Competitiveness of stationary planar low concentration photovoltaic modules using silicon cells: A focus on concentrating optics

摘要

The economical competitiveness of stationary Low Concentration Photovoltaic (LCPV) modules is evaluated, starting from detailed expressions of the Levelized Cost of Energy (LCoE). For trackless LCPV to be competitive with standard modules, the key approach is to maximize the performance of concentrating optics in terms of yearly averaged effective optical power ratio. To express this a novel parameter named P_(ro,eff) is introduced and its contribution to the expression of LCoE for LCPV modules is discussed. By comparing the LCoEs of standard and LCPV modules, threshold conditions for P_(ro,eff) and for the relative unitary cost of concentrating optics C_r are found, in dependence on the geometrical concentration gain G and as a function of other sensitive design parameters. Aiming at the maximization of P_(ro,eff), the novel design of a modified prism-coupled compound parabolic stationary concentrator is introduced, as a trackless LCPV solution compatible with standard flat panel size, weight and installation infrastructures. It provides geometrical concentration gain G = 5, an acceptance angle of 24° and P_(ro,eff)= 81%, using a reflective primary concentrator and high refractive index dielectric for the secondary optics. A first experimental validation of the approach is given by a proof-of-concept prototype, implemented in commercially available polymethylmethacrylate, suitable for quasi-stationary installations requiring seasonal adjustment.