also for ultimate Level 3 situations, and if you base your electricity generation on diesel, you know that, sooner or later, you’ll run out of diesel.  So if you wish to be best prepared for the future, you’ll recognize that electricity storage, while not necessarily the most economical solution for Level 2 events, is essential for Level 3 preparedness.

Any type of preparing of course ideally involves multiple solutions to each single problem, so as to have redundant approaches, and for this reason too, it makes sense, even in planning for shorter term problems, to have at least some way of storing some electricity.

How to Store Electricity

It is difficult to store electricity, with the only ‘true’ form of electrical energy storage being a device known as a capacitor.  While capacitors are remarkable and very useful in some applications, they are sadly not really well suited for storing the large amounts of energy we wish to store, and for the lengths of time we wish to store it.

We’ll spare you the science, but suffice it to say that all other forms of energy storage involve using the electricity to create a different form of energy which can be conveniently stored and converted back to electricity again in the future.  Even a battery, which might seem to be a pure store of electricity, actually converts the electricity to a chemical form of energy.

In considering an electricity storage method, you need to consider a number of factors :

  • System efficiency – for every kWhr of energy you put into the system, how much do you get back again when you convert it back to electricity again?  In the broader scheme of things, efficiency is of course important, but in this application, where you’re essentially storing spare/surplus power, it isn’t quite as important as it would be, for example, for a utility company that is paying for all the electricity it generates and seeking a way to cover the ups and downs of daily demand.
  • Storage losses – does the stored energy slowly – or quickly – dissipate over time, or does it stay unchanging for long periods of time?  In our case, we will have a mix of requirements – some energy needs only be stored for 15 hours or so (ie from when PV cells stop providing power around sun-down until they start again shortly after the next dawn).  But you will want to be able to store some energy for a longer term in case of extended periods of insufficient power supply during the day.  Storage losses are an important factor.
  • Size and other requirements – is anything special needed?  Does the storage thing take up a lot of space?
  • Maintenance and useful life – how many times can electricity be transferred in and out of the storage system?  What types of ongoing maintenance are required, and how easily can the system be maintained in a future situation where you’ll not have high-tech equipment, and sooner or later will run out of replacement spare parts?  How many years until it fails entirely and needs to be replaced?  Clearly these are very important issues for us.
  • Capacity – how much electricity can be stored in the system?  Are there limits to its ability to grow?  Of course we need to have adequate capacity – that goes without saying, and if there’s a low tech way we can grow the system in the future, so much the better.
  • Cost – what are the costs of storing electricity in the system?  Do we need to comment on the fact that, as preppers, we are always confronted with too many different high priority ways to invest our money and insufficient money to invest!

Although there are very many different ways to store electricity (perhaps better to say ‘to store energy’ because the thing we are storing is not actually electricity, but something else which can be converted into electricity), in our case there are only one or two which are practical to the size, scale, budget, and other requirements we are likely to have.

The most obvious storage system involves batteries – probably some sort of lead-acid batteries.  A less obvious form is to store energy in a rapidly spinning flywheel, and a third approach, which may work well for some people but not well for others, is to store energy in the form of pumping water up to a higher elevation, and then to reclaim it as needed by having the water flow down through a micro-hydro power generator.

Continued in Part Two

Please now click on to read part two of this series, ‘Using Batteries to Store Electricity‘, and then continue on to parts three and four (Other Energy Storage Methods and Strategies to Reduce Your Need to Store Electricity).

We also have other articles on the general topic of Energy.

Jun 042013
 
A cutaway view of a typical lead-acid battery.

A cutaway view of a typical lead-acid battery.

This is the second part of a four-part article series about how to store electricity (better thought of as storing energy rather than electricity per se).  If you arrived directly here from a link or search engine, you might wish to start from the first part of the series here, then read on sequentially through this article and the balance of the series.

Lead-acid batteries use a technology that has been around since the mid 1800s.  The relatively recent Lithium-ion technology is showing some signs of promise as a possible replacement to lead-acid, but that is still a way off, and for now, for our purposes, lead-acid batteries, while far from innovative, remain probably the best general purpose way to store electricity in circumstances that typical preppers are likely to encounter.

Batteries offer between about a 50% and a 85% efficient means of storing electricity, making them neither particularly better nor particularly worse than most other forms of storing electricity.  They have acceptably low storage losses, typically losing somewhere between 2% – 15% of their charge each month.

As old-fashioned as they may be, the generic concept of lead-acid batteries masks the fact that there are many different types of lead-acid batteries, designed for different purposes, and with greatly varying suitability for our requirements.

They also have a surprisingly complex series of requirements for how to charge and maintain them so as to get the optimum life out of the batteries – to prolong the amount of electricity they will store, to maximize the number of charge/discharge cycles they can withstand, and to protect against sudden failure.  For optimum use, it is important to be sensitive to many aspects of their care and conditioning that we never consider with our car battery – and the proof of the need to look after our storage batteries should be evident when you consider how quickly car batteries fail!

Lead-acid batteries fall within three general families when it comes to how they are made.  The oldest technology is the ‘wet’ or flooded type battery, then there are gelled batteries and AGM (Absorbed Glass Mat) batteries.  Flooded batteries typically have removable caps and you should occasionally check the level of the liquid inside the cells, adding distilled water as necessary, although some now have ‘fully sealed’ cells (which actually aren’t fully sealed).  AGM and gel batteries are always sealed and in theory need no maintenance.

