HVDC transmission lines could cut US greenhouse emissions by 80%
A network of high-voltage direct current transmission lines carrying power from renewable resources could eliminate the need for energy storage and help to reduce greenhouse gas emissions to 80% below 1990 levels inside 15 years, according to a study in Nature Climate Change. However, overlapping federal, state, county, and city jurisdictions, as well as a lack of incentive from utilities to pay for transmission lines has hampered their deployment and maintained a reliance on fossil fuels.
The Denver-based company behind the project hopes to erect a series of steel transmission towers that would stretch a high-voltage direct-current transmission line 730 miles across the American West. It could carry as much as 3,000 megawatts of Wyoming wind power to the electricity markets of California, Nevada, and Arizona. With the right deals in place, the transmission line could deliver solar-generated electricity back as well, balancing Wyoming’s powerful late-afternoon winds with California’s bright daytime sun.

How Wyoming wind (in green) could balance out California solar (in red) throughout the day in June. Source: Wind Diversity Enhancement of Wyoming and California Wind Energy Projects, 2015. Jonathan Naughton, Wind Energy Research Center.

The $3 billion TransWest Express Transmission Project is among a handful of proposed direct-current transmission lines in the United States, and one of the furthest along in the planning process. It underscores the huge promise of these high-capacity lines to unlock the full potential of renewable energy.

Transmission isn’t sexy (see our story art above). It’s basic infrastructure. Long wires and tall towers (see “How Blockchain Could Give Us a Smarter Energy Grid”).

But a growing body of studies conclude that building out a nationwide network of DC transmission lines could help enable renewable sources to supplant the majority of U.S. energy generation, offering perhaps the fastest, cheapest, and most efficient way of slashing greenhouse-gas emissions.

Developing these transmission lines, however, is incredibly time-consuming and expensive. The TransWest project was first proposed in 2005, but the developers will be lucky to secure their final permits and begin moving dirt at the end of next year.

There’s no single agency in charge of overseeing or ushering along such projects, leaving companies to navigate a thicket of overlapping federal, state, county, and city jurisdictions—every one of which must sign off for a project to begin. As a result, few such transmission lines ever get built.

A macro grid

Direct current, in which electric charges constantly flow in a single direction, is an old technology. It and alternating current were the subject of one of the world’s first technology standards battles, pitting Thomas Edison against his former protégé Nikola Tesla in the “War of the Currents” starting in the 1880s (see “Edison’s Revenge: The Rise of DC Power”).