Hunter Transmission Project -
EIS map

This map provides details for the EIS for the Hunter Transmission Project (HTP).

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Back to main menu Overview

This section provides a summary of the Hunter Transmission Project (HTP), outlining its critical role in NSW's energy future and the key infrastructure components involved.

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The Hunter Transmission Project is both a critical State significant infrastructure (CSSI) project and a Priority Transmission Infrastructure Project (PTIP). As the remaining coal-fired power stations close, the Hunter Transmission Project is critical for energy security in New South Wales (NSW).

The Hunter Transmission Project includes:

a new overhead 500 kilovolt (kV) double circuit transmission line of around 110 kilometres
two new switching stations (Bayswater South and Olney)
upgrades to the existing Bayswater and Eraring substations
adjustments and upgrades to existing transmission lines
property adjustment works to facilitate access to the transmission lines and switching stations
utility adjustments required for the construction of the transmission network infrastructure
ancillary works to support construction including road upgrades, establishment of new access tracks and upgrades to existing access tracks, construction support sites (some with temporary worker accommodation), and other construction facilities such as laydown areas.

The Hunter Transmission Project corridor runs mostly through power station, mining and government land between Bayswater and Broke. It then traverses the Pokolbin, Corrabare, Watagan and Olney State forests where it joins the existing 500 kV transmission line running between Eraring and Kemps Creek in Western Sydney.

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Mines

NPWS reserves / national & state conservation areas

State forests / recreation areas

The Hunter Transmission Project corridor runs mostly through power station, mining and government land between Bayswater and Broke, then traverses the Pokolbin, Corrabare, Watagan and Olney State forests to join the existing 500 kV transmission line between Eraring and Kemps Creek in Western Sydney.

The Energy Corporation of New South Wales (EnergyCo) selected a corridor that sought to balance different land uses in the Hunter and minimise impacts on people and the environment.

The corridor avoids sensitive land uses including vineyards, tourist areas, State forest recreation areas, Watagans and Werakata National Parks, Corrabare South and Warrawolong Flora Reserves, Werakata State Conservation Area and Sugarloaf State Conservation Area.

It also avoids other high conservation value areas including existing biodiversity offset sites and intact remnants of threatened ecological communities such as the Central Hunter Valley Eucalypt Forest and Warkworth Sands Woodland, which provide critical habitat for the Regent Honeyeater and Swift Parrot. Significant Aboriginal cultural heritage sites are avoided or impacts minimised, including rockshelters, cultural places, grinding grooves and Flat Rock Lookout.

Back to main menu Biodiversity

Protecting the natural environment is a key priority. This section details the assessment of potential impacts on local biodiversity, including native vegetation, threatened species, and ecological communities, and outlines measures for avoidance and mitigation.

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Sensitive biodiversity areas (SBA)

Native vegetation extent

During corridor selection, EnergyCo prioritised avoidance of high conservation value areas, including Watagans and Werakata National Parks, Corrabare South and Warrawolong Flora Reserves, existing biodiversity offset sites, and intact remnants of the Central Hunter Valley Eucalypt Forest and Warkworth Sands Woodland threatened ecological communities. These communities support threatened species and critical habitat for the Regent Honeyeater and Swift Parrot.

Following selection, the transmission line design underwent iterative refinement based on ecological field surveys and site constraints, resulting in substantial further avoidance and minimisation of biodiversity impacts. Cumulatively, these refinements are expected to reduce clearing of native vegetation by over 200 hectares, including avoidance of more than 100 hectares of threatened ecological communities and important habitat for a range of serious and irreversible impact entities.

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Disturbance Area A (full clearing)

Disturbance Area A (20 m centreline)

Disturbance Area B (partial clearing)

Hazard tree zone (HZ)

A disturbance area has been used to assess potential impacts on biodiversity values. It includes the following categories:

Disturbance area A – the area where vegetation would be completely removed.
Disturbance area A (centreline) – a 20‑metre‑wide centreline area between transmission towers where all vegetation would be removed.
Disturbance area B – the area within the transmission line easement, excluding disturbance area A and disturbance area A (centreline), where partial clearing would be undertaken.
Hazard tree zone (HZ) – areas where hazard tree management would occur during operation.

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Threatened ecological communities

While significant efforts have been made to avoid and minimise impacts, vegetation clearing is still required in some areas of high biodiversity value, including threatened ecological communities and threatened species habitat listed under the NSW Biodiversity Conservation Act 2016 (BC Act) and the Commonwealth Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act).

BC Act: 207 hectares aligning with seven endangered ecological communities (≈64 ha BC Act only; 142.78 ha dual‑listed under BC Act and EPBC Act).
EPBC Act: 158 hectares aligning with three critically endangered ecological communities (15.22 ha EPBC‑only; 142.78 ha dual‑listed under EPBC and BC Acts).

Two communities are identified as potential serious and irreversible impact entities: approximately 4.22 ha of poor‑condition Hunter Floodplain Red Gum Woodland and 12.37 ha of Warkworth Sands Woodland.

