Fracking, short for hydraulic fracturing, is a process which has been around for over 60 years but because of recent technological changes is being used to increase production of oil and gas. Basically a fluid is pumped underground under high pressure causing the substrate to fracture which allows oil and gas to move more readily through the fissures created into the well and up to the surface.
The historical precedent goes back to the post civil war era. Civil war veteran Col Roberts received a patent for a method to increase production in oil wells that involved dropping a nitroglycerin filled “torpedo” down the well shaft. The explosion would fracture the formation, increasing oil production.
Hydraulic fracturing began about 1950. The recent fracking boom is the result of a combination of advances to the technology including directional drilling and the use of “proppants” like sand and glass beads which prop open the fractures. The technique was pioneered here in the US but its use is rapidly expanding around the world.
There is no question that it is a hot button issue. Some claim that it is a useful, even necessary way to produce fuels for a growing economy. Others suggest the the environmental problems associated with the technique are so untoward as to require banning its use.
Natural gas, regardless of its source, has been called the Prince of Fuels. Among fossil fuels it is by far and away the cleanest burning. It has essentially none of the noxious impurities like sulfur and heavy metals that occur in both coal and oil. It also has a considerable advantage in that it produces more energy for the amount of carbon dioxide produced. Older coal fired power plants have been closing across the country, due in part to it replacement by natural gas plants. Natural gas could even replace liquid fuels for transportation as compressed natural gas (CNG) or by catalytic conversion to a liquid fuel.
Natural gas can be burned in turbines to generate electricity. Gas turbines are ideal as a source of rapidly dispatchable energy that combines well with intermittent renewable energy sources such as wind and solar panels. If the wind blows hard, you idle the turbines, light wind, power up just a few, no wind, turn ’em all on. Over half the natural gas produced in the US comes from fracking.
There are however serious downsides. Fracturing requires a toxic witches brew of hydraulic fluids and some suggest that these pollutants in the fluids have found their way into groundwater. Although it is not hard to imagine how this could happen, the evidence of it actually happening is scant. A more clearly defined problem is the cluster of shallow earthquakes that correlate well with spent fracking fluid reinjection sites. Once the fluid has been used it is disposed of by permanent injection into wells. This fluid under pressure lubricates the subterranean rock layers allowing them to move, hence earthquakes.
Natural gas, essentially methane, is itself a potent contributor to global warming. A final negative is the growing evidence that fugitive emissions from gas production and transmission facilities is a serious contributor to global warming.
These negatives are not insurmountable. Better well casing and location limitations can minimize the risk of ground water pollution. Reprocessing of used fluids, rather than injection will end the earthquake issue, and simply “tightening up” the production and transmission facilities will lessen the fugitive emissions.