Background

As the main electricity organization, EGAT recognizes the importance of maintaining the balance of energy sources particularly the appropriate and sustainable diversification of fuels in electricity generation. Thus, renewable energy which has available natural sources around us whether they are solar energy, wind, hydropower, geothermal energy, biomass, and biogas energy which include agricultural produce and waste have been an alternative to which EGAT has always placed importance.

Along with electricity generation from the main fuels, EGAT has conducted research, development, and demonstration on renewable energy projects continuously. For example, in 1978, EGAT, in cooperation with other organizations, made an exploration of the source of geothermal energy and in 1989 the first geothermal energy power plant in Thailand was constructed. For wind energy, “Phrom Thep Renewable Energy Station” has been used as the testing station for electricity generation from wind power since 1983. The first solar cell hybrid demonstration station was established in 1986. The project of development of power plant downstream of irrigation dam has been implemented since 2007. The alternative energy will help to reduce the use of fossil fuels. Technological development and innovations relating to renewable energy will also help to enhance the stability of electricity generation with more reasonable cost, strengthening the security of the power system coupled with sustainable environmental conservation.

Renewable Energy

Renewable energy is the energy collected from renewable resources that are inexhaustible and naturally replenished. It includes sources such as sunlight, wind, water, geothermal heat, biomass and biogas including agricultural produce and waste such as husk, bagasse, cassava pulp or manure which can be used as raw material in producing renewable energy.

At present, renewable energy is an alternative energy to replace energy from fossil fuels or conventional energy such as petroleum, coal, natural gas, oil shale, and tar sand, etc. Renewable energy is clean and causes no pollution, environmental impact, or climate change. It helps to reduce greenhouse gas emission which is the cause of global warming, reduce imported fuel, and also promotes community participation in electricity generation.

Types

Renewable energy commonly used globally are hydropower, solar energy, wind energy, geothermal energy, and biomass heat.

Hydropower

Hydropower is an inexhaustible natural resource. Water is essential for the subsistence of all life. Human beings, in particular, use water for several purposes including consumption. Water can be used as energy source for electricity generation by the transformation of potential energy of water stored in the dam to the kinetic energy of water passing through the pipes to become mechanical energy to rotate the water turbine and generator to produce electricity. The amount of energy depends on the height of water level and the flow rate of water used in electricity generation.

Power plants are classified into reservoir power plant, run-off river power plant, pumped-storage power plant, and downstream power plant of irrigation dam.

Solar Energy

Solar energy is clean energy that is available abundantly in nature. It can be used to produce electric energy by means of solar cell which is a device made of silicon semiconductor. Solar cells convert sunlight into electric energy directly as direct current.

EGAT has conducted a study on electricity generation from solar cell and constructed 2 Solar Cell Demonstration Stations at Khlong Chong Klum, Wattana Nakhon District, Sra Kiew Province and another one at San Kamphaeng, Mae On District, Chiang Mai Province.

EGAT’s solar cell power plants are Pha Bong Power Plant, Mae Hong Son Province, Sirindhorn Dam’s Power Plant in Ubol Ratchathani Province and Tub Sakae Power Plant in Prachuab Khiri Khan Province.

EGAT’s hydro-floating solar hybrid system is in operation at Srinagarind Dam in Kanchanaburi Province and at Sirindhorn Dam in Ubon Ratchathani Province.

Wind Energy

Wind energy is the energy from a natural phenomenon that is caused by the difference of temperature and atmospheric pressure of each position on the Earth’s surface. The air in the area where the temperature is higher will be hot and have a lower density. It will then expand and rise up and is replaced by cooler air with higher density creating the air movement which is called the wind or airflow.

Nowadays, wind energy is used in electricity generation as it can be found everywhere and is clean causing no pollution and can be used endlessly. Wind turbine technology is used in electricity generation. The wind which strikes the blade of the wind turbine will convert wind energy which is kinetic energy to be mechanical energy for electricity generation. The amount of electricity obtained depends on the wind speed, the length of the wind turbine blades, and the installation area.

Electricity generation and distribution process from wind energy of EGAT is at Phrom Thep Cape, Phuket Province and at the upper reservoir of Lamtakong Jolabha Vadhana Power Plant, Si Khiew District, Nakhon Ratchasima Province.

Geothermal Energy

Geothermal energy is, like petroleum, the heat of the earth’s molten interior. It is contained in water or steam. Geothermal energy originates from the movement of the earth’s crust (lithosphere) which consists of moving tectonic plates. The plate motion causes faults in the rocks which become smaller under the ground. When it rains, some part of the rain will pass through the faults and is collected under the ground. The water which is heated up by the molten rock emerges through the faults to the surface of the earth as hot water or steam as hot spring, geyser, hot steam, boiling mud pond, and gas.

In electricity generation by geothermal energy, the heat is transferred from the hot water to the working fluid of low boiling point to become steam which is used to rotate the turbine of which the shaft is connected to the generator.

Biomass

Biomass energy is the natural energy generated or produced by organic matter such as crop residue, agricultural waste or industrial waste, and energy crop. Examples of such organic materials are husk, rice straw, bagasse, sugar cane leaf and bud, wood scraps, fast-growth wood, palm kernel and fiber, cassava pulp, corncob, coconut coir and shell, brew’s yeast, garbage, industrial wastewater, and animal waste.

Electricity generation from biomass energy is of 2 types:

1. Direct combustion which is used as fuel in the biomass power plant
2. Thermochemical conversion to obtain biogas is used as fuel in the biogas power plant. An example is the anaerobic digestion of cassava pulp, corncob, or Napier Grass.

EGAT has placed importance on electricity generation for the security of the power system coupled with environmental conservation. In cooperation with Kasetsart Agricultural and Agro-Industrial Product Improvement Institute (KAPI) of Kasetsart University and the Rubber Authority of Thailand, EGAT has implemented the project “Planting Seedlings of Fast-Growth Wood to Increase Income for Community”. The objective of the project is to promote the members of Cooperatives and rubber planters in 4 districts in Beung Karn Province (Muang District, Si Wilai District, Phon Charoen District, and Seka District) to plant seedlings of fast-growth wood and grow them in their rubber plantation and open space of the community. The trees to be planted are Acacia auriculaeformis Cunn and Acacia mangium wild. The objective of the project is to promote local jobs and generate income to the community. When the fast-growth trees are 3-4 years old, they can be sold as biomass fuel to local and foreign biomass power plants. Thus the project will promote occupation and quality of life of the community.