The Huntly IDG's terms of reference require it to assess environmental issues. And Environmental Consultants "Environmental Management Services Ltd" (EMS), were engaged to assist Huntly IDG advisers undertake an environmental review of the assets allocated to the Huntly SOE. This documentsummarises their findings and recommendations.

2.2Environmental Constraints and Opportunities

The Huntly SOE has been assigned a number of operational assets. These are the:

Tongariro Power Development Scheme;
Huntly Thermal Station;
Meremere Station and Development Site;
Te Awamutu Co-Generation Station;
Kinleith Co-Generation Station;
Waikaremoana Hydro-Generation Scheme.

This Environmental Report identifies and comments on relevant matters concerning any existing effects on the environment, operational constraints and existing regulatory compliance, for each asset.

2.3Tongariro Power Development Scheme

2.3.1Status of Current Consents

The Tongariro Power Development Scheme (TPD) comprising the Rangipo and Tokaanu Power Stations was initially established under an Order in Council in 1958. With the enactment of the Water and Soil Conservation Act 1967 and the Resource Management Act 1991 (RMA), the taking and diversion of water associated with the TPD was authorised firstly through water rights under the 1967 Act and subsequently through deemed resource consents by the transitional provisions of the RMA.

The transitional provisions outlined in section 386(3) of the RMA assigned a duration to the TPD resource consents of 10 years. Therefore, the TPD consents expire on 1 October 2001 and new resource consents must be lodged prior to that date.

2.3.2Current Environmental Effects of the Asset

2.3.2.1Historical Background

The environmental effects of the TPD Scheme are diverse, with associated structures located in 35 rivers and streams. The scope and scale of the environmental effects are complex, as expected for a scheme as extensive as the TPD. According to EMS, these environmental effects do not however, threaten the ongoing operational viability of the TPD in terms of renewing its resource consents. Since 1991, a project aimed at obtaining the necessary resource consents for the TPD has been undertaken by ECNZ involving an extensive consultative network of interested parties and the commission of a large number of technical reports. It is considered that the resource consents process for the TPD is well focussed and robust. As such, EMS considers that the necessary resource consents for the TPD are likely to be obtained.

2.3.2.2Current Issues

Two areas of potential deficiency in terms of the technical studies in progress have been identified. These are Tongariro River flooding issues and the temperature stratification of Lake Taupo due to the TPD inflows.

There are a number of competing interests in the management of Lake Taupo maximum lake levels. Any significant reductions in the maximum control level would severely reduce the operational capacity of the TPD. Issues have also been identified concerning flooding in the Tongariro River Delta area.

Further issues exist with respect to the residual flows on the Moawhango and Tongariro Rivers. Existing Whanganui River minimum flows are included in the Manawatu/Wanganui Regional Council's draft General Regional Plan and as such, may be subject to further public submissions. Other issues relate to the Whanganui Diversion, Lake Otamangakau and Lake Rotoaira.

2.3.3Volcanic Activity

The TPD is located within an area of regular volcanic activity. There are two areas of significant risk associated with this activity. These are:

Volcanic eruptions discharging ash falls that enter the TPD water system and significantly increase the repair and maintenance requirements for power generation assets such as turbines;
The breach of the Ruapehu Crater Lake and the subsequent destruction or severe damage of the Wahianoa Aqueduct by the resulting lahar.

A range of options have been identified for dealing with the Crater Lake issue, including a controlled spill down the Whangaehu River combined with an early warning system.

2.3.4Tangata Whenua Consultation

The TPD covers an area that affects three Tangata Whenua groups:

Ngati Tuwharetoa;
Whanganui Iwi;
Moawhango Iwi.

Consultation with each of these groups has commenced in the last twelve months. Progress with Tangata Whenua is ongoing in light of the crucial importance of the relationship with Maori.

2.4Huntly Thermal Power Station

2.4.1Status of Current RMA Authorisations

The consents for operating Huntly Power Station have all been granted and are outlined in the following sections. Programmes are currently in place or are being developed to monitor compliance with consent conditions.

