It was a fortune to obtain automated reliable results locations for certain years as some of MCCB failure results in disconnection of PV panels to the grid. There was a concern on Sadeem Building recorded data; therefore, it was adjusted to become more sensible. Table 2 displayed the solar PV yield from the 4 sites of the project listed in Table 1.

The Expected solar electricity in Table 2 is based on Solar Home design Manual Shawna Henderson and Don Roscoe [11]. This means that the expected solar energy for Bahrain environment shall be 1477 kWh/kW/year (1 kW yield yearly 1477 kWh or 1 kW = 4.1 kWh daily). Hence, for example, expected energy for the 518 kW PV system at University of Bahrain (UoB) facility for one year is 1600 × 518 kW = 764,950 kWh. The actual solar electricity actually recorded at UoB in 2014 was 718,563 kWh, in 2015 it was 795,158 kWh and in 2016 it was 711,814 kWh. However, if we use Alnaser’s estimation [12] then the expected annual solar electricity from UoB solar PV field will be 984,120 kWh which means 1898 kWh/kW (1 kW yield yearly 898 kWh or 1 kW = 5.2 kWh daily)! This means that the expected yield from ref [11] is more sensible than from ref. [12].

Figures 8-11 display the correlation coefficient between the expected and

actually measured data in 2016 for the 4 Sites of the distributed 5 MW Solar PV project. We have chosen 2016 as it is the most accurate recorded results. The correction coefficient (R²) indicates how the sunshine is actually steady or interrupted by dust, clouds, haze, humidity, invertor performance, and temperature effect on PV performance [13]. Low R² means your expected income or yield from solar electivity will n0t be accurate. The customer or developer may be disappointed when he found the payback period becomes much larger than its planed! The figures show that best correction was 0.83 (Refinery Site) and the least was 0.58 at UoB site. For the expected solar electricity the value of R² is always near 0.9.

What is interesting in this table is the last column which leads to an experimental result indicating that 1 kW of solar installation will give daily solar electricity in Bahrain equal to 4.1 kWh or 125 kWh monthly or 1517 kWh annually. That was an important finding for consumer and providers in putting a tariff for feeding the solar electricity to the grid. Currently, the government of Bahrain through Electricity and Water authority had allowed special facility for roof top Solar PV installation which is for a size of 7 kW at a cost of BD 3500. This full 7  kW photovoltaic system the customer will pay USD 9100 (PV panels plus invertors and charge regulators). If the government purchase each kWh at a cost of 1 c$ (3 fils) then the payback period (PBP) will be 118 years, while if the tariff is purchased at a cost of 26 c$ (100 fils)—if Feed-In-Tariff is initiated—the PBP will be 4.6 years [14] ; more accurate calculation of PBP is available elsewhere [15]. Also, this figure (1 kW yield 125 kWh per month ) is important for net metering because each household will realize that if he installed 7 kW on his house rooftop he will be able to generate monthly solar electricity of no more than 890 kWh per month. This production of solar electricity will financially waive only BD25 (USD 68) from his monthly electricity consumption which no less than 3000 kWh, in average, in Bahrain as electricity consumption per capita per year is 17,493 kWh or 1457 kWh per month [16].

One of the major reasons for the poor performance of PV systems in the MENA region is dust accumulation. Unlike concentrated solar power (CSP), poly-crystalline and single-crystalline PV panels have shown power reduction in excess of 60% due to dust particles.

This project (the Bapco 5 MW solar PV) had allowed researchers to study the effect of dust on PV performance in Bahrain [17]. The study was based on eight PV panels out of an array of 2088 PV panels forming the 500 kW system. The eight panels under study were not been cleaned since October 1, 2013. The density of the accumulated dust ranged from 5 to 12 g/m² with an average PV power drop to 40% of the maximum available. The collected dust was analyzed revealing that the main elemental contents were Si (~15%) and Ca (~15%) in addition to Al (~6%), Mg (~5%), and Fe (~5%). Finally, two important empirical equations were established that allowed the estimation of the loss in light transmissivity (in %) due to dust accumulation (g/m²) on the PV panels, as well as a drop in PV power output as a result of dust density.

In this project, two sets of PV panels-each set consist of 8 panels. One set was cleaned two times in one year and the other was set naturally, i.e. naturally cleaning [17]. The accumulation of dust on PV panels became more significant in August and September due to humid weather during these two months with less wind speed that contributed to the adhesion (sticking) of dust on the panels, leading to loss of solar electricity production. This is apparent by the drop in the expected generated power ranging from 14.1% to 24.9% in August and from 21.6% to 32.5% in September.

The effect of dust on the performance on the two sets of PV panels was found to be less serious than expected! The maximum monthly average drop in the expected PV output did not exceed 32.5%, and in a single day, it did not exceed 50%, before the panels had been cleaned even after seven months of installation. On the contrary, the panels were found to produce more solar electricity than the expected monthly average of 26%, and on some days up to 50%, after cleaning. The overall performance of these panels in a 9-month period (Feb to Nov., 2014) was found to be greater than expected by 5.1% (Panel CP8) and less than expected by 4.8% (Panel CP2).

