OFF
THE GRID
Thinking Alternatively... because we have
to...
What Mama Gives Us
Many families on the Rivers use Renewable Energy to power their homes. We did. We used micro-hydro power. With solar electric panels (photovoltaic) getting larger and less expensive they can be a viable power source also.
Sites
The first step in designing an
RE system is to evaluate your site. You need to “See what Mama gives you"
and graciously accept it. Mama being Mother Nature, of course.
Solar
Everyone gets sunshine to one degree or
another. In forested areas being able to evaluate your daily hours of
sunshine for PV generation use is critical. A south facing open area
is needed. I know that sometimes that is where your garden is. You can put
PVs on a pole in your garden. Plant some shade loving plants, like lettuce,
to the north of it. If your sun days are long it can be better to use a
tracking PV array that turns with the sun.
There is a tool called a Solar Pathfinder that can chart how many hours of sunlight any exact spot will have on any day of the year. It is invaluable when working on PV siting. A good solar contractor will use one. If you are DIY (do-it-yourself), see if your solar equipment supplier will let you borrow one.
Micro-Hydro
The Rivers communities are lucky in that many people have
micro-hydro generation potential. It is a very site-specific power source.
It is the RE source to be envied. It will fill your batteries twenty-four
hours and day, rain or shine. You have to take care of and maintain your
intake, pipeline and turbine. Barring flooding or leaf drop in the fall it
is pretty easy. But
who wouldn’t enjoy a walk up the creek to clean the intake
screen?
Bobo Schultze
The main thing here is that you have enough head (fall or vertical drop), a big enough pipe and the right turbine for your combination of the two. Where we live now, across the county, we have 32 feet of head and over 900 feet of pipe. The PVC pipe is mostly 6 inch with some 5 inch down by the turbine. We use a two nozzle ES&D runner with a Harris Hydro PM alternator. This generates 13 amps per hour into our 24VDC system. We can generate more, but we just don’t need it. Unfortunately our creek here is seasonal, but it is our main source of power in the winter.
Wind
Fortunately we live in a canyon where spring through
fall we have steady afternoon breezes. During these seasons we use both PV
and wind power. In order to use a wind turbine for power you must have a
steady wind of 7 MPH or more at least several hours a day. One way to tell
if you have enough wind is that all the trees or bushes are flagged. That
is, they are all growing leaning to the leeward side (away from the
prevailing wind).
Wind would only be an option in a very few places on the river. Another requirement of wind turbines is that the unit must be placed above any surrounding trees or buildings that would cause turbulence. A bare ridgeline would work, but you do not want the turbine too far from the battery bank and inverter. Wind is usually seasonal. Don’t be fooled by wind that comes up just before and during storms. It is not sustainable for power generation.
Next time: System Sizing
Kathleen Jarschke-Schultze is ordering seeds and anticipating her garden at her RE powered home in Northernmost California. kathleen@electronconnection.com