In Lithuania, solar energy is expanding rapidly. In 2020, the installed capacity of solar power plants was 170 MW, and by 2025, it exceeded 900 MW. This growth reflects not only technological progress but also an increasing interest from consumers and businesses. With rising electricity consumption and more solar modules being installed, it is becoming increasingly important to analyse how technological efficiency is evolving in the Lithuanian climate and the influence of the legal framework on this process. Properly coordinated technical and legal development can ensure the sustainable and long-term advancement of solar energy. This research paper explores the interplay between legal solutions and technological efficiency in the development of solar power plants, analyses the main challenges facing Lithuania and the EU, and identifies areas that remain underexplored. Directions for further research are provided, emphasising system optimisation and long-term performance.