Off Grid

I have reached my dotage years without ever having paid a utility bill.  No electricity, no water and no sewerage bills in my entire life.  Because I have provided these services for myself.  There is some good news and some bad news.  Yesterday I got the bad news.  Whilst I was showing some interested guests my disgustingly chaotic cabinet of electrical equipment and the spaghetti of wires connecting them, there was a loud crack/bang and I just had time to think “that sounds expensive”, before the deafening report of a nearby lightening strike hit us.  From the crack/bang sound of electrical equipment blowing up, which I know quite well, to the house rattling clap of thunder was about 2 seconds.  This allows me to estimate, using the speed of sound in air, that the strike was 1 to 2 kms away.  There was no rain and there had not been the slightest rumble of thunder.  After the strike there was not a drop of rain or rumble of thunder.  Just a malicious, one off, outlier,  strike I could not take precautions against.  As storms approach with due warning, I listen to differentiate between cloud to cloud lightening (harmless) which is long low rumblings and ground strikes, like cannon fire, which blow up stuff and take appropriate action to unplug parts of the my local grid to protect the gear.  This time I had no warning and no chance to defend, and important equipment blew up before my eyes.  The main battery charger and the main inverter were trashed.  Of much less concern or expense was my phone/answering machine of the landline persuasion.  I have bought so many but they are the first thing to blow up.  The last one I bought at Harvey Norman, I joked to the checkout clerk that it was a great lightening detection device.  Blank stare then “that’ll be….  ”  If he had a sense of humour, he didn’t bring it to work.

I have already ordered new machines from the internet of higher capacity and lower price because the cost and time it takes to send off the damaged devices are prohibitive.  Last time I sent the inverter to the makers to fix it took ages, and costed over $1400.  The freight was $200 each way.  That just about makes it a disposable device.  In the mean time I have patched together and reconfigured the devices I do have, so that guests still have the lights on.  It doesn’t help that the creek has gone down and the hydro now on 60% full power.  Recent rains make it probable the power level will sink no lower before the wet season proper arrives.

Just a couple of weeks ago the hydro power dropped to nothing.  I had a number of ideas what might be wrong, such as a dead short caused by a forked branch dropping on the transmission lines to cause a dead short, or a blocked nozzle, but I was surprised to see the belt pulley lying on the ground as the turbine shaft had sheared.  It is a 25mm stainless steel shaft.  Close examination of the fractured ends revealed that 80% of the cross-section was ductile shear which is smooth, and 20% was brittle fracture which is a rough surface.  Diagnosis was ‘fatigue crack propagation’.  Which means that an alternating stress which concentrates the force at the end of the crack and makes it fail there.  Every time the shaft rotates, the stress reverses.

OK, this is an exercise for the reader.  “The shaft rotates at about 450 RPM.  It has been doing that for about 30 years.  To calculate the number of stress reversals, multiply the RPM by the number of minutes in 30 years.”  Simple calculation.  Also, “please estimate the amount of water in liters, that has been through the hydro in 39 years of operation at an average flow rate of 12 liters a second.”  Your calculator may not be able to handle that, so try to divide by 1000.  Then you will get the answer in tons of water as 1000 liters of water is a ton.  Answers to ‘comments’ please.

So not being on the grid and having no power bills may not be as good as it sounds, but I wouldn’t have it any other way.  That I couldn’t have it any other way made for an easy decision to invest in alternative power.  It is now common, and usually based on solar power with well worked out and well tailored plug-in systems.

Other news from my fungus farm is all pretty good.  Yesterday guests saw a cassowary on the track in and the golden bower bird has been performing well.  Hopefully his performance has led to satisfaction.  Grass is green, frogs are croaking and the spring growth threatens to overwhelm my tenuous attempts at civilisation.  Tree roos seen near the cottages and of course the possums continue to entertain as the most reliable bludgers in the valley.

I leave you a picture of my track clearing team with a determined stare.

Phil & Henry


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