G99 compliance: what developers need to know
For DNO connections for generation projects or demand with generation behind the meter

00:00:00 – 00:00:18 – Catherine Cleary

So, good morning, everyone, and thanks very much for joining Roadnight Taylor’s webinar on G99 compliance this morning. I’m Catherine, and I’m going to be hosting today, which is a bit of a first; we normally have Pete Aston hosting, so I will do my best to channel my inner Pete, and it’s really nice to be joined by Philip and Nikki, so hi guys!

00:00:19 – 00:00:20 – Nikki Pillinger

Hiya.

00:00:20 –m00:00:57 – Catherine Cleary

And in the background, I just said a few minutes ago, but for anyone who didn’t hear, it’s not actually Laura Porter, we’ve got Abi Leach today from our ops team, so Abi will be there if anyone’s got any, like, tech or sound issues or anything like that. Just let Abi know in the chat.

Okay, fantastic. So, we are talking about G99 compliance today, what developers need to know, and this is for DNO connections, for generation projects or demand with generation behind the meter.

So, over on to our, kind of, first question. I think, Nikki, I’m coming to you with this. So, I guess, for everyone who’s wondering if they’re in the right place, who actually needs to comply with G99?

00:00:58 – 00:02:06 – Nikki Pillinger

So, G99 is the standard grid compliance that everyone has to comply with, if you’ve got a new connection, unless you are under 0.8 kilowatts, which is very, very small. But there are lots of different levels of compliance. So, as we can see from the table, we’ve got Type A, which is quite small, so anything from kind of very, very small up to a megawatt. And then Type B, which is a megawatt to 10 megawatts, Type C, which is 10 to 50, and then Type D, which is anything over 50 megawatts.

So, all of the, kind of stipulations for, type A, B, C, D are all a bit different. So, for Type A, for example, you can kind of get away with, like, type-tested equipment, whereas you wouldn’t, wouldn’t really be able to do that for Type B, C, or D – y ou would have to do a lot more kind of on-site testing, and essentially the compliance levels kind of level up, if you will, as you kind of go through the stages, of G99.

00:02:03 – 00:02:18 – Catherine Cleary

And we said, so we said this is for generators and, and maybe, like, demand sites that have behind-the-meter generation. What about demand-only sites or storage sites, Nikki?

00:02:19 – 00:02:29 – Nikki Pillinger

Yeah, so demand-only sites, don’t have to, storage sites do, because they are generation assets. So yeah, anyone with any generation on site, essentially.

00:02:30 – 00:02:44 – Catherine Cleary

And are there any carve-outs for people who, so if you’re connecting, if you’re a new connectee, and you’re connecting to the network, and you’re going to kind of parallel up your generator, you need to comply with G99. There are some other types of generators, that have fewer restrictions, is that right?

00:02:45 – 00:03:10 – Philip Bale

I presume you’re thinking about store generation, Catherine, the short-term operating reserve, someone who has a generator that will operate in parallel with the transmission system, but infrequently. And that’s normally 5 minutes a month, I think, and no more than, there’s the rules on there, it’s once or twice a month in terms of operating. And I think for those, there is a G99 light requirement where you have to comply with some aspects of G99, but not all of them.

00:03:11 – 00:03:21 – Catherine Cleary

Cool, okay. Yeah, that was what I was thinking, Philip. So, we use the term long-term parallel, don’t we? Like, which just means a generator which is connected to the network, you know, and planning to export. Okay, fantastic.

00:03:22 – 00:03:39 – Philip Bale

I think the other one on this, always the nuance, is that you could end up having a 132 kV connected final demand, and if they want to connect a very small solar scheme to their site, they’ll automatically be a Type D generator, which means they’ll have the most onerous compliance issues around being connected at 132, if you find those scenarios.

00:03:40 – 00:03:42 – Catherine Cleary

Oh, yeah, because they’re connected above 110kV, yeah.

00:03:43 – 00:03:44 – Philip Bale

Yep.

00:03:44 – 00:04:03 – Catherine Cleary

You can tell that this was a standard that was written whilst we were still part of the EU, can’t you? And it’s been harmonized to some voltage levels that don’t look very standard for the UK.

Okay, fantastic. So, next question, Philip, perhaps you could talk a little bit more. So that was, Nikki’s kind of covered new generators, and when they’d need to comply with G99. What about existing generators?

00:04:04 – 00:05:32 – Philip Bale

Yeah, so this is something that we, we sometimes hear some horror stories on. So obviously, any generation that was connected before, I think it’s April 27th 2019, will have been connected under the previous policy, which is G59; which is arguably similar to G99 around protecting the distribution network and generation connected to them. But it was arguably a far lighter, compliance process. And schemes will remain that are under G59, will remain on G59, but there are some caveats with that.

If you are making material changes to that site, you then could need to re-comply with G99 again. And some of those elements are, if you have an existing, inverter for a solar farm, and that inverter fails, and you replace it with a new inverter, you would need to tell your DNO about that, and they could require the site to comply with G99. If you also change a transformer within your site, you’d need to tell the DNO, and it’s within the connection agreement – any material changes, a change of an inverter, a change of a transformer would be seen as material; especially if that transformer had a low impedance, which meant a higher fault level contribution, then you’d expect there is a risk that the DNO could turn around and say that the whole site would need to comply with G99, and that might have fairly material impact on your site, where it might not easily comply with G99 around replacing all of the inverters on the site.

00:05:33 – 00:06:30 –  Catherine Cleary

Okay, fantastic, thanks, Philip. I should have mentioned at the beginning, we’ve got a Q&A function on this webinar, so you should be able to find that on the bottom of your screen, or if you can’t, then under the three dots, dotted more, and so feel free to chuck questions in., we’ll try and take questions as we go, so if anyone’s got, kind of, queries about, you know, specific scenarios, would they fall under G99 or not, then feel free to pop geeky questions, or non-geeky questions in the chat or the Q&A.

Fantastic. So, I guess, that hopefully means that, that people listening have got a good idea about whether or not G99 is going to apply to them. I guess the, the sort of, the next question is probably, if G99 applies, what do you need to do, and when do you need to do it? So, Nikki, can I come to you on this one? So, when do you sort of start that whole G99 compliance process?

00:06:31 – 00:07:19 – Nikki Pillinger

So, the compliance process, it does start well, kind of depending on the developer themselves, and when they kind of want to kind of start doing things. But normally, we would have, kind of, the compliance process starting around, like, when you’ve got final design, you know, you’ve got your EPC in place, you’ve got your ICP in place, you’ve done your design, done your design freeze, you know what your transformers are going to be, you know what your inverters are going to be, and you’ve kind of, you’re in a point to start doing electrical studies.

