Microhydroelectric power is making a comeback in electricity generation for homes, farms, and small businesses. This trend is fueled by factors including favorable regulation, rising energy prices, and advances in automation. And do-it-yourselfers worldwide are diving in.
The only requirement to generate electricity is access to a stream with a two-foot drop in water level and two gallons of flow per minute. A hydroelectric system isn’t overly complicated, isn’t difficult to operate and maintain, has longevity, and is often more cost-effective than any other form of renewable power.
Although we’d never built such a system before, we did so by using low-cost components and free technical support, both supplied by AutomationDirect.
In 1980, my father, Arno Froese, began investigating the potential for generating hydroelectricity on his property. The land is situated near the dam of a 64-acre communal lake, allowing access to the 10-foot height differential between the lake and the tailwater on the other side of the dam.
My dad measured the water flowing over the spillway and determined that an average of 40 cubic feet per second flowed through the pond, making it a marginally feasible hydroelectric project. In 2004, my brother Simon discovered our dad’s research and decided to move forward.
This microhydroelectric power plant generates 20kW of power, controlled by equipment from AutomationDirect.
In March 2004, Simon began excavation. For two years, the project was a challenging and sometimes disappointing excavation site, requiring us to dig 17 feet below lake level for the foundation while groundwater and mud continuously seeped into the hole. By the end of 2006, the underwater portions of the plant had been built, a four-foot aluminum pipe through the back of the dam was in place, and a temporary cofferdam was removed. We then installed a refurbished 50hp Francis turbine. Testing determined that the turbine’s optimal speed would be 150rpm.
The hydroelectric system is powered by water draining from the lake that flows through a turbine, which drives three generators via a belt and pulley system. The generators are three Baldor Electric model L1177T 15hp single-phase induction motors.
Driving an induction motor at higher than normal speed generates electricity. Output from the three motors was tied into the local electric grid via the same transformer that formerly only provided power to the property. The utility’s meter now turns backward when our plant supplies more power than we consume.
This interesting case study spotlights the old rule that most great engineering efforts are 80% perspiration (actually, I think it's 90%) and 20% technical smarts. This project simply wouldn't have happened without all that digging, building, and dirt moving.
Great idea. Getting tied into the grid seems to be an important factor here. Saves the whole problem of storage. The perspiration will probably pay for itself in time, since the foundation is the least likely part of this power plant to fail over time.
I agree, Rob, this sure eliminates the storage problem. And it's heartening to read that the minimum for generating hydroelectric power is only a two-foot drop and two gallons per minute. That's a lot less than I would have guessed.
I've often wondered if we could generate power from the creek in back of our house. At least part of the year, it fulfills those minimum requirements.
If renewables are going to make a significant impact, a certain percentage of the power and a certain percentage of the storage will have to happen on the micro level. This is a great effort and it's a perfect example of what can happen at that micro level.
@letsthink: I agree with you that the numbers don't add up. If 40 cubic feet per second of water (18,000 gallons per minute) falling 10 feet generates 20 kW, then 2 gallons per minute falling 2 feet should generate about 1/90,000 as much power, or 0.2 W. Maybe you could make a LED light up with this.
What wasn't clear to me is if they generated single phase or three phase power. Why the three motors? 15hp is about equal to 20kW, so any one motor could have been a generator. Can anyone fill in the blanks here?
Also, I'm curious what prompted the report--it does read suspiciously like an Automation Direct ad....
I agree that there needs to be support and commitment at the micro level. The challenging economic climate of the last few years has definitely fanned the flames of the local movement and a do-it-yourself mentality. Perhaps that will translate into more people attempting projects as ambitious as this one.