Also known as High-Voltage Direct Current (HVDC) transmission. Consists in the transmission of power in direct current at high voltages. Used principally for bulk transmission of energy over long distances (>600 km), due to its lower costs and lower electricity losses. 

Main advantages:

Environmental advantages:

• Smaller easement corridor
• Less visual impact

Economic advantages:

• Lower construction cost (structures, conductors, etc.)
• Lower operating costs (Joule losses)

Technical advantages:

• Permits unsynchronised connections 
• Rapid control of power flow 
• Helps to reduce oscillations of AC system 
• Intermediate substations not required 
• No skin effect

International background:

HVDC technology has been in use for more than 50 years and is still being developed. 

Some examples of HVDC projects in other countries: