CAPTURING WIND ENERGY

ON THE SATURDAY MORNING after Thanksgiving, the sun is shining brightly, but a cool late November breeze is blowing from the northeast. I’m in the kitchen, reading the newspaper and watching for our guests to arrive. Julie, Tom, and their friends on the solar and water power teams are out of school for the holiday, and I’ve invited them to the Cape this weekend. The six children will stay overnight and head back to Boston tomorrow.

Aside from a short holiday, they’re coming to have a look at my wind turbine. Back when we were divvying up assignments, I promised Tom and Julie that I would find out about how to make electricity with the wind. This was a no-brainer for me, because I already have a wind machine, perched on top of a 100-foot steel tower in the woods behind my house. It uses a turbine, very much like the ones we saw at the Connecticut River dam earlier this month—only way smaller.

Actually, I have two wind machines. The other one is a sailboat, which I love to cruise around in every summer. You might not think of a sailboat as a wind machine, but that’s what it is. I love sailing: being pushed along by the wind is so quiet and peaceful, and you’re using completely clean energy. My sailboat has a little outboard motor, but I almost never need to use it. Usually there’s enough wind to carry me where I want to go.

Climate Change for Kids
Gramps’s Wind Turbine

When I next glance out the window, two cars filled with people are creeping along the driveway between me and the water. My son, Monny, is behind the wheel of the first car. Standing behind him on the back seat are Julie, Amaya, and Natasha, their heads and shoulders poking up through the sunroof. Julie spots me coming out on the deck and shouts, “Hi, Gramps!”

My daughter-in-law, Marnie, is driving the second car; with her are Tom, Paul, and José. The cars have hardly come to a stop when the doors fly open and the kids tumble out onto the lawn, all bundled up in their winter jackets. Yelling and calling, they sprint down the path toward the beach, leaving Monny and Marnie to join me for a late cup of coffee.

Being pushed along by the wind in a sailboat is so quiet and peaceful.

We take a few minutes to catch up on family news. They remind me that Julie and her water power team are still working on their class presentation, which is scheduled for mid-December. Then we wander down to the beach to see what the young folks are doing. Just beyond the path, all three boys are clustered by the water’s edge, skipping stones across the surface and hunting around for more of the right kind of flat rocks. The girls are down the beach a little ways. Even though the water is pretty cold by now, Julie has taken off her sneakers and is wading in the shallows. She reaches down, picks up a horseshoe crab by the tail, and runs back up the beach, laughing and waving it at her girlfriends. Natasha and Amaya run toward us, squealing, “Help! Yuck!! Help!”

After “saving” them, I call all the children over and ask whether they can see any wind machines nearby. Some look at me blankly, but Paul quickly points toward the water, where my sailboat is riding quietly at its mooring. I try to delay taking it out for the winter for as long as possible.

Climate Change for Kids
Gramps’s Sailboat
Sailboats are wind machines, too.

 
“Good call, Paul,” I say. “In the summer, this bay is filled with sailboats, and they’re all powered by the wind. The sailboat was the very first wind machine designed and used by humans, four thousand years ago.”

José has a real light in his eye as he looks out at the boat. “Cool,” he murmurs, then turns back to me. “Could we take a ride in your sailboat sometime?”

“Sure, I love taking friends out sailing. Another cool thing is that when people built the first windmills, they used sails from sailboats to make them spin. I can show you a picture of one. But first, let’s take a tour of my modern wind machine.”

I lead the way back up the beach path. From this direction, we can see the blades of the wind machine turning above the pine trees. “Race you to the bottom of the tower!” Tom shouts suddenly, and the boys sprint ahead. Absorbed in their conversation, the girls hardly notice.

Soon we’ve arrived at the base of the tower. Above us, the blades of the machine are turning steadily in the northeast wind. “Do you hear anything?” I ask.

Turbine with blades turning

 
“No!” Several answer in unison. “It’s completely quiet,” Natasha continues. “I thought we’d at least hear a whooshing sound as the blades go around.”

