The National Wind Technology Center is situated about 6 miles south of Boulder in Jefferson County, on 305 acres of land that was originally part of the Rocky Flats buffer zone but has now been cordoned off by the Act of Congress that made Rocky Flats a national wildlife refuge, which designated this, in perpetuity, to the Department of Energy, land that is for testing wind turbines.
We have 4 rows situated perpendicular to the primary wind direction, which comes out of Eldorado canyon from about October to May at about 292 degrees from due north; that's when we do our testing, mainly from October to May..
We have the smaller turbines up front, which is the upwind side, closer to the canyon. The downwind side has the larger machines, so that the smaller machines do not interfere as much with the larger machines.
We can do testing on about 20 or 25 sites at once. All the machines are able to be hooked up to the grid or not, depending on the design of the machine. That is, we can put the electricity back on the power grid or have them free standing to charge batteries, go through a heater, or anything that diminishes or gets rid of the power.
Industrial User Facility: Component Testing
This is the industrial user facility, which we've had for about ten years and began designing about twelve years ago. It's used primarily to do blade testing. That is, utility-class blade testing like you can see in the background. We're doing currently an edge-bending fatigue test. That's one of several kinds of tests we do in this facility. The two principal fatigue tests are edge bending and flap bending—flap bending being a direction that's about 90 degrees opposed to this. Those are the two principal loading directions that the blade sees during its lifetime, so we simulate that here by accelerating the blade in a resonant frequency in both the edge and flap directions to excite those frequencies that occur in the field over its lifetime—over twenty or thirty years—but we do it sufficiently quickly that the blades actually can be tested over a period of several months rather than many, many years.
The second kind of testing we do is a static bending test, where the blade is loaded with very heavy weights in one direction or the other-in flap bending or in edge, again—to its load—carrying capability to its design load and then, ultimately, to a load that will break the blade.
The third kind of testing we do here is modal testing. That's a frequency test in which the flap-bending or edge-bending frequencies where the blade naturally resonates are measured and understood so designers can learn how to better design the machines when installing them in the field.
Secondarily, the facility was designed to be able to take apart and put back together drivetrains and other components for wind turbines that are going to be field tested. So we've divided up the teardown facilities adjacent to the labs where the blades are tested so that competitors can actually work at the same location and not see what the other groups are working on at the same time. The building is keyed specially and able to be cordoned off so two maybe three competitors can be working at the same time.
Dynamometer Facility: Drivetrain Testing
Here we have a 2.5-MW dynamometer facility that's used to test integrated drivetrains for wind turbines. This facility was designed about eight years ago so that we can do testing on utility-class size machines for both prototypes as well as commercially available turbines. What's unique about this facility is the fact that it's able to test up to 2.5 MW but, generally speaking, a little lower-around 2 MW at the maximum so that we can overload the system that we're trying to test and decrease the amount of time that's necessary to do a test. It's unique in the world in that way because of the very, very low RPM levels as well as high torque levels that we're able to achieve. We're also able to move the platform up and down about 10 feet so that we can accommodate interaction with the test article without having to put the test article in any kind of an awkward configuration. We offer the wind industry the ability to test integrated drivetrains on both prototype machines as well as industry commercially available machines. To that end, we're able to test fully integrated drivetrains as well as individual components, gear boxes alone or control methods alone, or even just the lubrication properties that go into the gearbox. That's what makes this facility unique, along with the higher torque capabilities and the lower rpm that we can apply to a test article. So, we're able to work on anything from about 100 KW up to about 2 MW in size.
Building #251: Main/Administrative Office
Here in Building 251, we do engineering analysis and research and development. One of those groups is called the Engineering Design or Engineering Code Group. These people build engineering codes, or computer codes, to simulate structural dynamics in wind turbine design so that we can predict behavior and pass those designs along to the wind turbine community at large once they have matured.
In Building 251, we have a couple of capabilities. One is a 250-kW dynamometer that can test smaller machines—machines up to about 200 kW in size—so we can test inputs, loads, and outputs just like we can on the larger dynamometer but for much smaller machines. We also have an environmental test chamber that is able to test wind turbine blades or other components in non-ambient conditions, such as at -50°C, so that we can simulate conditions that go on in Antarctic installations and make sure those machines operate like they should.
Advanced Research Turbine Advanced Controls Testing
We're here with the ART and CART wind turbines behind me. The Advanced Research Turbine and the Controls Advanced Research Turbine are used for testing wind turbine control algorithms. The CART machine has been completely retrofitted and uses inflow devices in the meteorological tower in front of it to operate at variable speed and to actively control power with "pitchable" blades with new algorithms designed to minimize the loads on wind turbines and increase the amount of power output from a given rotor size. The wind turbine next to it that doesn't have a rotor right now but is going to have a three-bladed rotor, and we're going to do side-by-side controls experiments with two-bladed and three-bladed rotor designs-again with advanced controls.
Test Pad Wind Turbine Testing
We have 20 or 25 wind turbine test pads on site with the ability to install even more. The advantage they bring is that we can test machines in atmospheric conditions that simulate installations in the Great Plains or in mountainous regions at a location that is neutral-compared to testing at somebody's own facility. We bring to that table engineers that are able to help do these tests and bring insight into what's going on with the power curve of the machine, or noise, or other attributes the machine may have, and do it in a neutral fashion for industry members and others who want machines tested here.
