Island Power x2

During the winter of 2003, I built my first microhydro system on Orcas Island in Washington state’s San Juan islands. At the time, I was installing RE systems all around the Islands. I found a spot on my family’s land where I planned to build an off-grid, microhydro-powered homestead. The system was designed and the cash saved for the materials.

As luck would have it, one day I got a call from Home Power’s Ian Woofenden, who lives on nearby Guemes Island, inquiring about any microhydro projects that could serve as a hands-on workshop.

I jumped at the chance to have a 20-person crew for a day. Installation of the 4-inch-diameter HDPE pipe would be a big job and a good time to have a bunch of people to help. The workshop also provided a serious deadline, an extra impetus to get the rest of the system elements in place. Our goal was to be ready with everything so that the workshop participants could install the pipe, connect the turbine, wire the controller and batteries, and then open the valves to make power—all on the same day.

Microhydro History

In 1978, my family moved to Orcas Island from the suburbs of Seattle. As a kid, I spent many happy days playing in the creek that flows through my family’s land, from the spring 1,000 feet up the side of the mountain to where the water joins the ocean in East Sound. Like most kids, I learned about the power of flowing water by playing with it. We built pools and dams in the creek, digging new channels for the water to follow as it was pulled ever downward by gravity’s incredible power. In the early ‘80s, my dad and some of his friends started raising salmon in the ponds and creek channels of the lower sections of the creek (see “Long Live The Kings” sidebar).

Starting with the first homesteaders in 1875, everyone who has lived on this land has captured and utilized the bounty of water flowing down the mountain for drinking and irrigation. In earlier days, they also made electricity with the water, but the last hydro-electric system (before I started installing them) appears to have stopped working in the 1950s or early 60s, around the time when the local rural electric co-op installed submarine high-voltage cables to bring Columbia River-generated grid power to the islands.

As a teenager, I learned about the basics of hydro power and started reading Home Power magazine, scheming and planning for the day when I could build a system of my own. I learned about the power potential of head and flow, and the dangers of water hammer through trial-and-error experiments and the occasional, spectacularly wet, destructive blowout. I came to truly understand how voltage and amperage combine to create electrical power when it was explained how these two variables behave in the same way that head and flow combine to create hydro power.

System 1: DC Off-Grid

Planning the Penstock

For my home site on the family property, I chose a spot up the hill to be close to the spring—a 1-acre flat shelf about 900 feet up that projects out from the steeper slopes of the mountain above and below it. The spring sits about 80 vertical feet above the house, and about 700 feet to the northeast.

I found evidence of previous plans for hydro power: A small intake pond had been excavated in the creek at a spot with rough road access. A simple plywood dam and plastic-lined pond backed up the water to channel it through a rectangular weir for measuring creek flow. That was the easiest and most logical place to build the intake for my system. Because it sat about 50 vertical feet above the house site, I would also be able to use the hydro intake to supply pressurized domestic water to the house. A narrow, level bench at the bottom of a 100-foot drop, about 50 feet lower than the house site and 650 feet to the north, was the best place to site the turbine.