Understandings with respect to the Grid Code, and the Balancing and Settlement Code

Question

Hi, can anyone help by advising if my following understandings are correct, or otherwise, with respect to the Grid Code, and the Balancing and Settlement Code please? 
 BM provider: 
 Type D plant (greater than 100MW): BM participation is mandatory for transmission-connected generators (275 &ndash; 400kV), (whilst those connected to distribution networks can elect to participate in the BM through an appropriate contract with National Grid. Connecting to a distribution network would be through G99, up to 132kV). 
 Restoration Contractor: &ldquo;Restoration Services&rdquo; or &ldquo;Electricity System Restoration&rdquo; replaced &ldquo;Black Start&rdquo;? 
 Demand Response Provider: aligns with compliance with the Grid Code voltage and frequency requirements, and as a BM or BMU, they are able to adjust their generation or consumption in response to instructions from the ESO / NESO for (a) to (e)? 
 (a) Demand Response Active Power Control; 
 (b) Demand Response Reactive Power Control; 
 (c) Demand Response Transmission Constraint Management; 
 (d) Demand Response System Frequency Control; 
 (e) Demand Response Very Fast Active Power Control. 
 Also, are (c) and (e) part of the mandatory / obligatory requirements of the Grid Code? 
 A TERRE participant: plant that starts up when required, as opposed to "spinning reserve"? 
 Also, If there is more than one generator in a power station, each generator will likely be considered separate BMUs? 
 Also, do you know the status of integration between the UK Grid Code and European Grid Code (NESO / ENTSO-E) please? 
 Thanks, 
 Robert Shepherd

David Ward · Accepted Answer

Robert 
 I served on the Grid Code Review Panel for many years, but resigned at the end of 2010 when I stopped working full time for Magnox, so I am a bit rusty. Since that time of course, the European connection requirements (ECC) have been incorporated in the GB Grid Code, as have other requirements related to offshore wind, demand side participants etc. I have done a little bit of related consultancy since my retirement, so I am a bit aware of changes. 
 I will try to comment on your questions which I have copied below: 
 BM provider: 
 Type D plant (greater than 100MW): BM participation is mandatory for transmission-connected generators (275 &ndash; 400kV), (whilst those connected to distribution networks can elect to participate in the BM through an appropriate contract with National Grid. Connecting to a distribution network would be through G99, up to 132k 
 I believe that is correct, although I am not sure where the "mandatory" is stated. Might be in Grid Code, or BSC, or CUSC or some combination. If you find out, please let me know. As confirmation I found a NG document "Wider Access to the Balancing Mechanism Roadmap" which has the following " All transmission connected generators are part of the BM. For generation directly connected to the electricity transmission system, BM participation is mandatory ." 
 Restoration Contractor: &ldquo;Restoration Services&rdquo; or &ldquo;Electricity System Restoration&rdquo; replaced &ldquo;Black Start&rdquo;? 
 I think so. Stuff about provision of a black start service seems to have disappeared from the NG or NESO website. I think this was because less and less plant was able to provide the black start service as previously defined, and NG/NESO were keen to find any potential providers of anything that might help. So they have introduced a much more flexible definition of the requirements. 
 Demand Response Provider: aligns with compliance with the Grid Code voltage and frequency requirements, and as a BM or BMU, they are able to adjust their generation or consumption in response to instructions from the ESO / NESO for (a) to (e)? 
 (a) Demand Response Active Power Control; 
 (b) Demand Response Reactive Power Control; 
 (c) Demand Response Transmission Constraint Management; 
 (d) Demand Response System Frequency Control; 
 (e) Demand Response Very Fast Active Power Control. 
 Also, are (c) and (e) part of the mandatory / obligatory requirements of the Grid Code? 
 This is all new to me. I had a look at the definition of "Demand Response Provider" in the Grid Code Glossary, and it seems to cover most of that. The definition includes the words "... and has an agreement with The Company to provide a Demand Response Service(s) .". The definition of Demand Response Service says it includes " ... one of more of the following services:....". So I think it is up to the potential provider to decide whether it wants to provide a service, and if so, which of (a) to (e) it wishes to provide, and then sign an appropriate agreement with NESO. 
 A TERRE participant: plant that starts up when required, as opposed to "spinning reserve"? 
 Again, this is all new to me. I do not know the timescales for "Replacement Reserves" but I imagine it would normally be "standing reserve", i.e. plant that starts up, rather than "spinning reserve". You will have to go and read the rules for TERRE to see if they explicitly exclude spinning reserve. And do they allow demand side participation? 
 Also, If there is more than one generator in a power station, each generator will likely be considered separate BMUs? 
 It depends. I recall that there was a bit of bother caused by some of the early CCGTs, which had two gas turbines feeding a steam turbine, where each had its own generator, but could only run together, and not separately. This was significant under the Electricity Pool, where generation was scheduled by the GOAL software, which might try to schedule a steam turbine without its gas turbines or vice versa. Hence NG had to introduce the concept of a "module" which has more than one generating unit, but is treated as a single entity. The module would be the BMU. Have a look at the definitions of "Power Generating Module" and "Generating Unit" in the Glossary. So your two or more generating unts could be a single BMU if they are considered a module, but not otherwise. (In Magnox, we had several power stations where a single reactor supplied steam to more than one generating unit; I told NG that we should be able to treat them as modules, but they would not agree. I occasionally brought up this issue to show that they were not treating us fairly.] 
 Also, do you know the status of integration between the UK Grid Code and European Grid Code (NESO / ENTSO-E) please? 
 I am not aware that there is a single document one would call the "European Grid Code". The GB Grid Code was definitely modified (I think around 2015) to reflect the European "Requirements for Generators", for example by adding the ECC section to replace the CC section for generators connecting after a certain date. (See "EU Code User" in the Glossary). I don't know if the GB Grid Code has subsequently been modified to take account of other European requirements. 
 I hope that helps. If you need more, try emailing me at david dot m dot ward at cantab dot net. 
 Dave Ward

David Ward · Answer

Robert 
 Something I just discovered - the change from "Black Start" to "Electricity System Restoration" was the result of Grid Code modification GC0156: "Facilitating the Implementation of the Electricity System Restoration Standard" which was approved by Ofgem in February last year, so should now all be in the Grid Code. 
 Here is a link to the papers for that modification : https://www.neso.energy/industry-information/codes/gc/modifications/gc0156-facilitating-implementation-electricity-system-restoration-standard 
 Hope that helps 
 Dave Ward

Understandings with respect to the Grid Code, and the Balancing and Settlement Code

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