Sunday, March 18, 2012

Wind turbines going up in Spring Valley

They are making fast progress on the Spring Valley wind farm in eastern Nevada. We were amazed to see so many towers up. The plan is to put up sixty-six 2.3 MW Siemens turbines over 7,673 acres of public land.  This will be Nevada's first wind farm.

For the record, I think that wind energy is great. It's renewable and it's fairly clean. However, this wind farm is poorly sited, with a cave that is an important migratory stopover for over a million bats each year only a few miles away. I talk more about the cave in this post, so I won't dwell on that here.

The cranes are enormous, although they don't look that big in this photo. I looked up the specs for Siemens 2.3 MW turbines. I'm not sure what model they're using, but here's more info on the 113. The 113 model means that the diameter of the rotor is 113 m (about 350 ft--longer than a football field!) Each of the three blades is 55 m (~160 ft) long. The swept area is 10,000 meters squared. The rotation speed is 6-13 rotations per minute (that seems fast to me for such a huge rotor!).

This type of windmill gets very little power when the wind is less than 5 meters/second (11 miles per hour), and in fact the cut-in wind speed (minimum wind speed at which a wind turbine will generate usable power) is 3 meters/second (7 miles per hour). Nominal power is at 12-13 meters/second (27-29 mph). The hub height for each tower is 99.5 m (over 300 feet) or site specific.

So those cranes have to lift a nacelle (cover housing that houses the generator and all the other parts for turning the blades) on top of a tower that is taller than a football field. The nacelle weighs 73,000 kg (160,000 pounds). The generator that must also be lifted to the top of the tower weighs 66,700 kg (147,000 pounds). Three blades must also be lifted that high. That means those are some powerful cranes!

We've been seeing trucks carrying the blades go past on Highway 6 & 50. They usually travel three blades at a time, sometimes with some other assorted parts (like the nacelle or generator or tower parts). In Utah, each truck has a vehicle behind it and in front of it announcing an oversized load. They also have a police escort in front of and behind each of the semis. So for three blades, there are six Utah highway patrol vehicles!

On the Nevada side, I haven't seen the Nevada highway patrol escorting the oversized vehicles.

To get a little perspective of how long these vehicles are, check out the above photo. How many of those pickups could you place alongside the semi and trailer?

I couldn't manage to safely get a photo of the blades traveling down the highway, but when I saw them parked I just had to pull over and take a closer look.

Here's the view from the back. You can see that the blades are not straight, they curve.

Here's me next to one for scale.

These are where the blades attach onto the nacelle.

Yesterday it was too windy to put up the wind turbines (isn't that slightly ironic?). So there were six blades and a couple other parts parked at the Border Inn. If you figure a semi driver and two pilot car drivers per truck, that means 24 people got stranded at the Border Inn for the St. Patrick's Day party. It certainly turned out to be a big party!


John Mosley said...

Very interesting. I'd like to share with you some fossil fuel comments from a geologist's perspective - by email - if you are interested. I don't wish bore your dear readers. I'd be very interested an ecologist's opinions. I'll bet we share a lot of common ground. I'll be back in my office tomorrow. Spring break is over and it's back to work for me.

Desert Survivor said...

Hi John, sure, shoot me an email!

Anonymous said...

Gotta get that wind farm into service quickly in order to qualify for federal tax credits. I'm betting that the project is uneconomical without the tax credits.

jendoop said...

There are several wind farms here in Iowa. At first we thought they were neat, but as my husband and I talk about the long term viability we wonder if they will turn into a new kind of ghost town in a few decades. And I wonder the same thing about the tax credits.

Sandy said...

I'm interested if this will be successful or not..please keep us posted. =)

Ameilia Quimby said...

Great posting. A view of a little seen side green energy.

I am familiar with the Spring Valley issues - the bat cave and that the tribes believe the area to be special (if not sacred) because it is a massacre site.

Please keep us posted on how things work out, and the effects on the bat migration.

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