Blue Mountain Geothermal Power Plant, United States of America
The Blue Mountain Geothermal Power Plant is located in Humboldt County in North Nevada, US. Also known as Faulkner I, the geothermal plant was commissioned in October 2009, four months ahead of schedule. It is owned and operated by Nevada Geothermal Power (NGP) Blue Mountain I, a subsidiary of NGP.
Faulkner I cost approximately $180m. It has an installed capacity of 49.5MW. The plant commenced production with an initial output of 38MW. Recent tests carried out at the plant revealed that it has a resource potential of 100MW. NGP is in the process of increasing the plant's output through an optimisation programme that began in the fourth quarter of 2010. As of February 2011, the plant's gross output had increased to 48MW.
The company is also planning to convert the existing injection wells into production wells for the second phase of the plant. Phase II will have an installed capacity of 25MW, taking the total production capacity of the field to 70MW.
NGP has signed a 20-year long power purchase agreement with NV Energy to supply all the electricity produced at Faulkner I.
The engineering, procurement and construction contract of Faulkner I was awarded to Ormat Technologies in 2008. The value of the contract was $76m.
The optimisation programme contract was awarded to Ensign Drilling in November 2009. The scope of work includes drilling two deep injector wells and one production well.
Estimated at $8.4m, the optimisation programme is being funded by the Senior Debt loan issued by insurance company John Hancock. The loan has been issued under the Financial Institutions Partnership Program (FIPP) and is guaranteed by the US Department of Energy.
John Hancock also provided a loan of $95m towards the construction of Faulkner I.
Faulkner I is the first geothermal plant to receive an Investment Tax Credit (ITC) grant of $57.9m from the US Department of Treasury.
Faulkner I is spread over an area of 11,120 acres and is 33km away from the state electrical transmission grid. Of the total 17 square miles, just two square miles has been developed so far.
The plant features three 16.5MW energy converters of Ormat make and consists of six geothermal wells, fluid collection and injection systems. It also has a water cooling tower, a control building, and fire protection and safety systems.
The Faulkner 1 optimisation programme will depend on the production capacity of existing injection wells 44-14, 91-15 and 36-14. Reservoir tracer studies of these wells were conducted in the third quarter of 2010 to determine the pattern of fluid movement between the injection and production wells.
The four injection wells 61-22, 58-11, 57-15 and 55-15 in the western part of the Blue Mountains will be connected to Faulkner I by insulated pipelines. These will be converted into high temperature production wells of 180-200ºC in order to increase the overall field production capacity.
To increase production injection fluids were distributed into the wells 57-15, 58-11 and 91-15 which are situated to the north and west of the production area. Each of these wells has an injection capacity of over 2,000 gallons per minute.
NGP completed the drilling of three injection test wells located to the south of the production fields between December 2010 and early 2011. The company is in the process of conducting long-term injection tests on the new wells 86-22 and 34-23 as well as on the completed wells 38-14 and 89-11. Reservoir production projections made using data from these wells will be used by the company to determine the future sustainable production levels of the plant.
The Blue Mountain Geothermal Power is a binary cycle power plant, a continuous closed-loop heat exchange system.
In this system, hot water or the primary fluid is brought to the surface of the earth by drilling 4,000ft-8,000ft deep wells inside the earth.
The heat of the primary fluid is transferred to a heat exchanger that contains a low-boiling point secondary fluid. The vapour formed by the secondary fluid operates the turbine to generate electricity. The cooled vapour is re-injected to heat the reservoir.
The ORMAT energy converter uses state of the art Organic Rankine Cycle technology to convert low, medium and high temperature heat into electrical energy.
The Organic Rankine Cycle is a thermodynamic process that uses organic fluid with a lower boiling point than water. Heat is transferred to the fluid to form vapour at a constant pressure. The expanded vapour in turn drives the turbine or generator to produce electricity.
Power generated from Faulkner I is transmitted to the national grid via a 33km-long, 125MW transmission line owned by NGP.
The line can accommodate the increased capacity of 70MW.