The US has had an abundance of natural gas, but much of the conventional reserves have been depleted. Recent changes in extraction methods for shale gas, known as hydraulic fracturing, or fracking, have contributed to a surge in production and extractable reserves. Technological innovation has had a sizable effect upon economically extractable supply and has also delayed depletion declines. But there is more uncertainty about future supply than its promoters want to suggest. The former editor of World Oil magazine, Perry Fischer, was fired for his contrarian comments about the future of shale gas extraction. A number of geologists say the probable total gas supply is less than 20 years, and that shale gas represents maybe seven years of that supply.
Shale gas wells deplete more rapidly than conventional wells, dropping between 45-70% average just in the first year. The wells then deplete completely by the fourth year. This creates a constant depletion treadmill. The number of wellheads must grow geometrically to replace depleting wells and increase production. At some point near term, shale gas won't be able to maintain growth because of constraints on manpower and drilling rigs.
Yet much of the frantic drilling frenzy now taking place appears to be a speculative bubble, which is further accelerating the depletion rate. Currently, there is an abundant supply of natural gas on the market. Therefore, prices have fallen considerably, to the point that many projects are not meeting operating costs. But in a con game with Wall Street, companies are drilling projects where they can't do more than break even, in order to boost stated reserves and obtain funding. This can't be a good situation! A recent front-page story in the New York Times gives the latest details.
Shale gas is to the natural gas industry what tar sands are to the oil industry – very polluting and requiring huge quantities of water. Water is mixed with a secret brew of toxic chemicals and injected under pressure into a well, forcing cracks in the shale. The water that flows back has even more deadly toxins added. Unbelievably, the practice falls outside the Safe Drinking Water Act, so it is contaminating waterways, groundwater and well water. Additionally, a recent study from Cornell University reveals that life cycle greenhouse gas (GHG) emissions from shale gas are 20%-100% higher than coal on a 20-year timeframe basis, especially considering that 70% of natural gas consumption is not used for electricity generation.
Several things need to be emphasized—first, natural gas is a non-renewable resource that faces energy uncertainty, and in all likelihood, supply constraints. So we will not be able to use natural gas as a reliable bridge fuel in any long-range energy plan. Second, its extraction has shifted to a method with demonstrated human, water and ecological effects that are so harmful and toxic as to beg for better regulation. Third, it has become apparent that these new methods of extraction are producing greenhouse gas emissions that are even more impactful for climate as coal.