HERE ON THE BIG ISLAND
By Kelly Moran
Could You Live Off-the-Grid? Part IV
AC vs. DC
Every electric motor and light bulb in an ordinary house runs on alternating current (AC). And though your cell phone or laptop computer runs on direct current (DC), you keep them charged up with a little transformer you plug into an AC outlet, that “transforms” AC into DC.
No matter how you (or the utilities) generate power, whether from fuel, wind, hydro, or the sun, it starts out as DC and must be changed – or, more accurately, “inverted” – to AC. That’s done through (what else?) an “inverter” that sits between your batteries and the breaker-box for the house’s electrical outlets. The inverter also keeps the electricity from fluctuating, so your power is as consistently smooth as it would be from the grid.
You could skip the inverter, and have an all-DC house. There are DC versions of most appliances, including TVs and refrigerators; and when people here started living off the grid, in the 1960s and ’70s, home-sized inverters were not commonplace; so going entirely DC was the only way they could have modern conveniences. But DC appliances are not cheap, and you won’t find them in local stores. Making an all-DC house also forces you to site all the components of your system, including the outlets, very close together, because (unlike alternating current) direct current loses strength if it has to run through more than about 50 feet of wire. So, to live off the grid, you need batteries and an inverter, too. The fact is: we live in an AC world.
As for cooking, you will have to forget about an electric stove – you can not possibly generate enough power for that. Get a gas stove, and make sure the installer sets up all the burners for propane (instead of natural gas, which is not sold in Hawaii).
Propane is easily obtained. Tanks range in capacity from backyard-grill-size, to four-foot-tall cylinders, to horizontal giants. You can take the smaller ones into town to be refilled, or pay an additional but small monthly fee (less than $10) to have a gas company driver deliver fresh tanks and/or refill them at your home.
There are, by the way, refrigerators that run on propane. They are more expensive and slightly less efficient than electric refrigerators, but if your generating capacity is limited, and you’re getting propane anyway, for cooking or heating water (which I’ll cover next time), you may want to at least check and see if a propane refrigerator will suit your needs. It is, in any case, one more way to stay off-the-grid.