In order to speed up the process of rendering scenes containing many light sources, spatial data structures are used, which allow the number of lights processed for each pixel to be reduced during lighting computation. Examples of algorithms using such data structures are clustered shading and hybrid lighting. Alongside the rendering time, it is important to consider memory consumption resulting from processing a large number of lights. This paper presents a novel modification of the hybrid lighting algorithm using an octree that allows for a significant reduction in the amount of memory required to store the data structure.The proposed modification uses an octree to store the information about the rendered space. Detailed analysis of the proposed algorithm, and numerical results obtained for various 3D scenes, as well as different input data, all prove that the proposed method significantly reduces the memory required to store lists of lights used by the algorithm.