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Questions and answers

Here are some common questions we’re asked. There are lots of other useful sources of information where you can find out more. We've highlighted these throughout the answers, which we hope you find helpful.

Third Menai Crossing

How are you working with Welsh Government on the Third Menai Crossing?

The Welsh Government is progressing with its plans for a third crossing at the Menai Strait. It recently completed a consultation on where the bridge could go.

Officials are also keen to understand if it’s possible for a bridge to carry the new electrical connection needed for Wylfa Newydd.  You may have seen the recent announcement that we’re carrying out a feasibility study for Welsh Government into options to use the bridge. 

There’s lots to consider before we know if putting our cables on a new bridge is possible.  Costs, technical considerations and timing are just some of the things to be worked out. 

At the same time, it’s vital we are able deliver a connection for Horizon by the mid-2020s, when they expect Wylfa Newydd to start generating.  That’s why we’re also continuing with our plans for a tunnel under the Menai Strait.

What will the feasibility study consider?

It will consider if additional equipment would be needed, safety, cost, technology options, and maintenance access.  A key point is how a connection could be routed to the bridge on Anglesey, off the bridge in Gwynedd and to our substation in Pentir.  Towns, businesses, other infrastructure and environmental sensitives would all be key considerations.

Will it be cheaper to put the cables on a bridge rather than in a tunnel?

It is not clear if a bridge is a cheaper option. Costs will be determined by technology choice, bridge design, safety requirements and the route to and from the bridge.

If there are savings, can you reinvest these to put the second line underground?

We must develop proposals that balance consultation feedback, policy requirements and regulations. One regulation is that we must offer value for money as the costs of our work are passed on through electricity bills.  Ofgem, the energy market regulator, would look for any savings to be passed on to consumers, not allocated to another part of the project.

What happens next?

Welsh Government is still developing its plans for a bridge and we need to complete the feasibility work for a connection. When this work is completed next year, the findings will be considered and next steps agreed.

Our proposals

What are you proposing for the new connection?

We’ve chosen a tunnel as the best way to go under the Menai Strait and identified areas where we could put the equipment we need to change from overhead to underground. At around 4km long, the tunnel is beyond the Area of Outstanding Natural Beauty (AONB) and means our equipment is further back from the coast and further away from communities. 
The route for the new overhead line is close to the existing line. This means we can take a direct route, keeping away from larger communities and avoiding putting pylons into new areas. We’ve also chosen a similar lattice pylon to the existing line. We think this is the best option to reduce visual effects as it won’t introduce contrasting shapes into the landscape.
We think our proposals are the best way to keep effects on the landscape, tourism, communities, cultural heritage and the wider environment as low as we can, while also providing a connection that offers value for bill payers. 

How have you considered the impact your work could have on tourism?

We fully recognise how important tourism is to the region and the economy, and it’s something we’ve considered at every stage of our work.
By keeping the second line close to the existing line, we stay away from the coast which is especially popular with tourists. It also avoids the largest towns and villages, heritage sites and landscapes that attract visitors.
At the Menai Strait, our choice of a tunnel extends inland away from the coastal area. This means we are outside the AONB and away from Plas Newydd and the Vaynol Estate – all areas that are popular with visitors. 
In 2014, National Grid commissioned a UK-wide independent study that looked at the effect of our major infrastructure projects on socio-economic factors: ‘A study into the effect of National Grid major infrastructure projects on socioeconomic factors’. This helped us to understand more about the impact of new connection projects on businesses, particularly those that rely on tourism.
This found that 93 percent of people felt there had been no negative impact on their business as a result of new infrastructure, and 83 percent of people felt there had been no impact on the local area as a result of new infrastructure.

We’re carrying out a local, similar study in North Wales to inform our ongoing assessments, together with further evaluation of potential effects on Anglesey. This will be considered in our plans and included in the Environmental Statement that will accompany our application for consent.

It’s important to note however that tourism is only one of many factors we consider and our job is to find a proposal that best balances the effects on all of them.  For example, property, landscape, heritage, ecology and technical needs (among others) must all be considered in balance.

Why do you need a second connection, can’t you use the existing line?

Wylfa Newydd will generate nearly three times as much power as the existing Magnox power station.
To carry all that power securely to the homes and businesses that need it, we need to use the existing line and build a second connection. Wylfa Newydd will use both lines.

Will the new connection operate at a higher voltage than the existing line?