Some people view gel cells as a transitional technology and suggest you avoid them, preferring either AGM or wet cells.  Gel cells require different charging procedures and voltages than regular and AGM batteries, and are more prone to degradation or failure if not treated optimally.  AGM cells are very low maintenance, but more expensive for the same amount of capacity as wet cells.

The most common measure of a battery’s storage capacity is how many amp-hours of charge it can give.  However, it is important to appreciate that the amp-hour capacity of a battery is dependent on how fast it is being discharged.  The slower the rate of discharge, the more total charge the battery will give you.  For example, a battery that is discharged evenly over 20 hours will typically give 10% less charge than a battery discharged over 100 hours.  A battery that is discharge over 8 hours will typically give almost 20% less charge than one discharged over 20 hours.

Our point is that it is important to understand whether a battery’s capacity is being measured on the basis of a 100, 20 or 8 hour discharge rate.

The lead-acid battery that most people are most familiar with is a car starting battery.  This is designed to store a small amount of charge which can be provided at a very high rate of current for a short period of time, for the purpose of starting the engine.

It has a secondary purpose to power the car’s various electrical loads for a moderately short amount of time while the vehicle is stopped and the engine switched off.

But these batteries are not designed to give up all their charge over a slow gradual period; indeed, they’re not designed to give up all their charge at all.  They are not ‘deep cycle’ type batteries.  Perhaps because of this, they are typically not even rated in terms of amp-hours of storage, but rather quote a ‘cold cranking amp’ current rating – the amount of current it can supply when being called upon to turn a vehicle’s starter motor.

Don’t use car batteries as storage batteries.  They are not designed for deep discharging and don’t last long.

No lead-acid battery should be fully discharged before recharging it again.  The greater the amount of discharge before recharging, the more the battery is stressed and the shorter its future life will be, in terms of additional charge/discharge cycles and capacity of charge that can be stored per cycle.

Deep cycle batteries are designed to allow for the greatest amount of charge depletion per cycle.  Typically these types of batteries (sometimes referred to as ‘golf cart’ or even as ‘forklift’ batteries) are designed to give up perhaps 70% of their capacity per discharge without suffering any severe consequences.  Some batteries allow for an 80% discharge, but it is probably better to go easy on them and not go all the way down to 80%.

Depending on the exact battery design, discharging to 50% is considered the ideal compromise, and you should avoid discharging beyond about 70% of capacity.

You can measure the state of charge of a battery either by testing the specific gravity of its liquid, or by testing the voltage it puts out.  The specific gravity measurement is slightly more accurate, but with so many batteries either sealed or AGM, these days most people use voltage readings as a measure of charge instead.  The voltage steadily declines as the battery discharges, starting from 12.6V when fully charged.  Am offload reading of 12.3V shows about a 50% charge, and a 12V reading (offload) more or less corresponds to a 75% discharged state.

Battery life also depends on other factors such as even ambient temperature (cooler is better than warmer).

Modern batteries such as these or these claim to give up to 2000 or so cycles, with discharge all the way to 80% each time.  That’s almost six years of daily discharging (or twelve if two-daily discharging, and so on for extended cycles).

In terms of actual elapsed time, these types of batteries seem to be talking of lifetimes in the 10 – 20 year range, if the number of cycles isn’t exceeded in a sooner time frame.  That’s starting to become a viable life.

Other highly respected battery suppliers include Concorde/Lifeline and Rolls/Surrette.

If you are building a high-capacity battery, there are several ways to do this to best effect.

The first is not to use a 6V or 12V based system.  Increase your voltage (by connecting batteries in series) to 24V or 48V.  This has several benefits, including reducing the electrical losses through your wiring and/or reducing the need for ridiculously oversized wiring to carry your battery current.

The second is of course to connect multiple batteries in parallel, but this needs to be done with caution.  The more batteries in parallel, the greater the chance that a ‘bad cell’ in one battery unit will bring down the entire set of batteries.  What happens is the battery with the higher voltage then starts ‘charging’ the battery with the lower voltage, and bleeds away its power into the weaker battery.

For this reason, it is always important to match batteries with like batteries, whether connecting in parallel or serial – batteries of similar capacity and similar state of life.

It is best to arrange for each individual battery in your battery array to be of as large a capacity as possible.

Beyond that, rather than to create one huge battery with maybe six individual batteries paralleled together, it is much better to create two three battery units, or even three battery units, each with two paralleled batteries.  That means you can better rotate your batteries in and out of service, alternately charging and discharging each battery in sequence, and stretching out the overall life of all the batteries.

Continued in Part Three

Please now click on to read part three of this series, ‘Other Energy Storage Methods‘, and then continue on to part four ‘Strategies to Reduce Your Need to Store Electricity‘.  If you’ve not yet done so, you might wish to also read the first part of the series, ‘Storing Electricity‘.

We also have other articles on the general topic of Energy.

Jun 042013
 
The fickleness of wind and other renewable energy sources means you need to store power as best you can when it is available, for future use when it is not available.

The fickleness of wind and other renewable energy sources means you need to store power as best you can when it is available, for future use when it is not available.

This is the third part of a four-part article series about how to store electricity (better thought of as storing energy rather than electricity per se).  If you arrived directly here from a link or search engine, you might wish to start from the first part of the series here, then read on sequentially through the balance of the series.

Flowing Water Uphill and Other Gravitational Energy Stores

Another interesting approach to storing electricity is by pumping water uphill.

If you have a hill on your property and sufficient water, you can use surplus energy to pump water up to a large reservoir on the top of the hill, and then when you need electricity, you run the water down the hill and to a hydro-electric plant at the bottom.

