| Abstract |
This paper quantifies the economic advantages and drawbacks of downhole separation of non-condensable geothermal gases. Using details of the performance of the downhole separator and estimates of the costs of placement and workovers a realistic assessment can be made. Such an assessment was carried out for a (hypothetical) power plant at Ngawha geothermal field. The use of the DHS gives rise to a reduction in the cost of gas extraction equipment. However high costs for workovers on DHS wells far outweighs the savings which result from using the DHS. The likely cost could be as high as $2,452,000 p Even given (impossible optimistic circumstances there would still be a nett cost of about $1,420,000 over the life of the project. The DHS is not economically viable for New Zealand geothermal fields. |