NEW DEVELOPMENTS - Te Aponga Uira
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NEW DEVELOPMENTS

Careful steps are being taken to optimise existing power system assets as well as new investments in generation, storage, grid stability and customer control assets.

 

In November 2016 TAU will release its Stage 2:  Rarotonga Renewable Energy Implementation Plan by 2020 and Beyond outlining its Investment Plan to achieve and successfully maintain the Government of the Cook Islands goal of 100% renewable energy over a 15 year horizon.

 

In the meantime TAU has some exciting projects that are currently being investigated.  Check out our fast-track projects below and let us know if you are keen to partner with us on this exciting journey to 100% renewable.

 

Wind

 

Compared to high penetration Solar PV, Wind generation offers a significantly less expensive investment as the generation profile better matches load (thus reducing the requirements for load shifting storage), and so is retained for consideration as a key RE generation source for Rarotonga.  TAU requires the following inputs:

 

  • Identification and securing suitable sites
  • Plant specifications to match operational requirements and site conditions
  • Design and build Wind generation plant(s) to increase RE generation contribution on TAU network

 

 

Time Shift Storage

 

Storage will play an important role in TAU achieving very high penetration from Solar PV & Wind generation.  Time shift storage is required to better manage the supply of electricity from high penetration nondispatchable generation to match consumer demand.  A combination of central and distributed time shift storage is being considered by TAU.

 

Depending on the generation source, it is likely Rarotonga will need at least 5MW/20MWh in storage.  TAU needs support in designing and acquiring time shift storage systems as well as developing and discharging of storage systems, in conjunction with TAU connection requirements.

 

Grid Stability Battery

 

TAU will need to address challenges associated with grid stability as intermittent RE penetration increases beyond current levels.

 

The systems for grid stability would respond very quickly to intermittent generation by either supplying or absorbing power to smooth out rapid changes in (effective) load associated with changes in distributed generation output on the network.

 

TAU needs support in developing specifications and defining TAU grid stability criteria at higher levels of generation as well as acquiring the technologies.  Having this system in place will ensure continued growth in RE penetration does not compromise the safe and reliable electricity supply Rarotonga.

 

Smart Metering

 

With growing intermittent renewable generation distributed around its network, and the introduction of SCADA, there is an immediate need for TAU to be able to communicate as well as control loads and generation across its network to maintain reliability.  This requires communication infrastructure between the power station and generating sites at low cost.

 

TAU needs technical support in exploring options and then putting the required infrastructure in place.

 

Having this infrastructure in place will also provide a platform for smart metering and associated customer usage management and control applications promoting energy efficiency.

 

Bio Fuel Testing

 

Following an entire Power Station upgrade and the installation of 5 high speed generators to better respond to unconstrained renewable generation on Rarotonga, TAU will be progressing Bio Fuel testing using its older generators – and will do so through its live power system.

 

What is required is holding tanks for bio fuels as well as configuring the connection times from tank to generator.

 

This is an exciting opportunity to lift Rarotonga to 100% and in doing so Rarotonga will consider partnering with other Pacific Island Countries seeking to also test theses technologies or their own bio fuel industry supply on a live power system.

By the end of this year, TAU will probably have the most fire safety measures of all facilities in the Cook Islands.

Although there is a way to go, the activity is very evident at the power station in Avatiu valley.

This month, local contractor D-Vent packed small red pillows containing fire retardants around ceiling penetrations of wire (see photo).   Similarly Landholdings Ltd builders have glazed windows and glass doors so they can withstand higher heat temperatures, thereby enabling staff more time to escape in case of fire.  These are jobs that a fire safety expert has identified could be done quickly using local skills and resources.  Other jobs that require equipment and resources from overseas will take longer to do.

The fire safety upgrade project which is sparking the above activity was originally put out to tender in April last year and was intended to raise fire safety at TAU facilities to New Zealand and Australian standards.  It involved engaging NZ fire safety engineer Peter McKenzie to review safety issues, design a fire safety concept, and oversee its construction and instalment.  The project covers both the Avatiu power station and at the TAU administration and network buildings in Tutakimoa.

McKenzie briefly visited Rarotonga last week to monitor progress, and is expected to return at the end of February for further supervision.

(27 January 2015)

What’s happening at the Avatiu Power Station?

This is the question that is being asked this week after a request for proposals to build a new power house was published in local news media.

Here’s the answer.  The Avatiu Power Station is being progressively upgraded to maintain system integrity as well as to cater for the transition to renewable energy generation.

The plan was first unfolded three to four years ago.  To date TAU has completed the upgrading of its fuel facility, replacement of cooling systems and the modernization of the control system on the existing generators.  The latter replaces mechanical control systems with electronic computer systems that respond faster to intermittent generation.

On the immediate horizon are new engines, a second power house, new switchgear and fire risk mitigation measures.  Each is a component of a package to support the transition to renewable energy generation.

New work will take place in the 2014/15 financial year which involves the staged installation of three new high speed engines including the associated switchgear and modern automated control systems. These engines will have rapid automatic start capability, and faster load response, to compensate for variable renewable generation output.

Two of the three engines are earmarked to be commissioned in the 2014/15 year and the third the following year although for costs benefits the procurement of the third engine will be committed in 2014/15.

A second power house that will accommodate the new engines will be constructed behind the existing power house, and will be commissioned in 2014/15 although the electrical connections will be in the existing power station.

Incorporated into the new power house is the installation of a flywheel system, a form of ‘enabling technology’, primarily to facilitate the transition of the intermittent PV and diesel generators but also provides spinoff capacity for the generating system. Basically, what this means is that the flywheels spin continuously, and will come on line should a renewable generator suddenly stop producing and fill in for seconds or minutes until a backup diesel generator can take over power production. The flywheel system is also designed to reduce the cost, and fuel consumption, associated with maintaining diesel-driven spinning reserve. An evaluation and analysis is currently underway that will not only specify the design parameters to suit our system but it will also provide a schedule of installation.

