How It Works: Off-Grid Solar Electric

 

Purpose.  Provide all electrical power with no tie to grid.

How It Works Summary.  Photovoltaic panels convert sunlight to DC electricity which is stored in battery bank and converted to 110V AC for usage.  Gas-powered generator backup.

Cost.  $30,000 including installation.  Also received large tax credit.    Battery replacement in 7 to 10 years biggest anticipated future cost.    We have no electric bill and never will.

 

System Components

12 Photovoltaic (PV)  Solar Panels each capable of producing 250 watts DC max for a total of 3000 watts DC max.  Actual wattage depends upon amount of sunlight which is a function of solar veiling (trees, structures, clouds, fog, snow, rain, ice..) and solar angle.  No trees and structures veil our panels.  Angle impact changes throughout the day, peaking at noon and falling to zero  between sunrise and sunset.   Angle impact changes throughout the year,  maximized on summer solstice and minimized on winter solstice. 

16 Deep Cycle Batteries each capable of storing 2500 watt hours for a total of 40,000 watt hours.   Batteries must be kept above 50% capacity (20,000 watt hours).    Battery depletion rate is roughly proportional to amount of electricity used.  Since our home typically draws only 100 watts at given time of day, the batteries store 4 days of electricity.  Upon hitting the end of useful life, our lead-acid batteries will be 90% recycled.

Tractor-powered PTO Generator capable of producing 6000 AC watts to recharge batteries before they fall below 50% capacity.   With generator plugged into 60amp AC service outlet and attached to PTO, diesel-fueled tractor is manually started and run 4 hours to recharge depleted battery bank. 

110V AC Electric Panel.   Like any home is USA, provides 110V AC power to outlets and fixtures. 

Multi-function Invertor.  Outback FlexpowerOne intelligently charges batteries from either the DC solar panels or the AC generator.  Draws DC power from batteries, converts to AC and routes through electric panel to provide home power.    Monitors and displays amount of solar-generated power, battery capacity and amount of power house is drawing. 

 

Maintenance.  Monitor battery capacity and recharge with generator (when approaching 50%).  Replenish water in battery cells (every 3 months).    Start battery equalization program (every 3 months).  Scrape snow off solar panels (as needed). 

Report Card.   Warm Season = A.   Cold Season =  A-.    (See blog post for details).

Biggest Challenge.  Can we get away from the house for a week?  Yes from February through October.  November through January remains uncertain.  (See blog post fordetails).

Biggest Success Factor.  Low power house (100 watts typical).  No AC, dishwasher, clothes dryer, or microwave.  100% LED lighting.  Ultra-efficient fridge and freezer.   Water pump is shallow not deep-well.    No toilet flushing power.   LP gas stove. 

Enabling The Connection.    Behaving like any plant, solar panels make transparent the amazing power of the sun.  Like the Land, off-grid  solar electric follows the seasonal cycle of scarcity and abundance, conserving energy in winter and joyfully “wasting” power in the summer. 

Insanity's Teacher

 

“Why would you ever want to ____?”

I get this question all the time, so feel free.   Fill in the blank.  How about “..drink water spilt off your roof?”  Or “…run low on electricity?”  Or the hands-down favorite, “….empty sloshing buckets of pooh?”

Some, including myself at times, probably wonder if I’m insane.  Maybe so.  But this wintry spring, I’m learning one thing.  I’m not nearly as insane as I’m going to be.  Or could be, if I learned from my teacher:  Home the Land Built.

I mean, here it comes, yet another mega-snowstorm in the coldest, cruelest “spring” I can recall---and that’s saying a lot for a lifelong Minnesotan---and what’s going on about Home the Land Built:  a celebration of life and light.   Never mind the frozen pond, I see ducks splashing in the frigid inrushing melt-waters.  Never mind the ice-crusted prairie, I see little kestrel hawk flap, flap, flapping his wing as he hovers in search of what? 

