Abstract:
Photovoltaics (PV) system is a prominent renewable energy technology that converts
sunlight into electricity. This study investigates the impact of uniform and non-uniform
soiling on the performance of photovoltaic (PV) panels. Soiling refers to the accumulation
of dust on the surface of solar panels. This reduces the amount of sunlight reaching the
solar cells and thus decreases the energy output. Uniform soiling occurs when the dust is
evenly distributed on the surface, while non-uniform soiling occurs when the dust is
unevenly distributed. In this thesis, we have conducted experiments and analyses using two
types of mainstream PV technology (namely, monofacial and bifacial panels) to evaluate
the respective effects of soiling. For uniform soiling conditions, we analyze the (i) tiltdependent soiling rate and (ii) the techno-economic analysis under the soiling-cleaning
cycle. Firstly, we developed an empirical soiling rate model that helped us to estimate the
tilt-dependent soiling rate of that particular location. This implies the soiling rate at an
arbitrary tilt can be estimated if we know the soiling rate of only one tilt angle PV panel.
Secondly, we analyzed the energy output revenue of various tilt angle PV panels under
uniform soiling conditions. From this analysis result, we were able to determine the
optimum cleaning cycle for each tilt angle. We also conducted a techno-economic analysis
based on the optimum cleaning cycle condition. Finally, at the optimum cleaning cycle, a
PV panel can generate the maximum revenue. Therefore, the PV power plant should adhere
to the optimum cleaning cycle to maximize its revenue. The PV power plant should follow
the optimum cleaning cycle procedure to maximize its revenue. The study finds that the
soiling rate is inversely proportional to the tilt angle, meaning that higher tilt angles have
lower soiling rates or vice-versa. The study shows that a 30° tilt angle PV panel has
maximum revenue and energy generation in Dhaka. The optimum cleaning cycle ranges
from 4 to 6 days depending on the tilt angle. Furthermore, non-uniform soiling conditions
and partial shading have been analyzed through our designed I-V scanner. This study aims
to understand the effect of partial shading and non-uniform soiling on PV panels by
conducting various controlled experiments. The experiments show that non-uniform
soiling, such as bird droppings, significantly affects the PV panel output and can cause a
drastic reduction in energy production. Therefore, immediate cleaning intervention is
necessary to mitigate the effect of non-uniform soiling on PV panels. The study in this
thesis is important for PV power plants to maximize their revenue by balancing the revenue
and the net cleaning cost. The study enhances the understanding of soiling physics and its
effect on the solar panel tilt angle for the South Asian region. The study also provides
insights into the effect of uniform and non-uniform soiling on the solar panel energy output
using infield characterization.
