Consents granted for Ngawha power station expansion

15 Sep 2015, 5:00 PM

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

Applicant Ngawha Generation Limited had applied to the Northland Regional and Far North District Councils for the more than two dozen resource consents needed for the proposed expansion.

Ngawha Generation 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 and in a just-released decision, the three commissioners who heard the application gave the expansion the go-ahead, 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.

In a nutshell, 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 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.

"We (the commissioners) 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."

The commissioners were also satisfied that monitoring and reporting conditions would enable the ongoing effects of the proposal to be assessed over time and that conditions could be reviewed accordingly if required.

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 of 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 in time for drilling and construction, this could effectively see a start to the first stage as early as 2017.

(Each 25MWe 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.

These 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 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. (Typically consents lapse if they are not exercised within five years, however, in this case commissioners felt the scale of the design, assessment and other work involved meant a longer lapse period was more appropriate.)

Those decisions can now be appealed to the Environment Court for 15 working days.

Meanwhile, the commissioners also approved a legal 'notice of requirement' sought by Top Energy from the Far North District Council for the additional land required for the expansion. Top Energy legally now has 30 days to confirm its acceptance of that notice, before a separate 15 day appeal period for submitters begins.