In its effort to achieve 100-percent renewable energy by the end of 2015, the city of Aspen will focus on two energy alternatives — wind and landfill gas — which nixes the controversial Castle Creek Energy Center from the discussion, the Aspen City Council decided Monday.
However, at the suggestion of City Attorney Jim True, the council acknowledged that the city still believes hydropower is part of Aspen’s renewable-energy future. That means the city intends to retain its water rights on Castle Creek and reserves the ability to improve upon its existing Maroon Creek hydroplant.
At a cost of $69,000, the city has contracted the National Renewable Energy Laboratory to evaluate Aspen’s electric-energy portfolio. At Monday’s work session, representatives from the lab presented its top four energy options: landfill gas from Des Moines, Iowa; wind from Colorado or other Western states; locally produced solar power; and the Castle Creek Energy Center.
Mayor Steve Skadron, the lone supporter for keeping hydro in the National Renewable Energy Laboratory discussion, called its nixing “an unfortunate step.”
“I think our hydro project is a well-conceived one, I think it’s sensitive to the environment, and I believe it to be a financially sustainable project,” he said, adding that it would be a significant step toward carbon-emission reductions.
To date, the city has invested $6.9 million in the estimated $10.5 million Castle Creek Energy Center. According to National Renewable Energy Laboratory representative, Mike Callahan, the $3.5 million that has been invested in penstock and a drain line has other uses besides the energy center, including operations at Ruedi Reservoir. He said the city also could recoup some of its investment on the $1.5 million turbine, at 20 cents on the dollar, if it chooses to sell the equipment.
In terms of its 100-percent renewable energy goal, Aspen is anywhere between 17,000 and 24,000 megawatt hours per year short. According to National Renewable Energy Laboratory, new wind contracts could provide between 5,000 and 20,000 megawatt hours per year, while landfill gas could provide an estimated 18,000 megawatt hours. Castle Creek hydro would provide 5,500, while solar would provide 1,500.
However, the life-cycle cost per megawatt hour differs substantially. Solar comes in at $130 or more for each megawatt hour, while Castle Creek hydro is an estimated $63, though that number could fluctuate given stream flows. Landfill and wind are both in the $90 to $96 range.
Councilman Dwayne Romero said he likes the idea of immediately converting fossil-fuel purchases into a landfill-gas platform, and he appreciates the city’s partnership with Ridgway hydro. Councilman Adam Frisch said it’s not realistic to expect hydro energy from Castle Creek in 2015, but he doesn’t want it taken off the table as a long-term option. Councilwoman Ann Mullins called hydro “a small part of the gap,” adding that climate change makes it an unpredictable cost.