FAQ | LF68325 Cilfynydd

A synchronous condenser is ‘stability hardware’ which will stabilise the electricity supplied by low carbon sources like wind and solar. This is linked to a large ‘flywheel’, which draws power from the grid to enable it to spin. The spinning element then acts like a shock absorber if there is a fault, such as a lightning strike. Cyddwysydd Syncronaidd yw ‘caledwedd sefydlogi’ bydd yn sefydlogi’r trydan sy’n cael ei gyflenwi gan ffynonellau adnewyddadwy fel gwynt a solar. Mae hwn yn gysylltiedig â ‘flywheel’ mawr, sy’n tynnu pŵer o’r grid i’w galluogi i gylchdroi. Mae’r elfen sy’n cylchdroi yn ymddwyn fel amsugnwr sioc os oes problem er enghraifft trawiad mellt.

As we move into a zero-carbon world, electricity will increasingly be supplied by sources such as wind, solar and tidal. Renewable sources like this do not have the stabilising properties that coal and nuclear fired power stations have. Therefore, a standalone stability system like this facility is required as we move to low carbon sources for electricity supplies.

Wrth i ni symud tuag at fyd di-garbon, bydd cyfran fwyfwy o drydan yn dod o ffynonellau megis gwynt, solar a’r llanw. Nid yw ffynonellau adnewyddadwy fel rhain yn cynnwys priodweddau sefydlogi fel sydd gan orsafoedd pŵer glo a niwclear. O ganlyniad, mae gorsafoedd sefydlogi annibynnol fel yr orsaf hon yn angenrheidiol wrth i ni gofleidio dulliau adnewyddadwy o gynhyrchu trydan.

No. The synchronous condenser is a bespoke development that is being installed to stabilise the electricity grid and will connect into Cilfynydd Substation, in response to the National Grid Pathfinder 3 initiative. Whilst it will stabilise the grid to facilitate a greater role for renewable energy generation, the synchronous condenser is not being constructed specifically in connection with the Twyn Hywel Wind Farm, energy park or any other energy-related development in the local area.

Nac ydy. Mae’r Cyddwysydd Syncronaidd yn ddatblygiad unigryw sy’n cael ei hadeiladu er mwyn sefydlogi’r grid a bydd yn cysylltu ag is-orsaf Cilfynydd, yn ymatebol i’r cynllun ‘Pathfinder 3’. Er bydd y datblygiad yn sefydlogi’r grid i alluogi gweithrediad cynyrchyddion egni adnewyddadwy, nid yw’r Cyddwysydd Syncronaidd yn cael ei hadeiladu yn uniongyrchol gysylltiedig â Fferm Wynt Twyn Hywel, ‘Energy park’ neu unrhyw ddatblygiad egni arall yn yr ardal leol.

Since planning permission was granted in December 2023 the Cilfynydd Synchronous Condenser project team has been working to make sure that everything is in place to allow construction to start on site. This has included finalising contracts with construction companies that are going to deliver the different elements of the development, discharging planning conditions and ensuring that all necessary permits and permissions are in place.

Ers i ni dderbyn caniatâd cynllunio yn Rhagfyr 2023, mae tîm y prosiect Cyddwysydd Syncronaidd Cilfynydd wedi bod yn gweithio er mwyn sicrhau bod popeth yn ei le i alluogi cychwyniad adeiladu ar y safle. Bu hyn yn cynnwys drafftio contractau terfynol gyda’r cwmnïoedd adeiladu sydd am gwblhau elfennau gwahanol o’r datblygiad, cwblhau amodau cynllunio a chadarnhau bod pob caniatâd angenrheidiol wedi’u derbyn.

The main construction works are due to start on site at the end of 2024, with construction taking around 18 months. The cable connection between the site and Cilfynydd Substation will start a couple of months sooner, in Autumn 2024.

Mae’r brif gwaith adeiladu i gychwyn ar y safle ar ddiwedd 2024, gyda’r gwaith adeiladu yn cymryd tua 18 mis. Bydd y gwaith i gysylltu’r cebl rhwng y safle ac isorsaf Cilfynydd yn cychwyn ambell fis yn gynharach, yn nhymor yr Hydref 2024.

The site working hours and access times are set out in the Construction Traffic Management Plan. This states that construction vehicles will access and exit the site between the hours of 0800-1800hrs Monday to Friday and 0800-1300hrs on Saturdays. No works will be undertaken on Sundays or Bank Holidays.

Where possible vehicle movements will be scheduled to avoid, or limit the number of movements, between the peak hours of 0830-1000hrs and 1530-1730hrs.

