Using waste heat to make electricity

By the end of February, Basin Electric’s base load generation will have increased by about 11 megawatts (MW).

In the grand scheme of things, it’s not a lot. But when we’re making electricity from something that used to go to waste, it’s pretty neat.

A sixth heat recovery unit is expected to be in operation near Manning, ND. The fifth one, near Zeeland, ND, was placed in operation at the end of December 2008.

Heat Recovery Map

Allen Boushee, distributed generation engineer III, said the two newest plants join an existing fleet of four other heat recovery stations that have been operating since 2006.

The two new heat recovery units are owned and operated by OREG 2, a subsidiary of Ormat Technologies. Click here to see a video we did with Lucien Bronicki of Ormat Technologies. Basin Electric has signed power purchase agreements with OREG 2 for the development of these two facilities. Two more stations will be built by the end of 2009.

The heat recovery generating stations – referred to as recovered energy generation (REG) units – are located at existing compressor stations along the Northern Border Pipeline.

Each REG unit uses the hot exhaust gases from the compressor station to generate electricity.

Technical explanation:

The compressor stations are driven by natural gas-fueled turbines. The exhaust temperature of the gas-fueled turbine is about 800-900 degrees F and that exhaust heat is recovered using heat exchangers in the exhaust stack. The recovered heat is then used to vaporize a fluid to drive the Ormat technology.

The Northern Border Pipeline travels in a southeasterly direction across North Dakota and South Dakota as it carries natural gas from Canada to the Chicago area.

Boushee said each of the sites has a generating capacity of about 5.5 MW. He said the projects will have minimal environmental impact, with the electric generation considered to have “zero or near zero” emissions. The new generators are considered to be base load generation, meaning they’ll run almost continuously, as long as the compressor station is running, he said.

The next two stations are scheduled to be operational by the end of 2009, and are located near Culbertson, MT, and Garvin, MN.

Construction on the substations for each of the two new units has been coordinated by Basin Electric members, Roughrider Electric Cooperative for the Manning site and KEM Electric Cooperative for the Zeeland site. Ron Rebenitsch, Basin Electric manager of alternative technologies, expressed strong appreciation for the support thatthat Roughrider and KEM have given these projects.

These new REG units will be added to the four existing REG sites that Ormat completed in 2006 from which Basin Electric already purchases power under contract. Those existing sites are located near St. Anthony, ND, and Aberdeen, Clark and Estelline, SD.

Comments

  1. I really liked that post, I am a little confused, and have a quick question. Can I send you an email?

  2. Keep up the hard work keeping the environment clean, I am right here with ya man! To a greener 2010!!

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