Obviously, you’ve got that kind of G99 form that you fill in right at the start of the process, but that’s not really compliance, that’s more of a, it’s more of a kind of an indication of what you might, what you might be installing.

00:07:20 – 00:07:22 – Catherine Cleary

An application form, Nikki, you mean?

00:07:23 – 00:07:52 – Nikki Pillinger

So, the G99 standard application form that you would fill in at, like, the start of the process, so that’s kind of, that will be something that you will then, do again when you’ve done your design freeze, when you’re actually kind of certain in terms of what you’re going to be installing on-site.

So yeah, so I would kind of encourage G99 compliance to start when design freeze has happened, yeah, I think we’re going to go through a timeline in a minute.

00:07:53 – 00:07:55 – Catherine Cleary

I’ll pop that up on screen in a minute.

00:07:56 – 00:08:04 – Nikki Pillinger

Depending on what kind of voltage level you are, you would want to be kind of at least kind of 12 months beforehand, really, especially for, like, for large projects, like for 132kV.

00:08:05 – 00:08:21 – Catherine Cleary

Yeah, so presumably, there’s a bit of a balance here. If you start the process too late, you’re at risk of kind of delaying your actual energization date, and if you start it too early, you might not have done that full design freeze, so you might end up needing to repeat things, I suppose, if you change the inverter model or something, or change the wind turbine model or something like that.

00:08:22 – 00:08:22 –Nikki Pillinger

Yeah, exactly.

00:08:23 – 00:08:42 – Catherine Cleary

So we’ve got, we thought there’s quite a lot of information, to absorb as part of the G99 process, which Philip and Nikki are very well aware of, so we thought it might be helpful to pop, a slightly more kind of detailed slide up, to show this timeline. Nikki, do you want to sort of walk through that point? And I’m sure Philip and I can kind of jump in on bits as well.

00:08:43 – 00:11:38 – Nikki Pillinger

Yeah, no problem. So, your initial PGMD, so PGMD is Power Generating Module Document, just so we’re not using loads and loads of acronyms. So, the initial submission, you would have, as I said, your standard application form, which is the form that you fill out at the start of the process, and then you fill that out again with all of your, sort of, thought-level information, inverter details, transformer information, and essentially how your site is going to operate, and what your site is going to have on it; you’d do that again, but with a lot more detail than you would have done initially. You had your single line diagram and your layout plan, your P28 study, your G55 studies, your harmonics, all your G99 studies, and all of your inverter and, power part controller data sheets as well, and your test schedules that you would get from your, get from your OEM.

The DNO will then look at your PGMD submission, so there’s no kind of fixed timeline for them to do this, but normally they would kind of fit in with a kind of ICP design sort of timescale, so they’d look at it within about 20 or 30 days. And you would then do any sort of revised PGMD submissions. Normally, there’s a few iterations of a PGMD – quite often, we’ll put in kind of a draft PGMD with the documentation that we have while we’re waiting for some other models, and studies to be done, just so we can kind of get some bits ticked off.

And you would kind of update anything based on what the DNO’s come back with, and you would then agree that sort of full compliance and testing plan.

After you’ve got that, kind of, agreement and you’ve got your initial energization, you’ve got your initial ion, which is only, kind of, 20% of your generation can be, kind of, initially, kind of, synchronized and turned on. And this is so you can do your basic voltage control tests on site.

The DNO will then kind of review those tests again, and once they’re happy that you’ve done everything, and once they’re happy everything’s safe, then they would actually remove that 20% restriction. And then you’ve got something called unrestricted ion, where you would do your remaining, like, on-site testing; this is, like, your reactive power, voltage control, frequency.

And then once everything’s completed, once you’ve done all of your, testing on site, then you put your Form C3 in, so you’ve got three forms, essentially. You’ve got Form C2-1, which is your initial, kind of, this is what we’re going to do, this is our initial, like, simulation studies. And then you’ve got, your second form, which is form C2-2, and then your final form C3 – so, this is when your witness testing’s been done, your interface protection results will come through, and all the on-site testing’s complete, and everyone’s happy. And then you get your form – which means you can connect to the network and generate.

00:11:39 – 00:11:40 – Philip Bale

You make it sound easy, Nikki.

00:11:41 – 00:12:41 – Catherine Cleary

… when we get to the end of that process.

So, we,  I mean, I think one of the things that we’ll obviously be delving into each step of this process, as we go through the webinar. One thing which we’re really interested, we normally, we like to try and do a sort of poll or something like that as part of these webinars to get a bit of feedback from you guys. We’re quite interested in what people’s kind of working assumptions are about how long this process takes them for their projects. So, I think, Abi’s going to try and pull up a poll, in the background to just ask how long do you guys generally assume that you’re going to take to reach that final operational notification? So, from energization through those initial ion and unrestricted ions to FON, you know, how long does that sort of take you for your kind of projects? And then we’ll share those results at the end, so you can feel free to kind of keep that in the background and revise your answer, if you like, as we go through the webinar, and we’ll share at the end. And we’ve also got some kind of Roadnight Taylor, sort of, timelines as well, which is what we sort of commonly see on projects, so I think good to share that as well.

Philip, did you want to add anything on the, kind of, timeline piece?

00:12:45 – 00:13:53 – Philip Bale

I think the, the bit from our experience is being that starting as early as possible is as sensible as possible, that the minute you do have that fixed design in place, that when it presents the opportunity to go through and start complying with these, having that earlier understanding as to what the DNO wants.

I think one of the things that will probably come through from more of the parts of the webinar is – this is quite a technical, involved process. There is a lot of documentation in place, but it can be interpreted in lots of different ways. So, understanding the person who’s going to be marking your homework, which is for your submission, understanding what they will require you to, or what they will require, what they want to see, and making sure that you’re presenting that information in that clear format for them is fairly key.

And what I’m sure many of the people that have been on this, that have gone through that process, is that you could have two identical processes with two same DNOs, but in different license areas, and get very different response back to identical submissions for it. So, it can be a process that can be quite frustrating, and so I think this webinar is trying to help reduce some of those frustrations.

