Aspen proposes increase in energy for Maroon Creek hydroelectric plant

Aspen's Maroon Creek Hydroelectric plant.
Jonson Kuhn/The Aspen Times

As part of an application the City of Aspen intends to file with the Federal Energy Regulatory Commission to maintain operations at Maroon Creek hydroelectric plant, the city is proposing the addition of 50 kW hydroelectric energy at the existing Maroon Creek diversion dam and headgate structure by adding either a new turbine or two new turbines.

One alternative would place a single 50 kW micro turbine inside the existing log structure at the diversion dam and would require expansion. A second alternative is installing a two-turbine inside the existing log structure for a combined capacity of 50 kW.

“Neither alternative would change the operation of the existing power plant,” said Aspen Utilities Engineer Special Projects Phil Overeynder. “All water used by the micro turbines would be immediately released in Maroon Creek in the same pool where water release is currently occurring.”

Aspen city staff held a public meeting and site visit to the Maroon Creek hydroelectric plant on Tuesday. Aspen Utilities Director Justin Forman and Overeynder provided a presentation at City Hall before offering transportation to the Maroon Creek hydroelectric site. 

Aspen Utilities Director Justin Forman and Utilities Engineer Phil Overeynder lead a group through a site visit of the Maroon Creek diversion dam and headgate structure.
Jonson Kuhn/The Aspen Times

The Maroon Creek Hydroelectric FERC license has been in operation since 1988 and is up for relicense after 40 years. As part of a FERC regulatory requirement, the project must start the application process 5 years in advance of the license expiration date of July 2028 to resume plant operations.

The existing project’s capacity is 450 kW with facilities located south of Aspen Highlands Village in the Maroon Creek Valley. Water is diverted at a diversion dam and headgate structure where it then travels to a powerhouse located roughly 6,900 feet downstream and is returned into Maroon Creek through an open channel tailrace. It produces an average of about 2 million kW hours per year, which equates to 3 to 5% of the city’s electric demand.

“This facility has anchored us in Aspen’s journey to 100% renewable electricity since 2015, and we’re really proud that this is local, cost competitive, and stable energy and we’re not out there trying to secure this in the market,” Forman said. “We’re really proud that this is in our backyard.”

Maroon Creek hydroelectric plant – seen here, the diversion dam where water is diverted and travels by penstock to a powerhouse roughly 7,000 feet downstream.
Jonson Kuhn/The Aspen Times

Forman added that the city has the option of either seeking a new license with FERC or applying for a small hydroelectric license exemption if the city decides to move forward with the additional hydro generation. While the exemption would still require the city to follow the same FERC rules and inspections, the benefit would be not having to continue with the process of license renewal every 40 years. 

City staff is favoring the exemption option but is continuing to seek public feedback on resource issues or studies recommended by Jan. 6, 2024. Additional information can be found at Forman said the next steps are to begin preparing the application to FERC, and he anticipates going before Aspen City Council with a work session to provide updates in late spring of next year. Following the work session, the city will hold a stakeholder and public review of the application draft for spring and summer of 2024. 

“We intend on filing our application to FERC in the summer of 2024. FERC will review that and likely provide an answer within two years,” he said. “We believe our commitments will continue to maintain the good ecological function of the creek.”