Geothermal energy is considered a clean, green, renewable source of power. The challenge is how to
economically capture the heat from the earth and turn it into electricity.
Neal Hot Springs 22 MW facility
U.S. Geothermal Inc. is a leading renewable energy company focused on the development, production and sale of electricity from geothermal energy. The Boise-based company began commercial operation of its newest and largest plant, the Neal Hot Springs 22 MW facility near Vale, Oregon, in November 2012.
Challenges
- Reduce operating and maintenance cost
- Minimize waste heat in the cooling system
- Initial costs of the heat rejection system compared to other similar power plants
- Extreme environmental conditions
Our solution
Early on in the project, U.S. Geothermal Vice President of Project Development learned about the direct drive cooling tower motor and was interested from the start as the advantages were crystal clear.
In geothermal power plants, heat rejection represents as much as one third of the total cost of
the installed power plant equipment. Consequently, even small improvements go a long way. Also involved in the project was the project developer, TAS Energy and was responsible for the technology of the power plant. TAS recognized the potential of using the cooling tower motor while brainstorming with the U.S. Geothermal team, and it was through the team’s interest that TAS really started exploring it as an option. It was a novel idea to use cooling tower motors with air-cooled condensers. The project developer always strives to find new and better ways of doing things, progress like this wouldn’t have been possible unless the customer was also pushing to do more.
The motor is unique because it combines the technologies of a laminated finned frame RPM AC motor with a high-performance permanent magnet (PM) rotor design, creating a high torque, direct drive motor specifically designed for cooling tower applications. The laminated finned frame construction provides a highly efficient, power-dense package that replaces the right angle gearbox and jack shaft installation found in conventional cooling towers. The fan couples directly to the motor shaft and is controlled by a variable speed drive for cooling towers for optimal speed performance.
First in the industry
Not only was U.S. Geothermal the first company in the geothermal industry to adopt the Baldor-Reliance cooling tower motor solution for air-cooled condensers, it was also the first in any industry to apply the the 5800 frame motor in such a large scale project. The air-cooled condensers at Neal Hot Springs are also innovative for the large diameter induced draft fans on the horizontal air heat exchanger bundles.
Big fans offer a huge advantage in terms of performance, and the motors supplement those advantages.