HERE ON THE BIG ISLAND: Could You Live Off-the-Grid Part II: (Electric) Power to the People September 25, 2009
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By Kelly Moran
Could You Live Off-the-Grid Part II: (Electric) Power to the People
In my discussion of catching rainwater, last time, I neglected to mention that in some places it’s possible to draw water from a well, especially if your land is near to places where Hawaii County draws its water. But finding a reliable and sufficient source of water underground is not easy, and on the drier, western side of the island, wells have to be drilled very, very deep. So, you may get lucky. Or not. And the cost of drilling could exceed the cost of a catchment tank. Besides, a well needs a pump – and that means you need electricity.
There are four ways that people here generate their own electricity: fuel, wind, hydro, and solar. I’ll cover the first three now, and discuss solar next time.
- Fuel. By far the easiest way to get power is to buy a generator, keep it stocked with whatever it burns — typically either diesel or propane — and run it until your batteries are charged, roughly six hours a day. With either fuel, you can assume that your electricity will cost a few hundred dollars a month — about what you’d pay Hawaii Electric Light Co. (HELCO), the local utility. Generators are not expensive, but you should balance that low initial investment against the certainty that the price of fossil fuels will keeping going up, even if renewable alternatives like bio-diesel or methane enter the mass-market. (No matter how you make your own power, if you live off the grid you should have a generator anyway, even if it’s only a portable gasoline model, for backup or emergencies.)
- Hydro. If you have a good-size stream on your land, a hydroelectric turbine may be the way to go. The machinery is not very expensive, and you do not need a waterfall, as long as the water level drops at least 40 feet from the intake point down (through a pipe) to the turbine. But the stream has to run year-round, and in a drought lasting several weeks, even some large streams may shrink or dry up. Ironically, the only serious disadvantage to hydro is that under normal conditions you may get too much power from it! Unlike breezes or sunshine, streams run 24/7. After your batteries have been fully charged, any excess electricity can damage your system: it must either be stored (in yet more batteries) or consumed immediately. One fellow I know had to buy a chest-freezer and an air conditioner solely to soak up all the electricity from the turbine in his stream.
- A stream this big could genereate electricity, but only if the water level drops 40 feet or more from the intake point down to the turbine.
- Wind. A small windmill may generate enough power for a barn (or a well-pump) but a windmill sufficient to power a household must be quite large, and hence expensive. On this island, that’s a viable option only if your land is really windy, which you’ll know because your trees are bent over, as they are near HELCO’s “wind farms” — clusters of turbines – -at the northern (Kohala) and southern (Ka’u) capes. On the Hamakua Coast, the onshore tradewinds are not constant; and on the Kona coast, daytime breezes tend to die down at sunset.
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