“Nope,” I say. “The only noise we sometimes hear is the ladder rattling when the wind is blowing really hard.”

“Not if you wear a safety harness. You clip it into the track that runs up the center of the ladder,” I explain. “That way, if you slip while you’re climbing, the clip grabs the track and the harness keeps you from falling.”

José looks as if he’d like to try. “Have you been to the top?” he asks.

“No, I haven’t. Once I went up partway to look around. But we have a wind machine expert who climbs up there several times each year to service the generator.”

Tom is lying on his back on the ground, watching the blades turning against the blue sky. “I noticed that when the wind blows harder, the blades speed up,” he says. “But when they get to a certain speed, they slow down again, even if the wind keeps blowing hard.”

I crouch beside him and look up. “Good observation. That’s because the generator inside the machine will burn up if it spins too fast. So when the computer here at the bottom of the tower senses that the rotor inside the generator is going too fast, it puts on a brake to slow the blades down.” I point out the control box.

Climate Change for Kids
Wind Machine Ladder
This ladder climbs 100 feet up the tower to the wind turbine on top.

“What happens if the wind blows really hard, like a hurricane?”

“If it blows more than about fifty miles an hour, the computer turns the machine off, and the blades don’t turn at all.”

The girls are standing in a tight clump gazing up at the machine, their arms around each other’s shoulders. “Gramps,” Julie asks, “does the generator inside that machine work the same way as the ones we saw inside the dam in Turners Falls?”

“Exactly the same—except the blades on the generators in the dam were turned by water rushing down a tunnel, and here the blades are turned by the wind.”

“Right, we knew that part,” Julie persists. “But how about the generator? Does it work the same way, with a magnet spinning past the copper wire to make electricity?”

Now the boys are listening to the girls with new interest. They haven’t learned yet about how generators make electricity.

“Yes, it does,” I reply to Julie. “Do you remember what you learned about how the electricity is actually made?”

A wind generator works the same way a water-powered generator does.

The girls look at one another. “Sure we do,” says Natasha finally. “Electricity is a stream of moving electrons. The magnet knocks those electrons loose from coils of copper wire in the generator.”

Julie explains further. “See, when the force of the magnet spins past the copper, it pulls some of those electrons loose from each copper atom,” she says. “Then they get carried along a big wire out to our houses, where they light our lights and run our fridges and things.”

The boys are clearly impressed. From their solar power project, they understand that atoms contain electrons, but the part about the magnet is new to them.

“So the magnet in the generator is kind of like the sun in the solar cell,” says Paul, slowly nodding his head. “The magnetic energy knocks the electrons loose, just like the sun’s energy does inside the solar cell?”

“Right,” Tom adds, “but in our solar cell, the atom is silicon from sand, and in the generator the atom is copper.”

“You’ve all got the right idea.” I’m pleased that they remember so much from their school projects. “To make clean electricity we need some kind of natural energy to pull off electrons from the atoms they belong to, and send them streaming out along wires. In the solar cell, the sun supplies the energy. In the generator, that energy is the force produced by the magnet. Back at the house, we can look at some pictures that help show how a generator works.”

I move to a little opening in the tower, trailed by the kids. “See that big wire?” I point inside the opening. “That’s what carries the electricity down from the generator. Then it passes through the control box, where a computer measures how much electric power is being produced.”

Wind Turbine Controls: These computers read wind speed and direction, and slow down the blades if they start turning too fast.
Wind Turbine Controls: The big switch (left) turns the machine on or off, and the glass-covered meter records the total amount of electricity the turbine generates.

They all take turns peering inside, and José, with his head inside the opening, hoots, “Woo, woo!” A loud echo in the metal chamber makes the others jump back a little. José laughs but bangs his head as he backs out, drawing a chuckle from Tom and smirks from the girls.

Next I show them a post with a gray metal box on it, about fifty feet from the tower. On the side of the box is a glass-covered meter. “A guy from the electric company comes out every month and checks this, to see how much electric power we’ve used in our house,” I tell them. “If you look carefully, you can see that right now the meter is running backward. That means the wind machine is making more electricity than we’re using in the house at the moment. That’s exactly what we want.”

