OAKVILLE, Mo. — A new $900 million power plant is coming to south St. Louis County, but no one yet knows whether the plant will be able to operate during Missouri's coldest days, according to Missouri Public Service Commission (PSC) documents.
PSC gave Ameren Missouri the all-clear to begin building the new power plant on Wednesday. The methane power plant, named "Castle Bluff," will be built in Oakville on the site of the utility's now-defunct Meramec coal-fired power plant. Ameren said the plant would only run if the St. Louis region's grid faces stress during the hottest summer days and coldest winter nights.
Ameren, however, won't know whether Castle Bluff can properly produce electricity for the St. Louis region until 2028, after the plant's construction is completed, utility representatives told the PSC. Jeff Moore, director of Ameren's combustion turbine generator plants, told 5 On Your Side the plant is being built to weather extremely cold temperatures and will have on-site backup fuel storage, but couldn't share specific details on the plant's infrastructure as the design process is ongoing.
"(Regulators) are actually issuing new cold-weather reliability standards that we're all going to have to adhere to to help assure we have winter reliability for our generation going forward," Moore said. "Ameren always applies all of the reliability standards handed down to us from regulatory agencies."
The reliability of methane plants during extreme cold has been a cause for concern multiple times in the last four years. Winter Storm Uri in 2021 caused power outages for nearly 10 million people in the U.S. and Mexico. The primary cause of the electricity grid's failure was natural gas fuel shortages at methane plants, according to to the Southwest Power Pool. Each winter storm after Uri, including Elliott in 2022 and Heather in 2024, also resulted in significant disruptions to natural gas production, according to the U.S. Energy Information Administration (EIA).
"Staff is aware of units in the Midwest region that were not able to operate during Winter Storm Uri due in part because they did not have testing and tuning done on fuel oil in winter," the PSC Staff Report on Castle Bluff said. "It is rather disconcerting that Ameren Missouri is saying we need these because of the extreme weather events that typically happen in the winter, but Ameren Missouri doesn’t have policies or procedures in place to determine if tuning is necessary and perhaps won’t until those units have run in winter."
The volatility of the natural gas market and methane gas power plants, and increasingly frequent and more severe extreme weather events caused by human-induced climate change through the burning of fossil fuels, led some advocates to question whether it would be more worthwhile for Ameren's millions of dollars to be invested in renewable energy rather than Castle Bluff.
Renew Missouri Executive Director James Owen, who leads the nonprofit's efforts to advance renewable energy in the state, said a better use for the $900 million would be investing in battery energy storage systems (BESS) like other states including Illinois, Colorado, and Minnesota.
"Ameren has been touting that they're going to go carbon-free by 2045, and their solution to that is to simply pump different garbage into the air as opposed to coal, which makes their promise of being more environmentally sustainable just more of a marketing pitch than an actual directive," Owen said.
The PSC, as part of its Castle Bluff approval, also required Ameren to increase its BESS development, including making its "best efforts" to install such a system by 2027.
Global scientific research into increased methane emissions found the greenhouse gas is worsening the extreme weather problem Ameren is facing with Castle Bluff. Burning methane traps 28 times more heat in the planet's atmosphere than carbon dioxide. Methane emissions, now at an all-time high, are the second-largest contributor to climate warming worsening extreme weather events throughout the world, according to NASA.
"As carbon dioxide, methane, and other gases increase, they act as a blanket, trapping heat and warming the planet. In response, Earth’s air and ocean temperatures warm," NASA said. "This warming affects the water cycle, shifts weather patterns, and melts land ice — all impacts that can make extreme weather worse."
Moore told 5 On Your Side methane wouldn't be directly emitted out of Castle Bluff's stacks and any leaks would be minimized at Castle Bluff, with all piping systems being designed to meet national piping code standards.
"Quite honestly, I've been in the power business here for 30 years, dealing with combustion turbines and have experience in design and operations and maintenance. I can tell you right now that natural gas leaks are really not a significant issue at all for our plants," Moore said.
Methane leaks are, however, a significant issue that the United Nations Environment Programme is trying to solve. The organization in a 2022 report said "secretive methane leaks" from the world's methane power plants are a major driving force of climate change.
"Massive methane leaks, known as super-emitter events, have been taking place at oil and gas fields all over the world, from the United States to Turkmenistan," the report said. "The releases, most of which can be traced to equipment failures, can last for weeks. One outside of a storage facility in Los Angeles in 2015 hemorrhaged almost 100,000 tonnes of methane — a potent greenhouse gas — into the atmosphere over the course of four months."
