Power sharing at Nam Theun 2

The Lao People’s Democratic Republic (Laos) is an utterly beautiful country that has seldom been lucky. One of Asia’s poorest nations, its history is bedevilled with quarrels with its neighbours and occupations by foreign powers. Despite abandoning economic communism in the 1990s and entering into the Association of South East Nations (ASEAN), it takes time to turn a country around. Even today when the nation has long been at peace most of its people still struggle to survive on meagre rations. But things are improving and the biggest investment ever considered in Laos is finally underway. Funded by the World Bank, the Asian Development Bank and the European Investment Bank, the US$1.25B Nam Theun 2 project involves the formation of a reservoir covering 450km2 in order to harness the hydroelectric potential of Laos’ mighty Mekong river.

The Laotian people are descendants of Thai tribes that were pushed southwards from Yunnan, China in the 13th Century. So it is appropriate that both Thais and Laotians should benefit from the Nam Thuen 2 project. The majority of the 5600GWh produced annually by the dam will not be used in Laos but rather exported to neighbouring Thailand, whose growing demand for electricity consistently outstrips domestic supply. The income from this power – enough to provide 750,000 homes with electricity – will be used to improve the lives of Laos’ 5.8M people, 70% of whom survive on less than $2 a day. With the taxes, royalties and dividends the Lao government will receive annually from Thailand, basic health, transportation, irrigation, water supply and education will all be boosted, as well as providing work for at least 4000 locals during the construction period. The small proportion of power that will be retained by Laos (about 200-300GWh) will also be used to promote economic and social development.

The project site is in the central provinces of Khammuane and Bolikhamxay and involves the development of a 1070MW trans-basin diversion power plant on the Nam Theun river, a tributary of the mighty Mekong. A 39m high dam will help form the 450m3 reservoir, whose water will cascade at 250m³/sec down a 350m long headrace and pressure channel into the power station. Having passed through the power station the water will flow along a 27km channel to the Xe Bang Fai, also a Mekong tributary. A regulating pond is also to be constructed downstream of the power house. The power generated will travel via a 138km long double circuit 500kV transmission line that connects to Thailand’s electricity grid. A smaller 115kV transmission line will travel 70km to tap into the regional Laos grid.

31 year concession

The project is being developed by the Nam Thuen 2 Power Company, a consortium comprising Electricité de France International (35%), Thailand’s own electricity generator, EGCO (25%), the Italian Thai Development Company, ITD (15%) and the Laos government (25%). A build-own-operate scheme, the project is structured as a 31 year concession, thereafter ownership transfers to the Lao government. Work began in May 2005 and is due for completion by the end of 2009.

The project is still in its early stages and the first jobs are largely enabling: building access roads, establishing quarries for aggregates etc. These tasks, along with forming the downstream channel, are the responsibility of ITD.

ITD has over 4500 people on site at Nam Theun 2 and has invested in a fleet of equipment from Volvo Construction Equipment. In 2005 it acquired 66 pieces of new and used Volvo equipment for this project. These include 49 crawler excavators (33 EC210BLC, 12 EC360BLC, two EC460BLC and two EC290BLCs). In addition there are eight motor graders (six G730B and two G720s), four A25C haulers and five wheel loaders (three L120E, one L150C and one L150E).

The six-cylinder Volvo diesel engines fitted to the excavators are mapped to mirror each model’s high-performance hydraulic requirements, so that engine speeds remain low, even in hard trenching or mass excavation duties, thereby providing high fuel efficiencies. A charged air cooler works in tandem with the turbocharger for more efficient combustion and lower emissions; while a three-stage air cleaning system helps prolong engine life, increasing uptime by effectively filtering out particles before they reach the engine. An optional oil bath pre-cleaner also provides additional particle filtration and easier maintenance.

Other aspects that keep Volvo’s crawler excavators productive include Contronics, an electronic system that monitors machine functions in real time. The ergonomic design of the cab is also important in maintaining a productive unit, this ease of use helping to reduce operator fatigue. Cab features throughout the range include an adjustable seat and joystick, integrated climate control air-conditioning system, a thin crossbar and large glass areas for good all-round visibility. Sound absorbing lining reduces internal and external noise levels. Features that aid functionality include: a common oil drain, centralized lubrication points and a three stage air cleaning system to keep dirt and dust out of the air intake system. All models in the B-Series offer a standard bucket, their capacities tailored to fit the weight and power of each machine: the EC210B has a 0.9-1.55m3 bucket range, while the EC290B’s is 1.08-2.1m³ and the EC460B 1.8-3.73m³.

The Volvo equipment is being put to a tough test, with many of the machines working around the clock, in eight hour shifts. But all equipment needs to be maintained, and a rapid supply of spare parts is crucial, with work being conducted by a nine strong maintenance team.

Like many hydro projects that involve flooding great areas and the displacement of people, the Nam Thuen 2 project has had its fair share of detractors. But with comprehensive environmental plans in place and over US$90M set aside to help ameliorate the transition, confidence is growing that the project will be an economic and social success.

For further information contact: Volvo Construction Equipment, Avenue du Hunderenveld 10, B-1082 Brussels, Belgium. Tel: + 32 2482 5021. Fax: + 32 2675 1777. Email: beatrice.cardon@volvo.com