Upgrading Ormesa Geothermal Operations

摘要

The first two wells drilled at East Mesa were petroleum exploration wells drilled in the 1960s. Between 1972 and 1974, five deep wells were drilled at East Mesa by the US BOR. These wells, whose locations were suggested by surface geophysical studies, confirmed the existence of the East Mesa thermal anomaly and had bottomhole temperatures ranging from 300 deg to 400 deg F. In 1975 - 1976, Republic Geothermal drilled three wells in the northern part of the field, confirming the extension of commercial temperatures, and proceeded in 1977 to drill seven additional confirmation wells. In late 1984 ORMAT purchased the development rights to the East Mesa geothermal resource area, along with the assignment of the Republic Geothermal's SO4 power sales agreements and acess to a DOE Loan guaranty. Subsequently ORMAT developed East Mesa Project, with a dollar50 million guaranteed loan for the 24 MW Ormesa I project, which was prepaid in full approximately one year after this loan was funded. With its December 1986 grid synchronization and subsequent continued successful operation, the Ormesa I project established the technical feasibility of larger scale commercial modular binary power plants and liquid dominated geothermal resources. From 1986 on. the East Mesa projects were expanded by: (a) the 20 MW Ormesa II project in 1998; (b) the 10 MW Ormesa IE project in 1988 and (c) the 12 MW Ormesa IH project in 1989. In April 2002, after sixteen years of third party ownership and operation, ORMAT acquired a 100percent interest in the four Ormesa binary power plants as well as the two adjacent Geo East Mesa (GEM) single flash power plants and the entire well field which supports these plants. The GEM plants did not have a power sales agreement and are supplying plant usage power to the four Ormesa power plants and the associated well field pumps. ORMAT eliminated the multi-entity field ownership, which constrained effective field management. By operating the well field to optimize power production, and replacing 20 of the original 1 MW ORMAT~(~R) Energy Converter (OEC) units in Ormesa 1 with two new high efficiency 10 MW OEC/ITLU units, the power production of the Ormesa complex has been increased from an average of 42 MW to over 55 MW, without drilling any new wells. This is a shining example of the benefits of a single, value-added upgraded plant and field operations and management program.