The $30,000 Hydro Development
George received a telephone call from Dave, a hydro industry consultant. “George, I gave your name to some monks. I hope you don’t mind. They’re looking for advice on a new hydro plant they contemplate building,” Dave said. A few weeks later, the monks visited George at his office and outlined their plans for the new facility.
However, they commented that George seemed a bit incredulous about the plan. George confirmed this. To prove they were serious, the monks produced photos of a 300-kW powerhouse they had recently completed to provide electricity for their residences. George was interested and asked the cost of this installation, expecting an answer of about US$1 million. So, George was surprised when they said, “Only $30,000.”
In fact, George was so interested that he arranged to visit the plant. The development was built on property owned by the monks. The monks provided the labor, and Dave had provided advice on turbine design. The monks’ experience included qualified welders, mechanics, and an engineer. Local businesses donated some materials in return for tax receipts, but the monks used several innovative approaches to reduce costs. Their main advantages were ample and free labor, along with plenty of time.
|Behind the plastic window in the draft tube, the monks who developed this hydro facility installed an orange string. When the unit is operating at its best efficiency point for a specific gate opening, the angle of the string matches a black line drawn on the plastic.|
The dam was a 6-meter-high concrete weir built downstream of an old timber crib dam. A local concrete factory donated the cement, and the monks sieved sand and gravel from deposits on the property. The monks built a concrete intake structure into the left bank of the weir. The monks designed the steel intake gate and fabricated it using steel donated by a local scrap yard.
The penstock arrangement was particularly unique. The monks assembled the penstock using discarded railway tank cars, after removing the frames and bogies (the wheeled undercarriage) and cutting off the dished ends. For the first car, the manhole was connected to an intake air vent pipe. In the last car, the manhole served to provide penstock access. For the remainder of the tank cars, the monks used the central portion of the dished end to close off the manholes.
The powerhouse was a concrete building nestled into the side of the river. The monks experienced some trouble during the excavation work, due to unstable side slopes, but the work was completed without further incident. The monks obtained steel beams for the roof and piping for handrails from a local scrap yard.
The monks were creative in obtaining equipment for the powerhouse. They spent considerable time searching for a suitable generator, eventually locating a 600-kW Peebles generator in good condition in a scrap yard. A turbine manufacturer donated an old Woodward governor suitable for a Kaplan unit, and the monks rehabilitated the governor. The monks manufactured the Kaplan turbine themselves, using profiles provided by Dave to cast the runner blades and wicket gates. They found a shaft in a scrap yard but designed and manufactured all the remaining components, including the spiral casing, operating ring, thrust bearing, and runner hub. The monks used drawings found in old references – Water Power Engineering by Daniel W. Mead (1908), Water Power Engineering by Harold K. Barrows (1927), and Hydro-electric Handbook by William P. Creager and Joel D. Justin (1927) – to manufacture this equipment. Quite a remarkable achievement!
Dave had instructed George to take note of the plastic string in the draft tube porthole. Apparently, Dave advised the monks that the governor cam – setting the runner blade angle relative the wicket gate opening – should be profiled to the best efficiency point. This was indicated when the water flowing off the runner was at an angle of 32 degrees. However, Dave had no idea how this could be measured inside the steel draft tube cone. The monks simply cut a square hole in the draft tube, just below the runner, and closed it with a thick, transparent sheet of plastic. They then attached an orange string to an upstream bolt that secured the cover and drew a black line on the plastic at the desired angle. The turbine operated at various gate openings and wicket gate settings. For each gate opening, the monks adjusted the runner blade until the string angle matched the desired angle – simple and very ingenious.
The monks obtained switchgear from an old powerplant that was being automated.
The only outlay – US$30,000 – was the cost of the computer and controls required to automate the plant!
Based on the success of this first hydro facility, the monks wanted to build a 3-MW powerplant, downstream from the existing plant. They intended to sell the output of the second plant to the local utility.
There are two lessons learned in this situation.
First, it is still possible to build small hydro developments at minimal cost, with sweat equity and innovative approaches. There are several more modern reference books, such as Micro-Hydropower Sourcebook by Allen R. Inversin (1986) and the Hydropower Engineering Handbook by John S. Gulliver and Roger E.A. Arndt (1991), which should prove useful.
Second, it is vital to obtain all permits before proceeding with design and construction. The planned second plant did not proceed because the monks neglected to obtain many of the necessary permits. These permits proved too difficult to obtain because none of the design drawings had been approved by a registered professional engineer. And, with no fee for services rendered, no engineer could be found who was willing to accept responsibility for the work.
– By James L. Gordon, B.Sc., hydropower consultant