TRANSPORT AND TECHNICAL SERVICES
JERSEY ELECTRICITY COMPANY’S APPLICATION TO LAY NEW 90KV CIRCUIT FROM SOUTH HILL TO ST AUBINS BAY PROMENADE (OPPOSITE TYNEVILLE LANE) IN THE HIGHWAY AND OTHER PUBLIC AREAS
Purpose of the Report
To obtain a Ministerial Decision regarding outline approval of the Jersey Electricity Company’s (JEC) proposed street works in terms of service route, programme, traffic management and final reinstatements as the ‘main road’ Highway Authority and as the Authority with responsibility for St Aubin’s Bay Promenade.
Background
As part of an extensive and ongoing programme of investment in their High Voltage infrastructure, the JEC is constructing a new 90Kv Switching Station at South Hill. The Switching Station will become the central hub of the High Voltage network and will be the most strategically important element of the Island’s electricity infrastructure as it will tie together all the other major substations in the Island and once commissioned will be the termination point of the proposed third interconnector to France and any subsequent future connections that are installed.
As such, the project includes an extension of the 90Kv transmission network between South Hill and Victoria Avenue (opposite Tyneville Lane) in order to integrate the new Switching Station into the recently commissioned circuits between Queens Road and the Western Primary Substation located at Jersey Airport. It is this ‘street works’ element of the project that is the subject of this report and the Ministerial Decision.
Work Details
In general the works will involve laying six 140 to 180mm diameter PVC ducts (to carry the 90Kv cables) over a distance of 2,365m, about 50% of which will be ‘off road’ whether in parking zones or grass verges or along the Promenade. The trench will in general be just over one metre wide (see attached typical section). In addition three large joint bays will be constructed, one ‘off road’ near the entrance to the Tunnel and one ‘just in’ the road near the Esplanade / Castle Street junction and one opposite Tyneville Lane in the Promenade. Cable pulling work will form the last phase of street works but will have minimal impact on traffic, etc.
Route
The project was first outlined by the JEC in 2007, since which time there has been an ongoing dialogue with the Department (as the project has evolved) about the optimum route. The proposed route (see attached plan) for the ducted cables has been derived from consideration of the following issues:
- The impact of the work on the traffic network, public and road condition.
- Compatibility with the proposed Esplanade Quarter and enabling works.
- Available joint bay locations and road service capacity.
- Work share opportunities (see below).
In addition use has been made, where possible, of the space currently occupied by an existing 33Kv transmission network (that will be decommissioned and removed) in order to provide route certainty and avoid service conflicts.
Shared Works
In the interest of reducing disruption to the public the Department has identified opportunities for the JEC to ‘work share’ with Cable & Wireless and Newtel Limited along the Esplanade, principally between Weighbridge Place and Castle Street.
Therefore, the Department has negotiated with all three companies who have agreed to this working arrangement and have appointed Geomarine Limited as their civil contractor and project co-coordinator.
Programme & Traffic Management
The programme (see attachment) for the street works element of the project has been principally defined by:
- The commissioning date for the new South Hill Switching Station (October 2011) by which time all cabling works must be complete.
- The programmed resurfacing of Commercial Buildings from March 2011 ahead of the commissioning of the EFW plant at La Collette later in the year.
- Co-ordination with Cable & Wireless and Newtel network expansion works along the Esplanade, principally between Weighbridge Place and Castle Street.
- Seasonal constraints, particularly in relation to the Esplanade between Weighbridge Place and Castle Street during December 2010 and from the end of April 2011 (i.e. Easter). Also St Aubin’s Bay Promenade from the end of April 2011.
The major programme / traffic impact elements of the works are summarised as follows:
- South Pier / Commercial Buildings (Early October 2010 for twelve weeks): The section from South Pier up to the ‘Old Harbour’ is likely to cause disruption to commercial traffic to and from La Collette as Portable Traffic Signals will be needed. Along Commercial Buildings significant parking suspension will be required to maintain two way traffic.
- Esplanade from Weighbridge Place to Castle Street (Early January 2011 for seven weeks): Eastbound traffic will be diverted along Commercial Street. This traffic management arrangement has previously worked well, with normal operation of the Bus Station possible. The critical issue is that the works will be cleared by Easter (i.e. late April) although final resurfacing (see Road Reinstatement) may not take place until the Autumn.
- Esplanade from Grand Hotel to Gloucester Street (Mid February 2011 for two and a half weeks): Following a staged crossing of the Esplanade the eastbound kerbside lane of the Esplanade will be closed, potentially causing significant delays. However, this has been mitigated against, so far as it is possible, by starting the works over the Spring Half Term when traffic flows are at their lowest annual level, and carrying out evening / weekend working.
Otherwise works such as junction crossings, etc. will be carried out during ‘off peak’ times or out of hours such as in the evenings or on Sundays etc. as required to minimise disruption to the network.
Negotiation Agreement
The Department has negotiated the following package of concessions from the JEC in relation to its’ agreement to permit the use of main roads and St Aubin’s Bay Promenade as outlined in this report.
Further to compliance with the ‘Specification for the Reinstatement of Openings in Main Roads’ the JEC will undertake a series of ‘enhanced’ reinstatements as set out in the attached ‘Reinstatement Schedule’, the key ones being:
- Commercial Buildings: Due to the short time period between trenching works and the road resurfacing (i.e. less than six months), Type 2 backfill material will be replaced with Foam Concrete to avoid settlement of the new road.
- Esplanade: Given that the area between Weighbridge Place and Castle Street was remodelled in 2007 as part of the development of Liberation Station and is of a high level of visual importance, Type 2 backfill material will be replaced with Foam Concrete and the surface course will extend from the kerb to the road centre line. Table tops etc. will be completely rebuilt. This work will be undertaken by TTS on behalf of the JEC, Cable & Wireless and Newtel who will share costs.
In addition, the JEC has agreed to make a financial contribution of One Hundred Thousand Pounds (£100,000) to the Department. The contribution is in recognition of the cost impact the project will have on the main road network and St Aubin’s Bay Promenade in terms of reduced pavement life and reduced visual acceptability, which are likely to lead to increased road maintenance and early resurfacing.
Recommendation
The Minister is recommended to approve the proposed service route, programme, traffic management and final road reinstatements.
Reason(s) for Decision
The JEC’s proposed route, programme, traffic management, road reinstatements and financial contribution (£100,000), in recognition of the cost impact of the project to the Department, are acceptable in the light of the positive benefits of the infrastructure work to the Island as a whole.
Resource Implications
Normal TTS street works inspections both during works and later in relation to the monitoring of reinstatements.
Action Required
Street Works Manager to inform the JEC of the Minister’s decision.
Written by: | Street Works Manager |
Approved by: | Director, Municipal Services |
Attachments: | Summary Route Plan & Typical Cross Section, Summary Project Programme, Reinstatement Schedule. |
WR JEC Application to Lay New 90KV Cable.docI:\Minister\2010\Ministerial Decisions\MD 00 JEC Application to Lay New 90KV Cable\WR JEC Application to Lay New 90KV Cable.doc