Performance evaluation of two PV technologies (c-Si and CIS) for building integrated photovoltaic based on tropical climate condition: A case study in Malaysia

Highlights

• Performance of two important PV plants (c-Si) and (CIS) was evaluated and compared.

• Different evaluation criteria are applied and showed superior findings.

• The c-Si exhibit poorer performance along the period, mainly under low light conditions.

• Feasibility of the system is also studied through using energy cost (CE) calculation.

• Comparing with the conventional power systems, feasibility of this system was superior.

Abstract

This paper presents two grid-connected photovoltaic (PV) systems (monocrystalline silicon, c-Si; copper–indium–diselenide; CIS) situated on the rooftop of the solar lab building in the National University of Malaysia, southwestern Malaysia. Various parameters were used to analyze the system performance; including array yield, final yield, capacity factor, and performance ratio. The recordings were noted down under the actual climatic conditions for an entire year. The variables of energy cost and payback period were also considered to calculate the economic feasibility of the system. Variations in the final yield of CIS were as low as 2.98 h/day in July to the highest value of 4.31 h/day in March. The final yield for c-Si power plant ranged from 2.92 h/day in July to 4.14 h/day in March. The calculated capacity factors for CIS and c-Si power plants were 15.6% and 14.4%, respectively, in July as the worst value, and 21.12% and 20.2%, respectively, in March as the best value. In the case of CIS power plant, the performance ratio ranges from 63.8 in July to 84.12 in March, and for c-Si power plant, it ranges from 59.92 in July to 79.14 in March. The energy cost and the payback period of the suggested system were evaluated as 0.045 USD/kWh and 28.44 years, respectively. Finally, this study provides valuable information for those who are interested in PV system installation in the tropical zones.

Introduction

Solar energy has become immensely popular as an alternative energy source due to the fact that solar energy is clean, environmentally friendly and secure power source. This makes it a valuable energy source. The amount of energy absorbed by the earth from the sun is hundred times more than the actual global energy demand [1].

However, the uncertainty in solar radiation, such as shadow conditions and other negative phenomena (e.g., the rapid change in the irradiance and temperature), makes the supply of energy by the photovoltaic (PV) systems unstable [2], [3], [4]. Due to these imposed realities, it becomes very important to investigate the performance of the PV systems. In addition to this, the continually growing demand of PV cells requires prediction and performance analysis of the PV systems with various PV technologies in actual climatic conditions [5]. These evaluations become more necessary when the PV systems integrate with the electrical power systems (grid-connected system). The performance of the PV systems is dependent on the variety of locations, which implies that the system performance is either negatively or positively affected by the geographical locations [6]. To determine the best candidate behavior of these systems, the performance of the systems must be analyzed and compared with different PV technologies. Therefore, it is important to consider PV system’s performance under highly uncertain weather conditions such as the tropical climate [7], [8]. Recently, many researchers conducted researches on PV system performance assessment under tropical climate conditions for better understanding of the impact of climate nature on the system’s performance.