00:13:54 – 00:15:33 – Catherine Cleary

And we’ve got a really good comment, actually, in the Q&A from James, so, who’s pointed out that, so the wording we’ve used here, we’ve talked about, the interim operational notifications, it does actually vary depending on whether you’re a Type A, Type B, Type C, or Type D, as to whether a DNO will formally issue you with a piece of paper, which is called an ion. So, James has very rightly pointed out, it’s only obligatory for the DNO to use that initial ion and unrestricted ion process when you’re a Type D, but the 20% restriction remains for types B and C, so the, you might not get an ion, but you would still get an email or a, you know, a notification that you were restricted to 20% until you’d done your kind of basic voltage control tests on site, and the DNO had removed, that restriction. So, I suppose, that’s a really, really good point James, the actual documentation process does differ for the different types of G99 compliance, but it’s important to kind of know, is your project going to be subject to a 20% output restriction until you’ve passed those tests, and if so, to factor that into the timeline.

Okay, fantastic. So, we’re going to come on. Christian, thank you very much for your comments in the, your questions as well in the chat, I’ll probably leave, Philip, to have a mull over those, and we will come back to them, so thank you for your patience. I mean, Nikki, I think just, sort of building on that timeline, and sorry, actually, I’m coming to Philip on this one, aren’t I, not Nikki. But who actually does that kind of, who owns that whole G99 compliance process, typically on projects that we see, and who should own it?

00:15:34 – 00:17:19 – Philip Bale

Yeah, so I think, who does own it is, is the developer owns it, so it is the developer who’s generating the project who is responsible for this element, but quite often they will subcontract out that requirement. So, quite often, we’ll see that if a developer is developing a project with an ICP in place, they might decide to put it in as a wrap; that your ICP is then responsible for all of this, which includes engaging with the EPC that’s developing and delivering the generation aspects of the projects, and they would often subcontract it, because these are quite specialist skills and tests, and other elements that’s, that’s going through on there.

So, and the downward, or the downside of having that ICP wrap is that ultimately, they could end up subcontracting it to anyone. And that may not necessarily be the person that you would pick. We have seen in the past some quite, sort of protracted negotiations between the person doing the studies and the DNO, multiple iterations on multiple different elements. And it can, and has, and will, delay projects, which is one of the reasons why we would suggest doing it earlier in that process, and also being mindful that if you are subcontracting this out to someone else, and someone else is responsible for it – just being fully aware as to what are the risks and the implications if it takes a long time to comply with any of the requirements, any of the tests, and if you can’t demonstrate compliance to the DNO, it can and will delay the project. Not sure if anyone else wants to add anything else on there?

00:17:20 – 00:17:42 – Catherine Cleary

And Philip, what’s your, sort of, view about so, some, developers will obviously have lots of, kind of, internal technical capabilities, so they might, you know, they might very well, kind of, like, run this process themselves. Some people will want external consultants, so I guess Roadnight Taylor do manage this process for some parties. So, I suppose, does it matter as long as there is a kind of, like, a driving technical party?

00:17:43 – 00:18:16 – Philip Bale

No, I think it doesn’t matter who does it, as long as there is a clear understanding of roles, responsibilities, to make sure that ultimately the whole site gets compliance. There’s some quite varied requirements that are in here associated with G99, so power system stability tests, as an example, are very different to cybersecurity compliance, very different skill sets. So, as long as that leading party has the right people to support them,  to demonstrate that they can comply with the various different requirements – I think that’s the key, the key message to take away.

00:18:17 – 00:18:42 – Catherine Cleary

And I guess you can, sort of like plan for success in that respect, right back well before the kind of design freeze point and things, when you’re actually setting up EPC contracts and so on, and make it clear in contracts who’s responsible, for that, and it’s normally, as you say, Philip, I guess it’s going to be a bit of a team effort in the sense of, there’s going to, you’re going to want to make sure that each of your contractors has an obligation to provide information into this process, even if they’re not the ones running it.

00:18:43 – 00:19:07 – Philip Bale

Absolutely, and if you are doing it as an ICP wrap where someone else is responsible for all of it, you may want to be quite specific as to the parties, or have rights of refusal of who is going through and doing those works, or demonstration that they have previous success at doing this in a timely way. So yeah, there’s lots of different ways of going through and doing it, but I agree entirely with your comment there, Catherine, of planning for success, rather than winging it.

00:19:09 – 00:19:31 – Catherine Cleary

Fantastic. Thanks, Philip. Okay, we’re going to come well, we will next come on to, sort of, some of the documents that we talked through in that, kind of, timeline. So, we talked about things like the PGMD, and then I think, if it’s okay, I’m then going to come back to Philip, on the question around, sort of, backup generators and emergency generators and compliance requirements for those. So, Nikki, do you want to just talk us through the PGMD first?

00:19:32 – 00:21:49 – Nikki Pillinger

Yeah, so PGMD form is, so you can find it on the ENA document catalogue, so I think we’re going to provide a link to that. So, as I said, you’ve got a few different forms, so you’ve got your standard application form, which you fill in with all of your inverted details, transformer details, spot levels, etc. And then your first one that you fill out would be your, kind of, your C1 form. So, this is for type C and D, so we’ll kind of focus on those ones.

So, your C1 form, references a lot of other documents as well. So, you’ve got quite a lot of other studies that will be done that will be referenced in this, alongside lots of things, like, you know, your, just basic admin things, like, sort of, project name, project reference, and, like, who the contact is for that. And then, like, a kind of high-level descriptor of what you’ve got, on-site, like, what your technology is, and all your technical specifications.

And you’ll then kind of move on to ticking off where you’ve got your, where you’ve got your other information. So, you’ll have things like your harmonic studies, your earthing, P28, P29, fault-level studies, like fault ride-through studies, load flow reactive power studies, site SLD, cyber security – lots and lots of different things that you’ll have in that kind of, C1, sorry, C2-1 form. So that’s more of a, this is kind of what we’re planning to do, and here are our test schedules, here are our studies that we’ve done that show that this site should be compliant.

Then you’ve got your C2-2 form, which actually shows the results of your testing, and then that’s submitted, and then you’ll have your C3 form, which kind of is like a confirmation that all of this testing’s been done, and that it’s been witnessed, and everyone’s happy that that’s, that that’s been completed.

So, it’s not just a single form, it’s lots and lots of different things. That will go to the DNO and kind of all be checked through, so it’s the process that it goes through is more of a, you know, this is our testing in theory, you know, these are all our studies, we’ve done everything that shows that it should be fine. Then the testing, and then the actual confirmation.

00:21:50 – 00:22:45 – Catherine Cleary

And I guess, importantly, Nikki, you actually submit, so, the C2-2 form, that second one, that deals with, the protection interface tests, for example, which lots of people will be really familiar with, you know, an ICP will kind of, you know, be able to do those with their eyes closed. That’s testing your G99 relay on site, for example. It can be really easy to sort of miss a form, you know, so to think, well, I’ve done this, I’ve done G99 compliance, because I’ve done that, that G99 relay test or something. But actually, there’s a really, really significant kind of bulk of effort required in this C2-1 form, which is what we call the PGMD, and it gets resubmitted, doesn’t it? So, it’s that initial plan, as you say, this is our compliance studies and what we’re planning to do in terms of tests, and then it gets resubmitted once you’ve got all of your test results.

