Δημόσια Διαβούλευση της ΡΑΑΕΥ επί της εισήγησης του Ομίλου EnExGroup για τον σχεδιασμό της Αγοράς Επόμενης Ημέρας και της Ενδοημερήσιας Αγοράς, το χρο

(12)του προοιμίου και στην παράγραφο 1 του άρθρου 53 του Κανονισμού (ΕΕ) 2017/2195, οι Ορισθέντες Διαχειριστές Αγοράς Ηλεκτρικής Ενέργειας (ΟΔΑΗΕ/ΝΕΜΟ) υποχρεούνται να παρέχουν στους συμμετέχοντες στην αγορά τη δυνατότητα να πραγματοποιούν συναλλαγές ενέργειας στις Αγορές Επόμενης Ημέρας και στις Ενδοημερήσιες Αγορές, σε χρονικά διαστήματα που να είναι τουλάχιστον τόσο σύντομα όσο και η περίοδος εκκαθάρισης αποκλίσεων στην Αγορά Εξισορρόπησης, ήτοι δεκαπέντε

(15)λεπτά. Επιπροσθέτως, στις αποφάσεις του ACER 05/2020 και 37/2020 ρητώς αναφέρεται ότι τόσο ο Αλγόριθμος XBID της Συνεχούς Ενδοημερήσιας Συναλλαγής (CIT), όσο και ο Αλγόριθμος EUPHEMIA της Ενιαίας Σύζευξης Αγοράς Επόμενης Ημέρας (SDAC) και των πανευρωπαϊκών Ενδοημερήσιων Δημοπρασιών (IDAs) θα πρέπει να υποστηρίζουν προϊόντα 15 λεπτών, 30 λεπτών και 60 λεπτών. Συνεπώς, οι ΟΔΑΗΕ θα πρέπει να διαθέτουν προϊόντα ελάχιστης χρονικής διάρκειας 15 λεπτών και οι αλγόριθμοι που χρησιμοποιούνται για τη λειτουργία των συζευγμένων αγορών θα πρέπει να υποστηρίζουν προϊόντα 15, 30 και 60 λεπτών. Λαμβάνοντας υπόψη τα ως άνω, η ΡΑΑΕΥ, στο πλαίσιο των αρμοδιοτήτων της κατά το άρθρο 18, παρ. 5 του ν. 4425/2016 και το άρθρο 23 του ν. 4001/2011, θέτει σε δημόσια διαβούλευση την εισήγηση του Ομίλου EnExGroup όπως υποβλήθηκε στην Αρχή με το υπ΄αριθμ. πρωτ. ΡΑΑΕΥ I-364345/22.12.2023 (ΕΧΕ 2090/22.12.2023 και EnExClear 956/22.12.2023) έγγραφο μετά από σχετική συνεργασία με την ΑΔΜΗΕ Α.Ε. (υπ΄αριθμ. πρωτ. ΡΑΑΕΥ I-364858/04.01.2024). Στην εν λόγω εισήγηση περιλαμβάνεται η πρόταση του Ομίλου για την εισαγωγή προϊόντων υπό-ωριαίας διάρκειας στην Αγορά Επόμενης Ημέρας και στην Ενδοημερήσια Αγορά και το σχετικό χρονοδιάγραμμα υλοποίησης, καθώς και για τη χρονική ανάλυση της έμμεσης κατανομής διασυνοριακής δυναμικότητας στις αγορές αυτές. Οι ενδιαφερόμενοι μπορούν να συμμετέχουν στη διαβούλευση υποβάλλοντας τις απόψεις τους επί της ως άνω εισήγησης ηλεκτρονικά στη διεύθυνση elecodes-market@rae.gr ή εγγράφως, έως και την Παρασκευή 26 Ιανουαρίου

1. Η ΡΑΑΕΥ, με την επιφύλαξη των διατάξεων της παρ. 3 του άρθρου 5 του Κώδικα Διοικητικής Διαδικασίας (ν.2690/1999, ΦΕΚ Α’ 45), θα δημοσιοποιήσει κατάλογο των συμμετεχόντων στη διαβούλευση καθώς και το περιεχόμενο των σχετικών εγγράφων, με εξαίρεση την περίπτωση κατά την οποία ο συμμετέχων αιτείται τη μη δημοσιοποίηση των στοιχείων του και/ή των απόψεών του. Συνημμένα έγγραφα:
2. Πρόταση του Ομίλου EnExGroup
3. Ερωτηματολόγιο της ΕΧΕ Α.Ε. προς τους συμμετέχοντες των αγορών
4. Απαντήσεις συμμετεχόντων των αγορών στο ερωτηματολόγιο της ΕΧΕ Α.Ε 15min products in HENEX Spot Electricity Markets This document describes the main concept of market design adaptations to introduce 15’ MTU products in the Day Ahead and Intra-Day Auctions (DAM-IDAs) as required by ACER in 2020 amended CACM NEMO Algorithm Methodology and as stipulated by ACER and all NRAs to be developed in Single Day-Ahead Coupling (SDAC) and for Single Intra Day Coupling (SIDC). Market Context HENEX Spot Electricity Markets currently consist of the Day-Ahead Market (DAM) and three Complementary Intra-Days Auctions (CRIDAs). The continuous intra-day trading (XBID) is expected to go-live by the end of
5. CRIDAs will be converted into European Intra-Day Auctions (IDAs), which form an intra-day coupling in SIDC region, by Q1
6. IDAs will have almost identical timings with CRIDAs and will additionally implement implicit allocation of the Greece-Bulgaria cross-border capacity. The introduction of 15min products in HENEX Spot Electricity Markets, as described in this document, refers to the three following market segments: - DAM - IDAs - XBID Basic Market Design and Schedule Planning HENEX Spot Electricity Markets currently support products and relevant orders with hourly resolution. There is work in progress across European NEMOs & TSOs to introduce products and orders with 15min resolution in SDAC and SIDC. Adopting a 15min resolution framework means that a Delivery Day is split into 96 15min Market Time Units (MTUs) and Market Participants (MPs) are able to trade in finer time resolution. Trading in 15min time resolution can