Thursday, June 7, 2012
Building a Little Solar-powered House on the Prairie: Off-the-grid or Grid-tied? | dan-thiede
Building a Little Solar-powered House on the Prairie: Off-the-grid or Grid-tied? | dan-thiede:
Off-grid or not off-grid—that is the question. Indeed, that was a HUGE question Locusarchitect Paul Neseth posed to Linda and I as we sat down to yet another design session. Like “paper or plastic,” but a lot lot harder.
We’d still be designing if not for our one guiding principle, the principle by which all our design decisions were judged. Though on paper, our house was turning out to be “green, sustainable, earth-hugged, solar powered, masonry heated, humanure composting, rainwater harvesting,” we never told Paul that’s what we wanted. Instead, we asked Paul to design us a house that does one thing for us—enables the Connection.
First, connect us to the Land, our 62 beloved ridge-top acres overlooking Whitewater State Park. Second, connect us to our friends, family, neighbors and community. Third—if we dare admit such a wild proclivity—connect us to the Divine, the great mystery that flows through and binds all of these. That’s it Paul, just this little Connection; can you do that for us? Can any house do that for us? It is, after all, just a house.
Now, one month after moving into the house, it’s too early to say we did it. But, thanks to Paul, at least we attempted it, one decision at a time. And no decision was tougher than off-grid versus grid-tie (or not off-grid).
Grid-tied versus Off-the-grid
There was never any debate about solar electric. After all, what could connect us more to the Land than harvesting sunlight to produce electricity, not unlike the Indian grass on our 40 acres of newly planted prairie. The only debate was storage. Where do we store excess electricity so we can still “plug-in” when the sun isn’t shining?
There are definitely upsides to a grid-tied home—and we almost went that direction. By storing excess electricity on the grid, a grid-tied system would directly connect us to our neighbors and community. We’d become one of their electricity suppliers, potentially (and perhaps sneakily) reducing their reliance on fossil-fuel generated power. We’d also earn income by selling power to the electric company, hopefully offsetting the cost of power we purchased from the grid when the sun isn’t shining. And lower total cost means less hours employed means more time on the Land.
But for many reasons, we decided to go off the grid. Our first (and most valuable) step in going off-grid was touring four homes. By generously opening their off-grid homes to us, these pioneers gave us our first big “Aha!” There are as many good ways to go off-grid as there are good reasons to do it. And beyond all the good reasons for a grid-tied system, we discovered what draws some to off-grid. We knew about independence and self-reliance. But tinkerer? One guy had so much excess electricity that he not only drove an electric tractor, but he gutted a Jaguar to build his own electric car. Another recovered methane from cows to power his generator.
While we saw (and found online) much useful how-to information on batteries (for storing the electricity), charge controllers (for charging the batteries) and backup generators (for when the batteries get low), we didn’t anticipate the big problem—lack of local off-grid solar installers. Many installers do grid-tie. But few, we painfully discovered, have experience installing off-grid electric.
Powered by the Sun
So when we hired Curt Shellum of Solar Connection, we knew (because he was so forthcoming) we were buying his grid-tie skills and hoping that he’d close the gap to off-grid. And he did: He installed 12 ground-mount photovoltaic panels producing 2.9kW max, 16 batteries designed to store 4 days of typical electricity usage, 1 invertor for charging batteries (from solar panels or generator), inverting battery DC to usable AC and displaying performance (red means I better start the generator) and 1 generator (powered by our tractor’s PTO).
And the results never cease to amaze me. Since coming on line, our off-grid system has powered the remainder of the construction project: 3 inch drills, miter saw and attached vacuum, and fans blowing all night to dry the sheetrock mud. And now that we’ve moved into our home, the system has done all we need powering lights, 5 pumps, 2 fridges, freezer, computer, and phone. I was so relieved when I heard the roaring whir of the Vita-mix blender as it turned frozen strawberries into summer-tasting smoothies. Only once in 4 months, fearing the battery charge level would drop below the 50% spec. limit, did I start the backup generator. And it turned out I didn’t need to—the next day was plenty sunny.
The Off-grid Journey
And what of our highest value—the ultimate purpose for our house—the Connection? Today is the seventh consecutive day of low-slung clouds and gully-ripping rain. The batteries remain 82% charged. At 11am the solar panels are producing zero watts of electricity. Nothing. So I feel a little anxious. Will my batteries get overly-depleted? Will I need to hook up the generator? And this slight anxiety—or better put: this heightened awareness of real solar energy—connects me to the Land in a way I never knew possible. I feel perhaps like the summer-loving Indian grass. “Where’s the sun?” And when, indeed, the sun’s rays finally strike the PV, replenishing the batteries, powering our house and our lives, I too feel replenished.
I need to make a confession about our brief grid-tie experience. The moment we started exploring grid-tie, we started designing our house differently, to suck more juice. Bigger fridge? Why not? The grid is always there. The moment we went back to the off-grid, the big fridge disappeared. So did any light that is not LED. Off-grid drove a behavior change for us that grid-tie never induced. And I liked the change.
Unlike the steady, always-as-much-as-we-want grid-tied system, off-grid follows the cycle of abundance and scarcity. This cycle connects me to the Land because it’s how I’m coming to perceive the Land: life, death and life-renewed. Lately, as I watch the dance of the wind-whipped grass, I’ve even thought of adding a small wind turbine. Yes, it will help keep the batteries full. Better yet, perhaps I’ll learn to feel more thrilled as the wind stings my face. Who knows what we’ll do? Off-grid isn’t a destination. Off-grid is a journey.
What do you think about grid-tied versus off-the grid homes? Let us know in the comments!
You can follow all of Mike and Linda’s adventures in sustainable living and the house the land built at Mike’s blog, Rah-dur. This was originally posted on the MN Energy Stories blog from the Clean Energy Resource Teams.