Economics of High Voltage dc Networks

This report is the second from this Laboratory on High Voltage dc networks. It puts less emphasis on the technical aspects of dc networks (that was the subject of the first report), and concentrates on the economics, particularly the matter of trading off one implementation against another.

 

Our target audience includes the regulators and planners of the power industry, those whose decisions depend on understanding the implications of such new technology, and who can influence the development and implementation. We have in mind the US DOE, sponsor1 of the effort; the various engineers at the other government and non-government agencies, such as FERC and NERC; and the reliability coordinators. Utility planners are also likely to be interested, as the many advantages of a dc network await exploitation.

 

After presenting some of the basics of the trade-off, and discussing some of the things to be considered, a number of trade-offs that have appeared in the literature are examined.

 

We look in depth at four large networks for which dc schemes have been presented in the literature. Two are in the US (MISO and WECC) and two are in Europe. The section concludes that reliability and protection are two areas that deserve further attention, but that the problems can be assumed solvable when an economic trade-off is performed. The studies are instructive in that they make little or no use of the “breakeven distance” concept that has seemed to underlie most point-to-point dc systems.

 

Following the discussion of these four studies, we investigate a further seven more briefly.

 

The Report concludes that the economics of dc networks is challenging because of its complexity, but that any sufficiently well understood plan can be subjected to a trade-off that will show whether it has value. The method employed in a study by CIGRE is thought particularly appropriate.