Rainfall keeps hydro plants running strong

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(Host) This endless rain has left a lot of people cranky lately. But not the folks who run hydroelectric dams.

The rushing water has their turbines spinning at full tilt – generating plenty of electricity.

VPR’s Ross Sneyd has more.

(Sneyd) All the rain that’s fallen in the mountains has got to go somewhere.

And an awful lot of it passes through here.

(Sound of rushing water)

(Sneyd) This is a hydroelectric dam in downtown Winooski, just a few miles upstream from where the Winooski River flows into Lake Champlain.

The brown, muddy water here crashes and swirls as it pours over rocks and the dam.

Keith Bray wandered down for a look with his dog, Haley.

(Bray) “I’ve never seen it this high. It’s really interesting. We drive past it all the time. Usually you can see the rocks out there. And now it’s completely overflowing.”

(Sneyd) Bray figured all that water must be spinning off a lot of electricity.

(Bray) “I was like, Wow, the electricity must be really raging right now because the water turning the turbines and everything.”

(Sneyd) It would stand to reason. The Winooski is flowing at 11,000 cubic feet per second. The flow is projected to peak at more than twice that — 27,000 cubic feet per second before it slows down.

(Sound of turbine1 full)

(Sneyd) But the big pipes leading to the three turbines can handle just a fraction of this water.

(Clark) “Right now, most of the water that’s coming down the river is excess for us.”

(Sneyd) Station Operator John Clark monitors the dam from inside the hydro plant.

River water splashes against the window above his desk while the turbines rumble around the corner.

Ironically, all this water makes the plant less efficient. Instead of producing 7.5 megawatts, it’s making just six.

(Clark) “What does change is the amount of net head that we produce with. As the water comes up, it also comes up in the tail race. We need our net head, therefore our efficiency is not as good. As well, the amount of debris in the river also cuts down on our efficiency because it plugs the intakes, the racks with debris.”

(Sneyd) In other words, there’s less force pushing water through the turbines. Instead, the force of the water is actually flowing over the dams and downstream.

And it’s part of the reason Clark had to cancel a planned vacation. The station usually is staffed eight hours a day. But there’ll be somebody at the dam 24 hours a day until the water goes down.

Among other things, somebody’s got to monitor the turbines. When driftwood and other debris gets sucked into them, they rock and rattle and shake the building.

(Sound of hydraulic rig, then fade under narration)

(Sneyd) So Clark spends more time in a hydraulic rig hauling debris out of the river.

He doesn’t mind, though. He’s fascinated by the power of nature, just like visitors are.

(Clark) “It should be fun to see it either tomorrow morning or late tonight.”

(Sneyd) For VPR News, I’m Ross Sneyd

(Host) Other hydro stations upstream from Winooski will be able to make peak electricity for weeks. That’s because they have reservoirs behind their dams and they’ll be able to release the water slowly as it’s needed to turn their turbines.

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