As Robert Powelson, chairman of the Pennsylvania Public Utility Commission, waited to testify before a state Senate committee about his disbelief that a major coal plant was being driven out of the electricity market, he wondered what would be next.
Would he be back, a few months later, talking about a perfectly good nuclear plant knocked off its perch by cheap and abundant natural gas, he said.
Mr. Powelson is a proponent of natural gas development, both for its economic and environmental benefits. When burned, the fuel emits half the carbon dioxide of coal.
Still, negotiating how natural gas is transforming the electricity landscape has taken some getting used to.
Last week, a trifecta of good news hit the natural gas industry when the federal government announced that shale production is soaring, power plant emissions are dropping and total greenhouse gas emissions are the lowest they've been since 1994.
Natural gas has been successfully nudging dirtier coal plants out of the game. It was a major factor in FirstEnergy Corp.'s decision to close the Hatfield's Ferry plant, the move that rattled Mr. Powelson last month.
Nuclear power has begun to feel the shove as well, as have renewables such as wind, which means zero-carbon electricity sources are being driven out by the new fossil fuel darling.
With the exception of four nuclear plants currently under construction in Georgia and South Carolina, plans for new reactors have stalled or been abandoned. Three existing plants are closing ahead of schedule, and some utilities have even canceled projects that would have added capacity to existing plants through efficiency improvements. Illinois-based Exelon, for example, said it would abandon projects to boost capacity at its Three Mile Island reactors in Dauphin County and, more recently, at the Limerick Generating Station north of Philadelphia.
Nuclear utilities cited the low price of electricity and competition from natural gas as driving forces behind those decisions.
To the extent that natural gas replaces coal, the emission benefits are obvious. But when it starts to edge out nuclear and renewable sources, the benefits fade and even eventually reverse.
Researchers at Stanford University's Energy Modeling Forum invited 50 corporate, academic and government scientists to be part of an effort to chart the economic and emissions impacts from natural gas. Their report, released in September, concluded, "Shale development has relatively modest impacts on carbon dioxide, nitrogen oxide and sulfur dioxide emissions, particularly after 2020."
On top of that, the report suggests the positive economic impact of cheap and abundant gas -- manufacturers moving plants to the U.S., for example -- will drive up power demand and, therefore, emissions.
Another study by two NASA scientists published in Environmental Science & Technology in March cautioned that "long-term, widespread use of natural gas [without accompanying carbon capture and storage] could lead to unabated [greenhouse gas] emissions for many decades," since new energy infrastructure is built to last at least 20 to 40 years.
In Pennsylvania, 29 natural gas power plants are under consideration, according to PJM Interconnection, the Valley Forge-based grid operator that must be notified of possible additions to the grid. Meanwhile, the wind and solar projects in the queue would produce only 6 percent of the energy as the proposed gas plants.
The state's leaders don't see natural gas as a bridge fuel to zero-carbon generation.
"It's a destination fuel, if you will," said Patrick Henderson, Gov. Tom Corbett's energy executive. "Current production is 150 to 200 years. I think we look at it as a major baseline fuel and a key part of our portfolio that's going to be here."
Mr. Henderson doesn't think renewables are being displaced by gas because the state mandates that utilities buy a certain percentage of their electricity from alternative energy sources -- a figure that increases annually until it reaches 18 percent in 2020.
"It would be an interesting discussion if we did not have those mandates," he said.
The fact that electricity prices have dropped by more than 40 percent since 2008 in the PJM market has "been a reckoning for renewables and nuclear," he said.
But while the state is interested in having a diverse fuel mix, it has no plans to regulate carbon dioxide, nor should it, Mr. Henderson said.
"Carbon is truly a global consideration," he said. "With carbon, it's not as if climate change will be different in Pennsylvania if we have a certain standard [than] in Ohio, where there is not that standard."
Anya Litvak: firstname.lastname@example.org or 412-263-1455.