Wind Power and Related Technologies
There are several agencies in Thailand, such as Electricity Generating Authority of
Thailand (EGAT), Department of Alternative Energy Development and Efficiency (DEDE), and
other agencies have conducted research on the use of wind turbines to generate electricity.
Most of the works involve using secondary data to calculate and evaluate projects using
statistical methodology. Moreover, EGAT has a pilot wind turbine project at Laem Phrom
Thep, Phuket with 150-kW Nordtank wind turbines, model NTK 150/25. From the field visit
of the Energy for Environment Foundation, it is found that the project’s capacity factor is 14%,
with an investment cost of around 82.3 million Baht per MW. Other costs include maintenance
cost of 1.67 Baht per unit, electricity generation cost of 9.44 Baht per unit. These costs are
high when compared to the power production with fossil fuels. These results are similar
to the outcome of the feasibility study of using wind energy to produce electricity in the case
of wind farm project on Pha-Ngan Island, Surat Thani [17]. From the financial and economic
feasibility of the case study, it is found that the wind farm project is not financially feasible,
with a negative NPV and a B/C ratio of less than 1.
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Apart from the projects mentioned above, there has been a private proposal for
Thailand First Wind Farm by Fellow Engineering Co., Ltd. to construct a 360 MW wind farm,
whose capacity is equivalent to a 42.11 MW small power producer (SPP) of fossil fuel
power plant, operating at 90% load factor. The wind farm is proposed to be located along
the coastline from Pak Phanang, Nakhon Si Thammarat to Singhanakhon, Songkhla.
Wind turbine technology can be divided into 2 groups, namely (1) design technology
and power control system for wind turbine, and (2) technology for producing wind turbine.
Design Technology and Power Control System for Wind Turbine
In the past, the airfoil design for wind turbine blade usually used the standard airfoil
selection developed by agencies such as NACA or NASA. However, these airfoil sections
were designed for aircraft wings, which are different from the airfoil section for blade which
has more different specific requirements than aircraft wings. The length of a turbine blade
is likely to have a Reynolds Number lower than that of an aircraft wing. Airfoil section is
usually resized to be thicker, causing it to lose certain aerodynamic quality. The design
of a turbine blade requires individualistic quality of airfoil section, depending on the design
of rotor, control system, and other equipment used with the turbine blades.
Power Control System Technology for Wind Turbine
There are 2 modern designs of power control system for wind turbines with the capacity
at MWs level, namely (1) pitch control, and (2) stall control. Both systems have the same
purpose which is to reduce the aero dynamic force on the wind turbine when the wind
velocity is at a level higher than what the turbine designed for. This will help limit
the power produced and protect the structure of the blade from damages. Moreover, under
a high wind velocity environment, the system will prevent the power not to be transmitted
to the generator more than what it is designed for.
Technology for Producing Wind Turbine
During the recent years, there is the production of large wind turbines with diameter
no less than 80 meters. There has also been a construction of several wind turbine prototypes
with diameter 100-120 meters. Over 50 million kilograms of composite materials have been
used to produce wind turbines across the world.
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As there is a rapid growth of wind turbine, there has been a large quantity of technical
research on composite materials and the future trend of this technology, especially on the
design of large wind turbines with power production capacity at MWs level.
At present, a large number of wind turbine producers have their own factories. So there
is a diversity in the demand for materials and production process. Nordex and GE Wind have
built 40-50 m wind turbines using fiber glass in the manual layering process in an open mold
and coat a resin based material onto the fiber. NEG Micron is producing 40 m wind turbines
using carbon fiber, wood fiber, and epoxy-based material. Vestas has long used prepreg
system, using fiber glass as reinforcing material. TPI Composites is producing 30 m wind
turbines using vacuum-assisted resin transfer molding (VARTM). Moreover, Bonus uses infusion
techniques in making the whole of turbine blades in a single process to reduce gluing between
subcomponents in later stage. The wind turbine design technology in Thailand can currently
operate at 250 kW level. The experience in producing wind turbines is at 50 kW level.
Gearbox Technology
Gearbox is an equipment that transfers power from wind turbines to generator and
adjust the rotation speed of wind turbine to be at a level needed by the generator (increasing
the rotation