# Exploring the Benefits of Photovoltaic Non-Optimal Orientations in Buildings
###### Abstract
However, the power generation efficiency of BIPV systems is lower compared to current stand-alone PV systems, up to 41% due to irradiation loss alone [15], although it has the advantages of eliminating the additional space needed for power generation and presenting better aesthetics for the building structure [16]. Therefore, studies of the electrical efficiency of self-consumption in a building with solar generation are mainly based on BAPV systems. These electrical efficiency studies are conducted based on achieving near-zero energy buildings (NZEB) and grid parity [17]. This occurs when PV electricity costs are equal to the retail electricity price, considering fixed factors such as revenue, savings, implementation costs, maintenance costs, taxes and depreciation, and other variable factors (such as investment costs, credit discount rate, and variations in the retail electricity price that complicate the calculation to reach grid parity, which pose a scenario that requires economic incentives and support policies) [18]. These are the reasons why some solar markets are called mature, such as Germany and Italy, when reaching grid parity [18; 19]. Spain has recently reached grid parity [20] aided by the recent approval of Royal Decree 244/2019 [21], which develops the administrative, technical, and economic conditions of Royal Decree Law 15/2018 [22]. The new regulation introduces a simplified compensation mechanism in the electricity bill for consumers, following a net-billing scheme [23]. Regardless of the photovoltaic strategy selected, the analysis carried out by [24] outlines the features of the energy production of PV modules placed in a different orientation to the optimal energy-producing one. Due to the limited roof area available for placing PV, a strategy for increasing the electricity production of photovoltaic self-consumption systems (PVSCS hereinafter) is to place PV modules in suitable facades. For example, it is showed in [24] that, for buildings with administrative or office uses, an installation facing southeast provides a better fit for electricity consumption, which is higher in the morning [25]. This presents us with scenarios where installing solar panels in non-optimalorientations is possible to obtain a potential benefit. These scenarios would produce lower amounts of energy, but their hourly production profiles could shift beyond noon, allowing them to better meet demand [26; 27]. The main objective of the presented research is to analyze the technical and eco-nomic potential of the integration of PVSCS in non-optimal orientations in Spain, using reference installations with real consumption and PV production. For reaching this goal, the analysis of two case studies is carried out on a residential and an industrial PVSCS. Based on one full year of real operational data for the residential PVSCS, the operation of several alternative PV arrangements suitable for the building using different orientations are simulated and an energy and economic analysis is carried out considering past and new residential tariffs in Spain. For the investigation on industrial PVSCS, the reference case is a mid-size installation of 169 kW using orientations different from the South. It is shown the analysis of different layouts for the PV modules prior to the project that led to the use of this orientation. Due to the recent construction of this PVSCS, preliminary results are presented. Thus, the paper is divided as follows. After the introduction, Section 2 describes the case studies, with a description of Spanish residential tariffs and the methods used in the energy and economic analysis of energy consumption and production for each case study. Section 3 presents the results of both case studies, with including an economic analysis for the different configurations evaluated in the residential PVSCS, which will then be discussed in Section 4. Finally, in Section 5, the conclusions are presented.