On Tuesday the fifth-graders at the Manhattan Country School Farm took a field trip to visit two sites where water generates power. The first was Hanford Mills, a working historical sawmill and grist mill. The second was the New York Power Authority’s Bleheim-Gilboa Pumped Storage Power Project. One is old, relatively small and local; the other is huge and modern, and sends its energy all over New York State and beyond. Both use the same basic principle of capturing the force of falling water to turn wheels to generate power. This all ties in with the kids’ past study of simple machines, future study of electricity and ongoing study of sustainability.
At Hanford Mills, the kids learned that water comes from a small pond, and turns a waterwheel in the mill. The drop is about 12 feet. At Blenheim-Gilboa, the water comes from a five-billion gallon reservoir on a mountaintop and drops through a vertical shaft 1,000 feet to turn four enormous turbines in a power plant at the base of the mountain.
The power at Hanford Mills is used only locally and serves a small farming community. It is distributed throughout the millhouse by wide leather belts to pulleys that turn many different machines: saws, planers and lathes. The power generated at Blenheim-Gilboa is sent hundreds of miles away on high-voltage power lines to help meet peak power needs in New York City and around the state. As John often explains, “When the kids ride the subway in the evening, it’s running on electricity made here just north of the MCS Farm.”
At Blenheim-Gilboa, the students discovered once the water runs down from the upper reservoir to help make electricity in the afternoon and evenings (when it is needed most), the whole system is operated in reverse overnight. The generators become gigantic electric motors, drawing power from the state grid when there is excess power available to pump billions of gallons back uphill to be ready for the next peak-demand cascade of water down the shaft and into the turbines the next day.
Both places illustrated inventive and ingenious ways of capturing the force of falling water to do work for us.
The pond at Hanford Mills.
The waterwheel in the basement of the mill building. To request an opening of the gates from the pond to start the wheel rolling, we were asked to give the traditional call, “WHEEL!,” at great volume.
Some of the pulleys and belts powered by the waterwheel.
The big sawmill blade.
Sawing a plank from a log, using only water power.
We all got to crank an old corn-shelling machine, separating the dried kernels from the cob.
We also saw the tools for cutting ice from the pond in winter. Big blocks of ice are kept in an icehouse, insulated by sawdust from the mill, long into summer. Sawdust from the mill was also sold to nearby farmers for stall bedding for the animals, something all MCS Farm kids know quite well.
We used cant hooks (levers) to roll logs toward the mill. There was a ramp nearby that led up to the level of the saw.
After lunch at Hanford Mills and a short bus ride (including some very beautiful singing in unison, and even harmony), we arrived at the Blenheim-Gilboa power plant. The mountain, the power plant and a bit of the lower reservoir can be seen here in the background.
We watched a short film about the workings of the power plant, and then toured the visitors’ center, which is full of interactive displays about power generation.
There was great interest in—and sweat created by—the exercise bike hooked up to a generator.
And the key to it all: how a wire passing through a magnetic field creates electrical current.
How the system works:
One of the giant turbines (removed and replaced during a power plant upgrade a few years ago).