Chile’s Grid To Be Unified With New Transmission Highway

The Mejillones-Cardones transmission project will interconnect Chile’s north and central systems.
Published: Wed 08 Jul 2015

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Chile’s security of supply is set to be enhanced with a new transmission highway interconnecting the Central Interconnected System (SIC) and the Interconnected System of Norte Grande (SING), which is due for completion in 2017.

The 580km, 500kV double circuit Transmisora Eléctrica del Norte (TEN) highway will run from the Los Changos substation at Mejillones in the Antofagasta region in northern Chile through to the Cardones substation outside of Copiapó in the Atacama region.

It will have a dual role. The SIC, which covers central and southern Chile, with a capacity of approximately 15GW transmits almost 70% of the country electricity generation and serves over 90% of the over 18 million population. The SING, serving northern Chile, with a capacity of just under 5GW generates a further 20% of the country’s electricity with plans to produce more in the future. With energy demand growing at 4.5% per year, the interconnection will contribute to addressing the growing energy needs in the centre and south of the country. It will also enable mining operations in the north of the country to access surplus power from hydroelectric and renewable sources in the SIC.

At the Cardones substation, the line will connect with a 753km line currently under construction to the Polpaico substation, north of Santiago.

A unified power grid in Chile

The TEN project is being led by the Chilean generation company and subsidiary of GDF Suez, E-CL (formerly Empresa Electrica Del Norte Grande, Edelnor). Alongside the transmission line works the company also won the bid to construct a 375MW IEM thermal power plant at Mejillones. The US$1 billion plant is expected to start operation in 2018.

The unification of Chile’s power grid has been a longstanding goal of the country’s government. At the signing of the energy expansion plan giving formal go ahead to the TEN line on April 16, President Michelle Bachelet said the interconnection would allow more efficient use of infrastructure, improve the joint development of generation and transmission works, reduce exposure to hydrological risks or lack of gas supply, and facilitate the connection of wind and solar projects.

"With the launch of the interconnection works we are taking a major step towards achieving the objectives to give energy the importance it deserves to meet the needs of Chile in the 21st century,” said President Bachelet.

Chile’s new Energy Agenda, which was launched in May 2014, set goals of reducing the costs of energy and expanding the use of energy efficiency and renewable energies, with a 45% renewable target by 2025. [Engerati- Wind Of Change Blowing Across Chile]

According to Chile’s National Energy Commission (CNE), the unification of the grids should reduce energy prices for regulated customers in the north by US$13/MWh and in the central-south by US$3/MWh. For wholesale industrial consumers, the reductions should be US$17/MWh and US$9/MWh in the north and central-south respectively.

Substations for Mejillones-Cardones highway

Construction of the TEN project is now under way with the first tower started last week.

The contract for the substations for the interconnection, worth approximately €260 million (US$278 million), has been awarded to Alstom, which will supply four turnkey substations. These include the installation of three new 500kV substations in Los Changos, Chacayita and Cumbres, as well as the expansion of the Nueva Cardones substation.

Alstom will supply its air-insulated and gas-insulated substations that will contribute to a total of 1,500MW of energy transmission. The company will also provide its high voltage power compensation products to enhance the power quality of installations, making the electrical network efficient, secure and with stable energy flow.

Proposed new interconnections

In connection with the TEN project, two further interconnections have been proposed and will go to tender. These are a 3km extension from the Los Changos substation to the nearby Kapatur substation, and a connection from the Los Changos substation to a new Nueva Crucero Encuentro substation close to the coastal town of Tocopilla 140km to the north. These are anticipated to be in operation by the start of 2020.