There are a few societal costs to the development of shale gas. Potential contamination of groundwater, complications in treating and recycling water used in fracking. Then there’s air pollution from leaking methane (a potent greenhouse gas) and from the diesel-powered rigs and trucks involved in drilling.

But all things considered the benefits of shale gas appear to outweigh the costs. Many utilities are finding that burning natural gas to generate electricity is cheaper (and cleaner) than coal. Cheaper supplies of fuel and feedstocks benefits U.S. industry, especially manufacturers and chemicals makers which have been reinvesting in the U.S. Homeowners benefit from cheaper heating and cooling and electricity. Drilling for gas has created hundreds of thousands of jobs during this economic malaise and it’s generated billions of dollars of lease payments and royalties to landowners.

A group of Yale economics graduates, many of them energy industry executives, led by Yale Professor Emeritus Paul W. MacAvoy, were curious about whether they could quantify the economic benefit that shale gas has on America. So they recently set out to do a cost-benefit analysis, valuing and balancing the pros against the cons. They’ve released their findings in a paper called “The Arithmetic of Shale Gas.”

Their conclusion: the benefits of continued shale gas development are enormous and dramatically outweigh even worst-case scenario costs of pollution and clean-up.

Some specifics. Consider that back in 2008, before the shale boom really took off, the nominal price of natural gas (that is, the price at the Henry Hub in Louisiana) averaged $7.97 per mcf. In 2011, the price averaged $3.95 per mcf. Multiply that price drop of $4.02 per mcf by the 25.6 trillion cubic feet the country consumed in 2008 and you find that thanks to the shale boom, America is paying $103 billion a year less for natural gas. (With gas prices falling even further since 2011, in 2012 the benefit will be even greater.)

Had drillers not cracked the code on shale gas, the United States would instead have been forced to do what the experts expected five years ago: import massive quantities of gas, in the form of LNG from countries like Qatar, Australia, even Russia. Import-dependent nations like Japan and Korea pay upwards of $14 per mcf for LNG — more than triple U.S. prices. If the U.S. had to supplement domestic supplies with imports, the extra costs could have easily added $50 billion a year to the national natgas bill.

As the report’s authors write: “It is startling to acknowledge that consumer benefits from the technology of shale gas drilling and new gas production can be expected to exceed $100 billion per year, year in and year out, as long as present production rates are maintained.”