Paul and Tom get up close to the meter and watch it turn. “So what happens if there’s no wind?” Paul wants to know. “Does that mean you don’t have electricity?”

Connecting the Turbine to the Electric Power Grid

This is where the wind machine connects to the shared power grid.

Connecting the Turbine to the Electric Power Grid

When the wind machine is making more electricity than the house uses, this meter at the grid runs backwards, and we earn credits on our bill from the power company.

I shake my head. “Our house is also connected to the regular electric power lines, so we get electricity that way when our wind machine isn’t producing for us.”

Amaya chimes in. “All those power lines are called the electricity grid,” she announces, remembering what Ralph Jones had told us at Turners Falls. “All the power plants that make electricity send it out into that grid.”

Tom has another thought. “Couldn’t you have some big batteries down in the basement of your house that get charged up while the wind is blowing? Then when there’s no wind, you could run your lights and things off the stored power in those batteries.”

“We could certainly do that. Those batteries are pretty expensive, so we haven’t bought any yet. But someday we might.”

“Gramps …” Julie asks, “you know that dam on the Connecticut River and the pumped storage system in Northfield Mountain? The way they store water to make electricity at times when people need it? Isn’t that kind of like batteries?”

Tom, José, and Paul are looking at her blankly. Of course, they didn’t make the trip to western Massachusetts with us. “Maybe you girls could explain what you mean,” I suggest.

Natasha begins with pumped storage. “The way it works is, water gets pumped from the Connecticut River way up to a reservoir on Northfield Mountain, during the night, when people don’t need much electricity. Then in the daytime they can run the water down the mountain through turbines to make power. So the reservoir works like a battery, holding energy until people need it.”

“Yeah,” adds Amaya. “You can think of the water in the reservoir kind of like the batteries in a flashlight. When you need light outside in the dark, you switch on the flashlight. When families need energy to run things in the daytime, people at the Northfield Power Station open the gates, and the water spins the generators, making electricity and sending it out to everyone.”

“The other thing is, they have a huge array of solar panels out at Turners Falls,” Julie points out. “So they could even use solar energy to pump the water up the mountain and into the reservoir.”

Paul looks like a light bulb has popped on in his head. “I get it!” He smacks his hands together. “Different kinds of clean energy can work together and help each other out!”

Now the girls look a little uncertain, but I can see that Tom gets the picture. Paul explains: “During the day, we can make solar power while the sun shines. At night, we can make electricity by running dammed-up river water through generators. Day or night, we can generate electricity with wind machines, as long as the wind is blowing. So, when we can’t use one way to make electricity, we can always use another kind of clean power instead!”

“That is so cool!” Tom exclaims. “It’s a kind of teamwork, with the sun, wind, and water working together to protect the Earth and give us the energy we need.” He shows his respect with a knuckle bump, and Paul smiles shyly.

“The Clean Team: sun, wind, and water. I like that.” Julie smiles. “And we could add in the moon, because it makes the tides, and tides can be used to generate electricity too.”

“Sun, moon, wind, water … that does make a great team.” I start moving toward the house. “Let’s go grab a little lunch, and then I’ll show you some pictures of wind machines.”
 
AFTER LUNCH WE ALL ASSEMBLE in front of the TV, which is linked to my laptop. The first image I pull up from the Net shows what some of the earliest windmills looked like.

“When we were down on the beach, remember I mentioned that the sailboat was the first kind of wind machine? You can see this windmill has sails, just like a sailboat. It was used for grinding grain into flour to make bread.”

Climate Change for Kids
An Early Windmill
Notice that this windmill uses sails, like a sailboat.

 
“What happens if the wind changes direction?” José wants to know.

“The guys operating it could actually turn the sails into the wind when the wind shifted,” I explain, clicking ahead to the next picture.