2.4.1.1Waikato District Plan - Land Use

The Huntly Thermal Power Station site is located within a special "Power Station" zone in the operative Waikato District Plan. Within this zone,

"The use of land for activities and structures associated with the generation of electricity....is permitted in the Huntly Power Station Area....subject to conditions for permitted activities".

The conditions for permitted activities relate to yards, height, screening and services. New resource consents may be required for any future developments at the Huntly Thermal Power Station site, which do not comply with existing conditions.

The following "conveyance utilities" are also provided for as permitted activities in the Waikato District Plan:

The existing coal conveyance utility to Huntly Power Station within the energy corridor shown on the Planning Maps;
The existing ash pipeline and the existing and future ash disposal area serving Huntly Power Station shown on the Planning Maps;
The existing Maui gas pipeline shown on the Planning Maps.

Monitoring and management activities on the surface of the Waikato River associated with the Huntly Power Station operations are permitted activities in the Waikato District Plan.

2.4.1.2Water Take and Discharge Permits

A suite of water take and use and discharge permits were granted for the Huntly Power Station by the Waikato Regional Council in November 1994. These resource consents have a term of 20 years expiring in 2014. ECNZ is responsible for a range of environmental monitoring tasks associated with these resource consents and currently concentrates primarily on the monitoring of water quality and fishery habitat in the Waikato River.

2.4.1.3Air Discharge Permits

The Waikato Regional Council granted a suite of air discharge permits for the Huntly Power Station in December 1994. These resource consents have a term of 19 years expiring in 2013. ECNZ is responsible for a range of environmental monitoring tasks arising from these resource consents.

2.4.2Current Environmental Effects of the Asset

The primary environmental issues associated with Huntly Power Station are:

CO₂ emissions;
Cooling water discharges in the Waikato River environment;
Noise.

2.4.3Main Environmental Risks

2.4.3.1CO₂ Emissions

Huntly Power Station's CO₂ emissions are discussed in section 3.1.3 of this report.

2.4.3.2Waikato River Cooling

There are operational constraints on the Huntly Power Station during periods of high river temperatures to ensure adverse effects on fisheries are avoided.

While cooling water discharge consents have been gained for the site and these are in place until 2014, any change in the current operating regime at the Huntly Power Station leading to a higher thermal load on the river, or a reduction in current low flow requirements from Karapiro Dam, could potentially further constrain the operation of the Huntly Power Station.

2.4.3.3Huntly Construction Dump

A construction dump associated with building Huntly Power Station was identified in an environmental audit of the site undertaken by Kingett Mitchell Ltd. EMS considers that this site should be properly identified and any actual or potential environmental effects characterised and managed appropriately.

2.4.3.4Community Acceptance

Apart from the issues associated with the burning of fossil fuels, river cooling and the construction dump, EMS do not consider there are any overriding environmental risks that threaten the ongoing operation or viability of Huntly Power Station, as it has been well managed from an environmental and community relations perspective. All operational consents under the RMA have been obtained, with significant community input through the ECNZ convened "Huntly Working Party" together with the maintenance of good relationships with Tangata Whenua. This is particularly important given the close proximity and significance of Waahi marae and surrounding Maori owned land. The issue of noise emissions from the station site has had ongoing assessment since the early 1990's and mitigation measures to reduce noise effects have been progressively implemented.

2.4.4Potential Environmental Related Operational Constraints

EMS are aware of three issues that have environmental implications and may impose operational constraints on Huntly Power Station. These issues are outlined in the following sections.

2.4.4.1Cooling Water Discharge Constraints

The current cooling water discharge consent conditions constrain the operation of Huntly Power Station during periods of high river temperatures. Extensive monitoring and research has been undertaken concerning existing constraints, along with consultation with the community, to address any adverse environmental effects or concerns associated with the possible variation of this consent.

