Results and Discussion
Projected Energy Production
The proposed Photovoltaic plant would produce approximately 8.46 GWH annually of (Alternating power ) electricity available for export to the grid, which is equivalent to 0.079 percent of AL-DDur Plant Annual Production. This production figure takes into account losses from the annual module degradation, dust accumulation, ambient temperature and the effect of the inverter efficiency. The electricity generation in Bahrain was 26 Billion KWH in 2014 [2017 CIA World FactBOOK and other sources], Hence, the proposed plant would account for 0.032 percent of the total generation and it would be sufficient to cover the needs of about 736 people as the per capita electricity consumption in Bahrain is 11,500 kWh (EcoMENA- Echoing sustainability in Mena-2016].
In this Study the historical Ground measurement Data provided by the RETSCreen for Bahrain international Airport was chosen among the used solar databases as it was found to have the lowest RSME, MBE and RE(%) despite the fact that NASA ‘SSE reported that their database is having ”. That would be tested in the sensitivity analysis as shown in the following Table:-
Table No.
The statistical Analysis for the GHI Databases
Solar Database Ground Data for Bahrain International Airport provided by Nasa-SSE PVGIS- Meteonorm Solar Electricity Handbook
RMSE 26.28 44.97 26.67 33.65
MBE 19.03 22.08 22.08 25.08
RE (%) 13.27 27.18 15.68 17.49
It is worth mentioning that the annual production of the proposed site was achieved by setting the optimal array tilt angle as 22 ‘ facing South in the used database, as it tested for several tilt angles (16′, 20′, 22′, 25′, 26′ and 31′) generated the highest GHI and consequently the highest electricity production as shown in Figure No’.. , and this disagree with the findings of Reference [ Bahrain BAPCO 5 MW PV Grid Connected Solar Project], as it was showing the optimal tilt angle is 26 ‘ (i.e., equal to Bahrain’s latitude 26 ‘ N).
Figure No.
The Global Horizontal Irradiation At Different Array Tilt Angles
Figure No” shows the monthly generated electricity at the selected tilt angle, where it is starts declining from June till September (i.e., during the summer season) which might be attributed to the effect of the increase in the ambient temperature and other factors like soiling, which is reported by references [ Bahrain’s Bapco 5 MW PV grid connected solar project], [study of the effects of dust, relative humidity, and temperature on solar pv performance in Doha: comparison between monocrystalline and Amorphous PVs], [Dust Accumulation on the Surface of Photovoltaic Panels: Introducing the Photovoltaic Soiling Index (PVSI)], etc., to be one of the most factors affecting the performance of the pv system performance based on monthly to bi-annual performance evaluation. In Bahrain it was found that it has resulted in reducing the performance by 10% of the useful solar radiation when the panel were kept un-cleaned for 73 days and likewise in Qater pv plant smillaer trend was reported ( 9.5% in 100 days), while Hassan et al has revealed a higher degradation on pv performance ranging 33.5% to 65.8% for an exposure of 1-6 months.
Therefore, knowing Bahrain’s dusty storm and aerosols from the Meteorological Station in 2016, especially the days with horizontal visibility of less than 8 km, therefore, the following figure would present the estimated electricity generation during various dust losses
Losses Percentage Annual PV System Electricity generation (MWH) PV System Capacity factor
(%)
6 8,463.6 19.3
8 8,283.5 18.9
10 8,103.4 18.5
20 7,203.0 16.4
The capacity factor of the PV system is 19.3% which is considered reasonable if compared with similar PV plants around the world, for example in Kuwait it is ranging 21.6-22.5, 19.6 [Performance of grid connected photovoltaic system in two cities in Kuwait] in Oman and 15.05-15.85% in Malaysia [ feasibility study on solar power plant utility grid under Malaysia feed in tariff ]and 19.8% in Ethiopia [Visibility study of grid connected solar PV system in Ethiopia] and 12.1-32.5% in Saudi Arabia [10 mw Saudi Arabia pv sites testing], 14-24 in the USA [ the 2010 solar market trend report]
The highest generated electricity is achieved in May, and as the temperature increase to reach the heist level in July and august the electricity output reduces to show the harsh impact of the ambient temperature on the PV system performance. Hence, to minimize this impact the following can be done:-
To include Aluminmium fins at the rear of the module for cooling which reduces the thermal resistance and increases the surface area for convection. Alternatively, to amount the pv mdules above the ground at 1.5 m to enhance heat transfer by convection, or to install a water tanks at the bottom of the PV panels or flowing cold water. [large scale 20 MW photovoltaic system for peak load shaving in sahib industrial district]
It is noticed the lowest exported electricity can be achieved in November to January due to low solar irradiance.
The expected extracted solar electricity fed to the grid annually is approximately 9771.95 MWH (5.36 KWh/m2/day)*365 days*25,484 m2* 0.196) , while the calculated extracted annual electricity is only 8460.1 MWH ( which is less than the estimated theoretically efficiency of 16.96%).
Performance ratio (PR) [14-16] is a simple model that allows trivial prediction of the yield of a plant as in equation 1: Electrical yield = POA irradiance * PR * Nameplate rating/Ref. irradiance (1) where the electrical yield and POA irradiance are integrated over the same time period and the Ref. irradiance is the irradiance used to assign the nameplate rating (usually 1000 W/m2 ). Because the PR varies with temperature, shading, and many other details, the PR shows substantial seasonal variation and it indicates the PV system losses due to the surrounding environment.
The annual performance ratio is 0.822 with its lowest value in June to August where the PR reach 0.795 and the highest in January 0.867. It is falling within the range of Saudi Arabia 82.27% as per reference [ Technical and Economic Performance of 1 MW Grid Connected PV Systm in ] Suadi Arabia], but it is higher than higher than to the results of Reference [ Assessing the technical impact of integrating large-scale photovoltaic to the electrical power network of Bahrain] where the annual PR is 0.742 and the lowest value in July at 0.704. Reference [] http://chrosid.de/wp-content/uploads/2012/12/pr-vs-cuf-wp.pdf] and [Assessing the technical impact of integrating large-scale photovoltaic to the electrical power network of Bahrain] reported that for systems located in high temperature region a PR of greater than 70% indicates high system efficiency, though Solar Server shows a higher PR range (0.85-0.95).
Figure No.
Financial Analysis
The economic indicators are carried as per Table No” and the results are as follows:-
‘ Net Present Value
THE RETScreen Financial Results The NPV sign was positive and of
Indicator Value Formula Criteria Results
Net Present Value ($) 2,037,330.00 Positive NPV= the investment is profitable
Negative NPV= the investment is not profitable/ would loss value for the company
NPV=0
the investment would neither gain nor lose value for the company Positive
IRR-equity (%) 15.40
Simple Pay Back (Year) 21.0 The shorter the pay back period the better
Equity Pay Back
(Year) 9.80 The shorter the pay back period the better Short
Benefit ‘ Cost Ratio 3.08 Ratios > 1
Are indicative of profitable projects Ratios > 1
Energy Production Cost ($/MWh) 66.73