What is more interesting is our finding that on the 2^nd of April 2015 a heavy dust storm had hit Bahrain. The PV panels at UoB Site in this Bapco 5 MW project were covered by about 2 mm of Dust (Figure 12). Surprisingly, the solar electricity from UoB panels was not zero in this day but 25% of the expected yield (a daily of 2330 kWh for installation of about 518 kW) which is about 580 kWh!

On contrary, on the 28^th of Nov. 2014 there was a heavy rain in Bahrain (Figure 13). The PV panels were cleaned naturally-saving a lot of water and man-power. The solar electricity from UoB panels was slightly more than the expected in this day by 10%, i.e. an extra energy of 233 kWh.

The finding of our work on the effect of dust deposition of the dust on the surface of the photovoltaic solar modules [17] is in agreement with a reported

work from Iraq [18] where they reported a reduction in both the short circuit current (I_sc) and the output power compared to the same parameters of the clean module. The average degradation rate of the efficiencies of the solar PV modules due to exposed to dust is 6.24%, 11.8% and 18.74% calculated for exposure periods of one day, one week and one month.

In this Bapco 5 MW PV project, the Petra Solar’s Sun Wave was used which offered an advanced architecture providing two-way communications with each AC module (i.e. a Solar Panel plus Smart Energy Module, or SEM) for individual monitoring and control. This system enables the remote management of a large, geographically dispersed AC module population from a single, centralized location. A typical communications system, illustrated in Figure 14, comprises multiple AC modules, a communicator, and Intelli View.

Each Smart Energy Module (SEM) has a built-in revenue grade energy generation metering that measures the energy output to the electric grid and every SEM within the network is equipped with its own communication system. Using the Zigbee PRO® protocol standard, SEMs periodically transmit their measurement data to their local communicator. The communicator collects this data and periodically sends the aggregated SEM data to the Data Center over the local mobile communications network (e.g., GSM or CDMA), using the HTTP protocol.

The communications between the AC modules and the Data Center is bidirectional, so in addition to the measurement data being pushed to (or pulled from) the Data Center, the Data Center also has the ability to issue commands to each of the AC Modules, thus providing complete control of each device. It is part of a Smart Grid Networks.

The smart Grid Network (this Bapco 5 MW solar PV project) is a collection of AC modules connected by a single, common communication channel represents a local Smart Grid Network, which allows information to be exchanged between

the AC modules and the Data Center. Each network covers a specific geographic area and provides information about where the associated communicator is located, and which AC modules are expected to connect to the associated communicator. Figure 15 illustrates a typical network architecture design [17].

This project has inspired lots of Information Technology and Electrical and Electronic Engineering students in Bahrain and in the region to conduct research, projects, workshops and seminars at UoB and other private and governmental universities in Bahrain and neighborhood as well as units in government like Sustainable Energy Unit at Electricity and Water Authority in Bahrain [19] [20] [21].

With the successful Bapco 5 MW solar PV project, many developers and investors found necessary to invest in renewable and solar energy.

In October 2016, the Sustainable Energy Unit (SEU) had finalized the preparation of Bahrain’s first National Renewable Energy Action Plan (NREAP), which identifies feasible renewable energy options for Bahrain, sets the targets, and proposes policies and initiatives to achieve the targets [22]. NREAP represents the Kingdom’s efforts to deliver the sustainable energy transition envisioned in the Economic Vision 2030. The Plan sets a national renewable energy target of 5% by 2025 and 10% by 2035. The proposed renewable energy-mix consists of solar, wind and waste to energy technologies.

Under these circumstances, Bahrain’s drive to promote clean renewable energy solutions for sustainable development and environmental protection is highly commendable. Here are some interesting and important energy-related facts about Bahrain:

• The total installed electricity capacity in 2018 is about 3.6 GW, all coming from natural gas. Therefore, diversity or energy mix is important for energy security.

• In 2018, Bahrain had generated 17,000 GWh of electricity and it is expected to generate more in future.

• Its gas reserves should last about 50 years at present rates of consumption with the risk that it is only enough to meet current demand up to year 2018!

• Bahrain’s per capita energy consumption, which is among the highest in the world, has nearly doubled during the last decade and with an annual increase of 10%, it is expected to reach 4803 MW in 2020.

Now, if Bahrain target is to have 5% solar by 2025, i.e. say 5% out 4 GW which is 200 MW solar PV in about 6 years, then this means that Bahrain needs to purchase 33 MW per year requiring annual production of 100,000 PV @ 330 W or 280 PV panels daily with non-stop factory operation of PV! Such demand will allow for green-job opportunities besides the need for establishing maintenance and energy savings companies (ESC).

First positive impact of the successful Bapco Project is the establishment of Solar One Company. It is Bahrain’s first solar panel manufacturing facility. Its mission is to produce high-quality solar panels using state of the art technology to provide clean, free energy for everyone.