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Threatened flora records

Construction could directly impact 38 threatened flora species: 22 listed under both the BC Act and EPBC Act, 14 under the BC Act only, and 2 under the EPBC Act only. Eight species are potential serious and irreversible impact entities, including Acacia pendula (Hunter population), Eucalyptus castrensis (Singleton Mallee), Eucalyptus fracta (Broken Back Ironbark), Eucalyptus pumila (Pokolbin Mallee), Persoonia hirsuta (Hairy Geebung), Rhizanthella slateri (Eastern Australian Underground Orchid), Rhodamnia rubescens (Scrub Turpentine) and Rhodomyrtus psidioides (Native Guava).

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Threatened fauna records

Construction could directly impact 28 threatened fauna species: 15 listed under both the BC Act and EPBC Act, and 13 under the BC Act only. Six species are potential serious and irreversible impact entities, including the Large‑eared Pied Bat, Stuttering Frog, Brush‑tailed Rock‑wallaby, Long‑nosed Potoroo, Sooty Owl and Eastern Cave Bat.

Back to main menu Aboriginal heritage

EnergyCo acknowledges the Traditional Owners and Custodians. This section outlines the findings of the Aboriginal cultural heritage assessment, including identified sites of significance and measures to respect and protect cultural values.

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Aboriginal sites & places (significance coded)

Directly impacted cultural landscape

Survey efforts involved around 643 kilometres of linear pedestrian survey (about 2,259 hectares) and 7,702 individual points of observation across the project impact area. A targeted program of test excavations was also undertaken to support the field survey where sub‑surface material was likely.

The program identified 32 Aboriginal sites or places within the construction impact area. Of these, five sites of high scientific and/or cultural significance would be avoided (DEEP CK MOTHER SWA, Flat Rock Lookout (HTP‑C‑CP01), HTP‑C‑CVM08, HTP‑C‑GG03, HTP‑C‑GG05). Around 12 sites and places may only be partially impacted or unaffected because they are in areas with minimal or unlikely ground disturbance. One further site is mostly outside the impact area and would be minimally impacted.

Due to landowner and access constraints, the test excavation program is ongoing. Findings from additional investigations will be provided in an addendum or revised Aboriginal cultural heritage assessment.

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Cultural viewpoints (SL5, SL8, etc.)

Cultural viewlines & viewscapes

Detailed cultural mapping by an anthropologist, Elders and key knowledge holders identified 32 places of archaeological, traditional, historical and/or contemporary value. Field investigations assessed cultural views from Mount Sugarloaf, Mount Yengo and Mount Warrawalong with Awabakal Traditional Owners.

Of 11 locations visited that intersected broader viewlines, two were assessed as subject to significant impacts, five to partial impacts and four to no impacts. The two significant‑impact locations were: SL5, associated with viewlines between Mount Warrawalong and Mount Vincent and between Mount Warrawalong and Mount Sugarloaf (the corridor would encroach within ~500 m); and SL8, a promontory at the northern extent of Burma Road (the corridor would encroach within ~100 m of the viewline to Mount Vincent/Mount Sugarloaf).

Back to main menu Landscape and visual

The visual character of the region is an important consideration. This section assesses the potential visual impacts of the project on the surrounding landscape, public viewpoints, and private residences.

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The landscape character and visual study area was determined in accordance with the Transmission Guideline, Technical Supplement for Landscape Character and Visual Assessment (DPHI 2024). It includes: a landscape character assessment study area encompassing all areas within 5 km of the project, and a visual assessment study area encompassing all areas within 1.625 km of the corridor (based on a maximum tower height of 85 m). Construction support sites outside the landscape character study area were also considered for temporary impacts.

Sensitive receivers include dwellings, historic homesteads, tourist and visitor accommodation, places of worship, town centres and CBDs within the visual assessment study area.

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Landscape character zones (LCZ)

The landscape character assessment divided the study area into 12 landscape character zones (LCZs) based on similar topography, vegetation and land use. During the daytime, the project would have a moderate impact on three LCZs: LCZ 7 (Wollombi Brook rural valley), LCZ 8 (Forested hills) and LCZ 11 (Narrow rural valleys). At night, a moderate impact is predicted at LCZ 12 (Managed forestry) at the proposed Olney switching station due to occasional localised lighting. All remaining LCZs would experience low to negligible impacts during construction and operation.

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Public viewpoints (incl. Cessnock Rd 07)

A simple visual assessment was undertaken for 12 public viewpoints representing views to the project. Six had potential low visual impact and six had potential moderate or high impact. A detailed assessment of the latter group (Putty Road, Cessnock Road, Wollombi Road (east), Flat Rock Lookout, Olney Headquarters campground and picnic area, and Watagan Forest Road) found that Cessnock Road (07) would have a moderate visual impact; the remaining public viewpoints would have a low visual impact.