So, you’re sometimes submitting these forms multiple times, over that kind of PGMD journey, and when you’re going in to ask for FOM, that’s because you’ve got the final version of all of those forms.

00:22:46 – 00:22:47 – Nikki Pillinger

Yeah.

00:22:47 – 00:23:22 – Catherine Cleary

Fantastic. Okay, we are going to come back to Philip, then, with tricky questions.

So, Christian, thank you very much for questions around backup emergency generators. So, what happens if things have changed, Philip, in terms of the operating regime? So, Christian’s question is, if you have an existing backup or emergency generator, which was compliant under G59, but then, like, the export function was disabled, or I suppose the same might be true if you, you know, if you change the operating regime of a site, does that amount to a significant change? So, if they now wanted to export opportunity, would they need to be reassessed under G99?

00:23:23 – 00:24:26 – Philip Bale

Yes, I think it is. So I think my reading of that when I read Christian’s question is that these generators aren’t working in parallel with the grid anymore, so I’d say you check your connection agreement, but the whole aspect of having protection, light protection, on backup generators was so that when you were operating in parallel with the network, there was some level of control that was in place to protect the network, and in some instances, the generators.

If you are no longer operating in parallel with the network, I don’t think there will be any need for doing any sort of reassessment. If you did want to operate as part of in parallel with the network, and you wanted to export, then I think it would be more than just a re-compliance; you’d then need to apply to change your connection agreement to facilitate an export.

So I think if you are solely operating in island mode, I think your connection agreement would probably say, and G99 would say, that you wouldn’t need to comply if you were planning on trying to do anything else, you’d probably need to reapply to the DNO, and ask that question to them, so they can then take a view.

00:24:24 – 00:25:33 – Catherine Cleary

Oh, fantastic, thank you for it, Philip, good answer. So, and on a related note, and oh, fantastic, and Christian said, yes, that’s your correct interpretation. So, the generators, they’re still connected, but they’re not paralleling. Okay, so hopefully, good news, Christian, no G99 compliance and that is set out in G99, so within the kind of scope introduction of G99, it is very clear that the G99 requirements apply to long-term parallel arrangements and short-term parallel. They don’t apply to generators which never parallel with the grid.

The, right, there’s a good question, sort of related from John as well, so perhaps we can talk about that as well. So, have Roadnight Taylor experienced any difficulties when transitioning a power station from G59 to G99, where the DNO considers a change of inverters to be a material change, because the replacement inverters are not strictly like-for-like, even though, for example, like the original inverters might not be manufactured anymore. So, I mean, I think the answer is definitely yes, we’ve definitely come across this scenario, haven’t we, Philip? Do you want to have a stab at that one?

00:25:34 – 00:26:28 – Philip Bale

Yeah, I think it is a challenge, and I think it can have a material impact on the project. One of the biggest aspects is around what’s your registered capacity? So, quite often for G59 projects, they were installed operating at Unity Power Factor, and there wasn’t the requirement for them to be designed with a registered capacity, at worst case on the bowtie of 0.95, lead lag at the various different voltages, which means when you reassess them, that you would have a reduced export capacity. And the other challenge is that some of these older inverters just will not comply in the way that you want them to do to pass the G99 tests.

So I think there is a real risk that if you do need to take a site and to try and recommission it under G99, you could struggle with the legacy inverters to prove that they will comply with all aspects of G99.

00:26:29 – 00:28:31 – Catherine Cleary

And we should be, we should maybe break this down a bit, Philip, for people. So, if you have a site which has perhaps, say, 10 inverters on it, and what you want to do is replace one of those inverters because it’s had a failure, or something like that, the, there is so there is some provision, in G99 around this concept of sort of a like-for-like replacement – that’s not always possible, as John says, you know, you might you know, the inverter manufacturer might say, well, sorry, we don’t make that model of inverter anymore. So, if you end up installing a new model of inverter, that is generally deemed to be a material change.

Now, G99 talks about that kind of additional capacity, so just that one out of 10 inverters needing to comply with G99, which is obviously quite a kind of strange setup. If you’ve got a solar farm and, you know, 10% of it needs to comply with G99, and the rest of it could still comply with G59, then, you know, you could potentially have a system where you set up two controllers, you know, you had almost create, kind of, two mini solar farms within the project. I think it’s probably worth this flagging that that can actually pose some real, kind of, control challenges for a site, and you’d want to think really carefully about doing that. And so, I guess, Philip, what you were sort of referencing is the fact that actually a lot of people will find it easier to say, right, well, we’re effectively upgrading the entire control system for the site, to be G99 compliant, and then you’re trying to make those older inverters do something they weren’t necessarily designed to do.

We often find that when people are in a situation where they’re replacing; I would say this probably, perhaps, applies particularly to sort of battery and solar projects, when you’re replacing inverters; replacing turbines on a wind project tends to be a more, kind of, like, involved process, but there’s often a kind of cost-benefit assessment about, depending on how many inverters you’re looking at replacing, are you better off, sort of, starting again from scratch and replacing all of the inverters and ending up with a kind of fully G99 compliant site, you know, with enhanced, lifespan as well?

So, there’s definitely a bit of assessment to do at the time when you’re kind of scoping out that change, you know, how painful is it going to be to have this site, which is sort of half G99 and half G59? Really good question, John.

00:28:32 – 00:28:53 – Philip Bale

Particularly challenging where you have string inverters, where you have no circuit breaker to attach that relay to for that one individual aspect. But I think the key thing that I would say is that have that conversation with the DNO and understand from each DNO and each person that’s dealing with them whether that they deem that that requires that new inverter or section of the site to comply with G99.

00:28:54 – 00:29:11 – Catherine Cleary

Fantastic. Okay, awesome. Right, well, thanks for the amazing questions, guys. Keep them coming.

Right, I think, Philip, I’m going to stay with you here, but Nikki, feel free to jump in as well. What are, I think we wanted to kind of go through, what are some of the biggest red flags? What commonly trips people up from G99 compliance?

00:29:12 – 00:35:40 – Philip Bale

And I think it’d be good also to answer Keith’s question in here as well, because I think it probably feeds in quite nicely. So, Keith asked the question, how do you balance the need for early studies, P28G5, which may require long lead time equipment, versus a DNO wanting up-to-date data to be used?