This can store energy for a longer term – the only storage loss being evaporation – but involves potentially massive amounts of water and as much vertical rise/fall as possible.  If you double the height differential, you halve the amount of water you need, and vice versa.

Although this might seem like an unusual and strange technology, 93% of all stored power, world-wide, is stored this way.

To put the amount of water needed into perspective, if you wanted to store enough water to be able to generate 5kW for 100 hours – a good reserve for emergencies) you could either have an efficient diesel generator and about 50 gallons of diesel, or if you were able to store water somewhere 100 ft higher than ground level, you’d want to have about three million gallons of water in the reservoir.  That is about 400,000 cu ft of water, so think of a pond measuring perhaps 200 ft by 200 ft and 10 ft deep.  You’d also need another storage area at the bottom to hold the water prior to pumping it back uphill again.

This is of course not impossible, assuming you have a way to get the vertical rise that is necessary, and a source of water to replenish losses from evaporation.

The concept can be extended and slightly modified, indeed, it is merely an extension of the concept found on many cuckoo clocks, where a weight slowly descends, driving the clock mechanism, then is ‘rewound’ when you use energy to pull the weight back up again.  Anything that uses gravity as a way of storing energy can work.

There is a project currently being developed in California that uses rail boxcars loaded with heavy gravel.  Electric locomotives use spare grid power to haul the boxcars up a length of steeply inclined track, and then when the electricity is needed to be returned to the grid, the boxcars are allowed to push the loco down the track, and the loco now acts as a generator feeding power back into the grid.

Such a system can be 80% or more efficient, and will store energy indefinitely with no storage loss.  The boxcar example requires more power to push the boxcars uphill than would be available from a typical private power source, but this could of course be modified (lighter boxcars and/or less steep grade).

These types of systems can require a fair measure of space.  In the water example, if the water reservoirs at top and bottom are ten feet deep, you need almost 2 acres of space just to store the water, plus more space for the pipes and generator/pump.

But their biggest requirement is the height differential.  If you’ve got a fully flat property, you’re either going to have to create a raised portion, which would involve a prohibitive amount of earth working, or else look for other alternatives, which presently tend to invariably circle back to batteries.

Using a Flywheel to Store Electricity

Flywheel technology is becoming more practical, although still a technology that is equal parts experimental and/or not ideally suited for our applications.

With a flywheel, spare electrical energy is used to spin up the flywheel – a huge heavy massive device that spins rapidly – and then when electrical energy is needed, the flywheel is used to run a generator.

Flywheels can store surprisingly large amounts of power, and if in a near vacuum and with magnetic bearings, are slow to lose their energy (by ‘slow’ we mean the energy loss rate is acceptable for a device that charges during the day and discharges at night, but not quite so acceptable if you want to be able to store energy for several days).  They can provide a reasonably efficient means of storing power.

They are also fairly low maintenance, especially if kept in a semi-sealed environment.  But they are also large heavy devices, potentially weighing 5 – 10 tons or more, and require very precise balancing and bearings due to the speeds they spin at.

Flywheels are best suited for applications that require large amounts of sudden energy and/or applications that have large amounts of energy suddenly surplus.  That’s not to say they’re not potentially good for our sorts of applications too, and the good news is that the growth in renewable energy generation is feeding growth in related issues, particularly energy storage.

We expect to see small-sized flywheel installations continue to be developed to a point where they may become practical for storing energy for short-term overnight use, but we’ve not encountered a flywheel that is quite ready for prime time just yet, alas, although there are some hopeful developments underway at present.

There are many other technologies that are either in a development stage, or which are not suited for our sort of scale of energy storage – for example, compressed air.

How Much Electricity Storage Do You Need

Storing electricity is a somewhat wasteful and somewhat expensive process, although it could be convincingly argued that having extra spare electricity being unused at certain times of day to also be wasteful too!

Some electricity storage is both prudent and essential.  The question becomes – how much.

If your only renewable energy source is PV, then you need enough for two purposes :

First, you need enough to get you through a typical night from when the energy flow from the cells diminishes as the sun gets low until such time as the energy flow restarts when the sun rises the next morning.

Second, you need additional ‘spare’ capacity to cover times when the weather is bad, the sky is full of clouds, and the PV cells aren’t generating enough electricity during a normal day to replenish the store for the next night.  Indeed, in a worst case scenario, the PV cells might not even provide enough power to cover the normal needs during the day.

You can of course control this to a certain extent by increasing the capacity of your bank of solar cells.  If you need 20 kWhrs of electricity a day – 10 kWhr for daytime use and 10 kWhr to store for the night, then you’re less likely to run into shortage with a setup that is rated to provide 40 kWhr per typical day than with a setup that is rated to provide only 20 kWhr per typical day.

So the greater your surplus during a typical day, the less an amount of reserve storage you need.  If even a cloudy day sees your PV installation providing enough power for the day and the night, all you would seem to need is a single night’s worth of power to be stored.

We’d still like to increase that capacity to allow for mishaps and emergencies.  What happens if something fails in the solar setup and it takes you a day or more to repair/replace it?  Also, if you only need to recharge your batteries every other day rather than every day, clearly you’ll get twice the life from them, and if you are normally only discharging your batteries down to 50% full, you’ll again get much longer life than if every night you are discharging them down to 20% full.

If you are only using wind power, the first thing we’d recommend would be to rush out and buy some solar cells!  Some days there might be no wind, but some sun (and vice versa); by spreading your electricity generation between two different sources, you are reducing your risks and increasing your resilience.