 

And then, yesterday, while a stiff northerly slapped our cheeks, flock upon migrating flock of juncos--but a thumb with wings---flushed out of the prairie and across the driveway for ten solid minutes.  I couldn’t help but imagine the warmer, sunnier climbs they’d vacated to arrive here, now, in this endless April Fool of a spring.  And junco isn’t stopping here.  He’s going all the way to the arctic.  

Then there’s robin.  Dozens of them bob, bob, bobbing along in the punky yard, pecking morosely, for what?  What are they finding to eat?  Worms don’t wiggle well in ice.  But it’s not just the birds.

Even Home the Land Built itself is going insane.  Since the cold snap began in February, I haven’t started the backup generator once.  Not even close to needing it.  We’re toasty inside.  A sunny day, no matter how cold, warms us to a shirt-sleeve 75F.  And most of that extra heat is coming not from the passive solar windows---the 2.5 foot overhang already blocks most of the high-angled sun---but from excess solar hot water pumped through the concrete floor.   

And today’s storm, raw as it was, managed to squeeze out rain rather snow, rain which we joyously harvested.  Hurrah!  The long, rain-harvest drought of winter is ended.  And yes, when I emptied the toilet buckets into the Humanure Hacienda, the hay-covered compost actually raked away.  Thawed, if you believe it.   No Celtic priestess ever danced so at the arrival of light!  This, all of this, as an April mega-snowstorm bears down.

If insanity means “Follow the light to whatever end”, then I couldn’t have found a more insane teacher than Home the Land Built.  So, just to honor my teacher, I donned a heavy jacket, strode out into the raw, spring-lit elements and flung handfuls of prairie seed onto mucky, ice-crusted gopher mounds.  Why?    Because it felt great!  It felt great to join the splashing ducks, the hovering kestrel, and the arctic-bound juncos.  It felt great to join the energized solar panels, the guzzling cistern, even the sighing compost heap.  The celebration of the insane.  In spite of all evidence to the contrary, we say ”spring is here!”

On May 4, 2011, as I puzzled over my first Rah-dur blog entry, I realized I wanted a purpose-driven subtitle.  “Leave old job.  Leave old home.  Enter new home.  Engage new life.  Maintain what matters.”  Looking back, I had no idea what “engage new life” might come to mean.  I’m beginning to feel like the crew, or perhaps Starship Enterprise herself, when Captain Picard points his challenging finger toward the stars and utters, “Engage!”  Or maybe I’m like Captain Picard himself when confronted by the omnipotent being Que.  “It’s not about charting nebula,” Que shrugs.   “It’s about exploring the unfathomable reaches of existence.”  Hail to Que and Home the Land Built: Insanity’s Teachers.

Rah-dur!

The Humbling Crowds

“So, let me get this right,” I said to the seemingly shy yet determined woman before me.  “You attended last Thursday’s talk at Midwest Mountaineering and tonight you listened to us all over again here at REI.”     

“No,” she said.  “I came now, after your talk, because I wanted to know if you really meant what you said."

“What did I say?” I gulped, hoping I had really meant it.

Perhaps reading my nervousness, she put me at ease with a smile.  “You said anyone could come visit your home.  We’d like to come.”

I can’t recall exactly what I felt at that moment.  Sometimes I suffer from delayed emotion syndrome.  I probably experienced all the typical post-talk feelings:  exhaustion, adrenaline-rush, crowd-management anxiety, and most especially, the bliss that comes from connecting with the energies of an entire room.  But later, as the Prius exited the freeway and followed the two-lane home, my shoulders slumped as I recalled the shy yet determined woman. 

I still couldn’t believe she returned to our second talk in a week just to ask if she could tour Home the Land Built.  Of course I’d said yes, yes, yes and gave her my contact info.   We’re all about that.  But now, as the fields of dirty snow rolled past, all I felt was humbled.  To receive someone’s---anyone’s---undivided attention is such a great gift.  I mean, that’s where the Connection lives, doesn't it?   I felt myself blinking back the emotional surge.  I was driving after all.  But how often does someone hear my story, relate to it, and go far out of their way just to dive deeper?  That very evening, as we sat before our ritual fire, Linda and I offered a toast.  Clink!  Can you hear that generous woman?  That’s for you.

