Electrical power consumption has been increasing over the past few decades which in turn, has led to greenhouse gas emissions from fossil fuel burning as well as generation costs. Renewable energies, especially solar power, have received sig nificant attention from scientists and engineers to build efficient and reliable devices to utilize the newable energy in electrical power generation Photovoltaic solar cells are one of these devices, and the main issues related to them are the relatively high fabrication cost and the low efficiency. A renewable energy system consists of different parts. For example, a PV system includes a power generation component, which is the PV panel coupled with its converter, and an energy storage system such as air-compressed storage. This thesis deals with these two components included in the PV system. First, the thesis focuses on the improvement of cell efficiency using metamaterials. Then, it turns its attention to enhancement torque transmission using magnetic coupling technology due to the numerous advantages it has over mechan Kcal coupling In this thesis, enhancing PV efficiency will be performed via metamaterials per fect absorber. They have tremendous applications in various engineering fields, such a microwave, electronkandergy harvesting Adesign and development of tificial renant metamaterial inclusions, resembling an infinite structure have been explored to realize two harvesting devices for efficiency enhancement, as part of me newable energy solutions. The first metamaterial-based design is perfect absorber, which was designed to achieve the perfect absorption at 540 TH to lie within the Visible the unlight spectrum. A numerical full-wave simulations using COMSOL is to achieve the desired performance Mover, it takes puntas a matching layer in fabricated photovoltaic solar cells in order to mitigate the mult ple reflection of photos from the surface of traditional solar cells Based on the numerical co ver, efficiency of solar cells with metamaterials Layer was enhanced and increased by 1.8% as compared against a classical solar cell pune without Layer On the other side.hancement for motor generator system is investigated using magnetic coupling technology. A case study for mechcial coupling delivers 127 Nm is designed using akalandmucal wa ANSYS software The dimensions of mechncial coupling is used to build the magnetic coupling and investigate its performance. Two types of studies are conducted on magnetic coupling: magnetostatic and dynamic. The magnetostatic study is conducted using COMSOL, while the dynamic study using JMAG. The magnetostatic study aims to investigate (1) the optimum number of magnets to rotate load torque, (2) torque enhancement with changes in displacement distance, and (3) coupling performance in the case of angular and parallel misalignment. The optimum number of magnets is six magnets with a separation distance of 6.28 mm. The dynamic study aims to investigate the holding torque and the behavior of the coupling as the load torque varies higher and lower than the benchmark torque. The main contributions of this thesis can be summarized as follows: 1. Perfect absorption for the visible light regime. 2. Improvement of PIN solar cell efficiency from 7.4% to 12% using metamate rials as perfect absorbers. 3. An optical properties and performance study that includes the electron-hole generation rate. 4. An efficiency investigation for PV systems with and without metamaterials based on an electrical study 5. Extensive analysis using different FEM softwares 6. A comparative study between mechanical and magnetic coupling 7. An investigation of magnetic coupling performance in both normal and abnor mal conditions such as misalignment.