Considerations on the use of HVDC for CREZ transmission

On August 15, 2008, the Public Utility Commission of Texas (PUCT) executed a landmark decision when it ordered approximately US$5 billion in transmission expansion within the Electric Reliability Council of Texas (ERCOT) system. This transmission expansion is meant to serve over 18 GW of existing and future renewable generation within ERCOT. The competitive renewable energy zone (CREZ) transmission optimization study (TOS) contemplates an EHV transmission plan designed to move large amounts of renewable generation from relatively remote sites in West Texas to the load centers in the state (i.e., principally Houston and the DFW area). ERCOT´s proposed transmission plan for the 18 GW scenario relies on the use of heavily compensated 345 kV lines and does not recommend either HVDC or 765 kV. This paper proposes an alternative approach to the planning process which produces an equivalent result that could easily complement the current proposal. The alternative approach addresses uncertainties and discusses risk and cost comparisons.