Green light for Ngawha power plant expansion

THE PANEL: Independent commissioners Rob Lieffering (Nelson, left), Rob van Voorthuysen (Napier) and Bronwyn Hunt (Kaitaia) hearing submissions to the Ngawha power station expansion plan last month.

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

Ngawha Generation Ltd had applied to the Northland Regional and Far North District councils for the more than two dozen resource consents needed for the proposed expansion, and also sought to replace consents for an existing 25-megawatt facility that it operates on behalf of owner Top Energy some four kilometres east of Kaikohe.

The proposal, designed to triple the amount of electricity generated from the Ngawha geothermal field, was publicly notified in February, attracting 13 submissions, 11 of them 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 40sq km field, and other environmental and cultural concerns.

A joint hearing took place in Kerikeri over several days last month, the commissioners approving the applications, subject to a raft of proposed conditions.

Commissioners' chairman Napier-based Rob van Voorthuysen said Ngawha Generation had undertaken a thorough assessment of both the continued operation of the existing station and the proposed expansion, and the potential adverse effects were either "no more than minor or can be adequately avoided, remedied or mitigated by the imposition of conditions"

Mr van Voorthuysen said once the first station began operating the consent conditions required a minimum three years before the next could come on line, to help ensure that the geothermal reservoir was being managed sustainably.

The applicant must fund the appointment of a kaitiaki advisor and a special monitoring plan to assess the health of culturally significant flora and fauna interacting with Ngawha Springs and waterways in the area.

"We are satisfied that the final resource consent conditions, both singularly and in total, are necessary and appropriate to avoid, remedy or mitigate potential adverse effects identified by the technical reports and investigations, the peer reviews, the expert evidence and the submitters," Mr van Voorthuysen added.

During the hearing the applicant revealed that scientific and technical investigations commissioned by Top Energy supported an immediate 50-megawatt (MWe) 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 25MWe stages to more closely match forecast increases in demand for electricity.

Given the lead time for drilling and construction, that could effectively see a start to the first stage as early as 2017.

(Each 25MWe plant will require a site of about 2.9ha, with another 1.4ha needed for a 'construction lay down area' as well as several kilometres of pipeline, and new production and injection wells).

The commissioners said that overall, they considered the positive effects of the proposal to be locally, regionally and/or nationally significant. Those effects included economic, security of generation and reliability of supply, increased locally-sourced renewable generation and more competitive wholesale pricing.

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 the government's renewable electricity generation targets.

The commissioners' decisions allow for the consents to run for 35 years, but with a longer than usual 'lapse' period of 10 years. The decisions can now be appealed to the Environment Court within 15 working days.