The Olkaria Geothermal Field is located in the East African Rift valley, about 120 km north-west of Nairobi, The KenGen´s license area covers 204 km2. When the study was initiated, KenGen had two power plants in operation, Olkaria I and II, with a total capacity 150 MW and two power plants, totaling 280 MW, were under construction. The work was to study the possibilities to develop the KenGen´s concession area beyond the already constructed and planned 430 MW power plants.
The main tasks were:
Determination of the size, availability and quality of the geothermal resources.
Recommendation of the optimum utilization of the field.
Recommendation of locations, sizes and separation pressure of the future power plants.
Feasibility study for power plants in harmony with the optimized capacity of the geothermal field. That includes:
– Evaluation of existing power plants and recommended modifications.
– Recommendations for location, size and types of new power plants.
Training of KenGen´s employees
Evaluation of the environmental impact of the geothermal utilization.
The main outcome of the study was that total capacity of the geothermal field was evaluated 930 MW, i.e. 500 MW in addition to the already constructed and planed power plants. Five new plants and extension of one existing plant were recommended.
Verkís managed the project and provided expert input on all aspects related to feasibility study of the power plants and steam field.
The Challenge
Reykjavík Energy owns the Hellisheidi geothermal power plant, a combined heat and power plant located about 20 km from Reykjavík in south-west Iceland. The area is one of Iceland’s most active high enthalpy areas. A new area, at Gráuhnúkar, is being investigated for steam and fluid extraction. The purpose of the plants is to meet increased demand for electricity for industrial and domestic use and for hot water for heating. The 303 MWe geothermal power plant in Hellisheiði, Iceland, was commissioned in 5 stages during the years 2006-2011. The first stage was completed in 2006 with two high pressure geothermal turbines of 45 MWe capacity each. The second stage was completed in 2007 with one low pressure geothermal turbine of 33 MWe capacity. The third stage was completed in 2008 with two additional high pressure geothermal turbines, 45 MWe each.
In 2010 a heating plant for hot water generation was added to the plant, intended for district heating. The heat output of the first stage is 133 MWth and two further 133 MWth stages are to follow later. At the same time the Hellisheiði hot water main was put into service. The main is a 19,5 km long pipeline, 0,9-1,0 m in diameter, that carries hot water to Reykjavík. In 2011 the 5th stage of the plant was finished, which includes two new 45 MWe high pressure geothermal turbines, similar to the former turbines, situated in a new power house in Sleggjubeinsdalur.
The plant utilizes 500 kg/s of 180°C geothermal steam for electrical generation. The hot fluid is extracted from 30 wells, 2.000 – 3.000 m deep, and is led through steam and mist separators before entering the turbines. The high pressure steam gathering system operates at 9 bara pressure. The low pressure steam is generated with flashing of brine water from the steam separators at a pressure of 2 bara. The generating units are of single flow, single flash type with axial exhaust. Cooling is achieved through wet cooling towers of the counter flow type.
The main components of the electrical system for each unit consist of a 50 MVA generator, 50 MVA step-up transformer to 220 kV transmission voltage, an 11/11 kV transformer for connection to the 11 kV station service system and two 11/0,4 kV transformers for station service. The generating units, as well as the 11 kV and 0,4 kV distribution boards, are monitored and controlled by the state of the art control- and protection equipment.
Our Solution
Reykjavík Energy owns the Hellisheidi geothermal power plant, a combined heat and power plant located about 20 km from Reykjavík in south-west Iceland. The area is one of Iceland’s most active high enthalpy areas. A new area, at Gráuhnúkar, is being investigated for steam and fluid extraction. The purpose of the plants is to meet increased demand for electricity for industrial and domestic use and for hot water for heating. The 303 MWe geothermal power plant in Hellisheiði, Iceland, was commissioned in 5 stages during the years 2006-2011. The first stage was completed in 2006 with two high pressure geothermal turbines of 45 MWe capacity each. The second stage was completed in 2007 with one low pressure geothermal turbine of 33 MWe capacity. The third stage was completed in 2008 with two additional high pressure geothermal turbines, 45 MWe each.
In 2010 a heating plant for hot water generation was added to the plant, intended for district heating. The heat output of the first stage is 133 MWth and two further 133 MWth stages are to follow later. At the same time the Hellisheiði hot water main was put into service. The main is a 19,5 km long pipeline, 0,9-1,0 m in diameter, that carries hot water to Reykjavík. In 2011 the 5th stage of the plant was finished, which includes two new 45 MWe high pressure geothermal turbines, similar to the former turbines, situated in a new power house in Sleggjubeinsdalur.
The plant utilizes 500 kg/s of 180°C geothermal steam for electrical generation. The hot fluid is extracted from 30 wells, 2.000 – 3.000 m deep, and is led through steam and mist separators before entering the turbines. The high pressure steam gathering system operates at 9 bara pressure. The low pressure steam is generated with flashing of brine water from the steam separators at a pressure of 2 bara. The generating units are of single flow, single flash type with axial exhaust. Cooling is achieved through wet cooling towers of the counter flow type.
The main components of the electrical system for each unit consist of a 50 MVA generator, 50 MVA step-up transformer to 220 kV transmission voltage, an 11/11 kV transformer for connection to the 11 kV station service system and two 11/0,4 kV transformers for station service. The generating units, as well as the 11 kV and 0,4 kV distribution boards, are monitored and controlled by the state of the art control- and protection equipment.
The Result
Reykjavík Energy owns the Hellisheidi geothermal power plant, a combined heat and power plant located about 20 km from Reykjavík in south-west Iceland. The area is one of Iceland’s most active high enthalpy areas. A new area, at Gráuhnúkar, is being investigated for steam and fluid extraction. The purpose of the plants is to meet increased demand for electricity for industrial and domestic use and for hot water for heating. The 303 MWe geothermal power plant in Hellisheiði, Iceland, was commissioned in 5 stages during the years 2006-2011. The first stage was completed in 2006 with two high pressure geothermal turbines of 45 MWe capacity each. The second stage was completed in 2007 with one low pressure geothermal turbine of 33 MWe capacity. The third stage was completed in 2008 with two additional high pressure geothermal turbines, 45 MWe each.
In 2010 a heating plant for hot water generation was added to the plant, intended for district heating. The heat output of the first stage is 133 MWth and two further 133 MWth stages are to follow later. At the same time the Hellisheiði hot water main was put into service. The main is a 19,5 km long pipeline, 0,9-1,0 m in diameter, that carries hot water to Reykjavík. In 2011 the 5th stage of the plant was finished, which includes two new 45 MWe high pressure geothermal turbines, similar to the former turbines, situated in a new power house in Sleggjubeinsdalur.
The plant utilizes 500 kg/s of 180°C geothermal steam for electrical generation. The hot fluid is extracted from 30 wells, 2.000 – 3.000 m deep, and is led through steam and mist separators before entering the turbines. The high pressure steam gathering system operates at 9 bara pressure. The low pressure steam is generated with flashing of brine water from the steam separators at a pressure of 2 bara. The generating units are of single flow, single flash type with axial exhaust. Cooling is achieved through wet cooling towers of the counter flow type.
The main components of the electrical system for each unit consist of a 50 MVA generator, 50 MVA step-up transformer to 220 kV transmission voltage, an 11/11 kV transformer for connection to the 11 kV station service system and two 11/0,4 kV transformers for station service. The generating units, as well as the 11 kV and 0,4 kV distribution boards, are monitored and controlled by the state of the art control- and protection equipment.
Danish
Icelandic
