Thursday, September 17, 2009

Big Oil

The size of big oil and natural gas fields and their development is beyond the comprehension of most people. Here is an example I just ran across that gives you some numbers to try to wrap your mind around. This is from Geoffrey Styles' Energy Outlook blog:
I took some pride in Chevron's announcement earlier this week that it and its partners would proceed with construction of the Gorgon LNG plant in Australia. ...

At a planned production rate of 15 million tons per year of liquefied natural gas (LNG) and 300 terajoules per day of pipeline gas for use on the mainland, it's a little hard to put the scale of the project in perspective. It works out to around 2.2 billion cubic feet per day of total natural gas delivery, which is equivalent to the entire production of the largest independent US gas driller, Chesapeake Energy Corp., one of the most aggressive developers of the shale gas deposits that are transforming the US natural gas market. If Gorgon's entire output were sent to gas turbine power plants, it would generate around 85 billion kilowatt-hours per year, as much as 32,000 MW of wind turbines or 9 nuclear power plants of 1200 MW each--and over a similar 40 year operating life. However you look at it, it's big.

Among the challenges the field's owners needed to overcome in order to get to this point was a plan for handling the relatively high CO2 content of the gas in the Gorgon field, at around 12%. Even a decade ago, it was becoming clear that such large quantities of CO2 could not simply be vented to the atmosphere. According to Chevron's fact sheet for the project, the CO2 content of the gas will be separated and sequestered in geological reservoirs under Barrow Island, where the LNG plant will be located, and it will apparently rank among the world's largest carbon capture and sequestration (CCS) projects to date, with total storage of up to 120 million tons of CO2 over the life of the project.

Of course, that doesn't negate the entire greenhouse gas impact of such a project, which must be compared to the emissions that would occur if it didn't proceed. Chilling natural gas to -260 °F, at which it becomes a liquid, requires a significant expenditure of energy, typically generated by burning more gas. As a result, the lifecycle emissions of LNG are somewhat higher than those for pipeline gas, though they are still substantially less than from the coal or oil it would displace in power generation in the Asian market for which most of Gorgon's output is slated. According to a recent study by Pace Consultants, the emissions from gas liquefaction, LNG transportation, and re-gasification at destination would effectively increase the lifecycle emissions from a combined-cycle power plant by roughly 22%, compared to one running on domestic (pipeline) gas. However, that result would still come in around 40% lower than the emissions from the best coal-fired power technology without CCS, and 60% less than typical coal-fired power plants.
The above calculations show you how utterly simplistic more "greens" are in their simple equation of "CO2 = bad". Life is complex. All that a simple analysis shows is a simple mind. The trade-offs we make in real life are very complex. George Bush took a "simple minded" approach to Iraq and he has left a trillion dollar legacy and decades of effort by the US to make up the losses and problems he left behind by his simple-minded approach, his "Powerpoint presentations only!" approach to life.

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