The company has a great chance to lead the way in the renewable energy industry in the Middle East, and help steer the region towards meeting and exceeding its climate goals.

The company manufacturing capacity is 60,000 panels per year. This is equal to producing 15 MW of power. The prices of the PV panels are comparable to those available in China or India, without the import cost. Solar One is positioned to anticipate and facilitate a shift towards renewable energy [23].

An up-to-date review of the progress made on solar energy in the GCC Countries, together with the challenges and barriers hindering the development of Renewable Energy in these countries in technology, policy development, and insufficient application of RE technology integrated to the buildings and how successful projects could contribute to overcome such barriers, is explained in detail elsewhere [24].

One of the most important fruits of Bapco 5 MW solar PV project is the wide spread of installation of PV systems on a rooftop—making the building integrated with Photovoltaic BIPV—for power up to 7  kW at relatively low cost (BD 3500 or US$ 9100). This can be further spread if the government of Bahrain offers more incentives that were explained elsewhere [14].

In the past two years, several large-scale rooftops were made in Bahrain after people had learnt from Bapco Solar PV project. This includes installation 3.1 MW at King Hamad University Hospital roof top, 250 kW at Avenue Mall Building, 90 kW at Islamic Awqaf (Endowment), and several household houses in Northern Area and Khalifa Town.

Retrofitting the older buildings—due to the weight of these solar PV panels which weigh about 16 kg/m²—will further boost this roof-top application. The newer technology, provide solar panels around 3 - 4/m² [25] , which means that we can probably fit it on to the old canopies because the canopies are civil structures which need to carry the panel’s weight about 10 plus kg per m²; lighter panels is much easier for us to do the retrofitting.

In recent years, Bahrain has faced challenges brought on by climate change, and have therefore been obliged to devise plans that include projects to address these challenges. Bahrain is perhaps the most vulnerable to the threat of rising sea levels because of its location in a low-lying coastal zone, where most of its population and industries reside. According to Bahrain’s Second National Communication [26] , the current built-up and industrial areas in Bahrain account for about 300 km² of a total land area of 748 km² (about 40%), and are located largely along the eastern coastline of Bahrain’s main island. The study shows that 11% (83 km²) of total Bahraini land will be inundated by 2050 if the sea level rises by 0.3 m and 27% (200 km²) by 2100 if the sea level rises by 1.5 m. This is the expected scenario if there is no accelerated deglaciation. However, in the case of extreme deglaciation, 27% (199 km²) of Bahrain’s land will be inundated by 2050 if the sea level rises by 1 m and 56% (418 km²) of the land faces inundation by 2100 if the sea level rises by 5 m.

It is also expected that the climate change impact will lead to temperature rise and drought cycles, resulting in more frequent dust storms, which exacerbate air pollution and soil erosion. In 2006, Bahrain’s GHG emissions stand at an annual total of 29 million ton of CO₂ equivalent to about 28 tons per capita while in 2015 the emission reached 40 million ton and to about 33 tons per capita. The sources of more than 87% of GHG emissions come from energy-related sub-sectors, making Bahrain the second highest in the GCC after Saudi Arabia [27] [28]. More than half the electricity generated (~56%) is consumed by the residential sector in Bahrain, producing 20% of the Kingdom’s total CO₂ emissions.

In an effort to change the status quo, Bahrain’s political and economic leadership has wisely formulated its energy strategy to reduce CO₂ emissions by investing in the renewable energy sector.

The installation of 5 MW solar PV in Bahrain in 2014 had allowed for an annual reduction of CO₂ (Green House Gases) by about 8000 tons annually-assuming each 1 kWh from natural gas emits 1 kg of CO₂. This means that if every year Bahrain install 33 MW to meet its target by 2025 (5% solar or renewable energy from 4 GW national power capacity) then this will lead to an annual reduction of 56,000 tones, 108,400 tones, 168,000 tones, 224,000 tones,280,000 tones, and 336,000 tones in years 2020, 2021, 2022, 2023, 2024 and 2025, respectively.

Tatweer Petroleum in Bahrain has initiated 2 projects to utilize solar energy in the Bahrain Field: 1 MW Solar Power Plant (3980 polycrystalline PV panels having an efficiency of 15.4% with 16 invertors @ 60 kVA on an area of 14,900 m²) which was completed and in operation since March 2016 (Figure 16). The other project is 2.3 MW Solar Power Plant (8064 single crystal PV panels having an efficiency of 15.4% with 28 invertors @ 100 kVA on a land area of 50,000 m²) and it is under construction [29]. The PBP of the first project is 12 years and was constructed in 5 months only while the other has PBP of 9.25 years, will take 1 year for construction and will be completed in October 2019. The expected solar electricity gained annually is 5295 MWh. These two projects were inspired by the Bapco 5 MW project and fulfilling the Bahrain Vision 2030. The CO₂ energy saving in the first year of operation was 1.85 GWh—saving about 1800 tons of CO₂.