San Jacinto Tizate Geothermal Plant

Project Description and Location

The San Jacinto-Tizate Geothermal plant is located in northwestern Nicaragua, in the shire of San Jacinto, municipality of Telica, 20 km from the city of Leon. The Geothermal concession covers an area of 40 km2 and it was developed under an exploitation concession agreement between Polaris Energy Nicaragua (PENSA) and the Ministry of Energy and Mines (MEM) signed in 2001, with a term of 30 years. Also, a generation license was signed in 2003, which allows the generation of 72 MW project for a period of 30 years.

Nicaraguan law stipulates that electricity generation projects must obtain an environmental permit from the Ministry of Environment and Natural Resources (MARENA). The issuance of the permit requires the preparation of an Environmental Impact Assessment (EIA). The first EIA was introduced in 2003 and MARENA granted an environmental permit in September of that year, for a generation of 66 MW. Subsequently, MARENA issued a new Environmental Permit for the “Technological reconversion in San Jacinto-Tizate, for the Electric Power Generation of 72 MW”, to replace the 26.1 MW MCT turbogenerator for two steam Condensing turbines, Fuji brand of 38.5 MW each.

The San Jacinto-Tizate Geothermal Plant was conceived with a potential to generate positive socioeconomic impact due to employment generation, electricity generation and positive environmental impact through its contribution to climate change mitigation.

The Plant is connected to the National Transmission System through a transmission line of 138 kV, connecting with the electrical substation to Leon and Santa Barbara power substations.

Geological Setting

The San Jacinto-Tizate field is located in the vicinity of several young to active volcanoes that make up part of the Marribios Range, a chain of volcanic mountains in northwestern Nicaragua. Like essentially all of the principal volcanoes of Central America, Nicaragua´s volcanoes are created by the subduction of one tectonic plate (the Cocos plate) under another (the Caribbean plate) near the Pacific coast of Central America.

The volcanoes of western Nicaragua differ from the majority of the other Central American volcanoes in an important respect: they occur within the Nicaraguan Depression, a major topographic and tectonic feature that extends the length of western Nicaragua and is evidenced by Lake Managua, Lake Nicaragua and other low-lying areas. The depression has been interpreted as a half-graben (a zone of structural subsidence) that is bounded on its southwest side by steeply dipping faults.

The rocks exposed at the surface in the vicinity of the San Jacinto-Tizate field consist of deposits from the volcanoes in the area (principally from the El Chorro-La Bolsa, Telica, San Jacinto, Santa Clara and Lomas de Apante complexes). Interpretation of subsurface rocks from drill cuttings in the wells at San Jacinto-Tizate indicate that subsurface rock units (to a depth of about 2,000 m, the level explored to date by drilling, are also predominantly volcanic in origin (mainly of andesitic and basaltic composition), pyroclastic rocks (tuffs and breccias of varying texture and composition), and sediments that are presumably volcanogenic in origin (that is, reworked volcanic material deposited either sub aerially or in lakes).

These rock units have been interpreted to range in age from very recent to early Miocene age (that is, up to somewhere in the range of about 10 to 20 million years). The older sedimentary and volcanogenic units that are inferred from regional mapping to compose the basement beneath the volcanic deposits in the Nicaraguan Depression have not been identified in any of the wells.