Grid delays descending into farce, says Solar Energy UK

In the latest of his solar series for elemental, Dr Seb Berry examines the issue of grid delays.

Occasionally, I receive a media release which goes beyond the usual balanced fare pumped out by renewables trade bodies, keen to avoid upsetting government, Ofgem or the DNOs. The Solar Energy UK release of 7th February headlined “grid delays descending into farce” was one such release. Frankly, things must be really grim if Solar Energy UK feel they need to use that sort of language, and indeed they are grim, farcically bad.

Chris Hewett, Solar Energy UK CEO, told the Environmental Select Committee “Enabling sustainable electrification of the UK economy” hearing on 7th February that increasingly, DNOs are telling solar farm developers, “You can build it, you can connect it, but you can’t export to the grid, which is just a bizarre thing to be putting in writing.” As well as the negative economic impact on developers, grid delays are now frustrating the growth of cheap solar energy, at a time when the government’s wider net zero target and 70GWp solar target, demand a sustained acceleration in the deployment of solar farms.

It’s worth emphasising that grid delays are far from being a new problem. There have been legitimate complaints about solar farm grid delays for very many years, indeed from the very beginning of large-scale solar projects in the UK over fifteen years ago. In extreme cases, solar developers have been told to wait until the 2040s for a grid connection, but delays up to ten years have been more common. An LGA report last year pointed out that a total of 1,300 clean power projects (not all solar) had secured planning permission but were yet to be built, arguing that “challenges in connecting new energy power projects to the national grid are often cited as being the key challenge to getting projects off the ground.”

Removing barriers

Whilst this is not a new problem, government, Ofgem and DNOs have been very slow to react. It is now ten long years for example, since the then coalition government’s UK solar PV roadmap promised that ministers would “consider whether steps can be taken to remove any barriers to deployment and speed up the process of connecting to the grid”. A decade on, and the frustration facing solar developers was all too clear to see at the 7th February Select Committee hearing.  Hewett estimated that the number of solar projects being told that they can be connected but can’t export to the grid was “at least fifty and there are probably more since the beginning of 2024.”  The Carbon Trust, in its written evidence to the inquiry has emphasised that grid connection delays are not just deeply frustrating to solar and other renewables developers, but now “significant barriers to the UK’s target to decarbonise national power supply.”

Slowly, the DNOs are finally starting to act, promising to spend more on infrastructure and changing the management of the queue for connections, prioritising projects deemed certain to go ahead. But in doing so however, they have also introduced a new “technical limits” programme allowing projects to connect to the grid before local grid area reinforcements have been completed. Typically, this comes with the sting in the tail of “curtailment” of output, keeping solar output to within predetermined bounds, pending the finalisation of grid upgrades.  Solar Energy UK point out that grid consultancy Novogrid has seen 50 such messages over the past three months, all with curtailment above 90%. A staggeringly high number.

Jonathan Selwyn, Managing Director of Bluefield Development spells out the industry’s concerns about levels of curtailment coming on top of years of delays. He says: “The solar industry is investing hundreds of millions of pounds on upgrading the grid to enable projects to connect and, in return, is experiencing years of delays and a shockingly poor level of customer service from network companies.  Following years of lobbying, the government and Ofgem are finally taking notice of our concerns, but the myriad action plans are yet to yield real results. Long delays remain for most projects, with the suggested levels of curtailment in some new grid offers raising significant concern.”

Solar Energy UK cites the example of National Grid Electricity Distribution, which operates the low-voltage grid in the Midlands and other areas, deciding that a 49.9MW battery system would be subject to an absurd 100% curtailment, at every time of the day and throughout the year. In return the developer could expect to connect in 2028 rather than 2032.  Hewett comments that “you couldn’t make it up. The idea of offering a grid connection that you can’t use and calling that some sort of success is absurd. It is like being told you can open a shop on the High Street, as long as you keep the doors locked. This is bizarre behaviour, and an apparent attempt by the DNOs to make it look like they are doing something while they still fail to invest in vital upgrades,”

Solar farms

Solar Energy UK suggest that the root cause of the problem is “preposterous assumptions” about how battery and solar projects operate in the real world. In one case, a solar farm was assumed to be exporting at maximum capacity at 9pm in the middle of winter. It is also common to assume that solar farms and battery systems export at maximum simultaneously, which of course would not happen in practice: the solar farm would charge the storage system in the day, to sell the power at night.

One key issue is a lack of suitably trained staff at DNOs. Paul Manning, Co-Chief Executive of NovoGrid has said that the situation was the consequence of the “utter lack” of people trained to conduct power flow analysis, “which is the gold standard for this kind of work”. Manning emphasised that high pressure working environments can also lead qualified staff to leave DNOs for consultancy roles after only a few years, thus adding to the DNO skills shortage.

Solar Energy UK argues that rather than using dedicated network modelling software, grid operators have fallen back on a far more simplistic calculation system, based on Microsoft Excel. This delivers exceedingly cautious results, which in turn avoids potential DNO liability, if required curtailment turns out to be greater than estimated. “This is why they use such ultra-conservative assumptions to ensure that they can never be wrong,” said Manning.

The structural nature of the problem means that solutions are limited, beyond actively seeking to recruit and train new engineers. However, there are suggestions that the Department for Energy Security and Net Zero, or energy regulator Ofgem, could intervene. Some DNOs are also putting more data in the public domain so that developers themselves can calculate the risks more accurately. Solar Energy UK have suggested that it should be a requirement for all DNOs to do this.  They also point out that both the skills agenda and securing swifter access to the grid are “key themes” of the government/industry Solar Taskforce, which is due to publish its roadmap next month for reaching 70GW of solar.

Hewett is right of course to suggest that telling developers they can connect, but they can’t export to the grid is “bizarre,” but it’s not entirely unexpected. To put this issue into some sort of political context, it’s just a fact that very large scale solar farms have never exactly enjoyed overwhelming support from UK Conservative Ministers and the grid is still many years behind the trajectory needed to deliver our clean power future. Despite positive noises, it’s also unclear precisely how much weight the forthcoming new Solar roadmap document will put on solar farm expansion in England and Wales and the detailed changes needed to deliver it. Developers will be reading those sections of the roadmap with keen interest.  The current grid delay farce can’t be allowed to continue.