PENDLETON, Ore. — The road to Portland General Electric’s new 440-megawatt natural gas-fired power plant in Boardman is lined with stray onions, irrigation pivots and the lingering smell of beef cattle.
Yet among this isolated stretch of farmland is an all-too-perfect intersection of water, gas and transmission lines to feed the steel beast under construction on the Eastern Oregon countryside.
When finished, the Carty Generating Station will provide a dependable base load of electricity over the Cascades to roughly 840,000 PGE customers in the Portland metro area south to Salem. Officials say the plant should come online by mid-2016.
PGE is certainly no stranger to the Boardman area. The Carty plan — named for the nearby Carty Reservoir — lies within a stone’s throw of the existing Boardman Coal Plant on Tower Road, while the Coyote Springs Generating Station cranks out about 350 megawatts of power at the Port of Morrow industrial park.
Carty is designed for a 30-year lifespan, tapping into the TransCanada gas pipeline 25 miles away in Ione. Natural gas will eventually rush to the station via a 20-inch-diameter pipeline buried four feet underground, weaving its way around crop circles and the nature conservancy.
Project manager Jaisen Mody oversees the enormous development, which includes 600 construction workers running cranes, welders and a multitude of heavy machinery to bring the facility to life. From start to finish, it’s the longest job he’s ever seen planned and one of the more complex.
“It’s all being driven, in my mind, by the environment,” Mody said. “This is a very low carbon footprint plant.”
The easy comparison is right next door, where the Boardman Coal Plant is slated to close or convert to an alternative, renewable source of fuel by 2020.
Carty, on the other hand, represents 45 years of progress in energy technology, Mody said. Natural gas not only burns cleaner than coal, but the plant is able to capture a bulk of its own heat to create steam, which is then used to drive a second turbine at the plant.
The result, Mody said, is an increase in efficiency by as much as 15 percent.
“It’s a very important resource for our customers, and for PGE,” he said.
Carty uses what is known as a combined cycle system, splitting power generation between two Mitsubishi-manufactured turbines with a combined capacity of 440 megawatts. The first generator runs off the combustion of natural gas, burning at a temperature of about 1,100 degrees.
A heat-recovery steam generator, however, captures the majority of heat that would otherwise be wasted and filters in high-purity water to create steam, used to drive the second turbine.
Transformers at the plant take the electricity that’s generated and step it up to 500 kilovolts, which is essentially like pressurizing the power to move it over long distances. The power is carried first to the Grassland Substation a mile away, and from there fed onto the Bonneville Power Administration transmission system in Gilliam County.
At capacity, Mody said the station will be a dependable source of electricity for customers and enable PGE to invest in more renewable energy, such as wind and solar.
“We’re very excited to have this serve our customers next year,” Mody said.
Despite their close proximity, Carty was never envisioned as a replacement for the Boardman Coal Plant. The $513 million station was identified in PGE’s 2009 long-range energy plan to a customer demand that continues to grow at a rate of 1-1.5 percent every year.
Steve Corson, a spokesman for PGE, also said the plant will help minimize the utility’s exposure to fluctuating prices on the wholesale power market.