Today we discovered Al Zeitz, director of Iowa Lakes Community College Wind Energy Program, whom we have interviewed here, scrambling around inside a Gamesa 3.0 megawatt nacelle trying to hook up the internal heaters so they can prep the machine for mounting.
Our title is a bit misleading, as this one has already been dropped, but this is a story (with photoessay) worth sharing.
Iowa Lakes Community College, the undisputed world leader in wind energy operations and maintenance training, is the only training program in the world that also operates a utility scale turbine. This Vestas V82 was purchased by the college prior to the program's inception, but its presence coupled with Zeitz's energy and focused has produced something special here on the Iowa/Minnesota border.
Wind turbine operations and maintenance training is a bit like medical school - the "doctors" learn best when they've got patients ... both living and dead.
This particular Gamesa (guh MAY suh) (on the right) three megawatt nacelle suffered an interesting demise. The unit was dropped, all eighty three tons of it, from a height of about 10', while being unloaded for a project in Illinois. The crane operator had been removing turbines from delivery trucks and placing them on timber supports pending installation. This was in the spring, the ground was soft, he was in a hurry, and had removed several nacelles without incident earlier that day. The delivery driver made a strong suggestion he use the crane's stabilizers, he refused, and minutes later he, his 350 ton crane, and the nacelle all took a tumble.
The guy knew he was done and simply climbed out of the wreckage and walked away, dodging drug and alcohol testing. The industry is busy enough that he'll actually be able to get another job despite trashing a two million dollar nacelle and doing a similar disservice to a very expensive boom crane.
Oh, and the one on the left? A prototype Vestas V82 nacelle, stripped of everything but its hydraulics. This one was donated directly by Vestas, while the Gamesa unit was a donation from the insurance company who owned it after its fall from grace. The school thrives on cadavers from the industry - like these damaged blades which they use for teaching composite repair. These particular ones are from Zond 750kW turbines in the Storm Lake II project.
The donation did not include getting the machine off the trailer which cost $17,000 in crane services. The college is working their industry contacts in order to get a mounting built and get the nacelle installed for easy access, as the Vestas unit is now. Until then we're stuck climbing a ladder and scrambling over a very high sill to access the interior.
Working on a wind turbine is quite a bit like working on aircraft. The composite blades are actually airfoils, there are hydraulic controls, electrical systems, and control systems that have to respond to atmospheric conditions.
Here we see the mainshaft (gray) which connects to the planetary gearbox (blue), while behind that on the left (blue) is the three megawatt generator and on the right (gray) the cabinets containing the control and power conditioning equipment. The dark space at the very back contains three transformers which convert the 690 volt generator output to 34.5 kilovolt power suitable for direct attachment to a power grid. The horizontal silver beam (top) is a sliding crane for use inside the nacelle which can hold up to 800kg.
The following two shots give some sense of the scale of the equipment as compared to those working on it.
The gearbox connectors to the generator via a coupler. The gearbox is needed because the turbine blades rotate at about 1/20th the speed a generator needs to produce electricity. Gearboxes break and in this case the coupler between the gearbox and the generator has been removed to repair something else.
Wind turbines are irregular; its just the nature of the beast - the wind blows when its in the mood. The generator produces 690 volt output of varying frequency, this is sent to power conditioners, and then the up to 4,300 amperes of 690 volt electricity is fed into the transformers, producing up to 86 amperes of 34.5 kilovolt utility grid grade power. The big brown objects here are the three transformers that accomplish this conversion. The uninteresting beige stuff below that is the power conditioning equipment, which was very hard to shoot in the confines of the nacelle.
So, the long term plan for this much abused nacelle is that it will be mounted on a short tower like the Vestas unit, the insides will be rebuilt with assistance from Gamesa, and then there will be some modifications made to the control systems so that the machine "believes" it is operational. The instructors will introduce faults and the students will be sent up through the access hatch, shown below, to hone their troubleshooting skills.
The future looks bright for our friends at Iowa Lakes Community College ... unless the entire wind energy is laid low by the Senate's failure to extend the production tax credit (PTC). We'll be taking that issue up in another diary in the very near future.