Stakeholders will be given written notice of all exceptionally large or exceptionally heavy loads entering the site. These loads are known as ‘Abnormal Indivisible Loads’ (AILs) and they are carefully controlled and managed by a number of parties including the local highway authority and the police, who will also escort the deliveries to the site.

Mae’r oriau gweithio a mynediad i’r safle ar gael yn y Cynllun Rheoli Traffig Adeiladol. Mae hwn yn dweud bod cerbydau adeiladol am ddod i mewn ac allan o’r safle rhwng 0800 – 1800 Dydd Llun i Ddydd Gwener ac 0800 – 1300 ar Ddydd Sadwrn. Ni fydd gwaith yn digwydd ar Ddydd Sul ac ar Wyliau Banc.

Lle’n bosib, fe fydd symudiad cerbydau wedi’i gynllunio i osgoi, neu i leihau nifer y cerbydau sy’n symud rhwng yr oriau 0830-1000 a 1530-1730.

Bydd rhanddeiliaid yn derbyn rhybudd ysgrifenedig pan fydd unrhyw lwythau eithriadol o fawr neu eithriadol o drwm yn cyrraedd y safle.

Mae’r mathau yma o lwyth yn cael eu galw’n ‘Abnormal Indivisible Loads’ (AILs) ac maen nhw’n cael eu rheoli gan nifer o bartïon gan gynnwys yr awdurdod priffyrdd lleol a’r heddlu, a bydd y rhain hefyd yn hebrwng y cerbydau i’r safle.

The proposed development includes extensive re-planting, using native species to enhance biodiversity and create new habitats within the site while also screening views of the development.

During certain stages of the work an Ecologist will be on site to supervise and monitor, in accordance with the conditions of the Natural Resources Wales permit.

The development does not generate any energy and has no emissions to air. Noise will be minimised through the design process, with acoustic mitigation such as insulation and acoustic barriers being an integral part of the development.

Mae’r datblygiad yn cynnwys nifer o ail-blannu gan ddefnyddio rhywogaethau brodorol i wella bioamrywiaeth a chreu cynefinoedd newydd o fewn y safle wrth sgrinio’r olygfa o’r datblygiad.

Mewn cyfnodau penodol o’r gwaith, bydd Ecolegydd yn bresennol ar y safle er mwyn goruchwylio a monitro, yn unol â’r amodau gosodwyd ar y caniatâd gan Gyfoeth Naturiol Cymru.

Nid yw’r datblygiad yn cynhyrchu unrhyw egni a does dim allyriadau i’r aer. Bydd sain yn cael ei leihau trwy’r broses dylunio, a bydd lliniaru acwstig megis ynysydd a rhwystrau acwstig yn hanfodol yn y datblygiad.

The approved Construction Environmental Management Plan and Construction Traffic Management Plan set out the best practice working methods that will be followed to make sure that construction impacts are minimised.

There will be a small number of Abnormal Indivisible Load deliveries. This delivery process will be carefully managed, and the deliveries will have a dedicated police escort. Advance notice of the date(s) and time(s) of these deliveries will be reported to all that may be affected.

Should you have any concerns about the construction of the synchronous condenser please report them to the Project Team by e-mail: info@cilfynyddgridservices.co.uk

Mae’r Cynllun Rheoli Adeiladu Amgylcheddol a’r Cynllun Rheoli Traffig Adeiladol yn gosod y dulliau gweithio gorau a bydd yn cael eu dilyn er mwyn sicrhau bod effeithiau’r gwaith adeiladu ar yr ardal leol yn cael eu lleihau.

Bydd nifer bach o gerbydau ‘Abnormal Indivisible Load’. Bydd y broses cludo'r rhain yn cael ei reoli yn agos, a byddant yn cael eu hebrwng gan drefniant heddlu penodol. Bydd pawb sy’n cael eu heffeithio yn derbyn blaen rhybydd o’r dydd(iau) ac amser(oedd) pan fydd y llwythau yma yn cael eu cludo.

Os oes gennych bryderon am y gwaith i adeiladu’r cyddwysydd syncronaidd, codwch y rhain gyda thîm y prosiect trwy e-bost: info@cilfynyddgridservices.co.uk

In alignment with its supplier code of conduct, Cilfynydd Grid Services Limited seeks to support local industry development wherever possible via local sourcing of workers and job creation. Due to the specialist nature of the development work, however, specialist teams of contractors are required, whether local or from other areas, and will need to be employed during certain periods of construction.

Yn unol â’i god gweithredu fel cyflenwr, mae Cilfynydd Grid Services Limited yn ceisio cefnogi datblygiad diwydiant lleol lle’n bosib trwy ddefnyddio gweithwyr lleol a chreu swyddi. Ond, o ganlyniad i fath arbenigol y gwaith datblygu, mae angen timoedd arbenigol o gontractwyr, naill ai o’r ardal leol neu o ardaloedd eraill, a bydd rhaid cyflogi'r rhain am gyfnodau penodol o’r gwaith adeiladu.

