HERE ON THE BIG ISLAND: Could You Live Off-the-Grid? Part III: Here Comes the Sun


By Kelly Moran

Could You Live Off-the-Grid?  Part III: Here Comes the Sun

          Turning sunshine into electricity is the most popular way to generate your own power, here, although two conditions must be met.  First, you really have to have a good view of the sun all day: no trees or hills shadowing the house.  And second, you have to have dough: the initial investment is high, and likely to remain so for the near future.  A “family-of-four” will probably need a system costing $30-40,000, including batteries and control equipment. 

          But electricity from the Hawaii Electric Light Co. (HELCO) costs more than 30 cents per kilowatt-hour, pushing utility bills up into thousands of dollars a year, and the rates will only go higher.  So, a solar system should break even in ten years or less.  Moreover, the price of photovoltaic panels is slowly coming down, while their electrical efficiency keeps going up.  And there are no ongoing costs: once the system is in place, your electricity is free, and your batteries get charged up every day!

          Two recent technological developments make solar increasingly attractive. The newest photovoltaic collectors aren’t like heavy picture-frames, with glass on top.  They’re lightweight, flexible sheets of plastic that are available either as shingles or as peel-and-stick strips that lie flat, between the ridges of standing-seam metal roofs.   And these new materials are more sensitive to ultraviolet light than the glass panels are, so they keep on making electricity even on cloudy days, when there isn’t as much “visible” light.

Two ways to Capture Sunlight:

"Building-integrated photovoltaic" (BIPV) panels adhere directly to a standing-seam metal roof.
"Building-integrated photovoltaic" (BIPV) panels adhere directly to a standing-seam metal roof.
Framed-glass photovoltaic panels are mounted on a carport.
Framed-glass photovoltaic panels are mounted on a carport.

          If your land is close to an existing utility pole, the Hawaii Electric Light Co. (HELCO) may accept whatever electricity you generate and, in effect, store it for you in its grid.  But hey! – this is about living off the grid.  And that means storing your electricity in batteries.

          The right kind of batteries for home-size power-plants are similar to car batteries, but larger and heavier, with higher electrical capacity (24- or 48-volt, instead of 12).  And their installation has to meet building codes (e.g., you can’t put them in the crawl-space under the house).

          To keep your system operating at peak efficiency, you will have to take on some responsibilities that have traditionally been shouldered by the utilities.  Though you don’t have power-poles to climb, or high-tension wires to string, you will have to perform some regular maintenance tasks, the equivalent of those that utilities ordinarily do, and the cost of which they bundle into their monthly bill.

          So, for example, you must ensure that the fluid in your batteries is at the proper level, by topping them off with distilled water, once a month.  And as soon as you do that, it’s a good idea to run your backup generator for at least an hour or two, not only to help your batteries stay fully charged, but also to keep the generator itself in top running condition, so it’s always ready in case of emergency.

          Go solar, and you also ride the wave of the future.  If we in Hawaii are ever going to free ourselves from imported petroleum fuels, we will have to generate more and more of our electricity from the sun.

View Other Posts in the “Could You Live Off-the-Grid?” Series

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