Underground HVDC transmission via elpipes for grid security

Elpipes [1], [2] are polymer-insulated underground HVDC conductors based on low cost extruded metal conductors. Elpipes are designed for higher efficiency than is practical for overhead power lines so that cooling can be passive. Elpipes are mechanically strong, installed inside a conduit that is identical to a gas pipeline (except that maximum curvature is limited so that the elpipe can move like a train within the conduit). Elpipes would be difficult to sever with a backhoe or a small explosive, and are immune to weather-based outages. In a wide area blackout, a meshed grid “beneath” and reinforcing the AC grid would enhance stability and speed recovery from all sorts of system disturbances, including weather events, geological cataclysms, or solar magnetic storms The low ampacity in an elpipe gives them exceptional overload capacity compared to cables.