Construction – Triton Knoll Onshore Substation


Access to the site has required construction of a brand new 4.5km track which will remain in place throughout the substation's operational lifetime.  This has provided a key construction challenge requiring over 30,000 tonnes of stone, and crossings of a high pressure gas main and a number of locally important watercourses.

Construction is focused on a new Triton Knoll Onshore Substation platform which has a footprint of 4.7 hectares, equal to over 6 full size football pitches. Over 1,650 pre-cast concrete piles are installed at the new substation platform, providing a stable foundation for the buildings and electrical equipment. The substation consists of a control building, transformers and other key electrical infrastructure. Upon completion it will also have around 16 hectares of landscaping and screening to minimise any visual impacts.

Triton Knoll Onshore Substation will 'step up' the power voltage to 400kV for transmission to the nearby National Grid Bicker Fen substation via a 1.8km connection of 400kV cables, being installed as part of the construction works.

Principal Contractor: Siemens Energy Ltd

Expected completion: Q2 2021

Progress Updates

Image: Recent drone footage captured in December 2020

The team made significant progress in the construction of the Triton Knoll Onshore Substation in 2020.

The main construction and commissioning works are now complete. During October 2020, power was back fed from the National Grid Bicker Fen Substation and utilised to energise the electrical equipment for the first time to allow final checks to be completed. In January 2021 the substation started to back feed power to the offshore substations to allow commissioning to be completed on these. This means everything is in place to start and feed electricity from the wind turbines into the electricity transmission network and ultimately into peoples homes.

The 400kV cable route (the cable between the Triton Knoll Substation and National Grid Substation) is now complete, including the removal of the temporary access track. The cable corridor has been reinstated with some outstanding minor works to complete in the Spring of 2021 before all the land is handed back to landowners.

The Viking Link project will be utilising the stone from our temporary access track for part of their works which will reduce lorry movements on the surrounding road network by some 500 movements.

Reinstatement and removal of the temporary construction compound will commence in March 2021 and is planned to be finished in Summer 2021. The reinstatement involves returning some areas back to the landowners for agriculture as well as forming landscaping screening bunds that will be planted with trees and shrubs in the Autumn / Winter of 2021.

Aerial view of onshore substation,1 May 2020

Last year’s positive progress continued into 2020, as the onshore substation moved into the final year of construction ahead of commissioning and energisation.

Progress has been achieved where operations can conform strictly and fully to government guidelines and our own stringent safety controls, to ensure all of the Triton Knoll team can operate safely.

Since our last update in October 2019, we have now installed the high voltage (HV) 400kv cable to the new Triton Knoll Onshore Substation. This provides the critical connection into the National Grid transmission system so that we can ultimately deliver Triton Knoll’s wind generated electricity into the equivalent of more than 800,000 UK homes.

As part of the installation process, we successfully carried out the first high voltage test on both cables, to ensure it will function as designed.

Thanks to the progress made over the last 12 months at the Onshore Substation, the balance of activity at site has begun to transition from mostly construction work to a commissioning phase, preparing the site for energisation and ultimately operation.

To date, we have completed some 80% of the electrical build, and started to commission some of the components such as the transformers, the low voltage power systems and switchgear.

Earlier this year we began work at the site, to install the perimeter fencing, internal roads, footpaths and hard standings.

Looking ahead, the project expects to mark a major milestone this year in the delivery of the onshore electrical system, as the 220kv cable – the 57km underground cable route that connects the landfall at Anderby to the onshore substation at Bicker – will finally arrive at the substation ready for anticipated connection later in the year. Together with the 400kv connection into the national grid network, this means the various elements of the onshore electrical system will be physically connected.

As the year progresses, we plan to start second stage commissioning of the onshore substation, with the aim of energisation by the autumn. Reinstatement and landscaping will follow later in the year and be completed in 2021.

Two of the largest and most important components for the Triton Knoll Onshore Substation have arrived and been installed on site, marking an important shift in the phasing of the onshore substation construction works.

Our substations contract lead Siemens Transmission & Distribution Limited built and led the delivery of the components. See their film of the transformer's journey, below.

Each transformer weighs in at over 240 tonnes, heavier than 34 African elephants. They were each transported from Port of Sutton Bridge via an 85m long specialist transport arrangement to site under police escort, where they are being fully installed on purpose-built foundations at the substation in Bicker Fen, Lincolnshire.

Matt Archer, site manager for Triton Knoll, described the arrival on site of the first of the transformers which marked the change in focus.

“The weather was dreadful, it was just continually raining. But it did not dampen the excitement of seeing this huge component negotiating the roundabouts and bends, slowly making its way to the substation site.

“It might only be one component of the very many that are needed to build an onshore substation like this, but it’s an extremely large component and represents a significant milestone for the project.”

The arrival of the transformers and other electrical infrastructure follows nearly seven months of civil engineering works, carried out by sub-contractor BAM Nuttall. This focused on construction of the control and other specialist buildings, cable troughs and duct installation across the site.

The control building is the brains of the substation that monitors and controls all the electrical equipment installed at the substation.  The control building is complete, and the electrical equipment is starting to get installed within the building.

With the arrival of the transformers, each 13 metres long and 4 metres wide, Triton Knoll will now see a shift in emphasis of works to the electrical installation This includes the installation of the two transformers, shunt reactors, Static Vars Compensation infrastructure, cables, electrical panels and the connection of wiring.

The transformers are installed on bunds, requiring the further fitting of components to make up the full transformer. Following the build, each transformer is filled with a special oil, and is expected to be commissioned and energised by the end of Q3 2020.

Construction of all the permanent and temporary access roads, main substation platform, drainage works and installation of 1650 pre-cast concrete piles is now complete.

Siemens Transmission and Distribution Limited, our main contractor for the substation works, has appointed BAM Nuttall to carry out the main civil works and this is now well advanced.

The control building structure is now complete, cable troughs and duct installation across the site is well advanced.

We have poured approximately 75% of the structural concrete required to construct the foundations for the electrical equipment. This includes transformer foundations which are now ready and prepared for delivery of the 300 tonnes transformers expected to arrive later in October 2019.

We are looking to start installation of the electrical equipment in September 2019 and expect to complete the control and SVC buildings at the same time.

All of the Horizontal Directional Drilling and duct installation is now complete for the 1.8km 400kV cable installation to the National Grid Bicker Fen substation, and we are now looking forward to the construction of the cable joint bays, which is due to take place in the coming weeks, as scheduled.

Finally, the site is reaching the height of its construction phase, with approximately 150 people now currently engaged on the substation package of works, including local contractors who are undertaking a variety of works.  We expect the next six months to be a very busy period at the onshore substation as we push on to complete construction in readiness for commissioning works.

The main activities taking place at the Triton Knoll Onshore Substation site have been the construction of anew dedicated access road directly from the A17 to our new substation site. We recently finished constructing and tarmacking the bellmouth of the new road which ensures that heavy loads can safely exit and access the site from the A17. Temporary road narrowing which was in place on the A17 has now been removed.

In agreement with Lincolnshire Highways, a 40mph speed restriction will remain in place for the duration of the construction works, to promote the safety of all road users, including the Triton Knoll team, contractors and other road users.

We have commenced construction of the temporary access track from the Triton Knoll substation site to the National Grid Bicker Fen substation, which ensures access to the work required to connect the Triton Knoll substation into the National Grid electricity network. Enabling works started at the site of the new substation including topsoil stripping and archaeological mitigation.