By Patrick Anderson
PBN Staff Writer

Manchester Street power station in Providence and Brayton Point power station in Somerset are owned by the same company and separated by just 15 miles of Interstate 195.

But the two plants sit at opposite ends of one of the largest shifts in how the United States makes electricity in a century.

The majority of the power produced at Brayton Point comes from coal, the dominant electricity source in the United States since the 1800s, while all three of Manchester Street’s generators run on natural gas, which in 1950 accounted for less than 20 percent of U.S. power generation.

Thanks to a rapid expansion of domestic natural gas production from shale rock formations, the price of natural gas has plunged in recent years. With that drop, power companies have ramped up generation from natural gas and throttled back on coal usage.

According to a July report from the U.S. Energy Information Association, coal’s share of national fossil-fuel energy generation (that is, not including power created by nuclear or renewable sources), which stood at 80 percent in the late 1980s, is now descending toward 50 percent, while natural gas is closing in on the same market share from the opposite direction.

In New England, coal has traditionally played a smaller part in electricity generation than the rest of the country, while natural gas and petroleum had out-sized roles.

According to ISO New England Inc., which operates the regional electrical grid, 51 percent of the electricity generated in New England is fueled by natural gas and that share is expected to rise to 55 percent when new facilities in development come online.

In Rhode Island, natural gas accounts for virtually all of the power made within state lines, 99 percent, while there is no significant coal production, according to ISO figures.

But while New England has certainly benefitted from lower utility bills as a result of the decline in natural gas prices, the now overwhelming reliance on a single fossil fuel has left some concerned that the region could be vulnerable to supply disruptions.

“Natural gas is powering the region and, as a result, the price of wholesale electricity now follows the price of natural gas here … as a result, many utilities across New England have announced rate cuts for their electricity customers,” said ISO New England President and CEO Gordon van Welie in a recent editorial published in Commonwealth Magazine. “It’s evident that generating electricity with natural gas has its benefits, but becoming heavily reliant on just one fuel poses challenges to the long-term stability of the power system.”