500 kV Southwest Reinforcement Project

Colombia’s Energy and Mining Planning Unit (UPME in Spanish), whose mandate is to supply electricity and ensure efficient, safe and reliable operational services across the nation, awarded an electric energy transmission project known as the 500 kV Southwest Reinforcement Project to Grupo Energía Bogotá S.A. ESP (GEB), a multinational leader in the gas and energy sector. In late 2017, GEB commissioned WSP in Colombia to complete two mandates: detailed design for high voltage transmission lines and environmental impact studies (EIS) required for the environmental licences. 

Transporting Renewable Energy

The inception of the project stems from Colombia’s plan to provide electric energy from the Ituango hydropower plant to the southwestern part of Colombia through La Virginia, thereby minimizing the need of energy based thermal sources. Estimated at about US$ 330 million in total, the 500 kV Southwest Reinforcement Project aims specifically to provide hydropower throughout the interconnected system to decrease power outage, network fatigue and service suspension constraints generated by overloads. The project also seeks to improve the safety, delivery and reliability of the Colombian power grid, and the quality of life of more than 12 million people. 

Starting at the Medellín substation and extending south to the Alférez substation, the Southwest Reinforcement project comprises upgrades to substations and transmission lines to remove vulnerabilities and strengthen the transmission network capacity of electricity across the southwest and central regions of Colombia—Direct Areas of Influence—namely in the departments of Antioquia, Caldas, Risaralda and Valle del Cauca. The project encompasses the construction of a substation and related modules, the installation of two transformers each with a 450 MVA capacity as well as the construction of three 500 kV transmission lines with double circuit structures and one single circuit mounted, necessary feature in a future expansion that minimizes the environmental impact and the cost of easements. and a 230 kV double circuit line.

WSP provided detail designs for structures, foundations and nearly 400 km of 500 kV transmission lines. This entailed a slew of analyses including soil studies, foundation designs, transmission line structure spotting, tower and ground wire locations and their installation as well as height clearances and insulator lengths for:  1) the 158-km 500 kV single circuit line from the new 500 kV Medellín substation to the 500 kV La Virginia substation, 2) the 183-km 500 kV single circuit line from the La Virginia substation to the 500 kV Alférez substation, 3) a 35-km 500 kV single circuit line from the 500 kV San Marcos substation to the Alférez substation. In addition, detail designs were completed for a 2-km 230 kV double circuit line from the 230 kV Alférez substation to a point on the existing 230 kV Juanchito - Pance transmission line.

In addition, to minimize the project’s impact on the environment and communities, WSP completed the EIS for areas covering the municipalities of La Virginia and Alférez, and Alférez and San Marcos.  

This area also falls under Colombia’s electricity and territorial development laws, which respectively govern environmental management compliance and oblige municipalities to create regional land use plans that are in harmony with, among others, the conservation, preservation and defense of the environment, its natural resources and cultural traditions, as well as areas considered to be historical and cultural patrimonies.

WSP faced a multitude of complex and intertwined challenges including important issues regarding timeline constraints, landscapes, environments and communities. For example:

• The project had previously been mandated to a competitor whose contract was terminated due to the project falling behind schedule and failing to meet the quality our client expected. To get back on track, GEB required comprehensive expertise from an engineering consultancy that could manage both the technical and environmental aspects within the pre-established deadline.

• As designs and environmental studies had been underway, WSP had to assess work already done, make corrective measures, if any, and establish contact with communities who had already dealt with different stakeholders, a sensitive point for communities.

• Difficult-to-reach terrains, established agricultural industries and the protected status of lands and of minority communities provided additional constraints. At opposing ends of the transmission line, the landscape moved from rugged, steep and difficult-to-access mountainous terrains in Medellín to flatter lands blanketed with sugarcane fields and industrialized sugar plantations in Alférez.

• Communities were politically in tuned and actively involved in environmental issues. Although communications had to be maintained with all communities within and outside the Direct Areas of Influence, in some areas, legislation required that prior consultations be conducted with minority groups including ethnic communities whose concerns centered around the impact of electromagnetic fields, and how the towers would visually impact the landscape as well as affect their lands, properties and water sources, among others.

• With respect to the technical part, the use of small planes and helicopters were required to capture through LiDAR technology the terrain characteristics, and aerial photography of diverse terrain and ecosystem information along the entire transmission line corridor. And, in some regions, soil characteristics proved inadequate for transmission tower foundations and required an assessment of alternatives as well as strategies for soil capacity.

Several impacts were identified, including changes to wildlife habitats, interference with social community and economic infrastructure, involuntary displacement of people, damages and effects on crops and property improvements, and changes to coffee-growing cultural landscape. To address and minimize these impacts, remedial measures were implemented, including information and community participation programs, population resettlement programs, environmental education programs and coffee-growing cultural landscape management programs.

By taking a collaborative and interdisciplinary approach to the project, through coordinated efforts from technical, environmental and social work teams, WSP could complete and submit the detail design for the high voltage transmission lines and the EIS (currently pending comments from the environmental authorities to attain the licences) within tight time constraints.

The 500 kV Southwest Reinforcement Project is a great example of our work in the areas of electrical, civil, environmental, cadastral and forestry engineering, as well as in the fields of biology, social sciences and economics.

In 2017, GEB presented WSP with its “Best GEB Supplier Recognition in the Engineering Category” award for fulfilling the project objectives within strict compliance requirements, and for upholding environmental, occupational health and physical safety standards in alignment with GEB’s corporate standards.

Start-up of the 500 kV Southwest Reinforcement project is expected in 2020, pending confirmation from the Colombian government.