First, it is important to point out that despite industry claims that hydraulic fracking for natural gas has been in practice since 1947, the type of fracking used now is a new entity altogether. Ingraffea refers to it as unconventional hydraulic fracking because it combines four types of relatively new technologies to unlock unconventional gas shale.
Traditional hydraulic fracking involved one well that was drilled straight into the ground to tap a pocket of natural gas. The gas was trapped in a relatively permeable material such as sand or limestone. The new type of hydraulic fracking is trying to extract gas located in microscopic pockets and joints within relatively impermeable shale rock. In order to do this, there are two types of drills for each well: one that goes straight down for five to ten thousand feet to reach the shale, and another that drills horizontally through the shale for another five to ten thousand feet in multiple directions.
Unlike traditional gas fracking, shale gas fracking requires many wells and much larger areas of land. Ingraffea states that traditional hydraulic fracking required clearing a small area of land and drilling one well. But shale gas fracking must drill into as much of the shale in the area being extracted as possible. This means bulldozing an area of 10 to 20 acres and drilling 8 to 20 wells on that pad of land. This is repeated at other locations throughout the shale area. The Marcellus Shale Basin alone is expected to contain 400,000 wells.
Shale gas fracking requires substantially more energy and resources than conventional gas wells, too. In addition to the drilling rigs, each well requires a large generator to run the hydraulic pump, hundreds of truckloads of water and chemicals to provide 5 to 10 million gallons of fracking fluid, and traincar loads of sand. Each well consumes ten times the amount of water and produces ten times as much waste as a conventional well. When this is multiplied by the number of wells on a pad and the number of pads required to fully extract gas in an area, it becomes clear that the use of resources is exponentially greater in shale gas drilling - and waste continues to be produced over the multiple-year active life of the well.
The waste comes in three forms: liquid, solid and gas. Water and chemicals are injected into the well and they return to the surface carrying heavy metals, organic compounds and radiation picked up from the shale. Ideally, the fracking fluid is captured and safely transported to a storage facility. Mud from the well comes to the surface carrying toxins, too, and must be contained, transported and stored. Some of this waste is placed in open pools or landfills, or is spread on the land and roadways in areas that permit this. Some is injected into storage wells. And some is dumped into waterways illegally. Gas waste in the form of leakage to the atmosphere occurs. Ongoing research suggests that 3 to 8 percent of the methane produced from each shale gas well is emitted into the atmosphere.
According to Ingraffea, it is true that natural gas produces less carbon dioxide than other fuels when burned. What is not talked about enough is how fracking unleashes methane, which has devastating effects on climate change. Natural gas is primarily methane, and when methane is leaked into the atmosphere, it is a more potent greenhouse gas than carbon dioxide by a factor of 30 to hundreds, depending on the time period over which it is emitted and other factors. Every gas well leaks to some extent, but the current industry standard is that one out of every 20 wells leaks large amounts of methane before it is discovered to be failing.
It is known that shale oil wells release over 100 million of cubic feet of gas each day as the oil is collected. This gas is burned on site rather than captured because it does not make economic sense to capture it. Only recently have studies started to ask how much methane is leaking overall from shale gas fracking, and it looks like the answer is twice as high as initially anticipated. Rather than serving as a bridge to a clean energy future, Ingraffea states, natural gas will hasten climate change, and is a climate bomb with greater potential impact than the Alberta Tar Sands.