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Private viewpoints (moderate/low)

Private viewpoints associated with rural dwellings would experience visual impacts from the introduction of permanent infrastructure. Of 68 dwellings assessed, 34 had potential low impact, 22 potential moderate impact and 12 potential high impact in the simple assessment. Detailed assessment found moderate impacts for six private viewpoints (IDs 238, 465, 466, 467, 2920 and 2929); the remaining viewpoints would have low or no visual impact.

Back to main menu Traffic and transport

Managing construction traffic effectively is crucial for community safety and minimising disruption. This section details the assessment of traffic impacts, including proposed routes, vehicle movements, and necessary road upgrades.

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Construction traffic routes

Oversize–overmass (OSOM) routes (Within study area)

Construction of the project would generate both light and heavy vehicle movements, including some oversize/overmass deliveries, using national, State, regional and local roads as well as roads within NSW State forests and conservation areas. During the morning peak, up to 201 heavy and 300 light vehicle movements are expected; during the afternoon peak, around 172 heavy and 240 light vehicle movements are expected. Movements would be distributed across identified routes between work sites and construction support sites (Hebden Road, Pikes Gully Road, Gouldsville Road, Wollombi Road and Freemans Drive). OSOM deliveries include transformers to Eraring substation (≈7 deliveries), reactors to Bayswater South switching station (≈3) and auxiliary services buildings to each new switching station (≈2). A road capacity assessment indicates most routes would operate well even at peak times, with the New England Highway (west of Lemington Road) and Freemans Drive (south of Martinsville Road) near capacity or satisfactory.

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Access tracks – new

Access tracks – existing (upgrade)

Access tracks – existing (no upgrade)

Entry points

The project would use a mix of new and existing access tracks on private properties. Some existing tracks require upgrades to accommodate construction vehicles and machinery and to provide safe access during construction and operation. Where existing tracks are unsuitable or terrain prevents access along the corridor, new tracks would be constructed—preferably within already‑disturbed areas. In State forests, traffic control and passing bays are proposed to improve capacity and safety.

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Proposed road and intersection upgrades

To safely accommodate construction traffic and oversized deliveries, upgrades to public roads and key intersections are proposed along construction routes. These will be confirmed with the relevant road authorities and will require approvals under the NSW Roads Act 1993.

Back to main menu Noise and vibration

Minimising noise and vibration is important for nearby communities. This section outlines the assessment of potential noise impacts during both the construction and operation of the project.

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Noise catchment areas (NCA)

Sensitive receivers (potentially impacted residents/ facilities)

Noise monitoring locations & baseline

The noise and vibration study area reflects the possible distance within which sensitive receivers may experience noise and vibration from the project. It is defined by noise catchment areas (NCAs), which group receivers with similar noise environments around project components and activities. Sensitive receivers are primarily residential dwellings on agricultural properties, with other categories including commercial/industrial premises and other sensitive land uses (e.g. places of worship, recreation areas, campgrounds).

Existing noise levels are typical of rural areas and dominated by natural sources such as wildlife and weather. Unattended and short‑term attended ambient noise monitoring was carried out at six locations selected to represent background levels across the project area. Publicly available monitoring data from other projects were used to supplement measurements, given the large extent of the study area.

These results were used to determine project‑specific noise management levels—the thresholds used to assess and manage potential noise impacts at sensitive receivers.

Construction activities—including plant and equipment operation, construction traffic and workforce accommodation facilities—may temporarily impact sensitive receivers. On‑site monitoring and modelling indicate that short‑term exceedances above typical background levels may occur during peak construction activities. Exceedances are predicted at sensitive receivers within all NCAs apart from NCA 1 (Liddell and Bayswater), NCA 7 (Pokolbin) and NCA 10 (Cessnock). Nearby receivers may also experience short‑term vibration impacts. A noise and vibration management plan will be implemented to minimise impacts.

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Operation impacts from transmission

Operational noise from the transmission line and switching stations is expected to be low. Receivers are unlikely to experience noise or vibration impacts during fair‑weather conditions. Switching station noise is predicted to be well within acceptable levels. The high‑voltage line may generate a soft hum that is more detectable under certain weather conditions (e.g. light mist or rain); conservatively, up to 10 receivers closest to the corridor could experience operational noise exceedances during such events.

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Overview

Biodiversity

Aboriginal heritage

Landscape and visual

Traffic and transport

Noise and vibration

Project overview

Avoidance of environmentally sensitive areas

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Avoidance and minimisation of biodiversity impacts

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Disturbance area

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Threatened ecological communities

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Threatened flora

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Threatened fauna

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Aboriginal sites and places

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Significant viewlines and viewscapes

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Study area and sensitive receivers

Landscape character

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Public viewpoints

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Private viewpoints

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Construction traffic

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Access tracks

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Proposed road and intersection upgrades

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Study area and sensitive receivers

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Noise monitoring and noise management levels

Construction noise impacts

Operation noise impacts

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