And clink!  Here's another for all of you that listened to our story.  The hundred who crowded into the low-ceilinged basement of Midwest Mountaineering.  The next hundred who registered online to fill the spacious event room at REI.   And another clink of the glass for those who wanted to but couldn’t attend.   Who’d have thought the REI event would waitlist a week before the talk?  To all of you I want to repeat what I said to the generous woman.  “Yes.  We invite you to our home.  Come if you wish.  Our door is open.”  Home the Land Built rose to connect us to the Land and to you. 

And clink! to LocusArchitecture---Paul, Adam, Wynne---for spearheading these talks, assembling spiffy, twirling presentation graphics, and inviting us to share our story.    Clink! to Midwest Mountaineering and REI for granting your space and grabbing your customer’s attention.   Clink! to Minnesota Renewable Energy Society for your sponsorship.  Clink! to Tracy at Birchwood Café for sending those tasty treats for all our guests.  Whoa that coconut macaroon was just what I needed before the talk.   And whoa if we clink again I'll fall into the fire.

The most heartfelt thanks goes to all you of who came and offered us the gift of your attention.  And you, there in the humbling crowd---generous as the woman who dared ask to visit---feel free to follow her to Home the Land Built.  The least I can do is offer to hear your story.

By the way, since so many asked what happens to our house when we leave it, I can tell you what we returned to after a night away.    Though the masonry heater felt cool to the touch, the house was still 70F.  The batteries were 100% charged with electricity.  The 80 gallon solar-heated water tank was at 144F and being pumped into the floor.   The toilet bucket was no more full than when we left.  And I can only assume that the cistern still contains roughly 1500 gallons of water.  Maybe your trip down will inspire us to make the water system transparent. 

Report Card: Year 1

 

System	Description	Warm Season Apr 1 to Oct 31	Cold Season Nov 1 to Mar 31
Electricity	Off-grid Solar Backup Generator	A	A-
Hot Water	Solar Backup Tankless	A	B-
Heating	Masonry heater Passive Solar In-floor Solar	B	A
Cooling	Windows Slab	B
Water	Rainwater Cistern	A-	B+
Humanure	Sawdust Toilet	A-	A  / B+

 

I just did a report card inDecember.  Why another already?  In December we hadn’t really done winter.  Now we have.  And here in Minnesota, we never ever forget winter.  If we do, we die, recipient of a Darwin award. 

 

Also, we’re thrilled with the growing interest in Home the Land Built:  an article in the Star Tribune, visits by others on the journey, upcoming presentations at Midwest Mountaineering and REI, the conversation Linda is having right now with Jen, a freelance French TV journalist. Not only do we feel compelled to spread the good news about what is possible, but like the Shirtless Dancer at the concert, it feels good to know we’re not just lone nuts.  And these fellow dancers deserve to know what it feels like prancing around with our shirts off.  So here it is.

 

I believe that a report card is the beginning, not the end, of a conversation.   Since I released the last Report Card in December, this conversation concerns what we’ve learned about Cold Season performance.   To obtain the grades, Linda and I engaged in a (sometimes challenging) reflection.   Except for Humanure, our perceptions differed by no more than a third of a grade, e.g. A- / B+.    Being the tough teacher that I am, I’ve reported the lower of our two grades, so A- / B+ is reported as B+, excepting Humanure.  Alright, let’s get it over with:  on with the lowest grades.

 

But the lowest grade is only a B-?  I guess the first overall comment should be “this is amazing performance”.   Still, don’t we deserve a talking-to with ourselves?

 

Hot Water = B-.   OK.  I’ve beat the poor backup Bosch tankless to death.  No change here.  Fortunately, we barely use the backup now that the solar hot water has kicked into spring gear.

 

Water = B.  We were very impressed (and relieved) to finally discover we had 1800 gallons remaining in the cistern after 4 months without harvesting a single rain drop.  Yet the water situation is not as welcoming for guests as we’d like.  I must confess that my nephew once drank out of the forbidden tap rather than the Big Berkey filtered crock.  Why wouldn’t he, or anyone, drink from the tap?  A bigger challenge is communicating the scarcity of our winter water supply to guests so that they know not to over-consume.  We Minnesotans---with little awareness that water is actually not infinite---pretty much just let it gush.  Linda suggested we get a meter so guests can “see” how much water remains and better understand their impact.  It all comes back to the Right to Look.

