An alternative theory may also partly explain the slower recent growth of the US shale oil and gas industry. The New York Times has carried an opinion piece questioning the industry’s financial stability, written by Bethany McLean, author of an acclaimed book about the Enron scandal. The piece points out that between mid-2012 and mid-2017, the industry had an average ‘free cash flow’ per quarter of negative US$9 billion (€7.7 billion), reflective of a great deal of money being invested or loaned and not being paid back by operating profits. While this period includes the precipitous downturn in output following the oil price crash at the beginning of 2015, the huge inflow is still striking. What is more worrying still is the claim in the piece that there have been “Enron-esque deals” within the industry. These have allegedly involved loans against the future sale of natural gas, which on the face of it seems to be normal business, but becomes more concerning alongside the claim that the output of wells using fracking drops steeply after the first year of operation (in the region of 60%, compared to around 10% for a conventional oil well). A danger exists, therefore, that future production may not be sufficient to cover the loans already granted, and McLean speculates that “most things that are economically unsustainable…eventually come to a bitter end.” Such a bitter end would create a shockwave in the global energy picture.