No, both the existing and the new overhead lines will carry 400kV – the standard for an overhead line of this type. The existing line has been operating at 400kV since it was installed.

Why can’t you put the whole connection underground?

We know many people would prefer us to put the whole connection underground and we have looked carefully at this option.
We understand the visual and landscape benefits of putting the whole connection underground, but there are wider factors that need careful thought.

Undergrounding can introduce additional technical requirements as underground cables behave differently to overhead lines. The construction of open trenches or a tunnel for underground cables is likely to be more disruptive than the installation of overhead lines, which may result in significant environmental or socio-economic effects. It is also millions of pounds more expensive than overhead lines, which could lead to higher bills for electricity consumers.

Carefully considering costs is a duty placed on us by our regulator Ofgem and we have to put forward proposals that are value for money for bill payers. When the cost differences between underground and overhead connections are taken into account across all of the projects we’re working on in the UK, the cost to bill payers would be billions of pounds more if we were to put all connections underground.

We also have to consider the impacts of any unexpected repairs to our connections, for example damage caused by a third party or an exceptional fault on the line. If such an event occurs and the cables need to be excavated for repair this can take significantly longer to identify and fix for an underground cable when compared to an overhead line. This is something we have to think very carefully about because we have a duty to make sure that the electricity network is reliable at all times.

We typically use underground connections where there are no options to sensitively route an overhead line. To date in Anglesey, our assessments have led us to a tunnel 4km long, which we think reduces the potential effects of the connection around the Menai Strait and wider AONB landscape.  

Why can’t you put the existing line at the Menai Strait in the same underground tunnel you are digging for the new one?

When a new electricity generator asks to connect our network we must develop that connection in line with a number of conditions that are set and regulated by the government. This includes providing a connection that meets the generator’s needs and that offers value for money for consumers, as the costs of the connection are passed on to all of us in our electricity bills. Because of these conditions, we can’t extend our project beyond the work that’s needed to connect the new energy generator. In North Wales, this means we’re not able to fund undergrounding of the existing line as part of the project as it’s not a necessary part of making the new connection for Wylfa Newydd.
But we know how valued the Menai Strait and Anglesey AONB are which is why we’ve committed to undergrounding the new connection here.

You’re putting cables underground in the Lake District. Why can’t you do the same on Anglesey and in Gwynedd?

We take the same approach to developing connections across all of our projects in the UK. This includes taking into account any special designations like National Parks or Areas of Outstanding Natural Beauty (AONBs). Most of our projects use a mix of technologies and this is the case in Anglesey and Cumbria.

As part of the North West Coast Connections project we’re proposing to put the connection underground as it passes through the Lake District National Park and beneath Morecombe Bay. We’re proposing to make the rest of the connection (around 119km) with overhead lines.

Similarly, we’re proposing an underground tunnel at the Menai Strait that extends out beyond the AONB.

You can read more about this, as well as our approach to putting cables underground, here.

Why aren’t you putting the current overhead line across the Menai Strait underground as part of the VIP project?

The VIP project has been led by its independent Stakeholder Advisory Group which includes representatives from organisations including the CPRW, Cadw, Natural Resources Wales, National Parks Wales, Natural England, National Trust and Visit Wales.
To decide which shortlisted locations were taken forward, each one went through a detailed review and analysis process. The line in Snowdonia, near Porthmadog was one of the projects taken forward because it falls within a National Park.

If more energy generation is proposed, will you need a third line of pylons?

There is nothing to suggest a third connection is needed.
We’re only able to consider energy generation for projects that have a connection agreement with us. If there is more energy generation in North Wales and more developers approach us for connection agreements, we would then need to look at the best way of connecting that energy to the electricity network. All the energy currently being proposed can be accommodated on the existing overhead line and the second connection that we are proposing.

What does it mean now that Orthios has a connection agreement with you?

In December 2015 Orthios completed the purchase of the Anglesey Aluminium works on Anglesey. The Orthios Eco Park will include a biomass power station and it now has a connection agreement with us to supply the power it will generate to the national electricity grid.
The biomass power plant will generate a much smaller amount of power than Wylfa Newydd so we’ll only need to do a small amount of work to accommodate this extra power. This will include some additional equipment at our Wylfa substation and some work on the existing 132kV overhead line from Holyhead to Wylfa.

Construction and transport

How long will it take to build the connection?