And I think one of the ones that we would flag really early would be something like a P28 transformer energization. If you’ve got a very big transformer connected to a very weak 132 or 66kV network, where you have a big centralized transformer, I would flag that as being a significant risk – I would be wanting to do that early P28 study before you’ve even procured your transformer, because ultimately, if the answer is that there is a P28 issue, especially for 132 and 66kV projects; some DNOs won’t allow point-on wave switching on their circuit breaker, which then means you need to have your own circuit breaker, in addition, something special on the customer side of the substation – if you don’t know that until after you’ve ordered all of your main equipment, you’ve got planning for your site, you’ve started building out, and then all of a sudden you need to try and squeeze an extra circuit breaker in between the DNO’s metering circuit breaker and your transformer, it’s impossible. If you wanted to do something clever around pre-magnetizing cores, most people don’t, on transformers to try and resolve the issue, you need to do that before you start building your transformer.

So, I think for higher-risk sites, there is a benefit of potentially having to do the studies twice, rather than find a problem which ends up causing significant pain, delays, and costs. So P28 transformer energization, we would suggest that on sites which we would deem to be medium or higher risk to be done earlier. And if there are challenges, it can be very challenging and can result in restrictions going into people’s connection agreements, which can make a site less commercially attractive.

We are seeing a lot of challenges around harmonic specifications for lots of different reasons. We are seeing challenges with, number one, developers being able to get access to the background harmonic data, and it taking the DNOs or their subcontractors a very long time. We are finding issues where DNOs don’t have capacitive VTs on their network at appropriate points, they’ve only got wound VTs; they’re designed for 50Hz, they’re not designed to capture the harmonics from the 50th up to the 100th harmonic, so the higher order harmonics, which can result in DNOs putting an assumption of a background harmonic in there, which isn’t in the measured data.

We are seeing challenges around there being lots of customers on a particular network, which each of them have their headroom’s, and it diminishing under G55, which means that if you’ve got lots of people still doing studies, you could be towards the end of that process and have very little headroom in place, and other people have got headroom that they didn’t then use, which could be used and passed down across to other developers.

Cybersecurity is an interesting one. Some people, some network operators would accept that if all of the individual components can demonstrate cybersecurity, that’s fine. We have seen in the past, network operators say that they want proof that the whole system together is cyber secure, rather than just the independent, components.

Compliance modelling is another one. There is a various set of rules around what you have to go through and demonstrate your project does, and they can be incredibly prescriptive. And if the DNO doesn’t believe that you’re complying with the letter of the rules, and I think there is some interpretation on this, which can mean people having to redo these studies again and again and again, factoring in the comments back from the network operator.

And probably one of the last ones is that people go through a lot of effort around doing the PGMD and the compliance and the modelling, then sometimes the people that are on site that commission the site don’t know what was inserted in the models to make sure that the actual on-site demonstration of the project matches what’s been put in place for the, the study’s free IOM – so that’s sort of one of the other elements.

I think another aspect just to focus on is that there’s not a huge amount of people who have done this G99 compliance work, and the same from the network operators. This is very technical, very detailed – some of the network operators won’t be doing this regularly, and you will find different answers from different network operators to exactly the same submissions put in place. So, it isn’t an easy process, it can take quite a lot of time, setting yourself up for success with all of these various different, aspects, will be beneficial. And to go back to Keith’s earlier aspect, some of them, I would be prepared that you would do the studies twice, if you think that that’s going to reduce the impact of your project having an issue. Obviously, if you are doing your harmonic compliance for your G5 at the very end of your project, after you’ve already installed your inverters, and then you end up having a challenge where it fails, and the DNO refuses to energize you until you put a filter in place, or you have restrictions on availability until that filter is in place, that can take a significant time. It can also be incredibly challenging if you have no place to put your filter, if you need planning for it, if you have no suitable breaker to install your filter onto. So that is the benefit of doing it earlier, is that if the worst-case scenario comes in that you do need that harmonic filter, then you have a way of going around of delivering it on site, and setting yourself up for success is probably including a filter in the planning application, so you don’t need to go back and get planning for it, and possibly installing a building big enough that if you did need to extend your 33kV board to add its own transformer on there, or if you weren’t doing that, what would be your solution if a filter was needed? How would you connect it into your site?

00:35:41 – 00:41:27 – Catherine Cleary

Yeah, I really like that, Philip. I think, sort of, like, plan for noncompliance, you know, and then, so plan for the worst, and then, you know, iterate that design as the studies show that you don’t need the mitigation equipment. I think perhaps, like, the industry as a whole has shifted on this, and 10 years ago, it was very common to do this kind of concept design study work, really quite early on, you know, what is the risk of, you know, perhaps having, you know, am I likely to have a resonance because I’ve got a long cable? Am I likely to need a filter? You know, exactly as you say, am I putting a big transformer on a 1 through a weak 132kV network? And I think over time, obviously, kind of, like, cost reduction pressures, and timelines, streamlining sort of pressures have meant that we’ve tended to see projects skip that kind of early-stage design, but I think that is now coming back, to bite people, given the kind of increased risk of compliance.

So, we’ve got one of your red flags, Philip, was harmonics, and we’ve got a question, in the chat as well about, sort of what the DNO’s obligations are in terms of issuing harmonic data, and what is this issue, sort of so we’ve got a slide which kind of talks to that, specifically.

So, I think it’s probably worth making everyone aware that harmonics compliance has changed; this happened a couple of years ago, we went from, the G5-4, version of the harmonic compliance standard to, G5-5, and it is quite a major change. So, in the old days. you would have received some background harmonic data from the DNO, and you would have gone away and done a study that just showed by you adding your generator to the network, do you take the network over the kind of acceptable, what we call the planning limits in what was G54? So, it was kind of effectively a sort of a one-stage process where you take the background level as it currently stands today, and if you’re lucky and not very many generators have connected, that might be quite low, and then you would be allowed to utilize all of the available headroom right up to the planning limits with your one project. And if someone else comes along and connects to the kind of node next door to you, that’s just bad luck, because you’ve now utilised all of that background headroom, and they will probably have to install a filter.

You know, the industry obviously agreed that that wasn’t a very sort of sustainable way of doing it, so the big change in G55 is that there’s now a much more complex piece of work that must happen up front by the DNO, or by the DNO will often subcontract this to a studies consultant to issue what we call a harmonic specification.