Huntly could also be potentially constrained were any change to the minimum flow regime at Karapiro implemented. The Huntly IDG has proposed to the Waikato IDG that this issue be addressed as part of the agreements relating to the management of the Waikato River and Lake Taupo.

2.4.4.2Air Discharge Constraints

A variation to the Opacity Limits on the air discharge consent will shortly be sought and in EMS' view, should be a straightforward issue.

2.4.4.3Noise Emission Issues

Huntly Power Station has existing use rights with respect to noise emission impacts. The design of the Huntly Power Station buildings, and location and configuration of plant means that the site is not readily able to meet the normally acceptable limits of 45dBA (L₁₀) nighttime noise standard at the nearest residential boundary. ECNZ have however, been assessing the noise issue at Huntly Power Station since the early 1990's and has been progressively implementing engineering measures aimed at reducing noise emissions. According to EMS, the management of these issues do not pose significant risks to the ongoing operational viability of Huntly Power Station.

2.5Meremere Thermal Station (Meremere A and B Sites)

2.5.1Status of Current Consents

2.5.1.1Waikato District Plan - Land Use

The Meremere A and B Sites are located within a special "Power Station" zone in the operative Waikato District Plan. Within this zone,

"The use of land for activities and structures associated with the generation of electricity....is permitted in the Meremere A Power Station Area....subject to conditions for permitted activities".

The conditions for permitted activities relate to yards, height, screening and services. If any of these conditions cannot be complied with in relation to any future developments at the Meremere site, the new activity would be treated as a discretionary activity and thus may require resource consents.

Power Station activities at the Meremere B site and for "conveyance utilities" between the Meremere A and Meremere B sites are a discretionary activity. The following "conveyance utility" is also provided for as a permitted activity in the Waikato District Plan:

"Coal conveyance within the existing energy corridor to Meremere A Power Station area"- the causeway over the Whangamarino Wetland.

2.5.1.2Other Resource Consents

The Meremere sites do not have any other resource consents apart from historical Pollution Advisory Council (PAC) permits that expire in 2001, for the take and discharge of water.

Nga Puawaitanga have applied for a range of resource consents for a waste to energy plant at the Meremere A site and an agreement is in place between ECNZ and Nga Puawaitanga. Hearings for the resource consent applications are expected in early 1999.

2.5.2Current Environmental Effects of the Asset

The primary environmental issue pertaining to the Meremere A site relates to site contamination. In its report on the Nga Puawaitanga applications, the Waikato Regional Council concluded that:

"Staff agree with the applicant that the Meremere site is contaminated. Staff suggest that the contamination arises from a variety of sources:

Coal dust;
Coal ash residues;
Municipal waste- both domestic and industrial;
Treated sewage.

which potentially will require remediation. Staff further concur that the ground water beneath the site is potentially contaminated with leachate from these sources.

It is unclear from the information provided by the applicant the extent and significance of the leachate upon groundwater. Staff recognise that there is potential for contaminated ground water to adversely affect the Waikato River and/or the Whangamarino Wetland.

The applicant gives very little information about current ground water contamination. This is surprising given the history of occupation at the site and the current interest being shown elsewhere in toxic organic contamination of soils and ground waters.

In Staff's opinion the applicant needs to provide a more detailed characterisation of the ground water, in order that an assessment of effects can be made. This should include but not be limited to:

Chemical quality;
Flow rates;
Flow directions;
Appropriate treatment methods

These matters should be addressed at the Hearing."

The Waikato Regional Council has since indicated they did have concerns regarding responsibility for site contamination and remediation issues at Meremere.

2.5.3ECNZ

ECNZ has sought to develop a workable approach towards Meremere contaminated site issues. Historically, investigation and monitoring had been undertaken with specific problem areas progressively identified and rehabilitated to an appropriate standard. The approach taken by ECNZ to the contaminated site issues since the early 1990's is considered by EMS to be reasonable, considering the uncertainty regarding the future redevelopment of the site.

