Why PV Modules Should Preferably No Longer Be Oriented to the South in the Near Future

Abstract

PV modules tilted and oriented toward east and west directions gain gradually more importance as an alternative to the presently-preferred south (north in the Southern Hemisphere) orientation and it is shown to become economically superior even under the reimbursement of feed-in tariff (FIT). This is a consequence of the increasing spread between the decreasing costs of self-consumed solar power and the costs for power from the grid. One-minute values of irradiance were measured by silicon sensors at different orientations and tilt angles in Hannover (Germany) over three years. We show that south-oriented collectors give the highest electrical power during the day, whereas combinations of east and west orientations (E-W) result in the highest self-consumption rate (SC), and combinations of southeast and southwest (SE-SW) orientations result in the highest degree of autarky (AD), although they reduce the yearly PV Power by 5–6%. Moreover, the economic analysis of PV systems without FIT shows that the SE-SW and E-W combinations have the lowest electricity cost and they are more beneficial in terms of internal rate of return (IRR), compared to the S orientation at the same tilt. For PV systems with FIT, the S orientation presently provides the highest transfer of money from the supplier. However, as a consequence of the continuing decline of FIT, the economic advantage of S orientation is decreasing. E-W and SE-SW orientations are more beneficial for the owner as soon as FIT decreases to 7 Ct/kWh. East and west orientations of PV modules do not only have benefits for the individual owner but avoid high costs for storing energy—regardless who would own the storage facilities—and by avoiding high noon peaks of solar energy production during sunny periods, which would become an increasing problem for the grid if more solar power is installed. Furthermore, two types of commonly used PV software (PVSOL and PVsyst) were used to simulate the system performance. The comparison with measurements showed that both PV software underestimate SC and AD for all studied orientations, leading to the conclusion that improvements are necessary in modelling.

Calculating the Energy Yield of Si-Based Solar Cells for Belgium and Vietnam Regions at Arbitrary Tilt and Orientation under Actual Weather Conditions

“…The characteristics of these systems are illustrated in Table 2. The electricity harvesting at the converter outlet and DC power produced by PV panel was computed using Equations (15) and (16), respectively. Figure 6 shows a comparison between the output production of above actual installations and the results of this study as well as other PVGIS models.…”

“…Theoretical and experimental studies have illustrated that the actual harvesting efficiency, which is usually lower than the efficiency under standard test conditions, varies during the year and the drop in harvesting efficiency can be attributed to irradiance and temperature as major loss channels [12,13]. Other studies have addressed that angle of incidence is intimately related to the irradiance on a solar panel surface and an increase in electricity production of a PV system can be adapted by optimizing the panel orientation [14][15][16][17].…”

Impacts of Array Orientation and Tilt Angles for Photovoltaic Self-Sufficiency and Self-Consumption Indices in Olive Mills in Spain

“…The performance ratio indicates the overall effect of different losses on the output system due to array temperature and system component inefficiencies of failures, including balance of system components [50]. Moreover, this method is used in different works [51][52][53][54]. PR for conventional photovoltaic systems may be typically in a range from 0.70 to 0.80 in Spain [55].…”

Evaluation of Load Matching Indicators in Residential PV Systems-the Case of Cyprus

“…So far, there have been a variety of studies that evaluate self-consumption. Some of them focus on the economic performance [21] and the optimal orientation of rooftop PVs [22], while others investigate the long-term effects of self-consumption of a system level [23].Due to the fact that analyses, related to the SCR have been extensively performed, this indicator has been most widely used to guide policy making. The EU, for instance, has provided Member States with best practice examples for self-consumption, with the aim of improving the energy flexibility of buildings [24].…”

“…So far, there have been a variety of studies that evaluate self-consumption. Some of them focus on the economic performance [21] and the optimal orientation of rooftop PVs [22], while others investigate the long-term effects of self-consumption of a system level [23].…”