A windmill tour with TransAlta's Hal Jorgensen

A V90 windmill seen from the base
T. Lucas photos

Corrected for accuracy.

Toni Lucas, Pincher Creek Voice

Windmills dot the landscape throughout southern Alberta.  Although most of us know that they are used to produce energy, there are a lot of steps between the towers with spinning blades and the consumer flicking on a light switch.

TransAlta Control Center Supervisor Hal Jorgensen took the time to educate me, taking me on a tour of the Summerview wind farm.  Jorgensen  has been working for TransAlta for 12 years.  The purpose of a windmill is to convert the mechanical energy of the turning blades into electrical energy that can be used by consumers.  Walking up to a V90 model windmill I was very conscious of size of the structure.  It has a 90 meter blade diameter and each blade is 45 meters long. The tower that we visited went underground 32 feet, and rose into the air 80 metres, not including the blades.

Visible to the casual observer is the tower that rises from the ground, the nacelle that sits on top, and the blades in front.  The nacelle houses the gearing system and the generator that that is attached to the transformer that sends the power to the substation.  These components make the wind turbine generator or WTG.  The blades turn, producing energy in the generator which is then sent to the transformer and on to the substation.  It is then carried via transmission lines into the power grid.

Showing the interior of a tower, Jorgensen admitted that when he takes tours through a tower few are impressed by the computer inside the windmill.

Hal Jorgensen shows the computer within a V90 tower

A box hanging on the wall has a display that is smaller than a cell phone.  That is the computer interface for the tower. "It tracks your wind speeds,  in meters per second.  If you multiply that by 4 you have a rough kilometers per hour," said Jorgensen.   Other information that can be read from the display includes the power being produced, generator revolutions per minute (rpm), rotor speed rpm, wind speed, and the pitch of the blades.

A lot of changes have been implemented to make the towers more user friendly since Jorgensen started working with windpower.

Service lift mechanism to left beside ladder to the right

Examples of these improvements include a service lift designed for a maximum of two people that are wearing harnesses to elevate them to the top, and a climb assist cable on the ladders that can attached to harness that will that will take up to 75% of the weight of the person climbing.  "The advantage is that they're fast," said Jorgensen.  This will lead to significantly less stress to an operator's shoulders and knees.  "That's made a huge difference with our technicians."

Either of those methods or the ladder itself will take you to the nacelle.  At the top where the tower joins the nacelle, Jorgensen believes it is just over 2 meters across, narrowing considerably from four meters across or just over 12 feet across at the base.

"The nacelle is deceiving, but they are over the size of a bus and probably 9 feet tall,"  explained Jorgenesen.  Some of the older designs were not built with the comfort of the technician in mind.  "They have come a long way in designing these things."  Maintenance  does have to be done on the exterior of the nacelle but less so than in earlier designs. "These ones, honestly, are designed quite well.  Once you're up in the tower you don't have to go outside unless you have to check a sensor on top of the nacelle."

The V90 nacelle can turn automatically in any direction to face the wind, or at a 90 degree angle to the wind if it is too strong or erratic to for that model of windmill.  Once a V90 nacelle has turned 4 rotations it will turn in the opposite direction and untwist itself during a time that it is safe for it to do so.

T. Lucas in hard hat area
Photo by Hal Jorgensen 

Jorgensen invited me to put my hand on a black cable that runs from the top of the windmill down along the wall.  "Your hand is touching 35,000 volts," he said, grinning.  The heavily protected cable goes from the top of the tower to underground, out to the substation and then to the transmission lines.

"On a day where the wind is 90 k an hour, these towers can move up to four to six inches each way at the top," he said.

"The higher you go, the better the wind you get.  The steadier the wind you get.  It gets to be steadier, and tends to be stronger.  That's why companies have gone toward the higher towers," said Jorgensen.  "I think it is about 3% of the power that is produced in Alberta is from wind, so it's still relatively small."  TransAlta has 7 wind farms locally.  Capital Power, Suncor and Enmax are a few of the other companies that have towers in the area.

"It's very minimal," commented Jorgenson of the sound that is given off by a windmill.  "If it's giving off a whistling or rumbling noises the chances are that it has been damaged, and we (the company in charge of that tower) would appreciate being notified.  We have to fall within certain guidelines, certain decibel readings."  Off the top of his head, he believed it had to be under 40 decibels at 400 meters from the tower.  "Conversation is 65, so it's very, very low."