With the negotiation of the sub-lease option between ECNZ and Nga Puawaitanga, ECNZ have not implemented any further investigations or site rehabilitation at Meremere, pending the results of the resource consent applications by Nga Puawaitanga. Again, this is considered by EMS to be a reasonable approach by ECNZ, as a package of contaminated site remediation/management works for the non-rehabilitated areas would need to be implemented by Nga Puawaitanga, if they gained their necessary resource consents.

EMS are not aware of any other significant environmental issues at the Meremere A or Meremere B sites.

2.5.4Main Environmental Risks

If Nga Puawaitanga are unsuccessful with their resource consent application, the site will return to the Huntly SOE. In this case, the Huntly SOE would be responsible for site clean up. EMS estimate that outstanding liability could be either:

To rehabilitate remaining areas to the similar standard as the rehabilitated asbestos land fill, municipal waste landfill and coal stock pile, assuming that the current power station buildings stay in place, or
To substantially rehabilitate the whole site to an appropriate standard if the current power station buildings were removed and the site was returned to farmland.

2.5.5Potential Environmental Related Operational Constraints

The Meremere sites are not operational sites, and therefore there are no current operational constraints. However, EMS note the following issues:

ECNZ has maintained the lease interest in the Meremere A causeway. This lease provides wide operational flexibility for both sites in terms of any future fuel supply requirements;
Longstanding issues with the Department of Conservation associated with fuel and access corridors between the Meremere A and B sites and marginal strip issues have now been resolved;
ECNZ has made a submission to a "Notice of Requirement" by Transit New Zealand to designate land in the area for a new 4-lane highway. The submission was to protect the long-term operational integrity of the Meremere sites. As at 20 November 1998, this issue has not yet been finalised.

2.6Te Awamutu Cogeneration Station

2.6.1Status of Current RMA Authorisations

2.6.1.1Waipa District Plan - Land Use

The Te Awamutu Dairy Factory Co-generation Plant is located within the "Tall Buildings Area"in the "Industrial Zone" in the Waipa District Plan. Key performance standards relate to height, yards, screening and noise.

2.6.1.2Waipa District Council Resource Consents

A land use consent was granted to Anchor Products Limited by Waipa District Council in October 1994 to establish a Co-Generation Plant. The Waipa District Council issued a "Certificate of Compliance" to ECNZ in February 1997, confirming the permitted activity status of the addition of a Fresh Air Firing System to the Co-Generation Plant. As such, ECNZ is able to use these consents for the Co-Generation Plant, as specified in the joint venture arrangement between ECNZ and Anchor Products.

2.6.1.3Air Discharge Permit

An air discharge permit was granted to Anchor Products Limited (as part of a wider application) to discharge contaminants into the air from a gas-fired Co-Generation Plant and associated processes, which will expire in June 2009. In December 1996, the Waikato Regional Council confirmed that the addition of a Fresh Air Firing System to the Co-Generation Plant is generally in accordance with the conditions of the existing air discharge permit and that a change to the existing resource consent was not required.

2.6.1.4Water Take and Discharge Permits

Water takes and discharges associated with the Co-Generation Plant are provided for as part of the water permits and discharge permits relating to the entire site.

2.6.1.5Comments

Both the Waipa District Council land use consent and the Waikato Regional Council air discharge permit were issued Anchor Products Limited. In addition, water takes and discharges are provided for as part of the water take and discharge permits for the entire site. There is a high level of acceptance of the Co-generation Plant by the local community, Waipa District Council and the Waikato Regional Council. Prior to the commissioning of the Co-Generation Plant there were a significant number of complaints by local residents about particulate emissions associated with the burning of coal on the Te Awamutu Dairy Factory site. EMS consider that there are no environmental risks associated with this site.

2.7Kinleith Cogeneration Station

2.7.1Status of Current RMA Authorisations

2.7.1.1South Waikato District Plan - Land Use

The Kinleith Mill Co-Generation Power Boiler is located within the "Heavy Industrial Zone" in the South Waikato District Plan. Within this zone the following activities are permitted:

"Any Industrial Activity or Heavy Industrial Activity..." and "Buildings and activities accessory to any Permitted Activity."

