Photovoltaic (PV) technology is one of the clean sustainable energy technology which sourced from the sun. However, there are many issues that can potentially degrade the system. This paper extensively discusses on the hybrid system power generation for the photovoltaic (PV) system. In addition, this paper also reviews the factor that affecting the photovoltaic system performance including the types of PV cell, the effect of ambient condition, system components, and the power quality characteristics. The performance of the monocrystalline type greater than the polycrystalline type around 5-7%. The usage of an inverter gives an impact with 8-20% of total energy losses. Finally, this paper summarises the future research work needed to overcome the drawback of the available photovoltaic systems.

A study was conducted to investigate whether reflectance data of hyperspectral image of an area could be used to extract related physical features to produce mapping of vegetation density. This paper explains on estimating percentage of vegetation coverage based on Normalized Difference Vegetation Index (NDVI). Image segmentation based on thresholding was used to separate different features of the land entities like soil, water and road. From here, NDVI values can be integrated for further segmenting the vegetation features. The colour segmentation method is then able to classify the vegetation according to their density level, which can be used to determine tree crown density. Test conducted towards a hyperspectral image shows that different density level can be extracted, where it contains about 7.5% high level tree crown density, 1.8% medium crown density and 5% low. More tests need to be conducted in order to proof the workability of the developed algorithm in analysing hyperspectral images from tree crown density mapping.

The quantity of electricity produced from the photovoltaic (PV) system is depends on the PV panel’s performance itself. Recently, the challenges in the PV system have been greatly discussed by researchers and environmentalists. The non-uniform PV output power, partial shading conditions and high operating temperature of PV cells are the challenges that always known to reduce the PV system’s performance. This paper provides a literature review on the challenges and methods to mitigate the challenges. The future works involving of modelling and computational techniques also has been proposed to overcome the problems, hence, enhancing the PV system’s performance.