International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

In today’s global industrial environment, the need for sustainable, efficient, and energy-saving solutions for energy supply is more significant than ever and every enterprise that has adopted the policy of a green and low-carbon economy must seek such solutions. Enterprises must analyze their largest energy consumers and look for alternative options for generating and using “green energy”. Photovoltaic systems are among the most common solutions, but their dependence on weather conditions requires integration with energy storage systems. This report presents a model and analysis of an integrated hybrid photovoltaic system with battery storage, designed to provide electricity for energy-intensive production processes under the conditions of the Bulgarian climate and electricity market.

Unmanned Aerial Vehicles (UAVs) are increasingly being deployed across a broad range of applications, including surveillance, logistics, environmental monitoring, and military operations. However, their operational effectiveness remains fundamentally constrained by current energy storage technologies, primarily lithium-ion batteries. These conventional power sources suffer from low specific energy, limited endurance, prolonged charging times, and safety concerns under extreme operating conditions.
This paper presents a comprehensive review of alternative energy solutions for UAV platforms, focusing on hydrogen fuel cells, solar photovoltaic systems, tethered power configurations, wireless power transfer (WPT) technologies, and hybrid propulsion architectures. Each technology is assessed in terms of energy density, system complexity, operational endurance, and suitability for specific mission profiles.