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Start of of 31.5 MW Ngawha geothermal plant expansion on target for year-end 2020

Snapshot of Ngawha construction news update, Oct. 2020 (source: Top Energy)
Alexander Richter 20 Oct 2020

With work progressing on target, the expansion of Top Energy's Ngawha geothermal power plant in New Zealand is expected to start operation at year-end 2020.

New Zealand based power utility Top Energy has reported that the work on the 31.5 MW expansion of its Ngawaha geothermal power plant is remaining on target. In a project update, the company reports, that weather conditions at the site have been excellent for construction activities these past few weeks as we transition out of construction and into the commissioning phase of the project. With the expansion, the Ngawha power plant will reach a total output of 57 MW. Subject to a monitoring period to prove the sustainability of the geothermal resource, NGL’s resource consents provide for a second station to grow this to 88 MW by 2025.

The total investment for the plant is estimated at NZ$ 182 million (around USD 122 million).

The daily workforce is still over 250 people as the construction crew makes their final push to complete the power station and we prepare for the introduction of power and liquids to the site.

Construction of the 110 kV interconnection is now complete. The transmission line from Kaikohe to Ngawha substation was livened at the end of August, and the connection between the new power station and the Ngawha substation is now in place and ready to test.

Construction of the fluid conveyance pipelines between the wells and power station is largely complete, with only some painting and insulation of the lines to finish. Operational testing of motors, valves and instruments is underway.

Construction of the core power station equipment is largely complete, with the running of some 76km of electrical and controls cables the last major activity to conclude. Work on ancillary systems across the site continues.

The last major equipment (2 x 30 tonne brine mufflers) were lifted into place at the eastern end of the site. Geothermal fluid pipelines are being installed across the power station site. Fencing, planting, and landscaping work is coming to an end across the site.

Commissioning

Specialist engineers from the power station supplier, Ormat, have arrived to start testing and commissioning of the power station and its associated safety systems. Our local engineers already have testing and commissioning of the fluid conveyance system underway.

The first clearly visible commissioning activity will be when geothermal fluid from the production wells is brought onto the power station site and vented through the mufflers at the eastern end of the station platform. You can expect to see large plumes of stream rising from the mufflers, similar to those seen when the production wells were tested in late 2018. This will start late October, intermittently over several days while we test the function of the wells and separator, and then again a few weeks later when geothermal fluid is brought into the core power station for the first time.

The project remains on target for producing electricity from the new station towards the end of the year.

Source: Top Energy