So, there’s quite an involved process. The first process is you need to go to a DNO and ask for this harmonic data. So, that’s the first thing to know; this isn’t something that a DNO will necessarily do off their own bat, they will be waiting for you to ask for this information. They’re going away and undertaking their background measurements, so that’s kind of the same as before, but as Philip mentioned, quite an important change – we used to just measure up to the 50^th harmonic order, G55 now asks the DNO to measure up to the 100th harmonic order, and that can be an issue if the DNO perhaps doesn’t have measurements that have been undertaken recently, so their old measurements might only go up to the 50^th, and we’ve seen some DNAs kind of try and patch that by making assumptions about what happens between the harmonic order 51 and harmonic order 100. So, you know, understanding whether you’ve got recent background measurement data or whether you’re going to have some assumptions laid into that is important.

But it doesn’t just stop there. Once the DNO has done that, they then have to, and they would either be doing this internally, or several DNOs subcontract this out, calculate the harmonic headroom that’s available at the specific point of connection that you’re connecting into. They wouldn’t then just give you that harmonic headroom; they would apportion that headroom, and so there is a formula, essentially, in G5, which says how much of that headroom should you get? And importantly, if there are other customers who are contracted to connect at the same time, that apportionment calculation takes into account how many other parties are connecting in that part of the network. They then use that kind of apportionment methodology to calculate what we call incremental harmonic limits. So, you will get two sets of harmonic limits, unlike the old days, you just got given a total overall limit, now you get something called an incremental and something called a total limit – and you will then have to take that, that’s what’s issued as your harmonic specification. So all the DNOs will call it a harmonic specification, so it’s that pack. It includes the background measurement data, it includes the incremental limits, and it includes the total harmonic limits. You’ll then go to your studies consultant and ask them to undertake a study, and they will do two checks.

You know, firstly, does this project breach the total limits? Obviously, if it does, there’s a problem. But even if it doesn’t breach the total limits, have you breached those incremental limits that was apportioned to use the amount of headroom that you were given. And if you find that that is the case, then you’re going to need to start a conversation with the DNO about, kind of, appropriate mitigation, and that mitigation equipment could include a filter, and as Philip says, you know, you’re talking about significant lead times for harmonic filters, so, you know, even for a 33kV filter, that could be 9 months plus. So, if you’re doing these studies three months before you energize, you’ve probably got a problem, if you trigger that filter.

I was going to Philip, I don’t know if you would sort of agree, I would probably go out on a limb here and say that it’s, we are definitely seeing more projects trigger filters. You know, G55 is a more arduous standard to comply with, and so this does need to be a risk which is on people’s radar, that actually, you know, it’s not the very odd project that might need a filter. You know, we are actually seeing significant volumes of 33kV and 132kV connected projects need filters.

00:41:28 – 00:42:40 – Philip Bale

Yeah, and I think we’re also seeing far more around the G55 analysis around, if you ask the inverter manufacturer for the models, they might provide a fairly basic model, and then if there’s an issue with it, they might then have to look at that model to make sure that it’s actually accurately reflecting, what the actual inverter that’s installed on site is actually doing. The other challenge that I’d put in here, which also makes life very difficult for the developer, is that we often see network operators wanting the background measurements to be reflective of the network when the site is connected, so that you couldn’t use very older data, so you couldn’t ask for this 3 years in the past, and then expect to use that data, to go through and to connect your project onto the network.

So, around the timing of when it needs to be done, it’s a balance between having the information early enough, which then means that if you do need to have a filter, it doesn’t impact on the timescales of the project, or limits the impact on the project, also understanding that if you ask for the data too early and your project is significantly delayed, the network operator may then say, I want to retake new, updated background measurements and rerun the assessment based on those data.

00:42:41 – 00:43:38 – Catherine Cleary

So there’s probably a kind of sweet spot, which is maybe, sort of a bit over a year before you connect, you know, maybe 14, 16 months before you connect when you want to be requesting that harmonic data, knowing that it might take a DNO 5, 6 months to both get the harmonic background data and compile that harmonic specification, and then you’re doing your studies, you know, sort of at least 9 months before you connect. So, I think there is a kind of, there is a sweet spot timeline.

There was a question in the chat to say is there a, is there an obligation on the DNO to issue those background harmonic measurements? So, I think the answer here is yes, G5 does stipulate that a DNO need to issue that harmonic specification, there aren’t any statutory timeframes for them doing that, so, I don’t think we’ve ever seen a DNO, you know, dispute the need to provide a harmonic specification for a project, but we have seen delays in them being able to do so, just because of workload issues.

00:43:39 – 00:44:02 – Nikki Pillinger

Yeah, it is always worth making sure that you’re aware of whether there are any issues for DNOs with that, because sometimes, you know, they’ve got limited amounts of monitoring equipment, or people that can actually go and do that. You know, I’ve had harmonic specifications back within 6 weeks before, but equally, I’ve also had them back within kind of 8, 9 months. So, it’s just being  worth being aware of those timescales.

00:44:03 – 00:44:28 – Catherine Cleary

There’s a follow-up question, which is, what about the cost for a DNO to go and do this? So, is it right for a DNO to request a PO to cover their cost for providing harmonic specification data? So, there is a cost to doing this work, isn’t there? I think we should be clear about that, and that’s, you know, in particular, where that work is being outsourced by the DNO to a studies consultant. Philip, I don’t think I’ve ever seen a PO be asked for specifically for this kind of piece of work as an isolated item, but …

00:44:29 – 00:44:30 – Philip Bale

Oh, I have…

00:44:30 – 00:44:31 – Catherine Cleary

Be included. You have? Okay, alright, that’s interesting.

00:44:32 – 00:45:19 – Philip Bale

So yeah, I think it’s, there again, like you said, it’s, there’s two different ways of dealing with it, is some of the DNOs in the past will have done this internally, and they would have used their own monitoring equipment, they would have gone out to site, and they would have provided this. More increasingly, they are using third parties to go through and connect it.

If you are connecting to a project where the DNO is doing it internally, you are paying for it, but you’ll be paying for it in the overheads, and that they will have lifted all of the other elements of your project connection costs that would be assumed to be in there. Where they do it externally, that’s why they’ll raise a PO, and it will be a variation, because they’ve decided to put it externally, and then as a result, they’ll expect the network operator to pay for it, sorry, they expect the developer to pay for it.

00:45:20 – 00:45:27 – Catherine Cleary

And then, Nikki, this is probably on for you, actually, but follow-on question, do DNOs have a dedicated team for this, for harmonics, or do you just request it through your contract manager?

00:45:28 – 00:45:35 – Nikki Pillinger

So, you request it through your, your project manager, but they will go away and get their dedicated team to do it, essentially.

