There is a powerful trend happening across the country at the state level where large utilities like PacifiCorp, Xcel Energy and, AEP have decided to build new transmission infrastructure to deliver large amounts of onshore wind energy to market. Most recently, AEP announced a 4.5 billion wind + transmission project in Oklahoma. Why is this? Because it lowers rates for consumers and because there is strong upside for utilities to own and rate base the generation and transmission. It makes economic sense for all.
There are opportunities to take this same model nationally. One project that Clean Line Energy is developing is the $2.5 billion Plains & Eastern transmission line. This project will use direct current technology to deliver some of the cheapest wind energy in the country from the Oklahoma panhandle region to states further east. Another project, the TransWest Express transmission line owned by The Anschutz Corporation, will also use direct current technology to deliver low-cost wind energy from Wyoming to states in the West.
High voltage direct current (HVDC) technology is the right answer to tap distant renewable resources and deliver across regions. There are four main advantages to DC transmission: cost, reliability, efficiency, and footprint. First, delivering large volumes of power over distances greater than 350 miles via DC results in lower delivered energy cost than a 345kV AC line. Second, DC technology, unlike alternating current (AC), allows complete control of power flow and provides a variety of ancillary services that improve grid reliability. Third, over long distances, DC transfers more energy with lower line losses and with less infrastructure than comparable AC lines. Finally, DC requires a narrower right-of-way than equivalent AC configuration, resulting in lower land use impacts.
Building interregional transmission lines can reduce the cost of integrating wind into the system and can alleviate congestion in very windy areas. Transmission can work to connect uncorrelated variable resources (like wind and solar) and help to smooth the output profiles and reduce the overall intermittency of these resources, therefore increasing the value, not only to the grid, but also to consumers. Interregional transmission projects can maximize these benefits by delivering low-cost, reliable power from remote areas to places around the country where there is a need.
Without significant investment in our electrical grid, the U.S. will not be able to efficiently utilize the abundant renewable resources we have. Strengthening and adding new connections within the American electric grid will allow the lowest cost renewable energy to be developed where the resource is the strongest, and transported to load centers. Expansion of interregional transmission facilitates the necessary flexibility that will be essential in an evolving market.