Assessing the design options for the optimisation of a 2MWp ground mounted PV system in Malta

Abstract

The objective of large scale PV installations in space constrained countries has gradually shifted from production maximisation to that of reaching an optimised economic performance. The main reason for this is the ever decreasing price of the modules. This has resulted in systems with lower tilt angles, increased mutual shading and overloading of inverters by design, in the continuous quest of balancing reduced yield with development costs over the entire lifespan of the project. This approach has shifted the traditional view of evaluating a PV installation from a Euro/watt approach to the use of optimisation metrics such the Levelised Cost Of Electricity (LCOE) or Internal Rate of Return (IRR). Optimisation can be simply described as a balancing act, evaluating tradeoffs to assess which combination gives the best economic performance. By its very nature, optimisation is an iterative process. This paper evaluates a number of design parameters which, together with production modelling within the context of the Maltese solar climate, aims at identifying an optimum design for the building of a 2MWp ground mounted PV installation. Among the issues considered are; layout optimisation with issues of tilt, cross shading and cabling options, and inverter architecture whether string or central including dc-to-ac rating.