 

Humanure = A / B+.    This is the only system Linda and I disagree on.  She just wouldn’t accept how right I am.  Two issues.  Linda expected less odor from the toilet and is concerned about how it handles large groups.  And she’s right.  No doubt there can be, and probably should be, some odor.   Part of the challenge is guests don’t always cover well.  Covering well requires one skill:  you must actually look at what you’ve produced.  Hmmm.  And large groups do require changing the bucket more often, approximately 1 bucket an hour for every 100 people.  Our difference in opinion comes down to how much these things bother us.  What better learning institute than a committed relationship?

 

Mindful that B grades reflect smiley face performance, now we can move on and pretty much brag about the two Cool Season A systems.

 

Electricity = A-.  What a rally in performance.  ALL due to a glitch in the software that tells us how much juice remains in the battery.   Since toggling one algorithmically-critical parameter, we haven’t been close to the “plug-in-the-generator-now” level of 50% capacity.  In fact, we haven’t sunk below 80%.  But since the change took place during the “sunny” half of winter, we won’t know until next December if the system deserves an A.    Still, we never dreamed off-grid electric could perform so well here in Minnesota.  It begs the question why all new homes don’t at least consider it?

 

Heating = A.   Actually I gave it an A+.   We both agreed that the house always felt toasty, often a t-shirt 72F, while cruising up to a swimwear 80F on the coldest of sunny days.   I awarded an A+ for the added wow factor.  Every night we LOVE sitting before the fire---sipping our favorite beverage---like camping in our own house.  It’s hard to argue with cozy, clean-burning, and virtually free heat.

 

Done with the individual systems, I feel compelled to confess how much Home the Land Built has influenced our grading.  For example, I asked Linda what grade she’d have given our old Minneapolis toilet.  At first she said C+.  One of them leaked a lot and they both plugged occasionally.   Yuck!  Then she said, “that’s the grade I would have given when I lived there but only because I couldn’t see the rest of the system.”  Since discovering that our flushed Humanure eventually made its way---even depositing pharmaceuticals---into the Mississippi, she would now give our old Minneapolis Humanure system an F.    The point is, in Minneapolis, we didn’t even know there was a system.  All we saw was a toilet.  All we heard was a flush.   Knowing what we know now, or what we think we know, every Minneapolis system would probably get an F.

 

Home the Land Built’s Right to Look principle enables a more true grade.   Like it or not, we see it all.  And how can anyone possibly produce a report card on anything unless they know---with their own eyes, ears, and even nose---whether they like it, ALL of it, or not?  So, I guess I’d like the final comment on the report card to read, “I’m proud of you.  You hide very little.  Whatever grade you've earned, at least you can be truly graded.” 

We're Expecting!

Yes, we're expecting, or at least I am.   And I can’t think of anything reeking more havoc on my life right now. 

I’m expecting spring.  Now!  And it isn’t.  It most certainly isn’t.  As I gaze out the great south bank of windows, I can’t recall a more wintry landscape---not just drifts, but drift sculptures---than what I’m seeing on this, the 19^th of March, Equinox Eve.  

 

I think I’ll cry now.  That was my response to Linda after she texted her safe and sound arrival in Minneapolis at 11 this morning.  She’d survived her first drive on a red stretch of highway, the dreaded MNDOT color indicating “hazardous” conditions.  That’s worse than “difficult” purple but better than “travel not advised” navy.   My emotional response, the release of worry, was precipitated in part by expectation.  Grim and gory as it seems, part of me “expected” Linda to crash.  Why else would I worry so?

Perhaps my statistical mind can’t help but compare tonight’s predicted 4F low with the normal 26F low.   Perhaps last March ruined me for life.  The day we moved into Home the Land Built, March 17, St. Patty’s Day, it was a sweaty 80F, the earliest 80F in history.  A year later it’s 4?  Ouch!

