Enex

Salvadoran geothermal company LaGeo S.A. awarded an engineering, procurement, construction and management contract to Enex.

The EPCM contract with the Salvadoran geothermal company was for an 9.3 MW (8 MW net) expansion to LaGeo’s existing 56 MW Berlin power plant, bringing the total installed capacity of the Berlin field to 104 MW. The contract with Enex is for a bottoming cycle binary unit using brine from two separator stations.

Icelandic Engineering at Work in El Salvador

The contract was tendered by the local geothermal utility and operator LaGeo, under which Enex performed the engineering, procurement, construction and project management. Enex hired local engineering consultant Sertiproi and Icelandic engineering consultants VGK (now Mannvit), Rafteikning and Fjarhitun (now Verkis) as subcontractors for various sections of the contract. Enex also carried out all tests, commissioning and training for LaGeo's staff.

Generating Electricity from Low-Temperature Geothermal Water

The power plant is located at the Berlin geothermal area in El Salvador, where two existing flash-steam power plants are producing close to 100 MW. The binary power plant uses conventional ORC (Organic Rankine Cycle) technology that alternately vaporizes and condenses a working fluid. The working fluid flows in a closed loop and is circulated and re-used constantly. At the Berlin Binary Plant the working fluid is isopentane. The plant is a bottoming cycle binary plant that uses brine from two separators. The yield is ~300 kg/s and the temperature of the brine is 185°C. The heat exchangers are of shell and tube design with two units of pre-heaters and re-boilers. The binary plant enables 100% re-injection of the geothermal brine, which maintains the sustainability of the reservoir. Condensate from the two larger plants is used as make up water for the cooling tower.

Flexible and Reliable

The plant has an advanced control system, allowing for flexibility in the performance, while ensuring constant reliability with built-in redundancy. This control system enables the binary plant to run uninterrupted without loss of process control, even in the event of failure in the outside distribution grid.

ORC Plant

The Enex Binary Plant uses conventional ORC (Organic Rankine Cycle) technology that alternately vaporizes and condenses a working fluid. The working fluid flows in a closed loop and is circulated and re-used constantly. At the Berlin Binary Plant the working fluid is isopentane. The binary plant allows for 100% re-injection of the geothermal fluid. The plant is in online and operating at full capacity.