Research work on PV system performance in different tropical countries such as Indonesia, Singapore, Thailand and Malaysia can be found in the literature [9], [10], [11], [12], [13], [14], [15], [16]. In Indonesia, some studies were done to investigate the performance of PV systems. In Ref. [9], a hybrid PV system that consists of micro PV-hydro system was evaluated. The micro PV plant comprised of mono-crystalline and poly-crystalline silicon PV modules. The results showed that the performance ratio of this system was in the range of (70.2–79) %. However, these studies are conducted to investigate the system performance based on the aging factor (to test the system performance after long lifetime) of PV modules. In Singapore, Ref. [11] studied the performance of PV system from different PV technologies (silicon wafer and thin film) and under different illumination levels. The study highlighted that, thin film technology exhibits inconsiderable performance comparing with silicon wafer which registered considerable PV performance in the range of (73–82%), but for thin film in range of (63–71%). Nevertheless, in this system each plant was configured in different ways of connections. A comparison of the performance of different three PV plants, from different technologies, amorphous silicon (a-Si), poly-crystalline silicon (p-Si) and hybrid solar cell (HIT) PV under wet climate conditions (Tropical) in Thailand accomplished in Ref. [12]. This study had been analyzed to show the effect of irradiance and temperature on the performance of these three PV technologies based on the climate of each season. The results showed that change of irradiance and temperature affect more on the p-Si plant than on the HIT and a-Si PV plants. Meanwhile, another study was conducted in the equatorial savannah region of Thailand by Kamkird et al. [13], involving performance assessment of a-Si, p-Si, and HiT PV modules. This region has a winter dry climate [14]. Lower impacts were observed of module temperature on PV performance in the presence of a-Si PV than p-Si and HiT PV modules. Also same impacts on other factors recorded, like current, voltage, power outputs, and lowest negative coefficients for a long-term performance.

Recently, some studies have been performed in Malaysia to analyze the performance criteria of PV systems under tropical climate [15]. In this purpose, a comparative study of three different PV module technologies was conducted for the grid-connected system under climatic conditions of Malaysia [16]. The performance ratio was calculated as follows: 78.2% for polycrystalline, 94.6% for a-Si thin film, and 81% for monocrystalline PV modules. High performance was obtained using the Si-thin film PV modules in terms of the final yield, performance ratio, and array/system efficiency of the grid-connected system over the entire duration of the experiment. However, PV modules with different technologies were installed in different tilt angles and therefore it might decrease the value of performance comparison. Furthermore, comparison and assessment on performance of a-Si TEPV and c-Si PV technology showed that a-Si TFPV modules achieved a better performance than the c-Si PV modules and also was less dependent on the operating array temperatures [17]. Nevertheless, the study considered only a variety of temperature levels for the tests on the PV system performance.

On the other hand, the studies on the feasibility of PV grid-connected systems must be conducted [5], [15], [18], [19], [20]. Therefore, the feasibility of PV grid connected system should be examined in terms of system performance, productivity and its economic influence. In Ref. [19], a PV system installed in Malaysia was evaluated using the yield factor within a specific climate and was found the yield factor as 2.6 ± 0.15 kWh/kWp. Moreover, the authors in Ref. [15] used the payback period and in Ref. [18] used the impact of the cost of the generated energy to investigate the system feasibility. Nonetheless, in this study, both of the energy cost and the payback period are considered in the assessment of the economic feasibility of the proposed PV system.

This article includes the outdoor performance results and system economic feasibility of two different PV module technologies such as mono-crystalline silicon (c-Si) and copper–indium–diselenide (CIS) PV modules implemented over 12 months (January to December 2014) under Malaysian climate on the roof of energy’ lab building (The National University of Malaysia) in Bangi. Bangi is a city that mostly has a weather condition with a completely clear sky in the noon time (usually from 11.00am to 3.00pm), which is the duration of the high solar radiation. This study also considered the aging factor in the performance evaluation. This scheme was launched on February 11, 2004 as a roof-top project of solar power electrical energy in Malaysia.

The main objective of the current study is to analyze and compare the performance of two main types (technologies) of PV modules, c-Si and CIS. The first type (c-Si PV modules) is listed as the most famous and used type over the world [21], with a stable and expectable performance over the time period. The second one (SIC PV modules) is capable to achieve a very high energy conversion efficiency for civil uses which is actually available on the market [22]. This study performed to elucidate detailed information of PV performance for the future installations of PV systems in the region. No such study has been carried out on the aspects of performance analysis and economic feasibility of such PV technologies with a grid-connected system in such geographic location. In the current study, the authors demonstrated that the CIS PV plant is more productive in such weather conditions. Therefore, the outcomes of this study could be considered as a benchmark for PV performance in the places with a similar weather conditions. Finally to make a comparison of PV performance on PV modules came from other different technologies.