Windmill manufacturers paint them a duller shade of white or grey, to help them blend with their surroundings.  Enel manufactured windmills have a signature look that includes green bands low on the tower to help the lower area blend into the local landscapes.

Jorgensen touched on the various designs that have been developed.  Horizontal axis turbines are the ones we see most often.  They can have a fixed pitch where the nacelle stays still but the blades pitch differently to control blade rotation. The ones that Jorgensen seemed to appreciate the most were of a variable pitch design, where the nacelle can rotate.  Another option includes vertical axis turbines.  These are often described as 'egg beaters' and are not considered to be a viable design for this area.

According to Jorgensen the V80 model has an 80 meter diameter blade and produces 1.8 megawatt power.  "Enough for about 900 houses that function at full power."

Part of the control room

TransAlta wind farms across Canada are monitored and controlled from a small room in Pincher Creek . This includes wind farms in Alberta, Ontario, New Brunswick and Quebec.

TransAlta Operator Ken Noske, Control Center Supervisor Hal Jorgensen and
Western Canada Wind Manager Larry Bester in the control room

The control room is staffed 24 hours a day, 7 days a week.  If anything is amiss information is sent to Pincher Creek's control room and technicians there evaluate and respond to the issue as required.  The issue may be dealt with via computer directly from there or may require dispatch to the site.

"One of the more important components is the sub-stations.  Without the substations, the tower can't work," said Jorgensen.  The power goes from the turbine, to a collector to the substation.  From the substation it goes to a transmission line.  "That's what sends the power out."

"Whatever is produced must be used, and whatever you need must be produced instantaneously," he explained, saying that storing the power is not a very viable option.  "No one fuel source is going to be able to take care of all your needs, unless you massively overbuild."    

Different power sources produce differently.  Coal or nuclear power plants put out a steady supply of power that you cannot turn up or turn down quickly.   Instantaneous hydro or gas fired sources of power can respond quickly to changes in the load.  "Usually the jurisdictions that work the best are the ones that have a combination of fuel sources."

"Wind is variable.  There are times that there is no wind.  The advantage of the wind is that it's free.  You have the ability to respond instantly as well, as long as you have wind. It is one of the answers for fuel."  TransAlta uses coal, gas, wind, hydro, and biomass energy to supply electricity.

Jorgensen gave a brief history of TransAlta.  "It started in Alberta, as Calgary Power.  Our first plant was in 1911, so we had our 100th anniversary two years ago.  They used to handle distribution, transmission, and generation.  Now we focus on generation."

Cowley Ridge in it's 20th year of operation and is the oldest wind farm in Canada.  "We're doing a lot of work out there."  Because of the age of the KVS windmills installed at Cowley Ridge and the fact that the manufacturer is out of business, TransAlta has bought replacement parts from other wind farms that have dismantled their KVS windmills to have spare parts on hand for these 80 foot tall 375 kilowatt  towers.  Jorgensen comparing the black lattice style towers on Cowley Ridge to a modern V90.  "That shows you how much technology has changed in 20 years.  375 kilowatt turbine, 3 megawatt turbine.  So eight times the output," he said comparing the old to the modern mills.  

According to Jorgensen, newer towers might be installed at Cowley Ridge in the future or the area may be reclaimed instead.

TransAlta has played a part in the growth of the wind power industry.  "In the beginning years, we used to partner with Vestas.  So whenever they came up with a new turbine model, we would provide land for a prototype.  In the Summerview Wind farm the V80 that's there was the very first one in North America.  Their V90 which is out near Fort Macleod was the second one in North America."

Over 30 people work in the area for TransAlta.  "One of my desires, is that we offer opportunity for the small town local folks," said Jorgensen.  "People that have the heart and the desire that want to prove themselves.  I was a nuts and bolts guy pulling on a wrench, and they took a chance on me.  It's been a really good experience.  You will find that in the wind industry in particular, you get people in it who don't want to leave.  It's a relatively new industry, there's always something to talk about, most people are pretty excited to be in it."

Related link:  TransAlta