It's hard to miss the 160-foot exhaust tower surrounded by tall, yellow cranes just south of Interstate 84 near the New Plymouth exit, marking the construction site of Idaho Power's new natural gas-fired Langley Gulch power plant.
Natural gas is a new direction for the utility company, which currently generates a significant portion of its energy via hydroelectric power. Older, smaller natural gas facilities near Mountain Home provide supplementary electricity during peak usage.
This one, currently under construction in the southwest corner of Payette County, is the largest of the utility company's four new projects in the past decade, according to Idaho Power project manager Ryan Adelman. It's designed to bolster Treasure Valley's base electricity needs, and it's by far the largest natural gas plant in the state.
The skeletal structures of pipes and steel girders on the dusty construction site take form, hinting at the function of the buildings they will soon become, but Langley Gulch is still a work in progress. Construction began July 1, 2010, after over two years of planning. If all goes as planned, it'll go online summer 2012. Estimated final cost of construction: $427 million.
So why natural gas? After all, the buzzword in the electric industry these days is “renewable,” for reasons both environmental and economic. With solar, wind and hydroelectric, the fuel is free, plentiful and clean. Natural gas burns cleaner than coal, Adelman said, but it still burns. And while the price of natural gas is low at the moment, the market is volatile – there's no guarantee it'll stay low forever, or even for very long.
And although the utility remains committed to renewable energy resources — 48.8 percent of the electricity it generates comes from hydroelectric dams — Adelman explained that to ensure reliable service, a balance must be struck between renewable and traditional technologies. After all, with solar, wind and hydro, so much literally depends on the weather.
“The wind and the solar, there's a lot of interest in,” Adelman said. “But at the same time, we've got to be able to integrate those. If wind picks up, we've got to have a resource to back down; alternatively, if the wind stops, we need something to pick up pretty quick.”
In other words, putting all their eggs in one basket could jeopardize the utility's ability to provide seamless, uninterrupted service. And for something as ubiquitous in their customer's lives as electricity, that would be a problem.
“Everybody wants the power to come on when they flip the switch,” Idaho Power spokesperson Stephanie McCurdy said. “And this is one way to make sure that happens.”
The Langley Gulch project was not without controversy. Snake River Alliance, an energy industry watchdog group based in Boise, opposed the project when it was proposed in 2008, according to the organization's clean energy program director Ken Miller. They eventually came around, Miller said, but they still don't see it as a perfect solution.
“It's not that we oppose all gas plants, it's that we weren't convinced that, at that time, the need was demonstrated,” he said. “It's a very expensive plant.”
That expense will almost certainly be passed along to Idaho Power customers, Miller continued. Electricity in Idaho is among the cheapest in the nation, he said, largely because of the state's heavy investment in hydroelectric facilities, where the fuel is free. Anything other than hydro will cause an increase in electricity bills.
And although Miller said he and the Snake River Alliance would like to see a bigger move away from fossil fuels, anything that reduces the amount of high-emission coal-fired power — which currently accounts for 43.9 percent of the electricity provided by Idaho Power — is a step in the right direction.
“It comes as a surprise to people, because none of those plants are in Idaho. They're all out of state,” he said. “And to the extent that natural gas plants can replace the use of some of the coal plants, that's a good outcome. Gas plants still produce emissions, but they're cleaner than a coal plant is.”
The Langley Gulch power plant lies just south off Interstate 84, about nine miles from the Oregon border. With the highway on one side and wide-open Bureau of Land Management territory on the other, it's not exactly close to the bulk of the Treasure Valley customers it will serve.
But that's one of the reasons the site was chosen, according to the utility company's project manager Ryan Adelson. Despite its remote location, it's easily accessible off the New Plymouth exit, and there are no neighbors to disturb. And, he explained, it's close to existing natural gas pipelines and power transmission lines.
“There's an immediate benefit to the reliability of generation by providing a resource here on the west side of Treasure Valley,” Adelman said. “It really beefs up the reliability of the transmission grid.”
Ken Miller, clean energy program director for the Boise-based energy watchdog Snake River Alliance, agrees that easy access to fuel and transmission lines makes the location ideal for a natural gas-fired power plant: It's well-positioned to serve the state's largest population center, and doesn't require construction of expensive power lines.
“It costs about $2 million a mile to build those 500 kilovolt lines,” Miller said. “And they have environmental impacts. Sage grouse, all sort of problems that are associated with big transmission.”
The carbon emissions from burning natural gas are significantly lower than coal, according to Ken Miller of the Snake River Alliance, but they're not zero. Thus, if the Langley Gulch plant can take the load off coal-fired power plants, it may have a positive net environmental impact — just not as much as renewables.
And once the plant is operational, motorists on Interstate 84 may see plumes of white vapor rising from the plant. Don't be alarmed, plant manager Mike Williams said — it's just steam from the cooling facility.
From an economic perspective, the plant will bring 17 permanent new jobs to west Treasure Valley, Williams added, all of which have already been filled. And 175 construction workers are hard at work during the building phase, providing at least a temporary boost to the local economy.
Customers will very likely see their electricity bills rise a bit, although Idaho Power officials said it's hard to say how much. After all, electricity prices rise and fall constantly due to a wide variety of complicated factors. Until Langley Gulch is online, Idaho Power spokesperson Stephanie McCurdy said, it's difficult to predict how it will factor in.
How it works
It's pretty simple, at least in concept: A natural gas-powered turbine — which looks like a giant jet engine and, according to Ken Miller of the Snake River Alliance, even works on a similar principle — heats water into steam. That, in turn, powers a steam turbine, which generates electricity. Excess steam is condensed back into water and sent through the system again.
Langley Gulch will provide 300 megawatts of electricity, and can be quickly scaled from 60 to 100 percent capacity as needed, according to Idaho Power project manager Ryan Adelson. This capability is distinct from traditional coal-fired plants, he added, which are not scalable and can take hours to get back online once shut down.
A sound-proof enclosure will keep the turbine quiet — two people could have a conversation at normal volume right outside, Adelson said.