Beyond that, it becomes harder to predict how much wind power you can expect.  You need to look at detailed wind logs for your location, and approximating the above ground height your turbine will be situated at, so as to get a feeling for average, best case and worst case daily and nightly power generation.

Using a process a bit like that we recommend for working out your water needs, you can proceed to calculate some likely pessimistic scenarios about the amount of wind power you might get, and from that, you can then work out how much stored electricity you’ll need.  Don’t forget to allow for an unexpected several day outage occurring at exactly the worst possible moment, too!

But, wait – before you do these sums, you should first re-examine the question of how much electricity you will need and use, and reduce this amount as much as possible.  The next three sections cover this concept.

Continued in Part Four

Please now click on to read the final part of this series, ‘Strategies to Reduce Your Need to Store Electricity‘.  If you’ve not yet read them, you might also want to read the first two parts of the series too – Storing Electricity and Using Batteries to Store Electricity.

We also have other articles on the general topic of Energy.

Jun 042013
 
Using solar water heating brings two benefits - greater efficiency and an easy way to store energy as hot water for later use when the sun goes down.

Using solar water heating brings two benefits – greater efficiency and an easy way to store energy as hot water for later use when the sun goes down.

This is the final part of a four-part article series about how to store electricity (better thought of as storing energy rather than electricity per se).  If you arrived directly here from a link or search engine, you might wish to start from the first part of the series here, then read on sequentially through the balance of the series.

A Different Sort of Energy Storage – Time-shifting Electricity Demand

Storing electricity is usually both the clumsiest and costliest way of productively using up spare/surplus electricity.  You lose some electricity when you convert it to however it is stored, you lose more during the storage process, and then you lose even more when you convert it back to electricity again.

So it is better to time-shift as much as possible to times when you have spare electricity.  One example of a time-shiftable process would be washing clothes and dishes (assuming you still will use an electric dishwasher in the future, which is unlikely).

With these types of activities, you can wait until a day with lots of electricity coming from the PV cells or wind turbine before washing your clothes (and/or dishes).

If you have an electric range, you should use it to cook food during times of peak electricity production.  Maybe you’ll change your eating habits and have your main meal of the day in the middle of the day (something many societies already do and which many health experts think to be a better approach to eating) so that the cooking energy is sourced when the sun is shining brightly or the wind blowing strongly.

If you are vacuuming, do that when there’s spare electricity, and never when you’re using stored electricity.  There’s almost never an emergency requiring urgent vacuuming in the middle of the night!

Try and match your own sleep and wake times to the sun.  If you’re sleeping during the morning with daylight flooding in to the retreat, but then staying up late at night, using electricity to power lights and possibly heating too, that is more wasteful than using the sun for light as much as possible, and sleeping in a warm bed during the coldest part of the night.

Take your shower/bath in the morning if possible so as to allow the system all day to reheat the water.  Or, alternatively, after using hot water at night, don’t use stored electricity to heat up the replacement water, and instead wait until the morning to do that.

Which leads to another strategy.

A Different Sort of Electricity Storage – Storing the Results of Using Electricity

Another approach to storing electricity is to store the results of using electricity.  We started to get into that in the preceding section – heat your hot water when you have spare electricity to do so, and then deplete it when you do not have spare electricity, and only reheat it again when you have the spare electricity back to do so.

An easy and low tech type of storage is to store heating or cooling energy.  There are special ‘storage’ heaters that will run when you have spare electricity and heat maybe a large vat of oil or even a block of concrete, then at night, you expose this heat source and allow the heat to transfer out and into the surrounding areas of your retreat.

You can also do this for cooling.  When there’s surplus electricity, make large blocks of ice.  Then, when you need extra cooling but no longer have extra electricity, allow the ice to melt, cooling the area around it.

These are low tech but sensible concepts.  Indeed, many large buildings currently use these types of systems for more efficient heating/cooling.  You can do the same.

Replacing Electricity With Other Energy Forms

Electricity is an ‘expensive’ form of energy – it is close to the top of the ‘energy pyramid’, just like beef is close to the top of the food pyramid (in terms of the amount of feed and water needed per pound of meat).

If you can replace electricity with other forms of energy – forms which may be more abundant, and/or lower tech and more sustainable into the indefinite future – you’ll be doing yourself a favor.

One example of this substitution is to mount a solar water heater on your roof.  That way, instead of using solar energy to create electricity and then the electricity to heat the water, you go directly from the solar energy to the hot water, in a much more productive/efficient process, and also in a lower-tech form.

A solar water heater is easy to construct and easy to maintain.  But as your PV cells fail, you’ll absolutely not be able to repair them yourself, and no-way can you fabricate your own additional solar cells in a low-tech future.

Another example is to use wood (or coal or peat) as a heat source for heating your retreat, your hot water, and possibly even for cooking with as well.

Or, if you’re using propane to power a generator, get a propane rather than electric stove and burn the propane in that stove.  You’ll use less propane to directly power your stove than to first convert it to electricity and then to second convert the electricity to heat on your stove.

How Much Extra Electricity Generation Capacity Do You Need

Remember that the first part of an electricity storage system is having ‘spare’ electricity to store!

Once you’ve done what you can to minimize your reliance on stored electricity, the next question becomes how you will get the electricity to store.

Clearly, you will do this by increasing the capacity of your renewable energy sources so they can simultaneously meet your normal electricity needs and also send extra capacity into the storage system you selected.

And, equally clearly, the electricity source(s) you have must be able to generate enough spare electricity each day to be stored to be used each night.