“Here’s a windmill that was used on American farms and ranches to pump water up out of the ground. Many years ago, we had a water-pumping windmill like this right here on our land.

Windmills through History

This kind of windmill was used in the western U.S. to pump water.

Windmills through History

Fifteen hundred years of windmill evolution.

“This kind of windmill has a tail vane on it, see? The vane keeps the blades facing into the wind, so you don’t have to turn the rotor by hand every time the wind changes direction.”

I move on to a new series of pictures. “I thought you’d like to see how we built the tower for my wind machine. In this first picture, see, we had to start underground, installing a big concrete anchor to keep the tower from falling over. We built a big box, filled it with iron rods to make it really strong, then filled the box with concrete.”

Building the Wind Machine Foundation

The foundation frame, filled with iron rods, is located eight feet below ground level.

Building the Wind Machine Foundation

Pouring concrete into the frame.

Building the Wind Machine Foundation

Iron rods frame the tower connector.

Building the Wind Machine Foundation

Smoothing the foundation base.

Building the Wind Machine Foundation

Positioning the ring that connects the tower to the foundation.

Building the Wind Machine Foundation

The completed foundation with connector ring.

The children lean forward to look closely. “You mean all that stuff is under the ground?” José asks.

“That’s right.”

Amaya is wide-eyed. “But how did they get that big heavy tower on top?” she asks, turning to Julie.

Julie bounces off the couch and throws out her arms. “That’s the best part! They brought in this amazing crane to lift it up! Do you have pictures of that, Gramps?”

“I do! The tower actually came in two pieces. Here we see one piece arriving at the site.”

I point to a picture of the big crane swinging in to lift the first tower section. “And these next ones show how the crane hoists it up onto the anchor. See, the bottom half of the tower gets fastened to the foundation with big bolts. Then the top piece goes on the bottom one.”

The kids are nodding in comprehension. “Wow, that crane is really awesome,” José whispers loudly. “Did you use it to get the wind turbine on top of the tower?”

Putting Up the Tower

Here comes the first of the two tower sections!

Putting Up the Tower

We needed this big crane to raise the tower and turbine.

Putting Up the Tower

Up goes section one of the tower.

Putting Up the Tower

Workers carefully lower the bottom section of the tower onto the connector ring.

Putting Up the Tower

Fastening the connector ring bolts.

Putting Up the Tower

Securely harnessed to the tower, a technician guides the upper tower section into place.

“That’s exactly what we did.” I show them how the blades were attached to the turbine and the whole assembly hoisted up to the top of the tower.

“The guy up there is fastening the turbine to the tower. The crane lifted him up, and here he’s getting a nice ride back down.”

Mounting the Turbine on the Tower

The turbine without its propeller blades, and with its shell open partway.

Mounting the Turbine on the Tower

Fastening the huge blades to the turbine.

Mounting the Turbine on the Tower

The crane lifts the turbine up to the top of the tower.

Mounting the Turbine on the Tower

Bolting the turbine to the top of the tower is the final step.

Mounting the Turbine on the Tower

The wind machine technician rides the crane cable back to the ground.

Mounting the Turbine on the Tower

Our clean energy guy wearing his safety harness. A bag of tools is attached to his belt.

Mounting the Turbine on the Tower

The completed turbine ready to go!

“Cool!” Julie breathes. “That would be so fun. There must be an amazing view from a hundred feet up in the air!”

José hops up and walks to the window, where he can see the turbine blades turning above the trees. “I’d totally like to climb the tower and look around,” he says softly, looking at me. “Would that be possible, do you think?”

Tom is grinning and rolling his eyes. “Not a good idea,” I answer. “But here, take a look at how the turbine works.” I bring that image up on the screen.

“This shows the different parts of a wind turbine.” I move the cursor so it points to the front of the machine. “This turbine has three blades, like mine. The blades can be adjusted so they catch more or less wind.

