The Electric Cooperatives of Arkansas Hydropower Generation Station is built on the Arkansas River near Dumas, Ark. The powerhouse was constructed near the dam that supplies water to the navigational lock. Most of the equipment used for power generation is beneath the surface.
By Derrill Holly | This article is reprinted with permission from ECT.coop.
When the Arkansas River’s navigational locks were planned and designed in the 1960s, electricity was cheap, so interest in the potential of hydroelectric power was limited.
But by the early 1980s, the leaders of Arkansas Electric Cooperative Corp. saw a disturbing trend toward expensive power and began exploring ways to handle the need for new generation to meet growing demand.
“There were visionaries on the board,” said Douglas White, now a vice president of the G&T, which signed three 100-year leases on federally controlled navigational rights-of-way, clearing the way for construction of hydroelectric plants that now produce 167 megawatts of power.
The success of the Arkansas projects has prompted some observers to call for more of the same small-scale hydro during a time of rising energy prices.
Of 212 lock sites operated by the Army Corps of Engineers nationwide, only 46 dams are producing hydropower. Many others offer some potential for that purpose, with limited additional environmental impact.
“You’re essentially just adding a powerhouse to structures that are already there,” said Fred Ayer, executive director of the independent Low Impact Hydropower Institute.
He cited a Federal Energy Regulatory Commission analysis, which suggests that modifications to existing dam structures could increase the nation’s hydroelectric capacity by as much as 25 percent.
Said Ayer: “I’m surprised there hasn’t been more of a development push at lock and dam sites, because almost everything that’s needed is already in place.”
In Arkansas, the first of three plants went on-line in 1988 near Fort Smith. A second plant, also on the Arkansas River at Morrilton, began operating in 1994, and a third, on the White River near Dumas, was added to the G&T’s portfolio in 1999.
While the U.S. Army Corps of Engineers operates the locks and dams, AECC operates the adjacent powerhouses. The three plants represent an investment of $330 million and supply power to 460,000 accounts served by 17 distribution co-ops.
“It was a huge investment at the time, and that money still represents about one-third of our overall investment in generation capacity,” said White.
Most of the equipment is buried along 100-yard wide approaches adjacent to the navigational channels.
The water used to generate electricity flows into the turbines through a series of underwater pipes and then returns to the rivers.
“We don’t affect habitat, or kill fish or other marine life,” said White. The land surfaces at two locations have been developed for camping, and anglers are often seen fishing along the river.
Changes in federal energy policy and the attitudes of consumer-members have made that investment even more valuable to leaders of the state’s co-ops, who can point to a decades-old commitment to renewable energy capacity that satisfies more than 15 percent of their demand.
“We’ve seen natural gas prices increase four-fold, so many utilities around the country are now facing the same decisions we were facing 25 years ago,” said White.