Rewiring the UK: a new National Grid-ESO plan

The National Grid’s Electricity System Operator (ESO) has unveiled a £58bn investment plan to fast-track the UK’s transition to a net-zero power grid by 2035.  It would connect an additional 21GW of offshore wind off the coast of Scotland to the grid, delivering a world-leading offshore wind sector with more than 86GW of capacity in total. It is claimed that that the proposed investment in onshore and offshore network infrastructure would lead to a net benefit to consumers of up to £2.1 billion from avoiding the costs associated with network congestion 

It's an ambitious programme which would involve some extensive grid upgrades on shore, but would also include a lot more undersea cabling- in all, three times more offshore than onshore by 2035, some of the new undersea grids being very long, linking north and south. There will be shoreline landing-point impacts for the subsea cables, and on shore links from them to the wider grid system, but in general, offshore location should avoid some local land use conflicts. However, undersea links are costly. NG-ESO note that subsea grids are up to 8 times more expensive than above ground tower mounted cables, which can carry 3 times more power. So there will still be some new land-based links, and we can expect some bitter local pylon siting battles. But on the socially positive side, the ESO claims the plan would create and sustain around 20,000 jobs annually, with 90% of the benefits occurring outside London and the South East, with, for example, a new electrical spine between Peterhead and Merseyside.

Extra grids are not the only issue. NG-ESO says that, as renewables expand, ‘one of the biggest problems Great Britain faces is the inability to easily store large volumes of electricity.’ It notes that ‘grid-scale storage is becoming increasingly important in managing peaks and troughs in the electricity system. Currently this is being done through large-scale batteries and hydro schemes, however it is unlikely that it can be built out in sufficient quantities to manage long-term fluctuations in output’. But it says that, as an alternative to storage, electricity can be used differently via Demand Flexibility Schemes, where ‘customers are financially incentivised to reduce their electricity consumption to help manage the energy system at times of peak electricity demand.’ It say that, in addition, ‘hydrogen and bioresources may play a significant role in storing energy for long periods of time in the future’. And in the longer term, ‘we may also have the opportunity to develop large-scale strategic or flexible demand closer to sources of generation. Connecting large-scale demand sources near to power generation can reduce the amount of new or additional transmission infrastructure required.’ 

There could also be some new cross channel Interconnectors links. Currently there is over 9 GW of grid link capacity between the UK and the EU and NG-ESO say at least 5 GW more could be beneficial. That could help with grid balancing and power trading - the UK can export some of its excess green power when demand is low and (hopefully!) import green top ups when demand is high. Interestingly, although, as the NG ESO says, the UK has for some while been a net importer of power, it has of late become a net exporter of power, in part since it has a lot of offshore wind capacity whereas France is having trouble with some of its old (and new) nuclear plants. 

However NG-ESO warns that UK power demand may rise dramatically:  ‘In the future we will need to generate significantly more electricity. We project that by 2035, demand for electricity may rise by up to 65% and that by 2050 demand could more than double’. And it says that, while system flexibility, interconnection, storage and hydrogen production can reduce the stress on the, given the rise in demand, ‘we will still need to redevelop parts of the transmission network’.

The NG-ESO ‘Beyond 2030’ plan, and back-up papers, certainly offer a quite detailed look at what may be ahead. The overall plan was generally well received by industry, who mostly seemed to want to get on it with as a matter of urgency. Indeed, in addition to promises of some welcome industrial movement on energy storage, some other aspects are already looking likely to get underway soon: for example, the first project to proceed under Ofgem's new fast track process has received a provisional £2bn funding package to deliver a subsea energy superhighway. 

So some progress may be made soon, although, while NG-ESO had been at pains to make workable compromises between local impact issues and system costs, there are obvious likely problems for local environmental groups seeking to resist pylons near them. As noted above, there may be no alternative to some new on shore grids and pylons, but it could be that new technology could help to reduce the scale of cabling by using cables with more efficient composite cores- so the same power can be transmitted with fewer links. NG-ECO do point out that High Voltage Direct Current transmission is also more efficient over long distances, but that will mostly be for the many new long undersea links. 

However, is NG-ESO right that we will need many more new links, whatever the type, since power demand will rise rapidly? Presumably that projection is partly based on the assumption that the use of electric vehicles and heat pumps will boom massively. But they may not - there are in any case alternative transport and heating scenarios, e.g. with bioenergy and green synfuels playing more of role. And, even leading aside the big debate about moving to an ‘energy sufficiency’ demand-matching approach and the wider de-growth issues, the potential for energy saving in most sectors is huge. The NG-ESO plan is pretty relentlessly an electrification plan. As I argue in my next post (out after an Easter break), local heat nets linked to heat stores and fed via Combined Heat and Power plants, can also play a role, not least in helping to balance the increasingly renewables-based system. 

*A new Ember report on Europe-wide power grid issues says many national grid plans are not ambitious enough and risk constraining renewable growth