Nucla Station Has Bright, Sustainable Potential
by Gus Jarvis
Oct 10, 2011 | 1676 views | 0 0 comments | 7 7 recommendations | email to a friend | print
SAN MIGUEL COUNTY – Given Tri-State Generation and Transmission Association’s 100-MW coal fired Nucla Station’s location in sunny southwestern Colorado, and the unique technical aspects of the plant’s steam turbines, one power plant expert believes the plant has the ability to move away from coal and become more powerful and sustainable by combining sources of solar and natural gas.

“We have an opportunity here that is very unique,” says Ridgway resident James Burke, who spent 40 years engineering the construction and operation of all types of power plants. Before retiring in 2000, he worked for seven years as plant engineer at the Nucla Station. “I don’t know of another place where you can take advantage of such a situation.”

Burke says this unique opportunity lies within the ability to easily mate new gas-powered turbines with the plant’s existing steam turbines to create a combined cycle power plant. Exhaust from the gas-fired turbines would generate steam to run the steam turbines that were previously powered by its coal-fired boiler.

Furthermore, Burke says the plant would have the ability to augment this power generation with the help of a new solar farm, built somewhere in the Dry Creek Basin, which receives intense sun year-round. With these two combined sources of energy, the plant could produce 300 MW of power and become cleaner and more sustainable at the same time.

“Combined cycle plants (combining gas turbines with steam turbines) are well recognized for their ability to accommodate the load swings of large blocks of solar and wind power, and the Nucla power plant is well-situated for such a source of renewable energy,” Burke says. “The location is right, and the fuel is there already. If we can make this conversion a reality, the plant would be three times bigger in terms of power production. I know of no other place in the country where there’s an opportunity like this to be taken advantage of.”

In order to understand the plant’s unique ability to be converted from a coal-fired plant to a combined cycle plant, Burke says you must look at the plant’s history.

From Acid Rain to CO2

To support the surrounding uranium boom, construction of the Nucla Station began in 1957, and was completed two years later as a 36 MW coal burning, stoker-fired plant. In the 1970s, sulfur dioxide emission standards were imposed on coal plants because of acid rain concerns. With the uranium boom a bust at that point, adding sulfur dioxide scrubbers weren’t feasible, so the Nucla plant was shut down.

In the early 1980s, according to Burke, Finland manufacturer Ahlstrom Pyropower came to the United States in search of a place to install a demonstration fluid bed combustion plant. This new (at the time) combustion technology reduced the amount of sulfur dioxide emissions. Nucla Station was chosen to house this demonstration, and the new combustor replaced the existing boilers; the plant was once again operational, and within the sulfur dioxide emission standards at the time. Nucla became the world’s first utility-scale power plant to utilize this technology.

At the same time, a new steam turbine was simultaneously installed in the plant, which increased its capacity to 100 MW.

Trouble came to the plant in 1989 when a control malfunction damaged the combustor while the plant’s owner, Colorado-Ute Electric Association, was in the midst of bankruptcy. In 1992, the bankruptcy court divided the assets of Colorado-Ute between Public Service Company of Colorado (now Xcel Energy) and Tri-State. Burk says neither of the power providers wanted the Nucla Station, but the court decreed that it must be operated. It was finally agreed that Tri-State would operate the plant if Public Service would purchase its power.

The plant was repaired and returned to service under the new agreement in the early 90s and has operated successfully since then, although Burke says, “chronic tube failures still plague its service.”

Burke first entered the Nucla Station in the early 90s, while he was working with the company that rebuilt the damaged combustor.

“When I first walked into the Nucla plant, I was immediately impressed with the potential of that plant being converted,” Burke says. “Even at that time, there was a possibility (of) converting (it) to a very much enlarged, and cleaner, combined cycle power plant.”

In particular, Burke says, the type of steam turbine that was installed is very adaptable, and is actually required in a combined cycle plant. But the focus at the time was acid rain and sulfur dioxide.

