2011 International Conference on Alternative Energy in Developing Countries and Emerging Economies
- 237 -
Use of TRNSYS for Optimization of Hybrid
Power Systems on an Island in the Andaman Sea
of Thailand
U. Boonbumroong*, C. Jivacate*, N. Pratinthong**, S. Thepa**, and P. Sripadungtham***
*
Pilot Plant Development and Training Institute, King Mongkut’s University of Technology Thonburi
(Thailand)
**
School of Energy, Environment and Materials, King Mongkut’s University of Technology Thonburi
(Thailand)
***
Department of Electrical Engineering, Faculty of Engineering, Kasetsart University
(Thailand)
Abstract--
This paper presents a technique on how to
optimize the configuration of stand-alone hybrid power
systems under TRNSYS environments. Koh Mak Noi
village in Phang Nga province, in the Andaman Sea of
Thailand, was selected for this study. An existing
PV/wind/diesel hybrid power system at Chik Island,
Thailand, was therefore selected as a reference system. The
design was posed as an optimization problem whose
solution allowed obtaining the configuration of the system
that simultaneously minimized the total cost through the
useful life of the system. The cost function was evaluated
using a TRNSYS 16 transient simulation program, in
assistance with a GenOpt optimization program for the
minimization of the cost function. The results showed that
the overall best cost reduction has been achieved by the
Particle Swarm Optimization algorithm. This method
requires just a few seconds to give the above results (the
number of generations is 46).
Index Terms
—stand-alone hybrid power systems,
particle swarm optimization (PSO), TRNSYS, GenOpt.
I. I
NTRODUCTION
Up to the present, electrification for most remote
islands in Thailand has been usually generated by costly
small diesel generators, limited electricity from solar
battery charging stations that depend on site
characteristics and the local supply options. The lack of
convenient, affordable and reliable electricity hampers
development efforts, and limits the ability of locals to
develop their communities as they see fit [1].
Today, the Thai government has provided each
household in most remote islands of Thailand with solar
home systems (SHS) which were installed in 2005-2006.
At the end of 2006, the Provincial Electricity Authority
of Thailand (PEA) had installed the SHS in about
203,000 households [1]. Each system comprises a 120
Wp PV module, a 150 W inverter/charge controller, a
125 Ah 12 V battery, and two 10 W fluorescent lights.
All equipment is assembled or manufactured in Thailand.
Total energy production from the PV module is about
350-450 Wh/day. Maximum power output is limited by
the inverter’s capacity.
Currently, the provision of electricity for household
appliances is limited to lighting, a radio or cassette
player, a small fan and an hour or so of black-and-white
television per night. The use of power tools such as drills
and saws necessary for boat and house repair and
construction is possible only through the use of diesel
generators. Refrigeration for food and for vaccines is
impossible for these communities, because solar electric
systems are too small to power refrigerators and high
diesel prices mean that diesel generators are run only for
several hours every evening.
SHS can eliminate or reduce the need for candles,
kerosene, liquid propane gas, and/or battery charging,
and provide increased convenience and safety, improved
indoor air quality, and a higher quality of light than
kerosene lamps for reading. However, the lack of local
knowledge of how to effectively use and maintain these
systems limits their effectiveness, efficiency, and long-
term sustainability. Additionally, the low quality
inverters and chargers were used in the system. Finally,
many SHS systems are failing. A study by Chris Greacen
[2] found that 22.5% of the solar home systems
completed in June 2006 in Tak Province had failed
within approximately one year, and that charge
controller/inverter and lamp ballast failures were the
most likely causes of failure. Importantly, it appears that
very few of the solar modules have malfunctioned.
However, the solar panels are a significant innovation
which could provide an integrated hybrid power system.
However, the design of hybrid power systems is complex
because of the uncertain renewable energy supplies, load
demands and the non-linear characteristics of some
components with a large number of variables. Therefore
the design problem cannot be solved easily by the
traditional trial-and-error methods [3].
The objectives of this paper suggest using the
TRNSYS simulation program [4] for the minimization of
the objective function that is evaluated by the GenOpt
optimization program [5], to find the optimum combi-
nation of the stand alone hybrid power system. The study
begins with an analysis of electricity demand on the
island (both current demand and expected demand
growth). The next objective is to devise an optimized
hybrid power system that would make use of existing
resources (solar panels) and new equipment to improve
electricity service and bring lower costs to end-users.
II. M
ATERIALS AND
M
ETHODS
A. Koh Mak Noi village
Koh Mak Noi village is located in Phang Nga province
in the Southern part of Thailand (latitude of 8°50’N,
longitude of 98°23’E). The island is located about 3