The overall strategy is to incorporate intermittent supplies from renewable energy generation together with diesel generation.  Diesel generation will ensure there is a backstop to deliver base load power whenever renewable energy generators are unable to produce.”

(Published 13 May 2014)

Te Aponga Uira has engaged fuel supply specialists Pacific Energy to carry out a prioritization exercise on the Avatiu Valley Power Station in order to determine the scope and nature of upgrades to its fuel facility.  This engagement of PE is a concrete step toward resolving a number of outstanding issues stemming from plant audit inspections, raised over past years.

Audit Reports have been conducted on TAU’s fuel storage facility at the Station in 2008 and 2010 under reviews of standards related to Dangerous Goods.  Existing legislation has thus far applied only to fuel retailers but Te Aponga expects to be embraced under new legislation currently being drafted.  Past efforts have been undertaken as a result of the audit inspections although rehabilitation and upgrade work has generally been perceived as slow-moving.

Now better-placed with renewed urgency to commence upgrades, TAU will be actively programming project work at the Avatiu Station.  Pacific Energy is expected to prepare a detailed plan of implementation for TAU based on prioritized rehabilitation and upgrades to resolve the outstanding issues.  Issued on 7 June 2012.

web generation

Te Aponga Uira’s Generation Division successfully traversed a re-roofing manoeuvre last week (4-5 April 2012) when an engine had to be shut down to allow for overhead construction work.  The temporary load reduction at the Power Station was compensated for with the close cooperation of three major customers, who agreed to run their facilities on standby generators – while the roofing work at Avatiu Valley proceeded.  This segment of roof replacement work spanned a 48 hour period with interior scaffolding over the affected area.  For safety reasons, the engine shutdown was required to allow the builders to complete the job.  The cooperation of the customers was only required temporarily, during peak hours of midday and the evening. Issued on 11 April 2012.

web office layout

This top floor office has received its finishing touches and is ready for layout planning and fitting.

web top office

office

The new office space atop the headquarters building in Tutakimoa is taking shape as builders continue to line the facility and prepare the flooring.  Work is on schedule and is expected to progress over the coming week.

Roof office

Te Aponga is organising the utilisation of its new roof top space to accommodate staff.  Originally, the space option was being taken up for storage (see below) but upon further consideration, it appears that the roominess of the area lends itself well to office space for personnel.  Taking advantage of the additional space makes sense for TAU Head Office as staff have been working under closely-stationed conditions for some years.  Local building interests are being considered to do the job of fitting it out for offices.  Issued 23 February 2012.

Roofing completed

The new roofing addition to the Admin/Network building at Tutakimoa will double up as storage space, in addition to catering for the installation of solar PV panels.  The Head Office building is nearing completion of its re-roofing with painting and interior work underway.  The new sloping roof is part of the Re-roofing Project for the Tutakimoa building and Avatiu Valley Power Station.  Te Aponga is undertaking the project in advance of an NZAID-funded solar project, which has commenced tendering for contract bids.  Two entities are targeted for solar installations under the NZ project:  TAU and the Ministry of Education.

Meanwhile, TAU will be utilising the new addition for the storage of archived files/documents and some equipment.  The original asbestos roofing sheets were successfully removed last week and will be disposed of by the contractor under National Environment Service regulations.  Work is expected to get underway on the Power Station building shortly.  Issued 7 February 2012.

cooling towers

Te Aponga Uira will be replacing the two cooling towers for three of its generators at the Avatiu Power Station.  The two cooling towers (pic) service three old engines, which pre-date the more modern radiator-cooled generators.

This upgrade project is necessary because of the aged condition of the cooling towers, which were installed at the time that the Power Station was established in the Valley during the 1970s.  Two of the generators (No. 4 and 5) requiring cooling under this system date back to the 1950s – to a time when they were housed in the original Power Station, at Tutakimoa.  The third generator (No. 3) dates from 1989.

Tenders will soon be sought by TAU for the design and installation of the two new towers to replace the existing ones.  The project is valued in the vicinity of $500,000.

Issued 14 November 2011.

Avatiu Power Station

Te Aponga Uira is seeking a contractor (or contractors) for the replacement and retrofitting of the roofs of the Administration/Network Building at Tutakimoa, and Power Station Building at Avatiu Valley.

Constructed in the mid 1960’s, the Tutakimoa location was the original Power House and Network Building before being transformed into the current Administration and Network building in the mid 70’s. Facing due north the building roof area planned for retrofit is approximately 480 sq. meters.

Constructed during 1974-75 the Avatiu power-house currently accommodates 7 generator sets with operational and maintenance facilities contained in one building. Facing east, the building roof area planned for retrofit is approximately 1000 meters square.

Both buildings are constructed of reinforced concrete floor and concrete block walls with concrete columns and steel beams connecting the steel frame that holds up the corrugated (asbestos type) roofing, cladding and guttering systems. Sections of the Tutakimoa building have concrete roofing.  The existing roof structure, cladding and guttering systems of both buildings are showing signs of fatigue and deterioration causing leaks.  At the power station, this has the potential to cause damage to the generators, and exacerbate concern of the harmful nature of the asbestos type material contained in the roofing and cladding system of the buildings.

Inspection reports have determined that the roofs require substantial repair and replacement and that the removal of asbestos cement has an inherent health risk, especially to those working in the buildings.  Therefore, the contractor undertaking the project will be required to recommend to TAU design options for roof replacement and disposal of asbestos cement products.
The contractor will be required to meet all environmental, Public Health, and Building Codes and Regulations.  Issued 15 October 2011.