A dedicated project e-mail address has been set up. This will be closely monitored by the Cilfynydd Synchronous Condenser project team and you will receive a response within 2-3 working days (standard) or 24 hours (for urgent enquiries). The e-mail address is provided below:

info@cilfynyddgridservices.com

Mae cyfeiriad e-bost penodol wedi’i sefydlu. Bydd hwn yn cael ei monitro gan dîm y prosiect Cyddwysydd Syncronaidd Cilfynydd a byddech yn derbyn ymateb o fewn 2-3 diwrnod gweithio (ymholiadau arferol) neu 24 awr (ymholiadau ar frys). Mae’r cyfeiriad e-bost ar gael isod:

info@cilfynyddgridservices.com

Frequently Asked Questions

Latest News

05/01/2026:

Looking Ahead:

The foundations for the High Voltage Switch Yard, the Synchronous Condenser and the Transformer bay are now complete.

Preparations are underway for the installation of the Transformer in the new year.

The main building steelwork is complete and cladding is complete to the roofline. Work has started on cladding the building walls and this will continue into the new year.

Road Cleaning:

The jet wash facility will remain on the construction site for the duration of the works as well as the Telehandler brush attachment. A road sweeper is also on standby to clean the public road as and when needed throughout the winter months and the wheel wash facility will be reviewed and used if/when needed.

Deliveries:

The Civils contractor is receiving ongoing deliveries for the building cladding and structural steelwork for the High Voltage switchyard.

The delivery of the first Transformer is due at the end of January/early February 2026.

National Grid Substation:

National Grid is continuing their work within the Cilfynydd Substation. The lorry movements are irregular. We are still working closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

25/11/2025:

Looking Ahead:

Foundations for the High Voltage Switchyard and the transformer bay are now complete, with preparations underway for receiving and installing the Transformers in December.

Work continues on the Synchronous Condenser foundations.

The building steelwork is completed and cladding installation has started. This will continue for the next 4 weeks.

Road Cleaning:

wheel wash facility will be reviewed and used as and when needed.

Deliveries:

In addition to miscellaneous deliveries for the civils works, with construction work progressing well on the main building, cladding deliveries are scheduled to be received by the site w/c 24 November.

The Transformers are scheduled to be received by the site in the 1st and 2nd weeks of December (subject to final programming).

The delivery of structural steelwork for the High Voltage Switchyard is also due in the 2nd week of December.

National Grid Substation:

National Grid is continuing their work within the Cilfynydd Substation.

The lorry movements are irregular. We are still working closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

30/09/2025:

Looking Ahead:

Work is progressing well on the foundations across the site. The main building foundation pads are now complete and the building steelwork is being erected. After this the cladding will be installed, in readiness for receiving the synchronous condenser plant deliveries.

Road Cleaning:

The jet wash facility will remain on the construction site for the duration of the works as well as the Telehandler brush attachment. A road sweeper is also on standby to clean the public road as and when needed. Being in Autumn and with winter approaching the wheel wash facility will be reviewed and used as and when needed.

Deliveries:

The site is receiving frequent steelwork deliveries for the main building frame, which is currently under construction. After this the building cladding will be delivered to the site, with subsequent deliveries focused on smaller equipment.

The first Abnormal Load (the transformer) is scheduled for delivery in November.

National Grid Substation:

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

29/08/2025

Looking Ahead:

Work continues on the foundations across the site in preparation for the start of the main building construction.

Road Cleaning:

Deliveries:

Deliveries are currently less frequent to the site but will increase towards the end of the year to meet the equipment and machinery delivery and installation programmes.

National Grid Substation:

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

07/08/2025

Looking ahead:

Foundation installation continues across the site. The main areas of focus are:

Within the High Voltage Yard;
The Synchronous Condenser plant foundations;
The transformer bays; and
Foundation pads for the main plant building.

Excavation and concrete blinding works associated with the trough runs are ongoing.

Road Cleaning:

Deliveries:

Deliveries to site will start to increase as we get further into the foundation construction stage and prepare for the equipment/machinery installation.

National Grid Substation:

National Grid is continuing their work within the Cilfynydd Substation.

The lorry movements are irregular. We are still working closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

07/07/2025

Looking ahead:

Foundation works continue across the site for the HV Yard, the Synchronous Condenser, transformer bays and the foundation pads for the main building. Drainage works and haul road construction are also ongoing.

Road Cleaning:

Deliveries:

Deliveries to site will start to increase as construction works prepare for the equipment/ machinery installation.

