News item | 2010-11-30 | 10:09 AM

Breakthrough in Panama

The hydro power project in Changuinola in northwestern Panama is approaching its completion. The headrace tunnel construction has come to a breakthrough.

Changuinola, PeruThe tunnel design is part of Vattenfall Power Consultant's assignment for the hydroelectric power plant project in Changuinola.

Gunnar Frostberg Gunnar Frostberg, Project Manager, one of three Vattenfall expatriate engineers at the location, says that the project has been a challenge for everyone involved.

“The tunnel was excavated from both ends and it is always exciting to see if and where the halves will meet,” Frostberg says. “This time the difference was only a few centimetres in the walls and one millimetre in the roof.”

The power station is expected to be in operation in mid 2011. Håkan Gustafsson, normally stationed at Storuman’s hydro power plant and responsible for the hydro power plants in Ume River, manages the commissioning coordination.

The pressurised headrace tunnel is 4,100 metres long in total, 12 metres wide and 10 metres high. Vattenfall’s engineers made the design of the tunnel as well as the geological examinations for the construction. The breakthrough was reached on September 25, 2010.

“The rock cover is between 100 and 350 metres and it is not possible to make a detailed examination of the geological conditions,” Frostberg says. “It is always a challenge to construct a tunnel in a complex geology as the one we have here in Changuinola.”

The rock is composed partly of limestone, partly of volcanic and sedimentary rock types. Before water filling of the tunnel can take place the final rock support of the tunnel perimeter shall be completed with additional spraying concrete and rock bolts where needed.

Project features also include a 100 metres high RCC dam, a 40 metres high power intake, and a powerhouse with two Francis turbines with a total capacity of 213 MW and a switchyard. Also a 10 MW mini hydropower plant is being built located at the dam foot. This is because the dam will release water all year around due to ecological considerations and the mini hydro plant will make use of this water for continuous electricity generation.

More information about the assignment

A basic design for the project was put in place between 2006 and 2007.
The preparation of detailed working documentation (e.g. drawings, descriptions and calculations) required to build and operate the plant began in 2007 and will be concluded in mid 2011.
It required in total about 6 persons working full-time, primarily within the fields of building construction, geotechnology, hydrology and hydraulics and  Geographical Information Systems (GIS).

Panama, design teamRepresentatives of the design team on site in Panama, from left: Daniel Salinas, Ulrika Johansson, Håkan Gustafsson (Commissioning Coordination), Fredrik Mikaelsson, Monica Tengzelius and Eva Gustafsson (Project Administration).

Facts Changuinola hydro power station

  • The Headrace-tunnel length is 4100 m and the diameter 10 m
  • RCC dam height is 100 m
  • Power capacity is 213+10 MW
  • Energy generation is more than 1000 GWh/year

Link to project plan (new window, in Spanish)

For further information, please contact:

Michelle von Gyllenpalm, Head of Communications Vattenfall Power Consultant,
Michelle von Gyllenpalm
Phone: +46 8 739 63 11