The key ratio is “energy return on energy invested”. Analysis by Tim Morgan at Tullett Prebon, a broker, estimates that oil discovered in the 1970s delivered around 30 units of energy for every unit invested. By itself this was well down on the returns from oil discovered in the 1930s, which were nearer 100-to-1. Current oil and gas finds, such as undersea reserves, may offer a return between 16-to-1 and 20-to-1. The return on sources such as tar sands and biofuels like ethanol are in the single digits.

Britain, Argentina, Indonesia, and others have become net importers in recent years. Mexico and Columbia are expected to follow suit within a decade. Clearly, we can’t all be net energy importers.

There is also the obstinate fact that aggregate net energy — the energy you get in return for investing energy in its production — has been dropping steadily. Oil net energy dropped from 100 in the early 1930s to 11 or less today. Net energy for natural gas is now in decline. We don’t have adequate data to know yet, but coal’s net energy is probably in decline too. Meanwhile, the net energy of all substitutes is low: wind, 18; solar, 6.8; nuclear, 5-15; all biofuels, under 2.

It is not surprising that a study of the Herold database (Gagnon, Hall, and Brinker, 2009) showed the amount of oil and gas produced per dollar spent declined between 1999 and 2006.”

Vincent West writes with news of a Russian project currently underway to populate the Arctic Circle with 70-megawatt, floating nuclear power plants. Russia has been planning these nuclear plants for quite some time, with construction beginning on the prototype in 2007. It’s due to be finished next year, and an agreement was reached in February to build four more. According to the Guardian: “The 70-megawatt plants, each of which would consist of two reactors on board giant steel platforms, would provide power to Gazprom, the oil firm which is also Russia’s biggest company. It would allow Gazprom to power drills needed to exploit some of the remotest oil and gas fields in the world in the Barents and Kara seas. The self-propelled vessels would store their own waste and fuel and would need to be serviced only once every 12 to 14 years.”

Posted by Euan Mearns on February 2, 2009

By sugarcane accounting the EROEI of tar sands is about 5.8 million BTUs (the value of a barrel of oil)/0.8 million BTUs (the approximate energy content of 0.8 MCF that was externally purchased), or 7.25. By true EROEI accounting – which includes the internally consumed energy as an input – the EROEI would be 5.8/1.5 = 3.9.

Of course then the oil has to be refined. For a light, sweet oil such as the output of a syncrude unit, that step is going to be 12/1 or better. Putting the two steps together, I calculate that I need to spend 1.5 million BTUs to produce the oil, and another 5.8/12 = 0.5 million BTUs to refine it to gasoline and diesel. Total process is then 5.8 million BTUs/2 = 2.9/1 for the production and refining processes. Conventional light, sweet oil is around 6/1 for the entire process of oil in the ground to gasoline in the tank.