Thousands of lost jobs, higher utility rates for consumers and more frequent power outages may all stem from emissions regulations that the Environmental Protection Agency predicted would instead generate billions of dollars in net benefits every year.

The regulations were implemented in December 2011 to limit mercury and air toxins emitted from power plants. The agency predicted the regulations would create 46,000 short-term and 8,000 long-term jobs, and generate health benefits valued at between $37 billion and $90 billion annually starting in 2016.

Four years later, however, a far different economic picture is emerging, one that contradicts EPA's rosy scenario.

The most visible difference is the fact that many more coal-fired power generators are being retired than the agency projected.

"It means a loss of jobs at these plants," said Dan Simmons, vice president for policy at the Institute for Energy Research, a right-leaning nonprofit.

Federal environmental officials predicted that only 4.7 gigawatts of power generation would be lost from the nation's 1,000-gigawatt overall electrical capacity due to the regulations. Agency spokeswoman Liz Purchia declined to say when that loss would occur or if the 4.7 figure accounted for replacement energy sources like new wind turbines and solar panels.

By contrast with EPA projections, nearly 13 gigawatts of power from 85 coal generators mostly located in Appalachia are scheduled to retire this year alone, according to the federal Energy Information Administration. Almost 17 additional gigawatts of capacity have already been retired since 2012, and another five will be lost in 2016.

In other words, EPA predicted only 4.7 gigawatts of electrical power generating capacity would be lost but to date it appears that 30 gigawatts have or will be lost and the total could reach 35 gigawatts next year.

The energy administration further predicted that 60 gigawatts generated by coal units would retire by 2020, 12 times more than EPA projected, assuming their prediction was for a total, rather than net loss.

The debate between the agency and its critics is further complicated by the fact that it's difficult to calculate precisely how many of the lost gigawatts result from the 2011 regulations or to other factors, including technological obsolescence and old-age.

"Announced retirement decisions are made based on the broad array of factors that affect the economics of individual power plants, including low natural gas prices, rising coal prices, and excess capacity in light of low electricity demand, as well as costs associated with retrofitting outdated power plants in order to reduce emissions to levels that would protect public health and the environment," Purchia said.

"Although generation owners in some instances publicly have attributed retirements exclusively to [the regulations], most analysts agree that these plants already have been facing decreasing utilization rates due to market factors," she said.

Most of the units that have retired or are scheduled to retire are at least 50 years old, she said.

Simmons and other experts also pointed out that other environmental regulations implemented around the same time also played a role in the lost power generation capacity.

Because of the number of factors, a retrospective look at the environmental agency's 2011 predictions would be "an apples-to-oranges comparison," Purchia said. In other words, the agency claims it can't analyze the accuracy of its past predictions or their effects.

Likewise, such factors made it difficult for experts to measure the mercury and air toxics regulation's effect on the economy.

No such qualifications came from the energy administration, which said of its 60-gigawatt prediction that "90 percent of the coal-fired capacity retirements occur by 2016, coinciding with the first year of enforcement for the mercury and air toxics standards." In addition, the energy administration said, the 13 gigawatts' retirement "is primarily because of the implementation of the Environmental Protection Agency's" standards.

John Moura, the director of reliability assessments at the North American Electric Reliability Corporation, an international nonprofit that analyzes the power grid reliability, said another cause of the retirements is power plant owners' concern of "looming" stricter emissions regulations recently proposed by the agency.

"We thought more retirements were going to occur, and we're seeing that trajectory," said Moura. "When you just look at [the mercury and air toxics standards], I would classify it in the same ballpark."

Even if the environmental agency's 4.7 gigawatt prediction represented a net loss and incorporated additions from other energy sources, the nation may still see harsh consequences due to the nature of coal's successors.

"Our most cost effective power plants are the ones that we're currently using," Simmons said. Coal generated nearly 40 percent of the country's energy in 2014, more than any other source.

Reliance on natural gas may also increase utility costs in the long run.

"Natural gas prices have been volatile … well, forever," Simmons said. "It means higher electricity rates."

The recent low price of natural gas made it cheaper than coal, but Simmons said if prices increase, or even fluctuate rapidly, energy providers may petition for increased average utility costs.

Replacing coal-generated electrical power with renewable sources presents a different set of challenges.

Essentially, power outages occur when energy consumption outstrips the capacity of solar and wind generators to produce power. When the wind doesn't blow or the sun is obscured by clouds, conventional gas or coal generation is required as a temporary substitute.

"When you think about wind and solar, they don't produce electricity on our schedule," Simmons said. "It means that, over time, it will lead to less grid reliability."

Basically, even if a coal generator and a wind turbine or solar panel provides the same energy capacity doesn't mean they will actually produce as much.

"Variable generation capacity such as wind and solar cannot be counted as equivalent to capacity from thermal sources such as natural gas, coal and nuclear," said Tim Shear, an Energy Information Administration energy economist. "Thermal sources generally can give you X amount of electricity for Y amount of hours, as directed by the plant and grid operators. Variable generation cannot produce electricity with such certainty."