Many see shale gas as a saviour, the “bridge fuel that can power our economy with less of the carbon pollution that causes climate change” as Obama put it recently.
Examined more closely, its merits are doubtful. An article in “Business Spectator” laid out the two principal downsides.
First, the greenhouse gas emissions
The Environmental Protection Agency has pegged natural gas leakage from production at 1.5 per cent. But the agency tends to rely on industry-provided numbers. A separate study by 15 scientists from institutions including Harvard, NOAA and Lawrence Berkeley National Lab looked at comprehensive atmospheric data and models, and concluded the leakage was at least 3 per cent. At 2.7 per cent or more, natural gas loses any advantage over coal in terms of its greenhouse effect.
That finding is backed up by other, more local studies by NOAA, which found a 4 per cent leakage rate from natural gas production around Denver, a 6-to-12 per cent rate from production in Colorado’s Uintah Basin, and a 17 per cent rate in the Los Angeles basin.
On top of all that, the fracking process consumes and pollutes enormous amounts of fresh water, which can leach from the wells into other groundwater supplies.
Second, the physical limits
A University of Texas study looked at a decade’s worth of information from the Barnett Shale – the formation near Fort Worth, Texas, with the longest history of natural gas fracking – and determined that production for most wells fell exponentially over that time. At this point, they’re on track to reach only 10 per cent of their potential – though the researchers did say well production could be “greatly improved” with better fracking methods, but that was a possibility only.
The problem boils down to pressure: as the amount of gas in the shale falls, there’s less pressure to push the remaining gas out. And since fracking involves splintering the shale to allow the gas to flow, the fall in pressure tends to interconnect across wells in the formation. The end result is that companies have to drill ever more wells just to keep the level of production constant over time. That drives up operational costs per unit of natural gas, and thus the price. Eventually, raw economics takes over, and the Energy Return On Investment – the amount of energy produced by the drilling verses the energy required to drill – falls too low. Drilling more is no longer worth it, and the wells tap out.