But in the end, what good comes of these expectations?  None!  If today we’re January I’d be in heaven.  It’s impressive out there.  For pity’s sake, we asked Architect Paul to design us a home the connects us to the Land and voila!  It works.  Just look at the drifting, billowing snow dust.  Just listen to the howl of the wind and the hammering thud of ice sliding off the yoga loft roof onto the steel roof below.  Feel the sting of air driven far south of its home by the sun. 

It’s one thing to plan for spring.  I’ve sipped many a Chai tea while browsing the Prairie Moon Nursery catalog.  Of course, spring is coming.  But to expect it today?   I’m only setting myself up for the expectation-reality delta: the difference between what I expect and what actually happens. 

This, my dear reader, is the challenge and blessing of my humanity.  Like all of us, I’m  gifted two lives:  my actual life and the story about my life.   And the Mike character in my own story is receiving too much foreshadowing, too much here’s what going to happen.  Mike is going to hear the song of the robin.   Mike is going to smell of the plum blossoms.   

So to fully engage in my new life (isn't that in the sub-title of this blog?), to put an end to my missed-expectation attitude, all I need do is rewrite my story.   “Mike’s an interesting fellow.  It’s not that he’s clueless.  It’s not that he doesn’t care.  He just doesn’t think about tomorrow in the usual sort of way.  To Mike, tomorrow is like his next breath of air, the next blink of his eye.”

 

The Well of Knowledge

“How much water you got left in that cistern of yours?”

You have no idea how many times I’ve been asked that question.  And you have no idea how many times I ask that question of myself.  Take this very morning, for example, when I heard Linda turn on the shower in preparation for her weekly work excursion to Minneapolis.   I couldn’t help but lean toward the bathroom door, fearing to hear that dreaded sound of sputtering water, followed by the even more dreaded sound of “Ah-h-h-h!”, or possibly even a choice word that wouldn’t normally grace this blog.  Because the truth of the matter is---and I’m embarrassed to repeat what I said back in my Report Card---I have no idea how much water is in that cistern.  Or at least I didn’t when Linda took her shower. 

Now, finally, I do.

The drama of water-worry builds all winter long.   Day after shower-running, dish-washing, coffee-brewing day, we know—we dread---that  our supply is dwindling.   Last November, in the middle our last glorious downpour, I ran outside with an umbrella and observed that yes indeed, water was gushing out of the cistern overflow pipe.  We were thrilled to know that our 5400 gallon concrete cistern had filled upon the very doorstep of the rainwater-harvest drought, our long frozen winter.    And that, I'm afraid, was the last time we “knew” how much water was in the cistern.

Until today.

I don’t know what inspired me to action.  Was it Linda’s shower?  Was it the extended forecast of more un-harvestable snow?  Was it the planned visit by Joyce, a fellow off-grid sojourner, and her plumber Jon, who were bound to ask the dreaded question.  Whatever it was, I finally invested the time to invent and deploy a method of measuring how much water remains in the cistern.  Oh yes, I invested all of 15 or 20 minutes (no task, no matter how important, is too small to procrastinate away).

Inspired perhaps by Queen Bitterblue---who escaped the castle on a rope of torn and tied sheets---I too tied together 3 lengths of musty old sheet and secured a couple pulleys, as weight, to the end.    I waded through shin-high snow out to the cistern manhole where, upon removing the cap from the PVC air vent, I lowered my rope into the abyss.   Slowly.  Slowly.  Slowly.  There!  I felt the slack.    Now up,  carefully up.  Gloves off,  I’m waiting, waiting for the feeling of wet rope, the sooner the better.   A gorilla like me isn’t made for such a patient task.  And yet, I was also afraid.  What if only the last foot of rope was soaked?  For all practical purposes, that’s the end, since our submerged pump draws from a filter suspended, at all times, one foot below the surface.    