help MPs increase the feasibility of their market schedules and reduce imbalances since the imbalance settlement period of IPTO Balancing Market is already in 15min resolution. When at least one market (DAM or IDAs or XBID) starts supporting 15min products & orders, the market schedule/position of a MP asset has to be defined in 15min resolution. Based on the current market design, HENEX sends the asset market schedules to IPTO, for the IPTO balancing functions (ISP, RTBM). Currently, the imbalance settlement period of RTBM is 15min and the dispatch period of ISP is 30min. Therefore, the prerequisite to introduce 15min resolution products & orders in any HENEX market is that the time resolution of IPTO ISP changes from 30min to 15min resolution. Hellenic Energy Exchange S.A. The introduction of 15min products & orders is not expected to be done simultaneously in all market segments (DAM, IDAs and XBID). Based on the current status of HENEX developments, as well as the work done in market coupling projects, the following planning is available: XBID XBID central algorithm already supports multiple time resolution contracts (15min, 30min and 60min). XBID is expected to go-live in Greece by the end of
7. Initially, only 60min contracts will be offered in the HENEX XBID implementation. 15min contracts could be offered later depending on adaption of 15min resolution in IPTO ISP. DAM DAM in the context of SDAC uses the PMB and EUPHEMIA algorithm assets. PMB and EUPHEMIA prototypes that support the use of multiple time resolution products & orders (15min,30min and 60min) are currently developed and tested. EUPHEMIA prototype has been developed with a cross-product matching functionality that allows 15min, 30min, 60min orders to co-exist in the same market session and be cleared simultaneously. The introduction of 15min orders poses challenges in the EUPHEMIA algorithm performance, therefore extensive research and development is being conducted to mitigate them. The challenges are greater when multiple time resolutions are present and cross product matching is being used (i.e. 15min and 30min and 60min coexist in the same market session) compared to a situation where only 15min orders are present. 15min orders are expected to be offered for DAM in Q1 2025, in the context of a big-bang SDAC go-live, which means that all Bidding Zones will introduce 15min orders simultaneously. IDAs IDAs will use the same coupling assets as DAM, i.e. PMB and EUPHEMIA algorithm. Therefore, the performance issues described above could also be valid for IDAs. IDAs are scheduled to go-live in Q1 2024 and are expected to offer 15min orders. Market Design options for the implementation of 15min in HENEX ETSS On a market design level, concerning DAM, IDAs and XBID, there are two main design options when a market segment moves from a 60min time resolution to 15min time resolution: • Option 1: 15min, 30min and 60min orders are offered in the market. • Option 2: only 15min resolution orders are offered in the market. Hellenic Energy Exchange S.A. In both Options different market segments could have different time resolutions, however the market schedule of an MP asset will be defined in 15min resolution anyway. An example of how this applies to Option 1 can be seen in the figure below. Q (MW) Accepted quantities of four 15min hybrid orders 30 20 15 10 Q (MW) Equivalent market schedule 15min 15min 15min 15min 60 t 60min Q (MW) 45 Accepted quantities of two 30min hybrid orders 40 20 30 10 30min Q (MW) 30min t 60min 15min Accepted quantity of single 60min hybrid order 15min 15min 15min t 60min 10 t 60min The two different options have different implications on different market design aspects. The pros and cons of these two options are displayed in the following Table and are analysed afterwards. The plus (+) sign implies a positive impact on the respective market design aspect. Market Design Aspect Option 1 15, 30 & 60min orders Option 2 only 15min orders Trading flexibility for MPs + - Algorithm performance - + Price formation - + Paradoxically rejected hybrid orders - + Local Market Trading System development, maintenance, and cost - + Hellenic Energy Exchange S.A. Trading flexibility for MPs In Option 1, MPs will have more options (wider range of MTU resolution) for trading. MPs who want to ensure a fixed market schedule within the same hour of the Delivery Day, may continue using 60min orders. In Option 2 where only 15min orders are provided, MPs would be able to submit only 15min which means that, in general, the market schedule could differ between the different 15min MTUs of the same hour. Algorithm performance This aspect refers mainly to the DAM and IDAs, i.e. the auction based market segments that use the EUPHEMIA algorithm. There are ongoing discussions in SDAC technical working groups and bodies concerning the algorithm performance issues that arise from the introduction of 15min orders in DAM (mainly) and IDAs (to a lesser extent). The algorithm performance tends to worsen, when the cross-product matching functionality is used, so that orders of different resolution can be matched between them. The ongoing discussion on the algorithm WGs focus on whether the algorithm can indeed accommodate orders of different duration for SDAC & SIDC IDAs, without jeopardizing the security of market operations. In that sense, Option 1 has a much worse impact in algorithm performance compared to Option
8. Price formation This aspect refers to the DAM and IDAs, i.e. the auction based markets that use the EUPHEMIA algorithm. Option 1 could potentially jeopardize price formation. When multiple time resolution orders co-exist in the same market session, it means that a 60min hybrid curve among 15min orders is treated as a “curtailable block” in order to have a fixed cleared quantity for the relevant hour. Therefore, a mix of 15min, 30min and 60min orders forms an “inflexible” mix that could worsen the price formation, compared to the case that these orders are submitted all as 15min orders. The degree of price formation degradation depends on the exact mix of orders of different time resolution and therefore it cannot be anticipated in advance. Paradoxically rejected hybrid orders This aspect refers to the DAM and IDAs, i.e. the auction based markets that use the EUPHEMIA algorithm. In Option 1, the cross-product functionality is implemented, i.e. the algorithm matches orders of different time resolution. When orders with multiple time resolution are present, the Market Clearing Prices (MCPs) are calculated in all resolutions (15,30,60min). The MCPs of coarser resolution are calculated as the average of the 15min MCPs. MCPs of different resolutions should be consistent with the acceptance status of the orders submitted in the respective resolution. It has been observed that, in some cases, trying to impose consistent MCP calculation, can lead in Hellenic Energy Exchange S.A. 15min MCP to exceed the price limits (i.e. -500€/MWh for price floor and 4000€/MWh for price cap). Since this cannot be accepted, the 15min MCP is limited to the price limit, which in turn modifies the higher resolution (30,60min) MCPs and leads to in paradoxically rejected orders of higher resolution. This issue is still under investigation in the Algorithm WGs. However, it seems that when all resolutions are available in a Bidding Zone, the cross-product matching functionality can lead to market inefficiency problems. This issue is not present in Option
9. Local Market Trading System development, maintenance, and cost In Option 1, the development effort/time, maintenance, and cost resources of HENEX Local Trading Platform (ETSS), would be much demanding, since GUIs, internal interfaces, DBs would need to accommodate the complexity of simultaneously hosting market orders of different resolution, implementing the necessary conversions, API adaptations etc. In Option 2, ETSS would accommodate orders of a single time resolution per market segment. For example, during a certain period, DAM could have 60min resolution orders, IDAs and XBID only 15min resolution orders. The option of moving from 60min to 15min and having only 15min would be much easier to implement, test and maintain and therefore lead to decreased costs and resources. HENEX perspective Based on the above analysis, HENEX favors Option 2, which means that a market segment should support products & orders of a single time resolution, because: - Algorithm performance is superior and coupling projects are