Excavation of the headrace tunnel at the Theun Hinboun hydropower plant expansion project in Khammuan province cleared a major hurdle on Sunday after almost a year of work.

Excavation of the tunnel is not only one of the most expensive parts of the project, but also involves unforeseen critical processes. "It involves expenditure of about 96.1 billion kip (US$12 million)," Mr Sisouvanh said. "Using the TBM, we can save time, money and protect the environment and it's also more secure than using explosives." The TBM allows an average of 21.66 linear metres to be excavated per day.

The completion of the tunnel was the basis for the on-time completion of the rest of the project. Construction of the whole project is now 62 percent complete, after commencing in May last year. "The tunnel is expected to be used to generate energy by July 2012," Mr Sisouvanh said. Currently the installation of high voltage power transmission lines is 67 percent complete, including the construction of an 85km long 230 kilovolt (KV) line that will facilitate the export of electricity to Thailand and a 51km long 115KV line that will be responsible for supplying energy locally.

Building work on the Nam Ngouang and Theun Hinboun powerhouses is now about 57 percent and 40 percent complete respectively. The project is running on schedule, with all work expected to be completed in June 2012. The Theun-Hinboun hydropower plant is located in Borikhamxay province, with the expansion project underway in Khammuan province. The expansion project will add a generating capacity of 280 megawatts (MW) and is due to begin commercial operation in July 2012.The project will cost the Theun-Hinboun Power Company (THPC) around 6.2 trillion kip (US$720 million).

Sixty percent of the company is owned by government shareholders, through Electricité du Laos, while Nordic Hydro (Statkraft) and GMS Lao each hold 20 percent. The expansion project aims to improve the distribution of energy both for local supply and export. It will also increase generator capacity from 220 to 500MW, enabling the plant to produce more than 3,000 million kilowatt hours per year. Upon completion of the project, 440MW of power will be sold to Thailand with the remaining 60MW being sold to EDL for local supply. Currently the plant exports 95 percent of its installed capacity of 220MW, with just 5 percent being put aside for local supply.

THPC was the first independent hydropower company in Laos, beginning in 1995, and has operated successfully since 1998. According to the Energy Promotion and Development Department of the Ministry of Energy and Mines, excluding the mainstream Mekong River, Laos has the potential to generate about 26,500MW from hydropower sources. Currently Laos has 15 power plants with a total installed capacity of more than 2,170MW, according to a report from the ministry's Planning and Statistics Division.