Four years after the Federal Government passed the Tennessee Valley Authority Act in 1933, People’s Electric Cooperative (PEC) began supplying power to rural farms, homes, and businesses in south central Oklahoma. Today, PEC strives to provide efficient power at reasonable rates to more than 15,000 members at 21,000 locations in 11 counties.
However, as a member of the Southwest Power Pool (SPP), People’s Electric faces fluctuating electrical rates based on power supply and demand. PEC has several power purchase agreements with other energy providers for traditional generation sources as well as natural gas, wind, and solar power. But as some contracts came to an end, PEC needed to find a way to replace 75 megawatts of power. After deciding to add natural gas generation to their own system, PEC installed 30 high-efficiency Cat® generators at five contiguous locations to meet their requirements.
“The G3520H has a lot of advantages; not only is it a very fast-loading unit, it’s also pretty hardy,” says Russ Brown, a senior generation engineer for PEC. “We see some very high temperatures through the summer when we’re running – we may have ambient temperatures well into the 100s – and we don’t have to de-rate due to temperature.”
PEC constantly monitors the price of grid power to decide when to run the generators. The SPP also analyzes the expected load on the system and decides what generators PEC will run. When SPP calls a real time unit commitment, the gensets can be fully loaded and online within ten minutes.
Since the gensets began operating in 2018, PEC runs them significantly more than originally predicted. Thanks to the generators’ unmatched efficiency, PEC can provide the lowest rates to its customers even when the cost of grid power is low and wind power is available.