So you need to consider the answer to this question – ‘assuming a less than fully sunny day, or a day with poor rather than optimum wind, how much power do I need generated for the day’s requirements and to recharge for the night ahead as well?’.

Remember that most solar and wind generators are specified as having a certain capacity on a good/close to optimum day.  You’ll need to adjust the claimed daily capacity to more accurately reflect the real-world rather than best-case probability of electricity it will create for you.  Maybe you need to get a system which is apparently twice the capacity you need, just so that in periods of low generating conditions, it still generates enough for both your immediate and your storage needs too.

Now, for an interesting additional factor.  The greater your storage capacity, the smaller your surplus daily generating capacity needs to be.  This is because the extra storage capacity gives you a greater ability to average out the peaks and troughs of actual daily electricity production.

One more consideration.  Most lead-acid batteries require a certain minimum charge rate in order to effectively charge, so you need to be sure that your electricity source will deliver enough charge to actually load electricity into the battery.  Think of a helicopter – it uses a lot of energy just to hover – you don’t want your battery to just hover, you want its charge level to rise, so you need to provide more than this ‘hovering’ amount of energy to actually raise the battery’s charge.

Whatever you come up with, you must have a system that on an average/ordinary day will provide enough electricity during the day for all the daytime needs in your retreat, plus enough left over to replenish a typical night-time’s consumption of electricity, plus perhaps still more left over to replenish one more typical night-time’s consumption, too.

Electricity Will Never Be Cheaper Than Now

Spending $10,000 for a 5 kW solar array might seem like a lot of money, and of course, by any measure, it is indeed a substantial sum.

But – and you can absolutely trust us on this – in a Level 2 and particularly a Level 3 situation – your future lifestyle and ability to survive will be totally linked to your ability to generate your own energy, particularly in the form of electricity.

So get as much electricity generating capacity now as you can afford.  Particularly if it is modular, it can be either used or traded in the future, and you’ll quickly discover the essential nature of energy in a future Level 2/3 situation.

Read the Rest of the Series

If you’ve not yet read them, you might want to read the first three parts of this series too – Storing Electricity, Using Batteries to Store Electricity and Other Energy Storage Methods.

We also have other articles on the general topic of Energy.

Mar 042013
 
Carbon dioxide (pictured) and monoxide meters are an important safety precaution if you plan on having any type of fires indoors.

Carbon dioxide (pictured) and monoxide meters are an important safety precaution if you plan on having any type of fires indoors.

So there you are, all hunkered down in your retreat.  The temperature is below freezing outside, but you’re happy and warm inside, both because your dwelling is ultra-insulated and also because you’ve a nice low-tech fire burning in the fireplace, providing a warm cheery ambiance and keeping you all nice and toasty.

That’s a nice mental image, isn’t it.  And if you have an open fire in an open fireplace, you’re probably okay, but many people – especially less well prepared people – when they find themselves encountering a situation where their normal source of heat fails, may resort to emergency methods of keeping warm that invariably end up with burning something in a way that isn’t a typical part of their normal living.

The problem is that if you have a fire in an enclosed area, what happens to the products of the fire’s combustion?  The smoke and toxic gases, carbon monoxide (CO) and carbon dioxide (CO2)?  If they have nowhere to go, or aren’t being vented at the same rate they are being produced, you will start to get accumulations of these products.  And that can be a bad thing.

About Carbon Monoxide and Carbon Dioxide

Carbon dioxide is naturally present in the atmosphere at a concentration of about 390 parts per million (by volume; by weight the measure is about 590 parts per million, but most measurements use the volumetric method).

People naturally produce CO2 as an output gas from breathing (assuming we breathe in air with almost no CO2  present then about 4% – 5% of the gas we breathe out is CO2), so any type of enclosed space with people in it starts to have elevated levels of CO2, no matter if there are any fires in the room or not.  The smaller the space, the greater the number of people, and the less the amount of fresh air that flows into the space and the less the amount of stale air that flows out, the higher the CO2 level may become.  Normal buildings typically have anywhere from maybe 1500 – 5000 parts per million of CO2 in them.

When carbon dioxide levels reach 10,000 parts per million (ppm) – or a 1% concentration, more sensitive people might start to feel somewhat drowsy.  At 5% people start to experience shortness of breath, dizziness, faster heart rate, headaches and confusion.  Concentration levels over 8% start to become fatal.

So we are fairly tolerant of elevated CO2 levels and the body quickly recovers from an exposure to higher than optimum levels of CO2.

Carbon monoxide is a much deadlier gas.  Normal concentrations of CO in the atmosphere are about 0.1 ppm (measured by volume not weight – CO is slightly lighter than air, whereas CO2 is slightly heavier than air).  In a typical house, concentrations are perhaps in the order of 0.5 – 5.0 ppm.

Whereas a 1% level of CO2 causes many people no ill effects at all, the same level of CO would cause unconsciousness within a couple of breaths and death within 3 minutes.  And whereas a level of 2500 – 4000 ppm of CO2 is considered normal inside a building, that level of CO would cause headaches, dizziness and nausea in 5 – 10 minutes and death within 30 minutes.

OSHA says that CO levels should be kept below 50 ppm.

Detecting Carbon Monoxide and Carbon Dioxide

The good news is that the smoke/toxic gases such as you get from a normal open fire (we’ll oversimplify and consider the two as being the same) are readily detected.  When your eyes start to water, and you find yourself coughing, you know you’ve a ventilation problem, and you’ll be forced to do something to solve the problem.