“Nobody was talking about CO2,” he says. “That notion was very unpopular with people who made homes in Nucla and Naturita, and didn’t want to see such a big change. At the time, there was no real incentive to choose such a goal. The problems of coal combustion that we are faced with today hadn’t come over the horizon yet, so I got shrugged off pretty quickly.”

Could Nucla’s Coal-Fired Days Be Numbered?

With global warming very much a reality today, and with new state standards in which municipalities and power-providing cooperatives, such as Tri-State, must provide 10 percent of its power from renewable sources by 2020, Burke asks the question: “Why not now?” Especially since the eastern end of San Miguel County, including Telluride, will soon be tied to the plant when the new Nucla-Telluride transmission line is completed next year.

In essence, Burke says, the solar farm would provide much of the day’s energy while the sun is high. When the sun drops below the horizon and families go home to cook dinner, creating a peak power load on the grid, gas turbines will kick on and supplement the power needed at that time. On an average day in this system, Burke says, gas will provide 35 percent of the power, solar energy will provide 28 percent, and the balance will come from power imported over existing transmission lines.

“The big handicap with solar right now is that there is no real way to store tremendous amounts of energy and then recover it as the night progresses,” Burke says. “Many, many people are working hard on that problem. There are systems being developed that haven’t reached maturity yet. What I’m proposing is that we supplement a solar development with a combined cycle gas fired plant that can pick up the load very quickly as the sun goes down.”

Michael Saftler, who is a board member of San Miguel Power Association, one of Tri-State’s 44 power-purchasing cooperative members, said Burke’s idea for converting the plant are good, but many questions remain unanswered.

“I think his notion is a good one, and we are certainly willing to look at proposals,” Saftler says. “He has been trying to get that particular concept through for some time. Even though the technology is feasible from a technological standpoint, from an economic standpoint, it would be so expensive to retrofit the facility. Chances are, Tri-State wouldn’t want to do it.

“The plant is still one of the more efficient plants they’ve got,” he adds. “That is not to say it doesn’t have some issues.”

Indeed, the future of the Nucla Plants’ source of coal is questionable. In January 2010, Tri-State commissioned a third-party “useful life analysis” of the Nucla Station. According to Tri-State spokesman Jim Van Someren, the study indicated that the facility has an estimated effective operational lifespan of 40 or more years. The current permit under which Tri-State receives coal for the plant from the nearby New Horizon Mine expires in 2014.

“We are currently working on obtaining a permit extension to continue to receive fuel supplied from that mine beyond that timeframe,” Van Someren says.

Even if Tri-State’s permit is granted beyond 2014 to mine coal from the New Horizon Mine, Van Someren said there may only be coal reserves at the mine to serve Nucla until at least 2018, based on current consumption rates.

Given the transportation costs, “we are initially exploring other future resource options within a 50-mile radius of the power plant,” he says. “We have considered and analyzed alternative fuel sources for possible use at Nucla Station – primarily biomass in the form of wood chips – but due to transportation costs, long-term availability and consistency of fuel supply, heat rate, etc., nothing has proven to be as efficient and economically viable as coal.”

As for Burke’s idea, Van Someren believes the availability of fuel and the cost of converting the plant’s infrastructure may be hurdles too high for Tri-State to jump.

“As far as converting the facility’s primary fuel source to natural gas, I think the principal obstacle is the availability of the fuel in the immediate area and the challenge of constructing the necessary infrastructure to deliver gas to the plant, especially considering the terrain in that area.  Again, I don’t think the economics would be favorable, compared to our current operations,” he says.

Even if his plan makes sense, and if natural gas can be found in the area, Burke understands that a move away from coal will not be an easy step for Tri-State to make. Still, he hopes his plans make sense soon.

“I just don’t know of another place you can take advantage of such a situation,” Burke says. “It’s the reason I continue to push this idea. I just know that we are overlooking something important here. If we were to do this, it would draw people from all over the world here to look and see what we have done, and it would spotlight an opportunity that people have no idea exists. The days of the coal fired plant are numbered.”
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