The constructed new transmission lines connect 37 million consumers in Panama, Costa Rica, Honduras, Nicaragua, El Salvador, and Guatemala.

SIEPAC network includes a 1,790-kilometre (1,110 mi) 230 kV transmission line with a capacity of 300 MW between Guatemala and Panama, as well as improvements to existing systems.

The median scenario foresaw that SIEPAC would induce annual investments of US$700m over a 10-year period once the regional electricity market had begun operating.

[5] SIEPAC is owned by a Regional Operations Entity (Empresa Proprietaria de la Red - EPR), created in 1999 with registration in Panama, and comprising the public utilities and transmission companies of the six participating countries (75%) and private capital (25%).

In some countries integrated utilities are shareholders - ENEE of Honduras, ICE and CNFL of Costa Rica - while in others shares are held by transmission companies - INDE of Guatemala, ETESA of Panama, and ENTE of Nicaragua.

Some critics also argue that SIEPAC will facilitate electricity exports to Mexico and not contribute to expand access in Central America.

It is also argued that much of the increased generation capacity facilitated by SIEPAC would be in the form of large hydropower with associated social and environmental costs.