Carbondale explores generating hydropower from Nettle Creek
Aspen, CO Colorado
CARBONDALE – Utility chief Mark O’Meara is not sure whether a hydroelectric power plant attached to this town’s main water supply would be a worthwhile project or not.
But he’s determined to find out, and the town’s Board of Trustees agrees that it is worth studying.
O’Meara, who has been Carbondale’s utility director for five years, is working with outside consultants, the federal government and other entities and agencies to investigate the potential for drawing hydroelectric power from South Nettle Creek.
Nettle Creek, fed by a spring that rises on the lower northwestern slopes of Mount Sopris, has been the town’s main source of drinking water for more than 100 years.
The town also has well fields along the Crystal and Roaring Fork rivers that supplement Nettle Creek if the creek’s flows drop below a certain level, or if demand rises beyond the creek’s capacity.
The idea of generating hydroelectric power from Nettle Creek has been discussed for decades, O’Meara said, but this is the closest the town has gotten to making it happen.
“There’s a whole bunch of players,” O’Meara said, including the Community Office of Resource Efficiency (CORE), CLEER (Clean Energy Economy for the Region), and the Federal Energy Regulatory Commission (FERC).
Despite the interest shown by the town and others, O’Meara emphasized, there are potential drawbacks to the idea.
“The payback on it is long-term,” he said, “as it is for all hydro projects. Green energy is very expensive. It’s as simple as that.”
That payback represents the amount of time it will take for the town to break even on the cost of installing the system, against the revenues saved by using locally renewable, hydroelectric power instead of electricity provided by utilities.
The town’s utility budget has about $70,000 earmarked for the permitting process, O’Meara said.
A cost estimate for the project provided by engineering consultant SGM of Glenwood Springs indicated that it might cost as much as $180,000 to get the turbines installed and operating.
According to SGM and O’Meara, the payback for such a system is estimated to be 20 to 25 years.
O’Meara and others on the Nettle Creek hydro team currently are working through the paperwork, permits, studies and applications required by the FERC and other entities.
The entities involved include the Environmental Protection Agency, the U.S. Forest Service (which controls much of the land surrounding the Nettle Creek water plant) and Pitkin County, according to the SGM memo.
In addition, SGM reported, the town may need to get involved in the Colorado water courts to make sure it can legally use Nettle Creek for hydroelectric power.
According to SGM, the town’s existing water rights are sufficient for the hydroelectric project. The town diverts between 400 gallons per minute and 600 gallons per minute from the creek, O’Meara estimated.
But, according to an SGM report, the allowed uses for Carbondale’s Nettle Creek water right do not currently include hydroelectric generation. Instead, the town’s water rights are decreed as being for municipal purposes, such as water service to homes, for treatment of sewage and for fire protection.
It may be necessary to go through the state’s water courts to add power production to that water decree as an allowed use, the SGM report stated.
The plant itself, as currently envisioned, would be a single hyrdroelectric turbine that would be installed in the South Nettle Creek’s 10-inch pipeline just before it enters the Nettle Creek water treatment plant.
The pipeline runs from a series of spring boxes, at an elevation of approximately 7,160 feet, down to the treatment plant, which sits at about 6,800 feet.
Carbondale itself lies at just below 6,200 feet.
According to SGM, the drop of 295 feet or so, from spring to turbine, should produce enough force to generate 10 to 15 kilowatts of power, equivalent to 80,000 to 120,000 kilowatt-hours per year.
The power generated, O’Meara said, would be enough to take care of about 80 percent of the electricity requirements of the Nettle Creek water treatment plant itself.
In 2011, he said, electricity consumption at the water plant cost approximately $10,000 in city funds, meaning the town could conceivably save $8,000 a year in electricity costs by switching to the hydro plant.
The actual electricity, according to the SGM preliminary analysis, probably would be fed into the state power grid under a power purchase agreement with Holy Cross Energy.
The town then would receive credits for all power produced, to be applied to the town’s utility bills.
At a May 8 meeting of the board of trustees, Trustee John Foulkrod expressed skepticism about the hydroelectric proposal.
“It seems overwhelming to actually get to the point where we’re generating electricity,” he commented.
He was concerned about such issues as start-up costs, which might reach $180,000, and the need for substantial research to determine whether the idea is feasible or not, even before the planning starts.
In response, town manager Jay Harrington noted that the experts working with O’Meara have concluded that the idea is worth trying.
But, he added, “These are just baby steps.”
Foulkrod, after hearing more about the proposal, indicated support for keeping the effort alive.
“I think it’s exciting if we can make it work,” he said.
The board as a whole concluded that the exploratory work should continue.
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