Creative Energies Blog

Last week, Scott Kane and I delivered a wind turbine that is going to be installed at the Rocky Mountain Oilfield Testing Center (RMOTC).  This is a federal facility that falls under the Department of Energy.  All types of prototype techniques and facilities are tested here, and Scott and I had the opportunity to check out one of the latest installations.  It is a low-temperature geothermal electricity generation facility.

When oil is removed from the ground, large quantities of water frequently come with it.  In addition, that water can be quite warm.  Nearby this facility is a well that produces 30,000 barrels per day (if my memory is good) of water that is 180-190 degrees F.

This water is not hot enough to be steam on it’s own and turn a turbine for electricity generation.  However, the water is hot enough to boil a fluid with a lower boiling point, in this case this fluid is isopentane.  The boiled isopentane is at a high enough temperature and pressure to turn the 250 kW turbine in this installation.  The isopentane is then condensed back into a liquid through the cooling towers, and the loop continues.

The facility is operating above expectations already, and the hot water flow must be controlled so as not to overwhelm the generator.  Particularly, at night, the isopentane is cooled to a lower temperature than during the day, so even more energy is available with the phase change to a gas.  Not a bad problem to have, as long as you have the generator to keep up with it.  These are the types of operational realities that can be learned through testing like this.

There are many sources of “low-temperature” geothermal waters like this around the world.  This type of geothermal electricity generation could be a significant piece of the energy pie in the future.

Extending tax credit incentives for renewable energy has been very difficult for Congress to agree on this year.  Whether or not tax credits are a long term answer, it will sure be an important boost to the industry in the short term (the extension may be for eight years).  A tax credit extension has been included in four energy bills that have passed the House, and it appears for the first time that the bill is likely to pass the Senate as well.  Big oil and gas seem to get off easier with this bill, which is what had been a show stopper in previous versions, including a presidential veto threat.  Hopefully we’ll know more soon.  The Solar Energy Industries Association (SEIA) is a good resource to stay updated - see link to the right.

It’s been a while since the last post - a testament to the business of the main install season for us here in Wyoming.  Scott Kane recently attended a meeting of the Renewable Energy Coalition of Wyoming, here’s his report.

On August 20th the wind pressed across the sage brush flats and swirled around the small office trailer of the wind farm in Medicine Bow, WY. It was hard to talk and hat wearing was out of the question. The board and members of the Renewable Energy Coalition of Wyoming had been offered a tour of Clipper Windpower’s impressive 2.5 megawatt Liberty Class wind turbine. One of the biggest land-based wind turbines in existence, it dwarfs the older Vestas turbines nearby, turbines that just ten years ago were themselves the biggest yet made.

Clipper Windpower (www.clipperwind.com), the Iowa and California based manufacturer of the turbine was generous to offer the tour. This turbine was installed three years ago as a prototype of its new class of turbines. If it can make it in Medicine Bow, WY, it will hold up anywhere. The thing is big. Its rotor diameter is 89 meters. At full outpt it can produce enough power to  run 100,000 CF lightbulbs at one time.

Before donning hardhats and harnesses to ride the lift up to the top of the tower we were given a view of the control and monitoring system. All of the operation and production data could be displayed on a single computer monitor. As the site manager finished his introduction he clicked a single control on the computer. Outside the wind-rattled window we watched as the massive blades slowed in their sweep and came to a stop. A single little number on the computer screen declined from 2.2 down to 0. It was talking about megawatts.

It then struck me for the first time how terribly expensive our tour was. Turn that thing back on! I thought to myself. Our little group of 20 guests was depriving the grid of 2.2 MW of renewably generated power. Our green-minded group quickly ran the math and it was bad. If our tour caused this machine to remain off-line for two hours we would be wasting 4,400 kilowatt hours. (2,200,000 watts x 2 hours = 4,400kWH) that is 220 kWh for each participant in the tour. 220kWh is what my house uses in a full month!

Though we sped through our tour a lot of air made it past our turbine with all of its energy still in it. Happily that Clipper Liberty turbine is once again whirling happily in the winds of Medicine Bow. I for one, will try not to get in its way again. Thanks again to Clipper for the chance to marvel at a great technical achievement.