The spatial resolution of energy system optimisation models (ESOMs) is often compromised for computational performance. Reducing the spatial resolution impacts the least-cost solutions when optimising the generation capacity and transmission capacity of the ESOMs with high penetration of variable renewable energy sources. Previous studies show that the two main effects of spatial resolution reduction are the increase in solar and wind expansion capacity and the decrease in transmission capacity expansion. This paper introduces a targeted method of defining regions during spatial scale reduction by using the max-p-regions clustering algorithm to aggregate similar areas into regions. The attributes used to determine the similarity between areas in the max-p-regions method are population; wind and solar resource potential; and pumped-hydro storage capacity. Two alternative spatial resolution reduction methods were used to compare how the effects of spatial resolution impacted the optimisation results of the ESOMs. Evaluation results for three country groups showed that using the max-p-regions method to define regions caused the two effects of spatial resolution reduction to be generally lower than using national jurisdictions. For the case studies Germany and Spain, the results showed that the max-p-regions method identified sets of regions, which were less impacted by the two effects of spatial resolution reduction.

能源系统优化模型（ESOM）的空间分辨率通常会因计算性能而受到影响。在优化具有可变可再生能源高渗透率的ESOM的发电能力和传输能力时，降低空间分辨率会影响成本最低的解决方案。先前的研究表明，空间分辨率降低的两个主要影响是太阳能和风能膨胀容量的增加以及传输容量膨胀的减少。本文介绍了一种有针对性的方法，该方法通过使用max-p-regions聚类算法将相似区域聚集到区域中，从而在空间尺度缩小过程中定义区域。在max-p-regions方法中用于确定区域之间相似度的属性是种群；风能和太阳能资源的潜力；和抽水蓄能。两种替代的空间分辨率降低方法用于比较空间分辨率的影响如何影响ESOM的优化结果。对三个国家组的评估结果表明，使用max-p-regions方法定义区域会导致空间分辨率降低的两种效果通常低于使用国家辖区的效果。对于德国和西班牙的案例研究，结果表明，最大p区域方法可以识别区域集，这些区域受空间分辨率降低的两种影响的影响较小。对三个国家组的评估结果表明，使用max-p-regions方法定义区域会导致空间分辨率降低的两种效果通常低于使用国家辖区的效果。对于德国和西班牙的案例研究，结果表明，最大p区域方法可以识别区域集，这些区域受空间分辨率降低的两种影响的影响较小。对三个国家组的评估结果表明，使用max-p-regions方法定义区域会导致空间分辨率降低的两种效果通常低于使用国家辖区的效果。对于德国和西班牙的案例研究，结果表明，最大p区域方法可以识别区域集，这些区域受空间分辨率降低的两种影响的影响较小。