Understanding HVDC Transmission
High voltage direct current (HVDC) is the preferred technology for moving large amounts of power across long distances. HVDC results in overall higher efficiency and reliability than an equivalently-sized alternating current (AC) system moving the same amount of power.
More efficient: Over long distances, HVDC transmission can move more power with lower electrical losses than an equivalent AC transmission line.
Lower Cost: Higher efficiency means a lower transmission cost, helping renewable energy compete with other power sources.
Improved Reliability: HVDC transmission can enhance system stability, allow the operator direct control over power flow, and facilitate the integration of wind from different resource areas.
Smaller Footprint: HVDC transmission lines require narrower right-of-way footprints than equivalent AC lines.
The major advantage of DC power lines is their efficiency—less energy is lost as it is transmitted and there is no need for reactive compensation along the line. Because DC flows steadily through the wires without changing direction many times each second and through the entire conductor rather than at the surface, DC transmission lines typically lose less power than AC transmission lines.