Happy on One Kilowatt

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What a disappointment we faced when we put the numbers together. While we undoubtedly could generate several kilowatts using the steepest run of our large creek, it would require at least 1,000 feet of 8" piping, plus custom-made generating machinery for high water flows. Such a system was well beyond our financial means.

But as time passed, we noticed that our monthly power bill rarely exceeded 750 kilowatt-hours That meant we needed an average generating capacity of only 1 kilowatt (24 hours a day X 30 days = 720 hours). even with an electric range, refrigerator, freezer. water pump, water heater and clothes dryer. We'd also overlooked a low-flow creek coning off our mountain that crops 360 feet after it crosses onto our property. We determined that it would easily generate more than a kilowatt. Hydropower was beginning to look more promising.

The trick was to figure out how- to handle the peak loads of our current-greedy appliances. We settled on a plan to install a small 1 l/ 2 kW DC Harris Hydroelectric system, with batteries and inverter, capable of producing 120 volts of AC, while leaving some of our 240V appliances - a range, a clothes dryer and the main water pump - hooked up to the grid. As backup in case the grid goes down, we've got a smaller 28V DC water pump, a hot plate and a toaster oven, all of which can be run off the hydro system. The clothes dryer is a luxury we can do without in a pinch.
For extra support, 1 1/2" galvanized steel pipe spans the main creek. Bill and a friend visit the source.

Going Hydro

The first step was to lay pipe down the mountain to check our calculations of pressure and flow - an arduous task, since the 360-foot drop brought us down some fairly steep and rocky terrain.

We knew we'd lose some pressure to friction, a result of the water running against the insides of the pipes (in general, the smaller the pipes, the greater the flow and the bigger the loss). We figured we could keep pressure loss to a minimum if we used 2" PVC pipe, but toward the top we switched to lighter, 1 1/2" PVC pipe to save on hauling labor. We also opted to use steel pipe for added strength where the system crosses the widest span of the main creek.

Rather than trying to blast through the rocky outcrops to bury the PVC pipes, we chose to lay them on the ground and depend on continuous water flow to prevent freezing. We planned to monitor the water temperature and, when things got too cold, to shut down the pipes until warmer weather returned. In our mild climate, we can usually count on hydropower for all but maybe a few weeks out of the year.

Next, we weighed various water pickup systems; whatever we chose would need to be capable of filtering out debris, eliminating air bubbles and removing sediment. This is probably the most critical component of the setup and certainly the one with the potential to cause the most trouble. Just to check on it requires a difficult climb.

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