00:45:36 – 00:46:16 – Catherine Cleary

Okay, and then staying on harmonics, which is, oh, this is great, great harmonics questions coming in, thank you very much, guys. So, Akis, really good question. So, if the headroom at a specific GSP is very limited, and all future connections are expected to require filters, is there a case to be made for the DNO to address that issue at the GSP level, instead of passing that requirement on to developers?

So, I mean, this is a very good point, you know, there’s nothing, from an engineering perspective, there’s nothing that says these harmonic issues necessarily need to be filtered out at a project-by-project level, but coordinated harmonic solutions are quite complicated, aren’t they? Philip, have you seen any appetite from DNOs for, kind of, resolving harmonic issues proactively on their networks?

00:46:17 – 00:47:02 – Philip Bale

No. I think, so, no, I haven’t in the past, and I think, I think it is something that is really starting to come to life now. I’ve had conversations with other network operators who have made it clear that in the past, they’ve probably not paid as much attention to this as they should have done, and then as a result, they’re now finding issues, for harmonics and having to deal with them. So, I’ve not yet seen anyone look to address it proactively, but I think that’s probably because these conversations are only really starting to bite people now and as was mentioned, that more and more GSPs have got very limited headroom, and that’s something that we’re only seeing more and more on projects now, rather than what we’d have seen 2 or 3 or 4 years ago.

00:47:03 – 00:47:47 – Catherine Cleary

Yeah, it’d be interesting to see if there is any kind of movement on that in future. This webinar is obviously explicitly covering distribution connections. I should just make people aware that at transmission, there is more precedent for shared filter solutions at transmission nodes, so there is a slightly different process that might be followed if you had a connection into one of the TO’s networks, but it’d be interesting to see if that kind of yeah, spreads down to DNOs.

There’s a great question, another great question from John Brereton. So, are there any other mitigation measures that generators could agree with the DNO, rather than just using a filter? So, the example he’s given is, you know, what if you’re only exceeding on the, like, 97th harmonic? So, you’ve got really high-order harmonic issue, or something like that.

00:47:48 – 00:48:21 – Philip Bale

So, I can go one of the options you could do is that you can re-look at your studies. It might be that you decide that you change your inverters, and you will find that different inverters will have a different harmonic profile, and it’s obviously a fairly extreme scenario, but if you were doing this early enough, before you ordered your inverters, you could model several different inverters to understand which ones would comply with the headroom you’ve got versus others that wouldn’t, and also trying to understand where there was an issue, where you were failing. Is there a resonant point? Is there a challenge that’s coming at that specific harmonic?

00:48:22 – 00:50:32 – Catherine Cleary

Yeah, I would really agree with you. Always go back to your inverter manufacturers, especially if you have high-order harmonic, non-compliances. So, generally speaking, harmonic non-compliances occur from two different well, maybe three different reasons. So, you could, there could just be very, very limited headroom on the network, and therefore, you know, even when you’re being apportioned a bit of that headroom, you know, it’s so small that in practice you were probably always going to breach it.

It could be that you might have a particular harmonic order where, for whatever reason, the inverter’s harmonic contribution, so the actual current contribution from the inverter, is slightly higher than some of the other harmonic orders. So, if you went back to your inverter manufacturer and said, oh, that’s interesting, your emissions at the 97^th harmonic are sort of twice what they are at the 95^th, could you do something about that? They will often be able to actually, you know even sticking with the same inverter manufacturer, they might be able to customize the harmonic, there’s a little normally a small harmonic filter on the AC side of an inverter, so they might be able to sort of customize the parameters within the inverter filter itself, and say, yeah, you know what,  we’ve made that problem at the 97^th go away.

The third issue, which people should be aware of, is that you might find that you’ve got a harmonic non-compliance because there is a resonance on the network. So this is typically when, you know, especially when you’ve got large amounts of cable in the network, but it can sometimes just be that by connecting a new generator and new equipment with impedance, you’re changing the background impedance profile of the network, and however small your inverter’s contribution is at that particular harmonic order, it’s just getting magnified by that resonance; that’s where you’re into filter territory, because there’s nothing you can do at your end, you’re already really, really small in terms of the actual current contribution you’re making onto the network, but it’s being magnified, and that’s causing a voltage distortion, which beats the limits.

So, yeah, I would say that, especially if you see higher order harmonic non-compliances, which tend, in general, to be less likely to be driven by a resonance issue, then it’s worth going back to your inverter manufacturers, finding out whether they tune the filters, to remove that, as a first step before going to the, we need to buy a 33kV filter or a 123kV filter step.

00:50:33 – 00:50:53 – Philip Bale

I think the challenge that can come with this very quickly is also, is that, especially where someone is not able to measure the higher alder harmonics anyway, it can be particularly challenging for a developer when looking to having to go through and do this work when it’s very difficult to measure if you don’t have the right measurement equipment and also the right VTs.

00:50:54 – 00:51:12 – Catherine Cleary

Fantastic. And I think last point on harmonics was, is there any precedent for energizing with a restricted ion while harmonic noncompliance is resolved prior to FON? I think we’ve had a bit of experience with this, haven’t we really about agreeing, kind of, energization strategies which have perhaps operational restrictions in?

00:51:13 – 00:51:38 – Philip Bale

Yeah, we’ve seen that in the past, and I think, ultimately, the thing that I would just state is that the onus is on the developer at that stage, and so that if that risk does occur, and if that operation restriction does occur, then it could result in the scheme being disconnected, or being reduced to an acceptable level, whilst there’s that, as a sort of, of checking of making sure that there isn’t a harmonic issue with the network.

00:51:39 – 00:52:00 – Catherine Cleary

Fantastic. Oh, thank you very much, guys, for really good harmonic questions.

So, if we, we’re going to move on now and cover off a couple of last points. So, G100 compliance. So, this whole webinar was termed as G99 compliance, Philip, people are probably thinking we’re trying to pull a fast one and squeeze two things into one here, but G100 is also very relevant for a lot of these projects.

00:52:01 – 00:54:32 – Philip Bale

Yep, so export limiting. So, often if you have a project where you, let’s assume that you are a 49.9, kilowatt 132kV connected scheme, in order to generate 49.9 megawatts worth of export, you will need to have significantly more inverters on your side, especially if you’re connected at 66 or 132, because you have that added transformer in place that if you don’t have any reactive power compensation to demonstrate at the point of common coupling between you and the DNO, that you can hit that 0.95 lead lag requirement Then that can lead to a risk that your scheme could theoretically, whilst not operating at those extreme power factors, export in excess of your agreed connection agreement of your maximum export capacity. As a result, the DNO could ask you to be compliant with G100, which is around an export limiting scheme put in place, and there’s various different ways that you can go through and comply with this.