Key performance standards relate to height, yards, screening and noise.

2.7.1.2South Waikato District Council Resource Consents

South Waikato District Council granted a land use consent to New Zealand Forest Products Pulp and Paper Ltd in October 1994. These consents were for the construction and operation of facilities for waste wood and ancillary fuel consumption, generation of electricity and other miscellaneous activities associated with a new Co-Generation Power Boiler operating at full capacity.

2.7.1.3Air Discharge Permit

An air discharge permit was granted to Carter Holt Harvey Pulp and Paper Limited to discharge contaminants into the air from a Co-Generation Power Boiler known as a No. 8 Primary Boiler and No. 1 Turbogenerator Set and ancillary activities with an expiry date of November 2024.

2.7.1.4Water Take and Discharge Permits

Water takes and discharges associated with the Kinleith Mill Co-Generation Plant are provided for as part of the water take and discharge permits relating to the entire site.

2.7.1.5Comments

The South Waikato District Council land use consent was issued to New Zealand Forest Products Pulp and Paper Ltd and the Waikato Regional Council air discharge permit issued to Carter Holt Harvey Pulp and Paper Limited. In addition, water takes and discharges are provided for as part of the water take and discharge permits for the entire site. There is a high level of local community acceptance of the Kinleith site particularly given its economic importance to nearby Tokoroa. The environmental issues relate to odour emissions and the discharge of contaminants to the Waikato River. However, both of these issues are unrelated to the operation of the Co-Generation Plant. EMS consider that there are no environmental risks associated with this site.

2.8Waikaremoana Hydro-Generation Scheme

2.8.1Status of Current Consents

The Waikaremoana Hydro-Generation Scheme (the Scheme) uses water from Lake Waikaremoana to generate power from three stations, Kaitawa (35MW), Tuai (58MW) and Piripaua (45MW). The Scheme diverts water from the:

Waikaretaheke River into Lake Kaitawa;
Mangaone Stream into the Waikaretaheke River;
Waikaretaheke River into Lake Whakamarino;
Kahutangaroa Stream into Lake Whakamarino.

With the enactment of the RMA, the taking and diversion of water associated with the Scheme was authorised through deemed resource consents. However, section 386(3) of the RMA assigned a duration to the resource consents of 10 years, therefore requiring renewal by 1 October 2001. ECNZ lodged its consent application in early 1998 and the Hawke's Bay Regional Council decision on the application was notified on 20 November 1998.

2.8.2Current Environmental Effects of the Asset

The Scheme is located within the Te Urewera National Park. The environmental effects of the Scheme relate to altered flow regimes in the Kahutangora, Mangaone and Waikaretaheke Rivers.

The scope and scale of possible environmental effects are complex, as expected for a scheme of this nature. According to EMS, these environmental effects however do not threaten the ongoing operational viability of the scheme.

2.8.3Status of Consents Renewal Process

Hawke's Bay Regional Council has granted resource consents for Waikaremoana with a 20-year term with 5 yearly reviews. The consent relating to the damming of Lake Waikaremoana imposes residual flow requirements in excess of those originally sought by ECNZ. However, those residual flows were negotiated and agreed to by ECNZ and the Department of Conservation prior to the Hearing.

2.8.4Main Environmental Risks

As the Waikaremoana Scheme has only just gained resource consents for a 20-year term, EMS do not consider that there are any environmental risks associated with the ongoing operation of the scheme.

2.8.5Potential Environmental Related Operational Constraints

The recent resource consents obtained by ECNZ include environmental offset and mitigation activities, related mainly to increased residual and recreational flow releases below dams and diversion structures. ECNZ have also committed to funding Department of Conservation pest control operations for the next ten years. EMS consider that there are no potential environmental constraints likely in the future.

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Printed: 30/07/2010

2.0 Approach to Environmental Assessment

2.1Background