[论文解读] Zonal vs. Nodal Pricing: An Analysis of Different Pricing Rules in the German Day-Ahead Market

Johannes Knörr, Martin Bichler+1 more|arXiv (Cornell University)|Mar 14, 2024

Merger and Competition AnalysisEconomics, Econometrics and Finance被引用 3

一句话总结

本研究利用ENTSO-E在投标区审查中提供的独特数据，比较了德国日前电力市场中区域定价、节点定价与非统一定价规则。研究发现，节点定价可将总系统成本与再调度成本降至最低，而像联合定价（Join pricing）这样的非统一规则则能提供强劲的阻塞信号且抬价支付较低，尽管在不同区域配置下的价格波动极小，其表现仍优于区域定价。

ABSTRACT

The European electricity market is based on large pricing zones with a uniform day-ahead price. The energy transition leads to changes in supply and demand and increasing redispatch costs. In an attempt to ensure efficient market clearing and congestion management, the EU Commission has mandated the Bidding Zone Review (BZR) to reevaluate the configuration of European bidding zones. Based on a unique data set published in the context of the BZR for the target year 2025, we analyze the short-run effects of various pricing rules for the German-Luxembourgish bidding zone. We compare market clearing and pricing for different zonal models, including their generation and redispatch costs. In numerical experiments with this dataset, the differences in the average prices in different zones are low. The total costs across different configurations are similar and the reduction of standard deviations in prices is also small. This might be different with other load and generation scenarios, but the BZR data is important as it was created to make a decision about splits of the existing bidding zones. We can replicate several results from the BZR study, except the large cost savings when moving from one to two price zones in Germany and Luxembourg. In addition to the four zonal configurations analyzed in the BZR study, we compare these against a nodal pricing system. While the total cost savings after introducing zonal splits were less than 1%, nodal pricing led to savings of 5-6%. We also evaluate differences of nodal pricing rules with respect to the necessary uplift payments, which is relevant in the context of the discussion on non-uniform pricing in the EU. While the study focuses on Germany, the analysis is relevant beyond and feeds into the broader discussion about pricing rules in non-convex markets.

研究动机与目标

• 评估德国日前电力市场中区域定价与节点定价的经济效率与配置效率。
• 评估不同投标区配置对市场电价、再调度成本与系统效率的影响。
• 比较非统一定价规则（IP、CH与Join）在传递阻塞信号与最小化抬价支付方面的能力。
• 确定将德国当前单一价格区域划分为两个、三个或四个区域是否能改善市场结果。
• 从福利与计算效率角度，评估Euphemia算法及其他定价机制的表现。

提出的方法

• 本研究使用ENTSO-E LMP研究提供的独特数据集，该数据集提供了德国在不同配置下的节点级市场出清结果。
• 通过线性化机组组合模型与节点边际定价（LMP）计算节点电价与出清计划。
• 在关键指标上比较全国、区域（2、3、4个区域）与节点定价模型的表现：发电成本（GLOC）、机会成本损失（LLOC）与市场福利损失惩罚（MWP）。
• 评估四种定价规则：整数规划（IP）、凸包（CH）、联合定价（Join）与当前的Euphemia算法，分析其效率与抬价成本影响。
• 将再调度建模为成本最小化问题，以计算发电机偏差的补偿金额，从而比较总系统成本。
• 使用2009年2月18日的历史数据，测试并比较不同配置与定价规则下的结果。

(a) 2 Zones (k)

实验结果

研究问题

• RQ1 与区域定价相比，节点定价是否能显著降低德国电力市场的总系统成本？
• RQ2 不同的区域配置（2、3或4个区域）如何影响价格差异、再调度成本与市场效率？
• RQ3 在IP、CH与联合定价中，哪种非统一定价规则能最好地平衡阻塞信号准确性与抬价支付最小化？
• RQ4 当前的定价机制（如Euphemia）在多大程度上导致福利损失或低效出清？
• RQ5 实施节点定价是否能在不显著提高平均电价的前提下降低再调度成本？

主要发现

• 节点定价使总系统成本最低，GLOC为1,024.32百万欧元，显著低于全国统一价格的1,430.45百万欧元。
• 四区域配置的GLOC为1,778.31百万欧元，表明与节点定价相比，区域划分带来的成本降低有限。
• 在节点定价下，再调度成本（LLOC）为86.48百万欧元，远低于区域定价下的水平（依配置不同，范围为25.13至170.36百万欧元）。
• 联合定价规则实现低MWP（34.68百万欧元）与低LLOC（86.48百万欧元），表明其具有强信号效率与极少的附加支付。
• IP定价可确保有效的阻塞信号，但需承担较高的MWP（72.94百万欧元）；而CH定价虽最小化GLOC，却因高LLOC（170.36百万欧元）而扭曲阻塞信号。
• 所有区域配置下的价格标准差均较低，且增加区域数量并未显著降低波动性，表明区域重组的收益有限。

(b) 2 Zones(s)