In total, we think the construction stage would take four to five years, with additional time to undertake planting and other measures to help restore the land.
We are likely to be working on different sections along the route at different times so wouldn’t be working on the whole connection all of this time. Some sections we will start and finish earlier on in the construction process, while others we will start and finish towards the end. Given its complexity, the tunnel will take the longest to build and we will be working on this throughout the construction stage.

What roads will construction traffic use and how will you reduce the risk of congestion?

To provide access for vehicles, we’re proposing to use the A55, A5, and A5025 as these are the main roads which are closest to our work. We’ll also need to use suitable smaller rural roads off the main road network so we can get to the sites where we'll build our equipment.
Most of the equipment we need will be transported on lorries (HGVs). We’ll also need vans and cars to take workers to and from site. Some larger vehicles will be required to deliver specific materials, such as the cables for the tunnel, which come on large cable drums.
In order to identify suitable construction traffic routes, we’ve considered how we can best reduce effects on all road users, including local people and tourists.
We’re working closely with local county councils, North and Mid Wales Trunk Road Agency, Welsh Government and other relevant bodies to get their feedback on which routes would offer the best opportunities to reduce effects on the area.

What construction traffic will there be from your work at the Menai Strait?

To dig the tunnel, we will need some specialist equipment. Some of this equipment needed is large and heavy and may require larger vehicles to deliver it and take it away from the tunnel site. These vehicles would be larger and move much slower when compared to normal HGVs and for safety purposes may require escort vehicles. However, we would only need a small number of these.
To construct the tunnel, we will need to remove many thousands of tonnes of rock and soil. We will also need to deliver lots of materials to site such as aggregates and concrete linings. This will require a lot of HGV journeys to and from the tunnel site. However, the tunnel construction will take place over a number of years and the number of HGV journeys each day will be spread out.
To further help reduce any inconvenience for local road users, we would also look at a number of measures. These would include, for example, timing restrictions on journeys to avoid busy periods such as the morning and afternoon rush hours.

Will you be closing any footpaths, cycle routes or bridleways?

In developing our proposals, we’ve considered popular routes for walking, cycling and horse riding. We don’t think our overhead line will have any permanent effects on these. 

However, we may need to temporarily close some routes during construction. It’s too early for us to say exactly where and when this might be. However, we have lots of experience constructing overhead lines around the UK and we’ll work closely with the Public Rights of Way officer at both Isle of Anglesey County Council and Gwynedd Councils to put in any appropriate diversions. We will make sure people are aware should any closures be needed and make sure these are for as little time as possible.

How are you planning on getting to your construction sites?

Most of our construction equipment and materials will be transported on heavy goods vehicles (HGVs), like lorries. We’ll also need to use light goods vehicles (LGVs)cars and vans, for  to get workers to and from our construction sites.

We anticipate construction will take two to three years and at our busiest time, our vehicles would only represent a very small increase in traffic. Where we’re using a tunnel to cross the Menai Strait, we think construction will take four to five years. 

We always look to stay on main A-roads for as long as possible, only using local roads to deliver equipment to when we get close to our construction sites.  When we leave the public highway machinery and materials are transported on temporary haul roads which only our vehicles use.  The haul roads are then removed after construction and the land reinstated (although sometimes landowners ask us to leave them for their own use).

We’ve recently made some changes to the construction routes we had previously consulted on. You can view these changes here.

Where we need to get from public highways to our construction sites, we’ll be building temporary access tracks. We’re talking to landowners where these will be required. 

How will you manage traffic during construction?

We don’t think our construction traffic will have a significant effecton local roads and we’re mainly using roads that are already well-used by heavy goods vehicles.

The safety of local road users and our own drivers is a main priority and we’ll be taking steps to ensure that.

If the project is consented, we will develop a Construction Traffic Management Plan. This will be agreed with Isle of Anglesey County Council and Gwynedd Council and include detailed plans for how construction traffic will be managed.  This would normally consider things such as:

  • setting appropriate speed limits for our vehicles
  • looking at peak road usage times and ways to avoid these
  • additional road users, such as holidaymakers or other construction projects
  • making sure roads are kept clean and clear of debris
  • any temporary measures to help traffic flow, such as temporary traffic lights or junction upgrades
  • keeping people up to date all through the construction programme

All in all, we have lots of options available to make sure roads continue be safe and efficient for everyone to use, just as they are now.

Is there the possibility of any debris or damage on the roads from your construction vehicles?

The highways we’re prosing for construction traffic are already well used by large vehicles travelling around Anglesey and Gwynedd. Our traffic will only be a small percentage increase on this and there is nothing to suggest our work will increase normal wear and tear.

