Photovoltaic (PV) modules are widely used for harnessing solar energy which ensure maximum output when their glass surface is clean. However, PV modules are open to dust, grime and other contaminations which get deposited on their surface causing reduction in transmittance and hence their efficiency reduces. It is therefore required to clean the glass surface of PV modules time to time either manually by labor or using some special arrangements such as automated systems. However, these techniques are either laborious or require extra energy. Therefore, another solution to offset such complications is to use chemical coatings which ensure self-cleaning of glass surface by increasing water contact angle. In the present study, two types of water repellent chemicals (such as trimethylchlorosilane and hexamethyldisilazane) have been used to coat the glass surface using dip coating technique. The performance of such coated glass slides has been investigated using some important characterization techniques, such as finding transmittance by spectrophotometer and measuring water contact angle using a high resolution camera. Moreover, the self-cleaning effect has been observed using a microbalance to measure dust on coated glass exposed to open atmosphere and compared with uncoated glass. The results revealed that these coatings have increased the water contact angle up to 149% which reduces friction between the glass surface and water droplets. Moreover, the friction reduction helps in mobility of water droplets which in turn can easily carry out dust along with them, thus improving the efficiency of PV module.

In June 2018, the power deficit in Pakistan hit a record high of 9000 MW. Although alarming, it is not unprecedented due to past trends of exponential population growth, inadequacy of conventional energy sources to meet demand and lack of technological advancements. This represents an urgent and unavoidable need to turn to alternate renewable energy sources such as solar, wind and hydroelectric power. This paper aims to explore the possibilities presented by solar energy to solve the power crisis. This technology can be used to generate electricity which can then be used in different thermal applications. This paper presents a detailed discussion regarding these technologies, the institutions working in this field and scheme of solar thermal plants as per energy needs of Pakistan.

Since the fossil reserves are depleting day by day, the trend of modern energy sector is going towards renewable energy. The demand of solar power plants is therefore at the peak nowadays across the globe. However, the construction of these plants is extremely dependent on feasibility study to estimate the real solar potential before installing it in any region. To evaluate the solar energy potential of Peshawar region in Pakistan, Ground-based global horizontal irradiance (GHI) and direct normal irradiance (DNI) were compared with satellite-based model SUNY. Ground measurements were done at the University of Engineering and Technology Peshawar (UET Peshawar) with the help of pyranometer and shadowband irradiometer. Comparison of the data showed that there was a maximum difference of 42.90% in ground and satellite-based GHI in the month of December. Minimum difference in GHI was found for the month of March that was −3.83%. Moreover, ground-based GHI was overestimated in the month of February, March, and April, while in rest of the months, satellite values of GHI exceeded the ground measurements. Similarly, maximum difference of 55.86% was found in the month of November between ground and satellite-based DNI while minimum difference of −3.34% was seen in DNI in the month of March between the two data. Furthermore, satellite-based DNI was underestimated in the months of February, March, and April while in rest of the months it was overestimated compared to ground measurements. In addition to this, correlation of ground and satellite-based GHI and DNI showed R2 value of 0.8852 and 0.4139, respectively. The results of this study revealed that the difference between ground measurements and satellite values was considerable and hence real time measurements are necessary to properly estimate solar energy resource in the country.

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