But what say you are using a clean burning heat source such as a kerosene heater or even just running all the burners on your gas stove full on?  Then there are few or no smoke/toxic gas byproducts that you can readily detect, but the fire is still creating CO and CO2.  It has to – all fires create CO2 and most fires also create CO to a varying extent.  The better fed with oxygen the fire, the less CO; the more oxygen starved, the more CO.

Both of these gases are impossible for us to detect.  They are clear, tasteless and odorless, and cause no irritation on our skin or in our lungs.  They are silent but deadly killers.

The good news is that there are inexpensive and effective detectors for carbon monoxide.

The bad news is that carbon dioxide detectors are more expensive.  However, as a rule of thumb, if the smell of the burning fire becomes objectionable, then you need to do something about that for all reasons, including concern about possible CO2 buildup.  Many people choose not to worry about CO2 levels at all, and certainly our advice to you is to have a carbon monoxide detection/alarm system operational as the higher priority (and regular smoke detectors simply to detect fires as a safety measure too).

You can conveniently buy a wide range of carbon monoxide detectors on Amazon.  Your local hardware store probably has them on the shelf, too, although probably not in quite such a wide range of makes and models.

It is much more difficult to find carbon dioxide detectors, and a Google search typically brings up only carbon monoxide detectors.  This difficulty is made even worse by the propensity for some people to confuse the two gases, and so even when people talk about CO2 detectors maybe they actually mean CO detectors.

Here is one website that clearly does sell CO2 detectors.

Oh – one more important thing.  When buying CO and CO2 detectors, be sure to get ones which are battery-powered.  They won’t be much use to you otherwise, because in an emergency where you need to resort to alternative heating strategies, this almost surely means that you’ve also lost mains power.

Smoke Detectors Won’t Help

Note that smoke detectors do not detect either carbon monoxide or carbon dioxide.  Although there are two different types of smoke detectors (ionization and photo-electric) both work by detecting particulate matter rather than gas.  They are simply – as their name implies – devices that detect smoke, rather than specific gases or even heat concentrations.

There are some combo units that combine a smoke detector and a CO detector too, but you should not assume your smoke detector also detects CO – and being as how that makes it more expensive, if it doesn’t say it does, then it probably doesn’t.

Summary

If there is any expectation that you’ll be burning fuel indoors, it is prudent to have carbon monoxide detectors to monitor the CO levels that will build up from the fire.  Modern super-insulated buildings ‘leak’ less air, and so can trap CO much more readily than older drafty structures.  It is prudent to insulate your retreat and regular dwelling as much as possible to save on energy, both normally and in a crisis, and when you do this, it becomes prudent to add a carbon monoxide detector too.

Carbon dioxide is much less deadly than carbon monoxide, so adding a CO2 detector is less essential, but still good practice.

Mar 022013
 
The red dots are pumping stations on our national gas pipelines.  The Chinese military may now have the capability to destroy a thousand of these simultaneously through only a few computer keystrokes.

The red dots are pumping stations on our national gas pipelines. The Chinese military may now have the capability to destroy a thousand of these simultaneously through only a few computer keystrokes.

Due to its current abundance and low-cost per unit of energy, the US is becoming increasingly dependent on natural gas.

Already, 30% of all electricity comes from power stations burning natural gas.  Conversion programs to convert buses and trucks from diesel to natural gas are becoming increasingly popular due to the massive cost savings operators can quickly get from their investments.  And if you have gas to your residence, you know that the cost of the gas has dropped over the last few years, while electricity costs have stayed the same or risen, making it more and more appropriate to use gas for heating your water and your house and on your stove top.

An interesting thing about natural gas is that most people perceive it as ultra-reliable and as close to guaranteed to be always available as possible.  We’ve doubtless all experienced power outages from time to time, but when have you ever had an unexpected unscheduled gas outage?  Probably never; indeed some people view their gas supply as so ultra reliable that their emergency generator uses natural gas as its energy source.

Unfortunately, while historically it is true that our gas supply has been ultra-reliable, today it is also true that the gas supply has become ultra-vulnerable to disruption.

Almost all the gas that is used somewhere comes from somewhere else, and travels from where it is extracted/processed to where it is consumed, by pipeline.  For sure, pipelines are physically vulnerable – a stick of dynamite could destroy a segment of pipeline any time and any where, but doing so requires ‘boots on the ground’ – you need people to physically get explosives, travel to vulnerable/accessible stretches of pipeline, blow them up, then escape safely.  None of that is impossible, but it is difficult and requires a substantial number of saboteurs if they are to have an appreciable impact on the supply lines.

We try to make it a little difficult for such attacks to occur; information on the exact location of gas pipelines and the related control stations is somewhat restricted.

But there’s an easier way, which the Chinese military have been preparing.  This article reveals that during a six month period in 2012, cyber-attacks traced back to the Chinese military were detected on 23 pipeline operators (there are about 30 major pipeline operators in the US), and includes the explanation that with the information stolen and access obtained through these cyber-attacks, it would be possible to cause enormous damage, either sequentially or simultaneously, and with the attackers never needing to leave the safety of their bases in China.

The article gives the example of using the access gained to mess up control settings so as to cause a thousand pumping/compression stations to simultaneously explode.  Destroying a pumping station is more serious than just knocking a hole in the side of the pipeline, and takes longer to repair.

Now think about the implications of this.  Not only would we lose the 30% of our electricity that is currently generated from natural gas, but we’d also lose the use of natural gas sourced energy in industry and at home, too, massively increasing our demand for the electricity that would already have become seriously in short supply.

