UPDATE: Litigation challenging Clean Line project has been commenced in Arkansas
Although some may not realize it, AC/DC is much more than an 80’s rock band.If you’ve ever been curious about the difference between AC and DC power, look around you. AC, or alternating current, is used in household appliances and comes out of the wall outlets from the local power company. The power company is hooked into a grid that covers the entire Eastern United States and Canada. The Eastern US grid is thought to be the single largest set of engineering facilities of any type in the world, and was by many accounts the most productive engineering project of the 20th century.
DC, or direct current, is only used in batteries, your laptop, and some of your small electronics (hint: if there’s a box somewhere along the power cord, it is most likely used to convert AC power from the wall to DC used by the device). Car batteries create DC, which the alternator converts to AC.
Thomas Edison, who is credited with inventing the light bulb, developed DC. DC was common in the early days of electricity. DC gets its name from running continually in a single direction. Because of this, it cannot easily be converted into higher or lower voltages.
Nikola Tesla—with financial support form George Westinghouse—developed AC, in which the direction of the current is reversed a set number of times per second, as a solution to DC limits. AC is easily converted to different voltages using a transformer. Edison attempted to discredit AC: this became known as the War of the Currents. Eventually, by powering the Chicago World’s Fair in 1893 and harnessing the hydroelectric power of Niagara Falls, Westinghouse ensured that AC became the standard. Today, all of the power lines you see anywhere in Arkansas (and most everywhere in the world) are AC.
Technology has improved and mitigated some of the early drawbacks of DC. As a result, DC is attempting a renaissance with Arkansas beginning as an involuntary experimental site. When transporting power over long distances, some of the power is lost along the way. AC lines lose more power than DC lines, so some power companies are considering the construction of high voltage DC (HVDC) to move power long, uninterrupted distances, including undersea cables. For this reason, HVDC lines are being considered for connecting renewable energy to the main grid, especially wind energy where the generation sources are in isolated locations.
Although Arkansas has no Wind Generation, Arkansas is planned by Federal authorities to be the site of a major first of its kind HVDC transmission line for renewable wind energy. The United States Department of Energy has agreed to partner with Plains & Eastern Clean Line to design and build a transmission line that will carry power over 700 miles, from a wind farm in the Oklahoma panhandle across Arkansas and into Tennessee. The project includes a converter station on the border between Pope County and Conway County, which may convert the DC power into AC power so that it can be interconnected with the existing power grid in that area, operated by the Midcontinent Independent System Operator of Carmel, Indiana.
However, the DC line has been opposed by many of Arkansas’s federal and state elected officials, and was rejected by the Arkansas Public Service Commission, the agency that approves transmission lines in Arkansas.
Significantly, this is the first time the Department of Energy (DOE) has exercised its statutory authority, under the Energy Policy Act of 2005, to partner with independent transmission developers to facilitate the siting and construction of transmission lines to relieve congestion due to increasing demand and to use the power of eminent domain newly authorized under the 2005 act. Until the 2005 amendments to the Federal Power Act, siting of electric transmission lines was beyond the authority of the federal government and even under the 2005 amendments its use was only for extraordinary projects to relieve congestion.
As the 2005 authority granted to the DOE for the siting of transmission lines using eminent domain has not been exercised to date, it is likely that this authority may be challenged. Five other HVDC transmission lines for wind and hydroelectric energy are also seeking Department of Energy approval. Two of them, Grain Belt Express and Rock Island, are being pursued in the Midwest by Clean Line, the same company pursuing the project in Arkansas. Two other companies are developing Northern Pass and New England Clean Power Link in New England, and a fourth company is developing Transwest Express, running through Wyoming, Utah, and Nevada. In sum, Arkansas may become the first time home of a major HVDC line in the United States not principally intended to serve customers in the state.
Arkansas’s landowners urged the DOE to reject the HVDC line, but their objections–like Arkansas’s elected officials’ objections–were rejected. Using eminent domain is always a distasteful undertaking of government so these issues may not be resolved finally until tested in the Courts.