Climate Change for Kids
Diagram of a Turbine

 
“Working our way back, here’s the low-speed shaft that’s turned by the blades. On this large turbine, the blades go around thirty to fifty times a minute. On my smaller turbine, the blades spin fifty to one hundred times each minute—depending on how hard the wind is blowing.”

Julie and her water-power partners are thinking about the big generator they saw in the river dam. “Is that shaft like the one that turns the magnet to make electricity?” asks Natasha.

“No—the magnet in a generator needs to spin even faster to knock those electrons loose from the copper atoms.” I move my cursor to a new spot on the turbine diagram. “See, below the low-speed shaft is a high-speed shaft. Gears connect the two shafts. The big gear on top is turning quite slowly, but the gear on the high-speed shaft is smaller, so it has to turn much faster to keep up with the big gear.”

“Okay,” says Julie, moving to the TV screen. “I see the high-speed shaft. And there’s the gear at one end. So, is the magnet at the other end, inside the generator?” She points to a blue cylinder labeled generator.

“It is,” I respond, “and the copper wire is inside that blue casing around the spinning magnet. That’s where the electricity is actually generated—which is why that part of the turbine is called the generator.”

“What’s that thing at the back end of the turbine?” asks Amaya. “It looks like a pinwheel.”

I move the cursor to the place she indicates. “It is a kind of pinwheel, but it’s called an anemometer. It tells the computer controlling the turbine how fast the wind is blowing. The computer won’t let the blades turn unless there is enough wind, but it stops them if the wind blows too hard. My turbine also has a little wind vane on it that tells the computer exactly what direction the wind is coming from.”

I explain how, in the original windmills, people had to turn the sails every time the wind changed direction. Now the computer adjusts the machine automatically. But I can see that my audience is starting to look a little restless, so we call it a day.
 
“HAVE YOU ALL ORGANIZED YOUR BEDS?” I ask. The girls are sleeping in the loft above my study, and the boys will bunk in a little guest cottage. We’ve had our dinner, and there’s still some light in the late fall sky. The boys have brought along a nerf football and want to head outside to play touch in the clearing around the wind machine.

“Everything’s all set!” comes Tom’s response. They throw on their jackets and dash out the back door. The girls climb up the ladder to organize their beds, chattering away.

I go back to the computer to look for information on wind farms and the size of modern wind turbines.
After a while, I hear the girls climbing down the ladder and realize that more than a half-hour has passed since the boys went outside to play football.

“We’re going out to find those guys,” Julie announces as she hits the floor. I tell her I’ll come along in couple of minutes.

Five minutes later, I log off, pull on my jacket, and head out the back door. As I step off the deck, Julie comes toward me at a run.

“Gramps, we’ve got a problem!” she gasps.

“What’s the problem?” I ask, zipping up my jacket.

“José and Tom are up on the tower!”

She spins and runs back toward the clearing, and I jog along after her. When we arrive, I see José up about thirty feet up, with Tom three or four rungs below him. José has stopped climbing and is looking down at Tom as they talk about something. The other two girls are standing at the base of the tower, gazing anxiously at them.

“Hey!” I holler. Six heads swivel in my direction. “I said earlier that I didn’t want you climbing the tower.”

Tom is already backing down the rungs. “Okay, we’re coming,” he says. Above him, José also starts climbing downward.

“Watch your step!” I say, afraid that they might slip. “There’s no hurry.”

Tom looks pretty nervous as he shifts carefully from the bottom rung to the stepladder, then hops to the ground.

José won’t look me in the eye. “How did it feel up there?” I ask him.

“Scary.” Now he meets my gaze guiltily. “Tom and I had decided to come back down even before you got here.”

“Good move. Like I told you, we need to wear a special harness to climb the tower safely. I want you guys to stay on the ground and stick to football.”

The boys grab their ball and move away from the tower, relieved that I’m not really angry with them. How can I be, knowing that at their age I would have been up that tower at the first chance?

As the girls wander over to join the game, I grab the stepladder and carry it over to the locked toolshed. That’s what I should have done earlier.

Continue to Chapter 6: Clean Energy for Whole Communities