Most households with gas for heating and cooking use more energy from natural gas than from electricity, so household demand for electricity would more than double (in winter, not so much in summer).  The same in many commercial applications, too.

As you may recall from the California electricity crisis back in 2000 – 2001, even a very small shortfall in electricity supply can be enough to massively mess things up.

Maybe this would not destroy our society entirely, but it would sure change our lifestyles substantially.  And all it would take to cause this is a few keystrokes on a computer somewhere in China – and who’s not to say that other countries hostile to the US don’t have similar capabilities or haven’t been given the information obtained by the Chinese cyber-terrorists?

Implications

Our point is simply this.  Scratch the surface of most of the essential underpinnings of our modern-day society and lifestyle, and examine the things we most take for granted, and you’ll find ugly exposed vulnerabilities that are growing rather than diminishing in size and scale and scope.  Barbed wire fences and armed patrols might provide physical security for our nation’s critical infrastructure, but the preferred form of attack these days is not this old-fashioned method involving real people doing real things to real structures, it is a ‘virtual’ attack via computer, a form of attack that we seem to be much less able to defend against.

Your non-prepping friends probably have no idea that a branch of the Chinese military, deploying a team of cyber-terrorists, now has the capability to destroy our natural gas supply system, which is part of the reason they are not preppers.  But you know, and hopefully you continue to prepare for and anticipate potential crises of all forms.

Oh – one last thing.  If a cyber-attack were to be launched against the US, of course it wouldn’t be only limited to our gas pipelines.  These same hacking exploits that created the pipeline vulnerability have been occurring regularly on other elements of our infrastructure, opening up vulnerabilities in many other parts of the fabric which binds our society functionally together.

The overwhelming impact of a cyber-attack would make Pearl Harbor look like nothing more significant than a gnat on an elephant’s rear.  A full-out cyber-attack would destroy just about everything we need to survive currently – energy, water, food, sewer, communications, you name it.  Such an attack, from start to finish, would take less than five minutes, and would have no prior warning at all.

Be prepared.  Be very prepared.

Jan 032013
 
This graph, typical of many wind turbines, shows power output (vertical axis) against wind speed for a typical wind turbine.  There is only a very narrow band of wind speeds suitable for measurable power generation.

This graph, typical of many wind turbines, shows power output (vertical axis) against wind speed (m/sec) for a typical wind turbine. There is only a narrow band of wind speeds suitable for measurable power generation.

One of the essential requirements of any retreat has to be some type of renewable energy source.

As we’ve stated elsewhere on the site, the ultimate and paramount issue in any post-WTSHTF scenario is availability of energy.  Almost everything else in your life is or will be energy dependent – certainly shelter, definitely food, and maybe even water too.  Whether the energy comes from yourself (worst case scenario), from hoarded supplies of energy sources such as propane and diesel (which are only good until they run out) or from other sources, sourcing energy is your most important issue.

There are two or three obvious renewable (or ‘free’) energy sources – hydro, solar, and wind.

Wind has some appeal to it, particular in its abstract form, and particularly from reading the glossy brochures, and in terms of cost, the capital cost per kW of generating capacity is very competitive with other renewable energy sources.  But there is a lot more to wind power than meets the eye, and most of the added issues are negative rather than positive.

To help you better understand wind power, we look in this article at some of the less talked about downsides of wind turbines.

Hydro is easily understood, and solar is not much more complicated.  If you’ve got an accessible flow of water dropping from a higher level to a lower level, you’ve a chance at hydro, and the more the sun shines, and the bigger your solar array, the more solar power you can hope for.

Wind Power Only Works in Some Winds, Some of the Time

But wind is a different matter entirely.  With wind power, you need wind speeds that are greater than the minimum which your turbine requires, but less than the maximum.  At greater than maximum speed, the turbine blades will ‘feather’ – they will turn into the wind and the turbine will cease to spin, and no longer generate electricity.  This is different to solar and hydro – there’s no such thing as ‘too much’ sun or ‘too much’ water.

There’s also less of an issue with ‘too little’ water/sun either – sure, no water means no hydro power generated, and so too does nighttime mean no solar power generated.  But the minimum amount of water or sun needed to start the electrons flowing is truly very low, whereas most wind turbines sit lifeless until wind speeds exceed somewhere in the 5 – 15 mph range.

So that’s the first disadvantage of wind.  Wind works best in a location with steady (rather than gusty) winds that flow regularly in the 25 – 40 mph range.  Not many of us have such locations.  Most of us have insufficient ‘suitable’ wind to make a wind turbine a sensible concept under any conditions.

Even if you do have a reasonably good location, you need to have a back up plan for when you have a ‘wind drought’.  We all know that just because a place averages so much rain in a month, that doesn’t mean it is guaranteed to rain an even equal amount every day, and the same is true of wind, too.  What happens if you have no wind, or too strong wind, for an entire week and are unable to generate any wind-sourced power during that time?  At least with solar, even the cloudiest day will still give you some power, but with wind, you could conceivably end up with a ‘wind drought’ that lasts a week or longer.

That’s a very big problem to confront.  Most solar systems are backed up by standby batteries, with the idea being that during the day, the solar cells generate enough power for your needs plus a surplus to be stored in the batteries, then when the sun goes down, you switch to the batteries for the night, until sunrise the next day.  Plus, with a bit of planning, you can shift your electricity consumption so that most of it happens during daytime and less of it happens at night, reducing the amount of power you need to store.  That only requires a 12 – 15 hour or so supply of stored power.

But what if you’re planning to be able to withstand a seven-day period with no wind at all?  You need at least ten to fifteen times more batteries (which – trust us – is a lot of batteries), plus the excess wind generating capacity to quickly recharge them.

