A thesis submitted in paiiial fulfillment of the requirements for the degree of Master of Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2003

The application of photovoltaic (PV) technology has shown a sustained growth in the recent past. Grid connected photovoltaic systems are increasingly being considered as an important option of electrification, especially in urban areas. The grid connected application shared 33% of the world's PV market in 1995, which increased to 53% in 1999. This research aimed to carry out studies on PV grid connected system in Bangkok, Thailand with a view to evaluate its performance and study its applicability in supplying clean electricity. The performance analysis was done for two of ten residential roof top grid connected PV systems installed in Thailand during 1998 amorphous silicon (2.88 kWp) and single c1ystalline silicon (2.25 kWp) PV module based systems. Solar insolation, module temperature, ambient temperature, PV array output (current and voltage) and inverter output (current and voltage) were collected for thi1ieen months. Analysis of data indicates that the annual final yield was higher in case of amorphous system than the single crystalline. The average performance ratio was also found to be higher in amorphous silicon system than in single crystalline system. The average system efficiency was 6.9% (single crystalline) and 4.7% (amorphous system). The grid connected systems were found to be maintenance free based on a survey done except for one system which was interrupted for one week due to problem with the inverter. The overall share of grid connected PV system to the total electricity consumption varies from 6 to 25%. The installed capacity of the grid connected PV system can be easily reduced to 3 kWp instead of 3.15 kWp with the use of simply fabricated compound parabolic collector. The price of electricity from PV grid based systems was calculated for four scenarios. Depending on the assumptions used, the cost varies from about Baht 3 7 to an optimum Baht 4 (discount rate 5%, annual final yield 1400 kWh/kWp, 100% demand shift with considering externalities). A study on the energy cost (taken from grid and supplied to the grid) indicates that the first phase roof top PV grid system in Thailand had the lowest cots as compared to other systems installed in Australia, Japan and Europe. An experimental study on a household of the second phase program in Bangkok during five weeks indicates that the share of the PV for the total electricity consumption varies from 16 to 20% of the total electricity consumption. The simple pay back period varies from 23.2 to 29.4 years (progressive tariff rate). With time of use tariff rate, the simple pay back period varies from 16.4 to 20.5 years in the particular household under study. In this particular house, time of use tariff rate seems to be beneficial.