HVDC

Where in the world are they using HVDC electricity grids?  I know they are using them to connect to connect Sweden and Poland.  It's also being used in Australia and Gotland and that 500 miles are open in the US today.  Will this HVDC system actually take over AC power grids.  Is this the technology that will bring green energy around the world.  TREC, The Trans-Mediterranean Renewable Energy Cooperation seems to thinks so and they published a 65 page white paper that explains their plans for worldwide cooperation, and how fossil fuels can be used solely to stabilize the grid and not run it.  Who is standing in the way?  Who is killing the HVDC electric grid, and who is trying to bring it into fruition.  Is this a David vs. Goliath story that might result in the survival of mankind if actually implemented?  Stay tuned.  Check out desertrec.org for updates.