Now, for the further bad news.  Even if you do have reasonably suitable winds in your area, there are two other problems with wind power.  Reliability/maintenance, and longevity.

Reliability Issues

Next time you drive past a ‘wind farm’ have a look at how many of the turbines aren’t spinning.  If the ones around them are turning, then the ones that aren’t turning have failed for some reason or another (that’s not to say that all the ones which are spinning are actually working properly either, of course – some electrical failures don’t result in the turbine blades stalling).  Depending on the location, the design of turbine, and the speed with which failed turbines are repaired, you’ll probably observe anything from one in 20 to one in 10 are not turning when they should be.

Think about that – if we say it takes on average 4 days for a failed turbine to be repaired, and if you see one in 15 turbines are not turning, that suggests that on average that every turbine is failing once every 60 days, and with four days down out of 60, that is a 93% uptime rate.

Okay, wind enthusiasts, let’s take an optimistic view if you prefer.  Let’s say only one in twenty turbines is failed, and let’s allow an entire week for the turbine to be repaired – that suggests the failure rate is once every 140 days, which is still nearly three failures per turbine per year.  That is a 95% uptime rate.

And, just to be fair, wind naysayers, let’s say one in ten are failed, and they can be repaired in two days.  That means an average time between failures of twenty days – not quite three weeks.  Ouch!

You should also remember that these turbines aren’t working 24/7.  Their duty cycle might be more like 8 – 12 hours a day – in other words, they are only working a third to a half of the time, and even at that low rate of application, they are still failing repeatedly.

In a ‘grid down’ situation and with the progressive loss of high-tech componentry and high quality machining, do you really want to rely on such maintenance intensive things as wind turbines for one of the most essential parts of your ongoing survival?  What will you do when you run out of spare parts?

Longevity Issues

The other dismaying thing is the total service life that you might get out of a wind turbine.  It has generally been considered that you can expect 20 – 30 years out of a turbine before it needs complete replacement.  But what if that’s not so?  What if you can only get ten years of life from it.  What happens when the turbine totally fails?

Here’s an article which reports that the actual life span of wind turbines in Britain is proving to be significantly less than was optimistically projected.  There’s such a huge lobbying effort behind wind power generation (in both the UK and US) that this type of data is unlikely to be widely reported or commented on, but go read the article and form your own conclusions.

It is probably okay to plan for a 25 year life for your Level 2/3 retreat’s power source.  But only ten years?  That’s not as long as you might think – the human mind tends to find it hard to appreciate the time to a future date, so as a way of appreciating it, think back ten years instead.  That’s probably not such an impossibly distant point in time.  And so neither is ten years into the future, either.

As a comparison, solar cells are also often rated vaguely for a 25 year or longer life, but unlike a wind turbine, that doesn’t mean that at the end of their rated life, they stop generating power entirely.  Assuming they don’t suffer ‘catastrophic failure’ (ie someone dropping a brick on them!) the output they provide slowly diminishes over time – generally about 0.5% every year.  So after 25 years, a solar cell array has lost only about 12.5% of its maximum power generating capacity.  This article points out that some solar cell installations are still providing 80% of their initially rated power after 40 years, and show no signs of failing.

Solar cells can easily outlast their owners.  Not so, wind turbines.

Integrating Wind Power into Your Total Energy Sourcing Strategy

You’re probably getting the feeling that we don’t like wind power.  That’s moderately correct – we love the abstract promise of wind power, but we’re not very happy with the present day reality.

We could be persuaded, however, to add a wind turbine or three to provide another semi-redundant source of power to our retreat, but as a supplemental ‘bonus’ power source rather than as a critical must-be-working source.  This not only give more total power, but also adds another fail-safe level of redundancy.

Maybe a ‘once in a thousand years’ hailstorm destroys a large part of your solar cell inventory.  Maybe your hydro dam breaks.  Maybe any one of many other catastrophic events occur, in which case you’d be very appreciative to have spread your risk and to have deployed some wind power too.

If you do choose to adopt wind power, we’d recommend deploying multiple wind turbines.  That way, when one fails, you don’t suddenly lose all your wind power.  You ‘only’ lose half (if you have two), or a quarter (if you have four) and so on.

Needless to say, you’ll need to have a truly impressive inventory of spare parts, and beyond that, a high-end machine shop to allow you to repair and rebuild damaged components as well as simply replace them.

You’ll also want to also add to your battery storage capacity, or deploy some other form of energy storage so that you can take the spare wind power, when it is available to you, and put it to some good use.

Summary

Wind power is a very specialized type of power that has many constraints and concerns associated with it.  The wind speeds with which the turbine will actually generate power are concentrated in a very narrow band.  The turbines themselves are very maintenance intensive and prone to failure on a regular basis.  And their total service life may be much shorter than originally anticipated and promised.

Wind power may be acceptable as a ‘top up’ source of power, particularly in our present world where the electricity grid has multiple redundant power sources and can manage even if all wind power was to fail simultaneously.  But we do not recommend wind power as a prime source of power in a retreat/off-grid situation.

If you choose to include wind power as an energy source, you’d need to reduce the impact of turbine failures by investing in multiple turbines – at least three, so that having one turbine go offline would only reduce your power by 33% or less, hopefully giving you still sufficient for your essential needs.  You’d also need an extensive inventory of spare parts, and a much greater reserve bank of batteries to tide you over sometimes lengthy periods when your turbine can’t generate due to the wind being either too weak or too strong.