 

There!  I feel it!  Not just damp, but a thoroughly soaked sheet.  Then, to my everlasting dismay and joy, I perceive how much of the rope is soaked.  Four feet.  Some quick math---that’s one thing this gorilla can do---delivers even more joy.  Eighteen-hundred gallons!   At 30 gallons a day, we could last until the middle of May without harvesting a single rain drop. 

 

I’m sure Linda’s smile would have been a lot bigger had I shown her the rope before her shower.    Still she looked as relieved as anyone rushing off to Minneapolis could.  Our joy, I believe, was tempered by our dismay, a lingering doubt about the accuracy of my makeshift measurement system.  But the real problem is that our rainwater harvest system violated our right-to-look principle.  We can’t “see” how much water remains.   Had we a cut-away, ant-farm view of the buried cistern, the dreaded question would never cross our mind.  We don't debate how long the grass is, only whether its long enough to cut. 

Yet I say hallelujah!  Hallelujah for daring the grand experiment.  Hallelujah for the amazing abundance of water, filling our cistern and our pond.  Hallelujah for our new life.  1800 gallons!  Come on down!  Come on down for coffee, tea, a long solar-heated shower, and after it all, maybe we’ll do dishes.

Is It Spring Yet Mom?

Wake up Mom!

Hush Bambi!  Can’t you see its high noon?  Now chew your cud and let me sleep.

But Mom, I got to know.

OK Bambi, I give up.  Know what?

Is it spring yet Mom?

Oh Bambi, look at all the fresh, deep snow around you.  Look at the falling flakes.  See how they pile up, one after another, on your darling little antler nubs.

But Mom, how can I see my own antler nubs?

Well…you have a point there.   Now something’s up and you can’t hide it from Mom, so you might as well tell her what you did.

Alright, alight.  You see that house up there.

Of course, where they planted those nummy cherry trees for us to eat this winter.  Nice folk.

Well...I went up there this morning while you slept.

What!!!???   In broad daylight?  You could have been shot.

You said they were nice folk.

Well…you have a point there.  Now tell me what happened.

I crept quietly into their house.

What!!!??? That’s impossible.  You can’t turn a doorknob.  You have no opposable thumb.

Nor do I have vocal chords, yet I’m talking.

Well…you have a point there.  Go on.

I snuck down the stairs---clump, clump, clump---into the cellar.  There were clothes on the line.

You ate their clothes!  That explains everything.  You’re delirious.  Let me see that cud you’re chewing.

Mom!  Do I look like a goat?

Well…you have a point there.  Go on.

There was a bright light on the far wall.   I couldn’t help myself.  It pulled me toward it. 

Not the bright light!  What was it?

An Outback FlexPowerOne Invertor, safely directing DC current from a 3kW photoelectric solar array through a charge controller to replenish a 40kW hour off-grid battery bank. 

You’re just my little bambino.  You can’t know such things…

We’ve been over this. 

My head’s spinning.  What did you want to know again?

Is it spring yet Mom?

Very well Bambi, tell me why, oh why---with snow flying all around---you think it might be spring.

Their solar array was cranking 1200 watts!  In the middle of a snowstorm!  What else but spring could shine so much light through so much darkness?

1200 watts you say, in the middle of a snowstorm, is that a lot?

Geez Mom!  Were you born in the backwoods or something?

Well…actually…

Mom!

OK Bambi, I guess your question comes down to this.  What is spring?   I’ve endured many a harsh and hungry winter, yet the end is always the same:  fickle.   The rain finally comes, then it snows again.  The warmth finally comes, then it’s cold again.   The plum tree finally blossoms, then it freezes again.  But from all I've seen, once the light chases away the dark, the light is here to stay.  So if spring is all about the glorious return of light, then yes my little bambino---in spite of the cold and snow----spring is here and it’s here to stay!

 

Nice, out of character soliloquy Mom.

Thanks Bambi.  I thought the Mom character needed to display a little growth in this vignette.

Fine, but now you’re confusing the point.  Readers are going to forget why we’ve wasted their time with all this silliness.

Oh no my deer boy, you have much to learn about our people friends. 

Do they live for the light Mom?

They’re nice folk.

But Mom I want to know…

Chew your cud Bambi.  Chew your cud.