operationally secured. - Price formation, which is of paramount importance for the sound market operation, is not jeopardized. - Market design is more robust and issues that could cause MPs’ discomfort, like paradoxically rejected hybrid orders, are not present. The ultimate decision for the market design will take also into account the following: - The feedback from the SDAC and SIDC WGs on algorithm performance with 15min orders. - The mandates of the Greek Regulatory Authority. - The view and needs of the MPs. Questionnaire for MPs MPs are encouraged to give feedback on market design options for the 15min products, by answering the following Questionnaire by 18 September 2022 Market Participant name: Question Answer Would market design Option 2 pose serious limitations to your trading activities? If yes, are there any mitigation measures that you would propose? Yes/No Do you anticipate that under Market Design Option 2 you would make increased use of block orders existing functionality, compared to Market Design Option 1? Yes/No Is the introduction of 15min orders urgent for your trading needs? If yes, is there a specific market segment (DAM, IDAs, XBID) where you believe that 15min orders should be introduced with priority compared to the others? Yes/No Comments Participant 1 2 3 4 5 6 7 Would market design Option 2 pose serious limitations to your trading activities? If yes, are there any mitigation measures that you would propose? Is the introduction of 15min orders urgent for your trading needs? Do you anticipate that under Market Design Option 2 you would make increased use If yes, is there a specific market segment (DAM, IDAs, XBID) where you believe that of block orders existing functionality, compared to Market Design Option 1? 15min orders should be introduced with priority compared to the others? No Currently we are using only hourly products on the DAM and I doubt this will change in the coming years so it really doesn’t matter for us if we are sending hourly profile or 4 No identical 15mins intervals. I am familiar with the limitations of the currently used algorithms and the attempts to modify them for the changes in the end of the year so I really prefer stability to multiple time resolution bids. It is safer and easier to submit 15 min bids than taking care of decoupling. No Yes XBID No No Even though we do not consider the introduction of 15min orders urgent for our Market design Option 2 will not pose serious limitations to our trading activities. Yes trading needs, it would be very helpful if these orders were introduced in the However, it will complicate our bidding processes since it will be more difficult to As mentioned above, we believe that we will make significantly increased use of block foreseeable future in XBID and IDAs. This would facilitate us in reducing our ensure feasible commitment schedules for our thermal power plants. Thus, it would be orders in order to ensure feasible commitment schedules for our thermal power plants. imbalances, especially regarding our RES portfolio. We believe that the introduction of critical to increase the maximum allowed number of blocks used in block orders. 15min orders in DAM is of less importance. No No No No We don’t use block products No No No No No 1st answer It would pose some problems for us. Flows between surrounding countries are made in hourly granularity, and if the only granularity existing in Greece are quarterly it can make it difficult to optimize best as possible, as some quarter product can end up being illiquid and thus difficult to trade. We would suggest to still have a hourly product which can be traded and thus flown against neighbouring countries. No No 2nd answer Yes There are by far most liquidity in the 60 minute products. Liquidity will become a huge issues for us, if only 15 minute products are offered and that lead to much higher and volatile pricing on the intraday markets. 8 HENEX comments No, it will not pose serious limitations. However, there should be a reasonable trial period in order to be able to adjust our trading tools and make sure that they match the new criteria. 