Some Thoughts on SOLAR and WIND POWER VULNERABILITIES

 

RE: Questions in response to Prepping for Seniors article by Coach

The typical off grid system consists of a PhotoVoltaic (PV) array (solar cells); diode back charge protection that may be incorporated in the PV frame, wiring, or charge controller; a charge controller that monitors battery charge condition; battery bank; inverter and battery charger connected to battery bank, generator, AC load center; and DC load center.

EMP vulnerabilities in such a system are manifold. The charge controller and diode back charge protection are very vulnerable and storage batteries least vulnerable. There is a silence of material regarding survivability of solar cells to EMP but I suspect they too are vulnerable.

Most solar cells employ a diode rectifier to prevent the battery from discharging into the solar cell. This diode is vulnerable and would likely present an open circuit if EMP damaged. I urge everyone using solar cells to locate these diodes and have the means to bypass them. This is the first thing I would check in a solar system exposed to EMP.

The hydrometer is an essential part of any off grid system using storage batteries. One can infer battery charge by measuring the specific gravity of the battery electrolyte. The charge controller is thus a superfluous luxury. The charge controller monitors battery bank voltage and PV array voltage. It automatically connects the PV array when output voltage exceeds that of the battery bank and disconnects the inverter when battery voltage reaches some pre-set discharge condition. These tasks can be manually performed but are a lot of work.

One might then conclude having a spare set of charge controllers and the very cheap diodes in protected storage to be a good thing. I have stored a complete PV system (less storage batteries) in a modified conex container thinking such would be exceedingly more valuable grid down than now while we have a working grid.

Anyone protecting electronics should realize a man made EMP event would likely be followed by a subsequent attack intended to take out protected stores. How long should you wait before pulling out the electronics? I think about a year would be optimal. That’s right, no single item electronics for a year.

As an aside, things like two-way communications and night vision are such potent force multipliers that one should have a variety of these things in individual protected storage. My plan is to break out cheap FRS radios immediately post attack for use with surveillance, sniper overwatch, and patrol. More sophisticated communications such as marine band HF and VHF, Motorola H/Ts, amateur radio, and the like would be gradually brought into service as a function of time and need. Same with other electronics. Small scale portable folding battery charger type arrays (see: http://amzn.to/1AVwMFd) would be first out of protected storage for use with our Sanyo rechargeable batteries and the large scale PV system capable of powering a home, last out of storage.

how to bug in

A robust adjunct to radio comms are battery and sound powered military handsets such as the ubiquitous EE8 field phone. See http://en.wikipedia.org/wiki/Sound-powered_telephone;

http://en.wikipedia.org/wiki/Field_telephone and

http://rarmy.net/armysurplus/military-surplus-field-phone/.

Now is the time to lay concealed telephone wire between various overwatch and sniper hides. I keep our military telephones in protected ammo box storage even though they are very robust. Post EMP attack, these will be taken to outlying overwatch areas, removed from the ammo cans, and connected to the pre-laid wires. The various hides then are interconnected by a communications net that is very robust and resistant to compromise.

In conclusion, I would be happily surprised if any currently emplaced PV system remained untouched and usable in its original condition following an EMP attack.

Backwoods Solar (www.backwoodssolar.com) offers a free 198 page handy planning guide for solar and wind powered systems and catalogue.

 

Panhandle Rancher

 

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6 Comments

  1. Panhandle Rancher
    Thanks for the info.
    Here is some info I hope you can use.
    Two weeks ago I purchased 32 GB., Lexar, thumb drives for $9.95 each from “Buydig.com”.
    I do not know if they are still making that offer.
    The Coach

  2. This is a quote from an electrical engineer I know,

    Only devices with coils that can concentrate EMP, or devices with micro-electronic circuits would be susceptible to damage from an EMP. The solar panel would not be able to concentrate the energy from an EMP into anything significant enough to fry the diode. Unless the EMP was very strong, in which case you would have bigger issues dealing fried DNA and being dead.

    Diodes are connected in parallel to groups of cells in a solar panel as a means of preventing reverse current flow when one section of the solar panel gets shaded. If the diodes become open circuits, the panel would work fine, unless you had a partial shade situation. In that case the efficiency of the panel would be reduced. You can fix that by keeping the panel out of the shade.

    If the diodes fried in a way that they became a closed circuit, then you would have a problem. The diodes would bypass the cells. The cure for this problem is to just open up the junction box and cut out the diodes.

    • Thanks Travis – he may be right, may be wrong. I have experts telling me something different. No one really knows for sure.

  3. Thank you Coach for your recommendation.

    Travis, thank you for your comments.

    To the best of my knowledge, it is more likely the smaller semiconducting diodes will fail in the open condition rather than the closed. Again, post EMP event with a failed PV array, I recommend replacing (or if necessary bypassing) the back charge protective diodes. Per your advice, even with a functional array post EMP, one should still check the diodes (if perchance they indeed failed in the closed condition which would result in either a battery life shortening condition due to overcharge, or battery discharge due to back charge condition). As a result, my recommendation to have spares in protected storage remains valid.

    The ability to troubleshoot failed electronics and electrical systems post EMP event is critical. Toward these means, we have a Fluke DVM in protected storage (http://en-us.fluke.com/products/digital-multimeters/fluke-179-digital-multimeter.html). I would urge anyone with the ability and knowledge to troubleshoot electronics to do the same and to acquire the older pre integrated circuit industry standard Simpson VOM (http://www.ebay.com/itm/Simpson-260-7-Multimeter-VOM-meter-with-Test-Leads-/171617290665?pt=LH_DefaultDomain_0&hash=item27f53009a9). The older Simpsons are likely more rugged and more EMP resistant than the otherwise more versatile and modern Fluke meter. I would think any d’Arsonval or Weston meter movement (http://www.engineersedge.com/instrumentation/electrical_meters_measurement/darsonval_movement.htm) such as used in the Simpson (which does have discrete semiconductors), just might be EMP susceptible so why not just put it into an ammo box? Those of us who can diagnose and align superheterodyne radios might want to protect the old industry standard 50,000 ohm/volt VTVM (vacuum tube voltmeter such as the Triplett – http://www.ebay.com/itm/Triplett-Model-650-VTVM-Vacuum-Tube-Voltmeter/291325241529?_trksid=p2047675.c100009.m1982&_trkparms=aid%3D777000%26algo%3DABA.MBE%26ao%3D1%26asc%3D20131227121020%26meid%3D8b2f2f7a11c2424695519bc92ad8e0a4%26pid%3D100009%26prg%3D20131227121020%26rk%3D1%26rkt%3D4%26).

    Our uncertainty is of course, strength, type, and distance of the EMP field from the electronic item. As you likely are aware, there are several disparate sources of potential EMP other than the high altitude nuclear explosion and range from flux compression devices (for more regional effect) and solar events. One could therefore experience a crippling EMP attack without becoming the proverbial crispy critter.

    The grid tied solar or wind generator system would likely be quite well fried due to induced EMP field via the AC mains with which it connects.

    For these reasons and others, every room in my home has Aladdin lamps and of course we have spare wicks, mantles, and globes (http://www.aladdinlamps.com).

    Best wishes,
    PR

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