Investigation into the potential of exploiting solar and wind energy on Co To island, Quang Ninh province
Because of these problems, the Vietnam Academy of Science and Technology and Quang Ninh provincial People’s Committee has assigned the task to the Institute of Energy Science entitled “A scientific study to make a general plan on providing sustainable energy for the socio-economic development and the insurance of national defence and security on Co To island district, Quang Ninh province.” Based on this, scientific bases will be proposed to find reasonable solutions to electrify the island district. The project was carried out between 2007 and 2009 and obtained positive results.
In order to produce exact data on wind activity and solar radiation, scientists from the Institute of Energy Science built a direct measuring system, including modern measuring equipment with high accuracy which can work sustainably in every weather condition on the island. Through the system, data on wind activity and solar radiation is continuously measured in 10 minutes cycles. This is done in order to suit wind electricity technology, modern solar electricity and present popular calculation software in the rest of the world.
Data on wind and solar energy is measured at two positions on Co To island, including a station on television hill beside the hydrometeorology station (position 1) and a measuring station at the post office in the centre of the district (position 2). Measuring equipment installed at position 1 includes four pieces of equipment designed to measure wind speed of 10 metres, 25 metres, 35 metres and 45 metres, two devices to measure wind direction at speeds of 10 metres and 45 metres, and a device to measure solar radiation at the height of 10 metres. Equipment installed at position 2 consists of a piece of equipment to measure wind speed and direction at the height of 25 metres. Data is updated and transmitted to a computer center at the Institute of Energy Science via an internet connection.
Diagram to collect data from Co To island to the Institute of Energy Science
Based on data measuring wind activity and solar radiation in one year from the Institute of Energy Science, as well as data from many years at the Co To hydrometeorology station and other surrounding areas, scientists calculated exact specific parameters to assess the potential of exploiting solar and wind energy for Co To island district.
Assessing the potential of exploiting solar energy on Co To island
Investigation on Co To island showed that the district has rather good potential for using solar energy to create an effective energy source. However, this energy source fluctuates sharply throughout the year. From January to April, in winter, radiation intensity is naturally low. February and March represent particularly barren months. However, in summer months, when solar radiation is naturally high, the effectiveness of using solar energy becomes much higher.
Due to annual fluctuations solar energy becomes a costly way to provide energy for the island. Therefore, scientists presented a proposal for the development of smaller solar electricity stations or a complex electricity providing station which provides different electricity sources for households, residential areas and border guard stations far from the electricity network of the district. The aim was to combine independent electricity sources with big capacity sources.
In addition, solar heat energy is cheap and brings advantageous economic effects. Therefore, solar heat technology needs to be encouraged, especially equipment to boil water by solar for households, hotels, restaurants and tourist areas.
Assessing the potential to exploit wind energy on Co To island
In Co To island district, there are two seasons per year, including a northeasterly season in the cold period from October to March and a southeasterly season in the hot period from April to September. This monsoon circulation in combination with complicated terrain conditions creates two wind directions; a North East wind and a South-component wind. The North Easterly wind is both the most plentiful and the strongest. The East wind also plays a remarkable role. On Co To island, regions which have favourable terrains for North East and Easterly winds will be the places which present the most potential in wind energy. High peaks which are not hidden by mountains, , lowlands among mountains along Northeast and Southwest directions, and ravines or mountain passes along the Northeast – Southwest or Eastwest directions create the best conditions for wind collection.
Based on the above results, scientists studied wind activity at differing heights. They found that the higher the wind, the stronger the energy. At the height of 10 metres, the average energy intensity and the total average energy per year is 55.6W/m2 and 489.1kWh/m2. At the height of 80 metres, the figure is seven times this, rising to 383,1W/m2 and 3371,5kWh/m2.
According to the World Wind Energy Association, a height of 25 metres is suitable to create wind electricity at a small capacity; whereas a height of 50 to 80 metres, creates a possibility to use an electricity generator at a medium to large capacity. The level of effective exploitation of this energy source depends on wind electricity technology. The more modern the technology is, the more energy it produces, therefore increasing the exploitation effectiveness of wind as an energy source. Therefore, scientists researched and chose modern wind electricity generators, with differing capacities, suitable with specific conditions on Co To island. Mountainous areas and near-shore seas to the north of Co To island allowed the building of high capacity electricity plants - meaning the energy demands of the district could be met. It also meant the island could contribute to providing energy for the national electricity system through under-sea electricity transfer systems.
Although wind and solar energy sources can supply electricity for the development demand of the island district, this energy source depends much on nature. So the possibility of providing continuous, unlimited electricity remains unstable. Scientists therefore proposed to combine reproductive energy (mainly wind electricity sources) with traditional electricity sources such as diesel electricity for the present period, with a view to including other electricity sources in the future.
With favourable conditions to develop a big marine economic zone in the northeastern region and a marine tourism city in the future, Co To island district’s demand for electricity will only increase. The research by scientists from the Institute of Energy Science has made an important contribution to socio-economic development and ensuring national defence and security for the island district in particular, and other island districts in Vietnam in general.
Translated by Tuyet Nhung
Link to Vietnamese version
