A microturbine like these now generates power at the Fargo Holiday Inn. It serves as an introduction to the technology, and to distributed generation, for Cass County Electric Cooperative and its customers. (Photo courtesy of Capstone Turbine Corp.)

Cass County Electric Cooperative has joined the growing list of utilities exploring new distributed generation sources.

This North Dakota cooperative and its customer, the Fargo Holiday Inn, opted for a microturbine and heat exchanger as a secondary water heating source.

Microturbines pack a big energy punch in a little package. Based on the same technology as a jet engine, the Capstone MicroTurbine at the Holiday Inn is the size of a refrigeratorÜbut it generates enough electricity to power a small business. The manufacturer has put the technology through 300,000 hours of testing and commercial operation in various settings to ensure its smooth operation.

High-speed generator
At the heart of the microturbine is a high-speed compressor-turbine that rotates at 96,000 rpm at full output. A high-speed generator on the same shaft delivers high-frequency power. Air bearings and cooling eliminate the need for oil or coolants, contributing to long life and low maintenance. But the microturbine offers more than just efficient, reliable operation. It features the lowest emissions of any noncatalyzed fossil fuel combustion system, a small footprint, light weight, no vibration, and less noise than reciprocating engines.

"The microturbine gives CCEC and its customers another alternative when considering on-site generation."

The 30-kilowatt stand-alone generator was commissioned at a ceremony in August. Representatives of both CCEC and the Holiday Inn commented on the benefits of microturbine technology, noting its versatility, reliability, and environmentally friendly features. Since beginning operation, the microturbine has performed well and data are currently being gathered for the Cooperative Research Network and the Electric Power Research Institute. CCEC is tracking many different inputs and outputs to determine efficiencies and availabilities accurately. The amount of BTU output captured from the exhaust stack is quite impressive.

Keeping pace with change
CCEC officials want to keep up with the rapidly changing electric industry. The shift from an infrastructure of only large centralized plants to more on-site generation is among the changes they foresee. The microturbine gives CCEC and its customers another alternative when considering on-site generation. CCEC has promoted generators for almost 20 years and offers a rate signal that encourages existing and new customers to install on-site generation to cover the peak periods of electrical demand.

"The Capstone microturbine is the optimal small-scale generator, suitable for applications ranging from remote locations to city centers," said Mark Hanson, CCEC's business account executive. "We believe it's todays best investment for clean, reliable baseload power generation."