We’ll also make sure we maintain the general condition of the roads by using wheel cleaning facilities when vehicles may get muddy, to avoid debris being taken onto the public highways.

Land and compensation

When do you pay compensation to people for the work you carry out?

We pay compensation wherever we cross land (overhead or underground) and we’re working closely with landowners across the project area to see where this is applicable. We’d encourage anyone with concerns about our proposals and their property to get in touch with us so we can better understand their circumstances and address their concerns where we can.

Is there compensation if there is an impact on house prices?

When we develop a new connection, we always try to avoid communities and individual properties as much as possible. We talk regularly with local residents so their comments can influence the design of the new connection and to help reduce any uncertainty. We also carry out regular reviews of our design to assess what effects there may be and if there are other options.
We’ve worked hard to do this in developing the second connection for Wylfa Newydd and feel the design we’ve put forward limits the number of properties close to our work. We only pay compensation if our equipment is placed on land or crosses it, but we know that people have concerns about the effect of our work on property. We’re committed to continuing to work with property owners to see if there are ways to further reduce any effects of our proposals. We’re always happy to hear from property owners and would encourage anyone with concerns regarding their property to talk to our team so your comments can be considered.


What are Electric and Magnetic Fields (EMFs)?

Electric and Magnetic Fields (EMFs) a produced wherever electricity is used. Most exposure comes from the wiring in our homes and the appliances we use but power lines (both overhead and underground) are also sources. 

Have you considered health effects from EMFs as part of your proposals?

We know people have concerns about possible health effects of EMFs and we take this very seriously when planning our work. The government has guidelines on acceptable levels of EMFs which have been independently set by the Health Protection Agency and its successors. Because we fully comply with all government policies on this, there will be no health effects arising from EMFs in relation to our proposals.

We’ve agreed with the Planning Inspectorate that we will publish a report on our approach to EMFs. This will include information on how our project will comply with all of the relevant guidelines and policies and will be publically available.

Does having two overhead lines increase health risks?

Our plans for the North Wales Connection, including placing the new overhead line broadly in parallel with the existing line, meet all of the relevant guidelines on acceptable levels of Electric and Magnetic Fields (EMFs). These have been independently set by the Health Protection Agency and its successors and because we fully comply with all government policies on this, there will be no health effects arising from EMFs in relation to our proposals.

What happens next?

What happens next?

Horizon Nuclear Power has submitted its application for Wylfa Newydd to the Planning Inspectorate and we expect to submit ours within the next few months.  

We’re continuing to have conversations with people and undertake assessments and surveys.

This will make sure our application takes into account the latest possible information.

You can find out more about our next steps here.

You’ll have further opportunities to have your say and put your comments directly to the Planning Inspectorate to be considered once we’ve submitted our application. You can find out more about the planning process here. 

If Wylfa Newydd is delayed, would your project be delayed?

We’re only able to plan for the timescales that we have available. Horizon plans for Wylfa Newydd to start generating electricity by the mid-2020s so we have to be ready to provide a connection by then.

Supply chain, career and job opportunities

What opportunities are there for careers with National Grid?

We want to inspire people in North Wales, and around the UK, to become the next generation of engineers. We also want to make a difference to the areas we work in by working closely with schools and youth groups.
Through school visits, our apprentice programme and educational resources we’re enabling thousands of people to realise their potential in science, technology, engineering and mathematics (STEM) careers that will benefit them, their communities, our economy and all of society. We’re already carryingout a range of activities with schools and community groups in North Wales. 
Whether you’re looking for an apprenticeship, you’re a graduate or have already started your career; we’re always looking for talented individuals to join our team.You can find out more at

Will your work create any jobs or opportunities for local businesses?

We’re part of Anglesey’s Energy Island Programme, which is aiming to put Anglesey at the forefront of low carbon energy development. 
Isle of Anglesey County Council estimates that the programme could contribute £12 billion to the Anglesey and North Wales economy over the next 15 years. This could bring major economic, social and environmental gains for all of Anglesey and the wider North Wales region.
At National Grid, we work with some of the best companies, big and small, all around the UK, ensuring our work meets the high standards the country expects.
The scale of our projects means that there are great opportunities for local businesses while we’re working in an area.
Whether it’s subcontracting construction works, plant hire or accommodation and catering, our projects bring a positive boost to local economies. As well as benefits for businesses, this can also result in new job opportunities.
You can find out more information about how to become a National Grid supplier here.


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