In the past, most people have gone and bought a box that has a capability that’s been type-tested that will demonstrate that it complies with all of the requirements of an export or import limiting device, in place. There is a working group, and there is some work being done by the ENA around a future upgrade to make G100 even clearer to state, that you can use, high set directional overcurrent relays in place. So, where you can’t demonstrate that your project is fully G100 compliant, you can have a non-compliant project and still demonstrate to the network operator that there is processes and systems in place, that means that should the site export in excess of the maximum export for a period of time, the site will be tripped off, in order to protect the network from that exceedance.

So, it is in there, it’s something that we’re increasingly seeing being picked up. Quite a lot of network operators would already say, you have more inverters on this site than you can, and you can’t demonstrate that with losses, you wouldn’t exceed, the maximum export capacity, so we require you to demonstrate that you are compliant with G100. If you are having the joy of filling in the G100 forms using a high set overcurrent relay, it’s very tricky at the moment, because you’re trying to provide an answer for a form that’s expecting you to have an ELS scheme, but those forms will be updated in the future to make it easier for people to fill in.

00:54:33 – 00:54:35 – Catherine Cleary

An ELS is export limitation scheme.

00:54:36 – 00:54:37 – Philip Bale

Yes.

00:54:38 – 00:57:52 – Catherine Cleary

Fantastic. Okay, so, I think that, so I guess, takeaway message for people, if they have more inverters than export capacity, think about G100 compliance at the same time as G99 compliance, so that you’re getting yourself ready for those forms, too.

Fantastic. The, right, we’ve got one last slide, which says, now I’ve energized, what next? So, this was really kind of pulling back into that quiz that we asked you guys, to kind of feedback on what you think, your kind of realistic timeframes are for getting all the way through to FON from when you’ve energized.

Again, sorry, forgive the terminology, which is related to ions, so specifically for type Ds and, and some type Cs, because DNOs, sometimes choose Type Cs as well. But we’ve popped some, Roadnight Taylor timings on that, Abi, I wonder if it’s possible to also show the results of the poll at the same time, to see, whether you guys, agreed with us. Okay, so we’ve got, I think, can people see that? Excellent, okay, Philip’s nodding, you can tell I’m a bit of a bit of a rookie host here.

So, we’ve got, okay, so majority of people have said 12 months, so a third, 12 months, a third, don’t know yet, that’s a very, very reasonable, reasonable assumption. So, we’ve got a few developers who are, who are super speedy at this within 3 months. So, if you kind of look at our timings, we generally reckon it takes nearly everyone at least two weeks, between the connection being energized to actually starting site tests – that’s just because you need to commission your inverters or your wind turbines, so you need to go through and do all your commissioning activities, make sure everything’s talking to the PPC first, and then, doing those initial tests, so the basic voltage control tests, and then getting the DNO to review the tests. I mean, 4 to 8 weeks is kind of a very rough guide; the tests themselves don’t take long to do, but making sure that you’ve got all of your contractors ready to do that test, making sure the test passes, and then that you’ve got, you know, someone lined up from the DNO to review that can take several weeks.

So, kind of four to eight weeks, kind of quite a good guide, we’ve found, for trying to get to that unrestricted ion, so when that 20% restriction is removed. The next bit is when we really find it interesting – battery sites can quite often then just push on with all of their tests, because they have no weather dependencies. If you are a solar or a wind project, the speed at which you can do your tests in the unrestricted ion period, where you’re asking to do higher output power level tests are going to depend on whether or not it’s sunny or windy. So, this is really worth being aware of for sites which energize, maybe towards the back end of the summer, you know, in September, beginning of October, you’re actually very unlikely to be able to do your unrestricted tests, during that winter period if you’re a solar project in the UK. So be really aware of the weather dependencies that might stop you getting to FON quicker. But it sounds like a lot of people have, you know, pretty realistic sort of expectations around that already, so that’s excellent to see.

The, I’m just going to go to the, Q&A here, and check on the last, kind of couple of questions. So, sorry, we’ve got one on G100, which I hadn’t picked up, Philip, so, at what stage do we submit a G100 application?

00:57:53 – 00:58:27 – Philip Bale

You want, it depends on which mode you want to go through and comply with G100, and how you want to go through and do it. Ultimately, you want to submit it early enough to give the DNO a chance to review it and accept it, so it’s not going to delay your energization of your project. So, I would suggest that you want to be doing it at the appropriate time, after your design submission has been approved, after you know what you’re designing; there should be plenty of time to go through and comply with that requirement at that stage. So it shouldn’t need to be a process that delays a project unless you leave it to the very last minute.

00:58:28 – 01:00:18 – Catherine Cleary

Fantastic. And I think, just, there’s some, some really, James, we haven’t, kind of covered all of your well, I think there are probably more conversation points rather than questions, in the Q&A. There’s some excellent, comments from James Gears. I think, probably just one to pull out, is that, you know, James is kind of highlighting, from a DNO perspective, obviously this process doesn’t necessarily kind of fully stop at FON, so the kind of the G99 compliance process is ultimately a self-certification, so whilst the DNO is reviewing these documents, you know, potentially witnessing the tests on site, ultimately the generator is saying, this is the evidence that I comply with G99; you want to make sure that you’re confident you do comply with G99, and that is an ongoing requirement. So, if at any point that you think, you know, actually, this site has stopped operating as it was meant to, you know, maybe you installed a filter, and then actually the filter has been decommissioned, or has had a failure, or something like that, you know, the DNO would be well within their rights at any point in future to revisit compliance if they think that a site is no longer complying.

So, I think this, that point about, sort of, you know, who the onus is on, don’t just think about this as kind of, you know, one and done once you’ve got your FON, making sure that when you are doing changes to a site, if you’re ever decommissioning equipment, that you’re still compliant is really important.

We’re almost at 11 o’clock, so, I just wanted to thank Nikki, Philip, thank you so much. That was, I really enjoyed that, good technical, webinar, and thank you so much for the excellent questions, that came in. I don’t think, we quite answered all of them, but oh, we’ve got a smiley face from James, that’s, that’s hopefully a thumbs up. So, we will, I think that was our last slide, hopefully, I can’t, yeah, that was our last slide, fantastic. So, thank you very much, everyone, for joining us, and we will leave it there.

01:00:19 – 01:00:20 – Philip Bale

Thanks all, bye.

01:00:21 – 01:00:20 – Nikki Pillinger

Thanks, Catherine – great hosting. Thanks, everyone, bye.