National Grid Substation:

National Grid is continuing their work within the adjacent Cilfynydd Substation.

The lorry movements are irregular. We are still working closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

11/06/2025

Looking ahead:

Work continues on installing the drainage system, the trough runs and foundations across the site, with the main building, High Voltage Switchyard and Transformer foundation excavations, blindings and pours due to start soon and continue over the summer.

Road Cleaning:

National Grid:

National Grid is continuing their work within the Cilfynydd Substation.

The lorry movements are irregular. We are still working closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

15/05/2025

Looking ahead:

Over the next 4 weeks the following works will be progressed on site:

The installation of Earthing tape;
Continuing the drainage works including the filter drains and attenuation pond;
Ongoing construction of the Haul Road; and,
Starting concrete pours for the synchronous condenser foundations and the step-up transformer bays.

Road Cleaning:

National Grid:

National Grid is continuing its construction work within the Cilfynydd Substation. The lorry movements are not as regular now; however, we continue to work closely with National Grid to ensure that disruption is kept to a minimum and we have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

14/04/2025

Looking ahead:

Excavation of the synchronous condenser foundations and earthworks for the wider site will continue over the coming weeks. Installation of the sustainable surface water drainage system will start, including the filter drainage and surface water carrier system, creating the attenuation pond base and installing the pond lining.

Road Cleaning:

The jet wash facility and telehandler brush attachment will remain on the construction site for the duration of the works.

A road sweeper is also on standby to clean the public road as and when needed.

National Grid:

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

19/03/2025

Looking ahead:

Excavation for the water management and drainage works has started and will continue over the coming weeks. The disused brickwork tank will also be removed. Unsuitable material will be temporarily stored on the Fairview field before it is removed.

Structural steelwork is being procured and will start to be delivered to the site in April.

Road Cleaning:

The wheel cleaning facility will remain on the construction site for the duration of the works. A road sweeper is also on standby to clean the public road as and when needed.

National Grid:

National Grid has started their work within the Cilfynydd Substation, which is generating regular lorry movements. We are working with National Grid to ensure that disruption is kept to a minimum and have regular calls to discuss traffic management.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

19/02/2025

Looking ahead:

Over the next 4 weeks excavation on the development site will continue, though movements of soil from the site to the temporary construction compound will be less frequent. The temporary welfare and office cabins in the construction compound will be removed at the end of February and steelwork will be delivered to the site in mid-March.

Road Cleaning:

The wheel cleaning facility will remain on the construction site for the duration of the works. A road sweeper is also on standby to clean the public road as and when needed.

Should you have any questions or concerns regarding the Cilfynydd Grid Services construction works please e-mail the Project Team: info@cilfynyddgridservices.co.uk

13/01/2025

Dŵr Cymru Welsh Water has completed the water main diversion and reinstatement works in National Road.

The synchronous condenser temporary construction compound has been set up in the ‘Fairview Field’, with the access, hardstanding areas and interim welfare facilities installed through November into December 2024. A perimeter fence has also been installed for safety and security purposes.

On the main development site, the initial topsoil strip has taken place and construction of the main access into the site has started. A perimeter fence has also been installed. Over the next two weeks site set-up preparations will continue, with the main earthworks scheduled to start w/c 27 January 2025.

October 2024
Meet the Contractor Events

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Cilfynydd Synchronous Condenser

Construction Phase Information and Latest News

What is a Synchronous Condenser? / Beth yw Cyddwysydd Syncronaidd?

Why is it needed in addition to the existing substation? / Pam mae’n angenrheidiol yn ogystal â’r is-orsaf presennol?

Is the development connected to the Twyn Hywel Wind Farm or any other energy-related developments in the local area? / Ydy’r datblygiad yn gysylltiedig â’r Fferm Wynt Twyn Hywel neu unrhyw datblygiad sy’n gysylltiedig ag egni yn yr ardal leol?

What have we been doing since planning permission was granted? / Beth rydym wedi bod yn gwneud ers i ni dderbyn caniatad cynllunio?

When will construction start on site and how long will it take? / Pryd bydd adeiladu ar y safle yn cychwyn a pa mor hir bydd adeiladu yn cymryd?

What will the construction working hours be? / Beth fydd oriau gweithio’r adeiladu?

What Environmental Impacts will there be? / Beth fydd yr effeithiau amgylcheddol?

How will the development impact the local area? / Sut bydd y datblygiad yn effeithio’r ardal leol?

Will there be any local employment? / Bydd unrhyw cyflogaeth lleol?

How can I contact the project team? / Sut gallaf gysylltu â tîm y brosiect?

Frequently Asked Questions

Latest News