corrosive species and scaling in wells at olkaria ... - Orkustofnun

hyaloclastites and basalt lavas. Nouralie (2000) described the stratigraphy as consisting mainly of
hyaloclastites in the shallower parts of the system, < 730 m. In the deeper parts, > 730 m, basalt lavas
are predominant. The hyaloclastites are mainly volcanics which are divided into four groups; Tuffs,
Breccia lavas, Basaltic breccias and Pillow lavas. The intrusives are predominantly basalts and are
found in the deeper parts of the system.
The thermal plant was initially commissioned to generate about 100 MWt of heat, but has since been
progressively expanded in tandem with better utilization of the resource. In 1991 the capacity of the
thermal plant was expanded to 150 MWt and in 1998 a further 250 MWt and 60 MWe were added.
This started the Nesjavellir co-generation plant which has two main functions; to produce electricity
from geothermal steam and to heat cold ground water for district heating. Currently, the installed
capacity for electricity generation is 120 MWe from four steam cycle turbines of 30 MWe each and
290 MWt. The Nesjavellir geothermal field with well locations is shown in Figure 7.
FIGURE 7: Well locations in the Nesjavellir
geothermal field
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