The State of the Art in Local Energy Markets: a Comparative Review

System operators are facing a significant challenge with the increasing number of distributed energy resources (DER) in the distribution grid. Local energy markets (LEM) are a solution to this challenge as these allow system operators to use DERs for alleviating grid congestions and aiding with supply-demand balancing. Continuously, studies on how to improve the capabilities of LEMs are conducted around the world. Inevitably causing differences in methodology and, possibly, missed opportunities. Therefore, in this paper, a comparative overview is given of state-of-the-art literature by classifying literature on four properties (transactivity, inclusivity, congestion management, and balancing) of LEMs. The goal is to observe the current progress of state-of-the-art studies on LEMs, align these studies, and give recommendations on structuring future LEM research. The recommendations found are the use of a standardized underlying structure, or framework, such that LEMs with different properties are compatible and work together if combined, the creation of a benchmark such that performance of LEMs is easy to compare, and considering the settlement problem of lacking reference profiles.