Here's my latest renewable energy project -- repairing the solar power "motherboard" at our Bale House -- a camp or cabin in the deep woods of Monroe, Maine, that Aimee and I built several year ago, and that was featured in several national newspapers (and even the Shanghai Daily!) because it was built using straw bale and recycled materials for less than $20,000.
This is a fairly standard small scale off-grid solar system. One solar PV module, a set of four 6V batteries connected in series and parallel to make 12V DC, a charge controller, and a 110V inverter -- what you'd need to make lights and a small amount of power for a cabin, camp, or remote home.
Now the most recent occupants are moved out, and before a friend moves in, I've been spending almost all of my spare time over there for a few weeks now repairing and restoring the old place, and as usual I'm mining the experience for lessons in renewable energy and climate mitigation.
This equipment was all set up because this house is too far from the nearest grid power lines. It would have cost about $50,000 to run ordinary grid power in, much more than the house is worth. Originally we had provided this small scale solar power system providing both 110V AC and 12V DC, backed up by a fairly expensive propane generator with it's own dedicated wiring system side-by side with the inverter system. It was enough to light the house, to listen to music, to pump water, and watch a show or two a night on a very small, energy efficient TV.
But the generator quit a few years ago, mostly because the occupants couldn't bring themselves to live without a TV, or at least without a fairly large TV. The generator, a brand name propane model, wasn't intended for nightly use, but that was what it was getting. Their TV was a cathode ray tube model now obsolete, and it likely drew at least 100W/hour.
When Aimee and I lived there we had a 13-inch portable that drew about 35 W, then to save energy we switched to a 13 inch flat screen model that drew 25 W, or less if you were watching one of those dark horror movies that Aimee likes to scare me with.
(I'm easily scared by horror movies -- this after a lifetime of volunteer rescue work in which I've seen the most difficult injuries and deaths up close -- go figure!)
When the generator quit on them, I was able to go over over and salvage the unit. I repaired it at home in my own shop, but decided they couldn't have it back if they were going to treat it so badly. They would have to live off their solar "income" instead.
But I failed to make allowances for the pervasive power of habit. Pretty soon the solar system was damaged in a lightning strike. It shouldn't have been damaged, and in fact had lived through dozens of storms in years past, but the ground wire to the wiring system had been disconnected, and so the excess voltage induced in the lines by the atmospheric electricity had nowhere to go. This most likely happened because the occupants had worn out the battery pack, but rather than tell me to have it changed, they had hooked up a car battery. In doing so they had failed to connect the wire to the household ground rod. The inevitable power surge eventually came and a very expensive inverter and charge controller were fried.
But having started, this round of user-error induced failure couldn't end there. A car battery can't run one of these systems for more than a half hour or so, so when that didn't work for them, they'd tacked all these twelve foot extension cords everywhere, which they'd hooked up to a very cheaply made gas generator running outside, no doubt using a veritable "Christmas tree" of double or triple adapters.
It was a very old gas generator to boot, and was probably producing pretty low voltage a lot of the time.
This burn is the result. Lucky the place didn't burn down. Those small hand-start gas generators are meant for emergency use, and even then they can only run one or two items at a time.
And of course, no-one bothered to hook the generator to a ground rod either.
Now I have to get the whole system back to the original level of performance and safety.
Luckily the price of these components has come down, while the technology has improved, so the cost of repair is less than it would otherwise have been, and the results better overall.
I paid a lot of money for the old inverter, a Trace 600 W standby type, and the old charge controller, a Trace C 40. These were standard equipment for small scale solar design for many years, and very robust and safe, as long as they were properly grounded and protected by breakers and fuses.
A solar power system needs two separate grounds, one for the panels, since they usually sit up on a roof and attract lightning energy, and one normal ground for the electrical distribution components.
I was able to replace the whole shebang with new, up-to-date gear for less than I paid for secondhand gear 8 years ago. I used a Cobra 1,000 RV-style inverter, which provides more wattage than the Trace but doesn't need a standby circuit because it draws very little power when on. The new inverter runs without a sound, and has a built-in input volt-meter and output wattage meter. The old inverter was slightly noisy, and the entire system had only a variably flashing LED (on the charge controller) for voltage, and not a very accurate LED at that.
Very nice. We'll see how long it lasts, though. It seems too good to be true.
The white thing on the motherboard is the new charge controller, which is a Xantrex C35, basically the old Trace C40 (with the same old LED!), but without a shunt for excess power, which experience shows is rarely produced by this particular system which has only one module powering four golf-cart batteries.
There were newer, fancier, and cheaper units, but the price of the C35 was much lower than before and they are very robust units despite being, or because of, a 30 year-old design. The black thing is the new inverter. I also went through and reconfigured the wires to make the connections more straightforward, and I put a smaller main breaker in to protect the inverter.
So far so good.There's a short in one 110 volt circuit left to trace today, and then the cabins electrical power system will be restored and even better than it was previously.
But what can we do to make sure that the people who live there are willing to live within limits? This turns out to be a question of major importance as we head towards a world wherein humans have exceeded ecological carrying capacity.
On reflection, I know and have always known that technological understanding evades some people. The level of complexity that is reflected in even a small scale solar power system is far more than a regular house with 200 amp supply, because the regular house doesn't run out of sunshine, while the breaker and grounding system is fail safe.
The solar house, especially the small scale, off-grid solar house, is always in danger of running out of power. You get a fixed maximum supply every day, and if the sun doesn't shine, you don't even get that. This particular house produces about 300-400 watts a day on average, about 1000 watts on a good day, and none at all on a bad day. That's enough for some light and music, a couple hours of a small TV, and to run the 12 V water pump, but no more. And it's only fail safe as long as you don't mess with it.
(And if the owner/designer says the house can't run a 100 watt TV, the house can't run a 100 watt TV.)
Here we provided the building with a proper breaker and grounding system that was initially fail safe, but we could never provide enough sunshine to run all the normal range of American lifestyle appliances that the occupants wanted to run. Instead of adapting to the new low power lifestyle, they tried to adapt the home to their original high power lifestyle. The result was a cascading system of failures, one after the other, each one adding another level of safety issues, and each one setting the system up for the next failure.
For the want of a nail. Even a secondhand 25-35 watt portable TV would have cost $50 and saved the whole system from this cascading failure.
If we ever do have a major climate and energy crisis, one greater than the current chronic disruption, it will cascade like this too. The trick to avoid this is probably to call a time-out right at the beginning and work to get systems back to a safe and functional level before making things worse.
Unfortunately, I fear we won't have the foresight to do that, and so we will make things worse, break more and more systems, before we come back to solving the original problem, which is the carrying capacity problem.
So what does my recent experiment all tell us about the ability of ordinary folk to learn to live within ecological and other system limits?
We're fairly certain that the new occupant, a masters-level biologist and ecologist who alternates between running an organic farm and teaching biology at Unity College, can fathom how to live within the limits of the house.
In any case, this new occupant doesn't watch TV. But I'm not sure it will be that easy getting the rest of society down to where we're living within the safe limits of the climate system.
A good job, though, that we don't actually have to give up on TV. We just need to reduce fossil fuel use by about 80 percent. You can run a TV set, and even a large one if you must, on solar power.
Although I think that this is the message a lot of ordinary people get about climate mitigation requirements -- that you have to give things up.
And the first day of the fall term is Monday. Global Change at 8am. Better get some coffee.
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