Abstract:
Renewable energy, particularly solar photovoltaic, offers great solutions to the current energy crisis that
people face in their daily lives due to its cleanliness, advantages, and low cost of technology. The
dissertation intends to demonstrate to the public, policymakers, and policy executors that sufficient
exploitation of available water resources and solar energy abundant in the country can ensure the
sustainability of electric energy as well as renewable energy development in Rwanda. The dissertation's
main goal is to design a floating solar photovoltaic system integrated with a hydropower plant (a case
study of the NYABARONGO Dam). The potential energy of floating solar photovoltaic (FSPV) on the
Nyabarongo hydro power plant (HPP) dam is modeled and simulated using PVsyst software, and Matlab
was used to validate the thesis results and analyze the impact of floating solar photovoltaic (FSPV)
integrated with hydropower plant on the national grid. The control system includes a maximum power
point tracker, which locates the point at which the photovoltaic modules produce the most power under
varying operating conditions. The phase locked loop (PLL) is used to quickly synchronize the PV system
with the grid by locking the converter output to the grid voltage. The rotating reference frame locked to
the grid is used to control current and voltage towards active and reactive power flow. Furthermore, the
study demonstrates the benefits and potential of using floating solar photovoltaic (FSPV) in Rwanda to
reduce the use of land-mounted solar photovoltaic (SPV), as floating solar photovoltaic (FSPV) is found
to be more efficient than traditional SPV due to its cooling facilities. A total of 33,750 photovoltaic
modules were used on a small surface area of 72,884 m2 extracted from a large surface area of the
Nyabarongo hydro power plant (HPP) dam, injecting 15 MWp into the grid at a nominal power ratio of
1. Five 3,000 kW inverters, each operating at 630-930 VDC and 400 VAC at its output, were used to
connect the FSPV to the grid, and MATLAB software (Version 2017) was used to simulate its
performance with an inductor-capacitor-inductor (LCL) filter. The proposed model includes PV arrays,
a closed loop boost converter to control the effects of weather on the floating solar photovoltaic (FSPV),
and an inverter with an LCL filter to suppress harmonics in the system. The system parameters were
tuned so that the total harmonics distortion of current and voltage respects the IEEE (519-2014)
standards. It is ensured that the production of Nyabarongo hydro power plant (HPP) has been improved
because with FSPV inject 28 MW or more into the grid at all times. The results show that the floating
solar photovoltaic (FSPV) makes the best use of existing infrastructure and could supplement existing
hydroelectric production as well as provide electricity in conjunction with hydro power plant's existing
generating units.
