Mountainous terrain and a rainy season that can make 60 per cent of the sites inaccessible for several months of the year are typical of the challenges posed by rural electrification projects. However, ABB’s current power transmission and distribution project in Laos poses an additional hazard in the form of unexploded ordinances. ABB project managers Joerg Holzapfel and Ruben Llaneza explain.
The underdeveloped state of the rural electrical infrastructure is a major constraint to rural economic growth and poverty alleviation in Lao People’s Democratic Republic (Laos), where only 18 per cent of households are electrified. The government has therefore implemented an electricity infrastructure development programme aiming for 90 per cent electrification by 2020.
In July 2001, as part of this ongoing infrastructure development programme, state-owned electricity utility Electricité du Laos (EDL) placed a $17 million contract with ABB to expand the power grid in the northern Laos provinces of Luang Prabang, Xayabury, Vientianne, Xaisomboun and Xieeng-Knonuan. The project, which includes the design and build of a 340 km transmission line and a 73 km power distribution network, will bring electricity to around 100 villages, increasing the number of electrified villages in the country by about three per cent.
The electrification project is being financed by the Asian Development Bank and its main objectives are to strengthen and expand the existing transmission and distribution facilities in the region to provide rural villages and towns with electricity in an efficient and reliable manner. Presently these communities either have no access to electricity, or rely on limited off-grid power supplies with high costs.
The involvement of the local community is important as it enables locals to understand the long-term benefits a project will bring as well as helping to reduce the potential for conflict
In addition to the social benefits, the ADB expects that the project will strengthen EDL’s project management capabilities as well as its financial management and operational performance.
“Accelerated completion of the network will enable EDL to focus its resources on delivering electricity to rural areas where it is greatly needed for economic growth and standard of living improvements,” said ABB on being awarded the project contract. “This project is an excellent example of how ABB can help a national power utility plan and implement a sustainable electrification programme.”
The electrification project is divided into three discrete ‘Lots’:
- Lot 1A comprises a 164 km, 115 kV transmission line between Nam Leuk and Phonsavan together with a 43 km, 34.5 kV distribution line and 53 transformer stations.
- Lot 1B comprises a 76 km, 115 kV transmission line between Xieng Ngeun and Xayabury, with a 20 km, 34.5 kV distribution line and 31 transformer stations.
- Lot 1C comprises a 100 km, 115 kV transmission line connecting Thalat Substation to Non Hai and Ban Don together with a 10 km, 34.5 kV distribution line and 15 transformer stations.
Many tasks have to be carried out by extensive manual labour, sometimes with the assistance of elephants
All of the power lines are overhead. The distribution lines will tap into the 115 kV lines in order to supply villages along the line route. The majority of the tapping lines will be short (less than 2 km). But two or three lines will be about 20 km in length to supply more remote villages. The survey for the distribution network is not yet complete, so the total length is only an estimate at present.
As part of the project, ABB is also supplying three 34.5 kV/20 kV substations as well as ninety-nine 34.5 kV/400 V transformer stations. Low voltage distribution boxes to tap the electricity in each village are also included, while construction of low voltage lines and connections to end customers will be made by EDL.
One of the particular challenges for this project is the different terrain that ABB has to deal with, varying from rice fields, which demand specific technology for tower mountings, to mountainous areas that require intense drilling for rock anchors. The company is also crossing virgin forest with no paved access tracks. Each tower location therefore requires the construction of access tracks ” ABB will build over 150 km over the duration of the project, and has two bulldozers in constant operation just for this purpose.
The rainy season from May to November also presents another difficulty for ABB since around 60 per cent of the project area is inaccessible at this time; in fact it takes ten days to inspect the area during the dry season!
There are no bridges in the construction area for Lot 1A. ABB has to cross three major rivers in this area and therefore construction can only be carried out in the dry season. This means that a two year project has to be telescoped into 12 months site access time.
These difficulties, though, are typical of the many rural electrification projects that ABB has carried out in Asia and Africa. However, this particular project in Laos poses an additional challenge in the form of UXO (unexploded ordinances) left over from the Vietnam war and later internal fighting between the monarchist and communist governments.
Laos received over 5.6 million t of bombs during the Vietnam war, equivalent to around 1 t per person. This means that ABB has to clear every single tower location, and in several areas the access tracks and line route, before it can start construction work. In total something like 2000 sites will have been cleared on completion of the project, including 950 sites for the 115 kV towers and 1000 sites for the concrete poles for the 34.5 kV lines.
In common with most projects of this type ABB has designed the transmission towers to suit EDL’s needs and the local ground conditions, and some 4000 t of steel will be used in their construction. Transformers, breakers, insulation, hardware and other electrical equipment are all standard ABB equipment.
An unusual technical aspect of this project is the use of the earth wires of the 115 kV towers as a 34.5 kV shieldwire distribution network. This means that instead of having the top two wires of the towers only as lightning protection, they are insulated and energized to function as the 34.5 kV supply for the local villages. The ‘normal’ three phase system is replaced by two energized wires on top of the towers that are connected to a three phase transformer. The third phase is grounded and uses the earthing system to connect to the substation. This system was developed in previous projects in Laos and Africa.
The project is being coordinated by teams from ABB in Spain and Germany, but the company has also placed a major emphasis on the use of local labour. Indeed, in some locations the lack of access means that it is not feasible to use heavy machinery, so many construction tasks have to be carried out by extensive manual labour, sometimes with the assistance of traditional methods such as elephants.
The involvement of the local community is also important as it enables locals to understand what the project is about and the long-term benefits it will bring, and it can also help alleviate fears and reduce the potential for conflict. At the same time ABB provides a valuable source of employment, which boosts the local economy.
The Laos project is being carried out on a fast-track basis and is scheduled for completion before July 2003. Currently it is well on target with around 80 per cent of material already shipped to Laos (100 per cent of the 115 kV and 30 per cent of the 34.5 kV equipment) while around 70 per cent of the foundation works have been completed.
Boosting power in Laos
Lao People’s Democratic Republic is a mountainous country with a land area of 236 800 km2 and a population of around 5.6 million, of which some ten per cent live in the capital Vientiane. Over 80 per cent of the population live in rural areas and are engaged in rice-based agriculture and harvesting projects. This narrowly-based economy is one of the least developed in Asia with a per capita Gross National Product of just $400 per annum.
With over 40 per cent of the population currently living below the poverty line, rapid economic growth is vital to alleviate the country’s poverty and to help achieve its goals for social development. But the options for achieving this are constrained by Lao PDR’s small domestic economy and limited trade opportunities.
The country does, however, enjoy a comparative advantage in one important sector. It has a large, and relatively untapped, hydropower potential (theoretically 26 500 MW) and a central location in a region characterized by expanding electricity demand. Laos has been exporting electricity to Thailand since 1979 and since the late 1990s the government has been accelerating development of the country’s hydropower resources as a means of boosting export earnings.
Nationally, only around 18 per cent of households are electrified, with urban areas accounting for 90 per cent of connections and 95 per cent of consumption. In fact, outside Vientiane, electricity consumption is small, accounting for just seven per cent of the country’s total consumption.