Geotherm Group has been granted resource consents to establish a new geothermal power station in Poihipi Road near Wairakei until 2026.
A panel of independent commissioners appointed by Environment Waikato heard applications for 12 resource consents by Geotherm for construction of the station, extraction of geothermal fluid to generate electricity and re-injection of separated fluid into the ground beneath Geotherm’s property.
The new power station will be similar to the existing Contact Energy Poihipi Road Power Station. It will be capable of operating 24 hours per day and generating 60 megawatts of electricity.
The consents are subject to conditions requiring Geotherm to inject the same quantity of fluid back into the Wairakei-Tauhara geothermal field that it extracts – called “zero net depletion”. This ensures that there will be no reduction of underground pressure from the station’s operation, to ensure that the new station will not contribute to subsidence in urban Taupo.
The same Committee recently found that subsidence in the Crown Road area in Taupo was ‘more likely than not’ the result of Contact Energy’s operations at Wairakei.
The zero net depletion requirement also avoids the need to apportion responsibility for subsidence damage between the two operators which will operate in the Wairakei- Tauhara geothermal field.
Taupo District Council opposed the Geotherm applications as it said the project would contribute to subsidence and assigning responsibility would not be possible unless zero net depletion was required.
Contact Energy said the viability of the Geotherm proposal was questionable and it had concerns about potential effects on its own operations if Geotherm’s re-injected fluid “short circuited” back towards Contact’s production areas, cooling down the geothermal resource. The Hearing Committee imposed conditions requiring tracer testing of Geotherm’s re-injected fluid and Environment Waikato was given power to curtail re-injection if a significant impact on Contact’s production was possible.
Local iwi Ngati Rauhoto Land Rights Committee was concerned about lack of consultation and potential adverse effects on Maori cultural and spiritual values. They reached agreement after talks, which would ensure ongoing dialogue and protection of taonga.
Local submitters generally supported the Geotherm proposal as it involved full infield re-injection and would not worsen subsidence in urban Taupo or discharge waste fluids to the Waikato River.
The Hearing Committee was concerned about potential difficulties in efficiently managing the resource following introduction of another operator into the Wairakei-Tauhara field, given the interrelated nature of the geothermal system and uncertainties about cause and effect. It decided management issues could be addressed by resource consent conditions and were not of a scale to warrant declining consent, having regard to the social and economic benefits of generating more electricity from a renewable energy resource.
Geotherm and submitters have until early February to lodge appeals with the Environment Court against the Committee’s decision.