Background:
When National Grid first came forward with their proposals for Norwich to Tilbury (formerly known as East Anglia GREEN), only 1 option was seriously presented – a huge swathe of pylons across the countryside. When my constituents asked about possible alternatives, such as offshore, they were dismissed as impossible. This is despite billions of pounds worth of offshore infrastructure being built from Scotland to Wales and the North of England - the Western Link & Eastern Green Link - at a cost of £6.50 pa on consumer bills.
Given that offshore is an option to protect communities and the countryside in Scotland and the North, I have consistently campaigned, alongside my MP colleagues, for fair treatment for East Anglia. This is not a case of us being against all electricity transmission infrastructure, I simply wanted to know how much alternatives to pylons would cost, so my constituents could be presented with all of the facts.
Following this campaign, National Grid ESO (legally separate from National Grid, and now NESO) agreed to undertake an independent study to assess different ways to transfer electricity once it’s landed from certain offshore windfarms off the coast of East Anglia to where it’s needed.
1. What’s the ESO East Anglia Study?
In March 2024, ESO published their independent study into alternative transmission options for the Norwich to Tilbury route. You can read the full study here: https://www.neso.energy/.../offshore.../east-anglia-study
2. What did the study find?
ESO found that by using HVDC cables underground, they were able to propose an alternative to pylons that could be delivered at comparable or lower cost, assuming a baseline of 2034. Of course, if National Grid’s Norwich to Tilbury project was restarted now, it would involve huge costs as the project is advanced, with planning permission expected this Summer. This is exactly why the 2034 baseline is useful in order to make a fair and accurate comparison between the transmission options.
3. Why is HVDC undergrounding cost comparable?
Assuming a 2034 baseline, ESO found that undergrounded HVDC was cost comparable to pylons – indeed, potentially cheaper, given the greater efficiency of this option and therefore the significantly lower ‘constraint payments’ involved. Constraint payments are made to electricity generators when there are physical constraints on the network (i.e. the network cannot physically transfer the power from one region to another), so ESO ask generators to reduce their output to maintain system stability and manage the flows on the network. I would stress that the findings on HVDC undergrounding costs were retested repeatedly by ESO’s senior engineers and found to be fully justified.
4. Isn’t undergrounding always more expensive and damaging to the countryside?
Traditional undergrounding with HVAC can be damaging in construction because it usually requires such wide trenches – though any option will have construction impacts. This is particularly the case with the current proposals for Norwich to Tilbury in areas where the pylon-borne power is undergrounded for part of its route, such as through the AONB and Dedham Vale – including the need for large sealing end compounds both where the pylons go underground and emerge. Instead, with a single underground HVDC network, there isn’t the need to have such wide trenches and there would be far less impact than partial undergrounding between pylons.
5. How credible is HVDC undergrounding?
Instead of pylons, we could have high-voltage, direct-current underground systems of the kind that are now the legal default option in Germany. Even if undergrounding was more expensive, it’s simply not the case that it’s 4.5x as National Grid claim and crucially, undergrounding would protect against the permanent despoilment of our countryside which pylons cause.
6. Isn’t all undergrounding disruptive?
In the short term, yes, but the benefit of undergrounding is that the land is covered and returned to how it was before. To take one example, there is currently a large water pipe being constructed through villages such as Raydon and I have not had one single email complaining about it because people know the land will be ‘made good’ once the works have finished. Pylons on the other hand have lasting visual impact on our beautiful countryside.
7. What happens next?
National Grid and the Government are unfortunately continuing to be dismissive of alternatives to the Norwich to Tilbury pylon proposals, which are due to be submitted to the planning inspectorate this August. I will continue doing all I can to stand up for my constituents and push National Grid and the Government to look again at alternatives, given all the evidence that we have of cost comparable alternatives that would be far less damaging to our countryside in the long term.
