Go ahead for Ngawha power station’s expansion

A panel of three independent commissioners has granted permission for a staged, multimillion dollar geothermal power station expansion at Ngawha.

Ngawha Generation had applied to the Northland Regional and Far North District Councils for the more than two dozen resource consents needed for the expansion. It was also seeking to replace consents for an existing 25 megawatt facility roughly 4km east of Kaikohe it operates on behalf of owner Top Energy. 

Applications for the proposed project – designed to triple the amount of electricity generated from the Ngawha geothermal field – were publicly notified in February this year, attracting 13 submissions, including 11 opposed to it in some way. 

Opponents’ issues included the potential impact of taking three times as much geothermal fluid (28 million tonnes annually) from the roughly 40 square kilometre field, as well as other environmental and cultural concerns.

A joint hearing was held at Kerikeri over several days last month.

Commissioners’ chairman Rob van Voorthuysen said the potential adverse effects were either “no more than minor or can be adequately avoided, remedied or mitigated by the imposition of conditions.” 

He said once the first station begins operating, the consent conditions require a minimum three years before the next can come on line to help ensure the geothermal reservoir is being managed sustainably.

Another condition is the appointment of an applicant-funded kaitiaki advisor and a special monitoring plan to assess the health of culturally significant flora and fauna interacting with the Ngawha Springs and waterways in the area.

During the hearing, the applicant revealed that scientific and technical investigations commissioned by Top Energy supported an immediate 50 megawatt (MW) development at the Ngawha field, the only high temperature geothermal resource in New Zealand outside the Taupo Volcanic Zone.

However, it proposed doing so in two more cost-effective 25MW stages to more closely match forecast increases in demand for electricity. Given the lead in time for drilling and construction, this could effectively see a start to the first stage as early as 2017. Each 25MW plant requires a roughly 2.9ha site area, with another 1.4ha required for a ‘construction lay down area’ and there are several kilometres of pipeline and new production and injection wells required.

The commissioners said that overall they considered the positive effects of the proposal to be locally,  regionally and/or nationally significant. 

The proposal could also help delay investment in more costly alternative electricity generation nationally and displace existing/additional investment in generation from fossil fuel sources, as well as help meet government renewable electricity generation targets.

The commissioners’ decisions allow for consents to run for 35 years but with a longer-than-usual ‘lapse’ period of 10 years. 

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