1st answer We believe that a combination of 15min orders and hourly orders would be optimal. And a combination of these would suit our needs. The priority of the orders should be put on XBID because the ability to trade skewness closer to delivery of a given product is important. 2nd answer No We would rather see the 60 minute market being introduced – as this is where the liquidity are. N/A 9 No No 10 11 12 No No No No No No 13 No No 14 No No No Yes, highest priority are IDAs and XBID, since the final Market Schedules must have the same time resolution as the Imbalance Settlement Period to avoid unnecessary imbalances and activations in the Balancing Market due to the different time resolution. DAM 15 min orders are not critical for the time being, however, this should also be planned for the near future to avoid specific bidding tactics by market participants especially during hours when supply and demand is changing rapidly, for example in the afternoon ramp-up. Lastly, we don’t think that adaption of 15min resolution in IPTO ISP is necessary to switch to 15min contracts in XBID, since the energy activations in ISP are indicative. IPTO just needs to define rules for converting the 30 mins capacity constraints for the 15min trading periods in XBID. Yes No No Yes The introduction of 15min products in HEnEX Markets is deemed necessary, given the fact that IPTO’s Balancing Market has been being cleared in 15min MTUs since the introduction of Target Model in Greece. Yes The introduction of 15min products in HEnEX Markets is deemed necessary, given the fact that IPTO’s Balancing Market has been being cleared in 15min MTUs since the introduction of Target Model in Greece. The participant refers to XBID, which does not provide the cross product functionality and liquidity in the 15min resolution is limited. HENEX proposes to RAEWW that in HENEX Continuous Intraday Trading, products of all time resolutions are included , so this concern is adressed. 15 No No For the current situation, Option 2 does not impose limitations to our trading activities. As RES Aggregator MP, block orders are not permitted due to regulatory framework. Yet, things might as well change in the short term horizon, as regulatory framework is So, our answer might as well change, as long as the regulatory framework changes. still premature for some technologies. Yes Yes, as a RES Aggregator MP, trading in 15min orders is a crucial matter for our trading activities. As delivery time comes closer, the respective markets (i.e., IDAs and XBID) should enable orders with finer time resolution. 16 Yes Yes No 17 Yes Yes No 18 Yes We would like to mention the issue that could occur in the case of cross-border exchanges with countries that offer only hourly products and that the Option 2 could pose an issue to the matching of the respective volumes. 19 No 20 No 21 No 22 No The Participant does not provide any explanation in his reply. The Participant does not provide any explanation in his reply. The Participant refers to XBID, which does not provide the cross product functionality and liquidity in the 15min resolution is limited. No In this case, we would like to mention that irrespective of which Option is chosen, a significant time period of at least 3 months should be given, so that we can adjust our No IT systems to the new products offered. Also, a UAT should be set up for the necessary HENEX proposes to RAEWW tests to be made. If any priority is given, we believe it should be given to the DAM as that in HENEX Continuous the main volumes are traded there, and also the Imbalance Clearing is done in 15 min Intraday Trading, products of periods. all time resolutions are included , so this concern is adressed. Not Applicable in our Portfolio No No No From our point of view, the first priority should concern DAM since this the market Our transactions as a Supplier comprise hybrid orders and therefore there is no impact with the major volume of transactions. This is expected to significantly decrease the expected from the integration of Option
10. balancing costs that occur due to the different time resolution applied by IPTO. Yes We are expecting a minor increase in BLK size to ensure that that Elpedison Power No Plants can cope with extreme fluctuation in market schedule due to ramp rate limitations. YES. Indifferent From high to low priority: XBID, IDAs, DAM