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Shell In-Situ Oil Shale Process Emits 21-47% More GHG on a Full Fuel Cycle Basis than Conventional Petroleum

Full-fuel-cycle emissions from low and high primary cases for Shell ICP, in grams of carbon equivalent per megajoule of refined fuel delivered as compared to conventional oil emissions. Click to enlarge. Credit: ACS.

Shell’s in situ conversion process for oil shale produces an energy output of 1.2-1.6 times greater than the total primary energy inputs to the process, according to a new analysis by Dr. Adam Brandt at UC Berkeley.

However, in the absence of capturing CO2 generated from electricity produced to fuel the process, well-to-pump GHG emissions are in the range of 30.6-37.1 grams of carbon equivalent per megajoule of refined fuel delivered (gCequiv/MJ RFD). These full-fuel-cycle emissions are 21%-47% larger than those from conventionally produced petroleum-based fuels. Brandt’s study is published online in the journal Environmental Science & Technology.

Oil shale is a fine-grained sedimentary rock containing kerogen—a solid organic precursor to oil and gas—from which oil and gas can be obtained through the application of heat. There are two basic approaches to processing oil shale: mining the rock and heating it in a surface retort, and heating the rock in the ground, to then pump up the resulting oil.

In its in-situ process, Shell drills holes into the shale resource, inserts electric resistance heaters, and heats the subsurface to around 343º C (650º F) over a 3- to 4-year period. During this time, very dense oil and gas is expelled from the kerogen and undergoes a series of changes, including the shearing of lighter components from the dense carbon compounds, the concentration of available hydrogen into these lighter compounds, and the changing of phase of those lighter more hydrogen rich compounds from liquid to gas.

These gaseous lighter fractions are now far more mobile and can move in the subsurface through existing or induced fractures to conventional producing wells from which they are brought to the surface.

Shell says that ICP results in the production of about 65%–70% of the original carbon in place in the subsurface. The carbon that does remain in the sub-surface resembles a char, is extremely hydrogen deficient and if brought to the surface would require extensive energy intensive upgrading and saturation with hydrogen. (Earlier post.)

The ICP process consists of four primary steps:

  • A freeze wall is created around the perimeter of an area of shale to be retorted (a production “cell”).

  • The oil shale within the cell is heated using electric resistance heating. The heat conducts through the formation, slowly heating the shale to the temperature of kerogen decomposition.

  • After kerogen conversion, the resulting hydrocarbons are pumped from the earth.

  • The production cell undergoes remediation: residual mobile hydrocarbons are flushed from the earth and the freeze wall is thawed.

(In 2007, Shell withdrew the application for a mining permit on one of its three oil-shale research and demonstration leases for economic reasons: costs for building the underground freeze wall of frozen water to contain melted shale had “significantly escalated.”) (Earlier post.)

Brandt modeled two commercial-scale cases of ICP deployment, representing low and high energy and GHG intensity, to come up with the 30.6-37.1 grams of carbon equivalent result. An earlier study of Shell’s ICP by other researchers derived a 27-34g carbon equivalent per MJ of refined fuel delivered.

Earlier analyses of surface retorting cited by Brandt projected emissions estimates in the range of 31-75 gCequiv/MJ RFD. Emissions from Alberta tar sand production are in the range of 29-36 gCequiv/MJ, while those from coal-based synthetic fuels are in the range of 42-49 gCequiv/MJ, Brandt notes.

Near-term emissions from the ICP are likely to be closer to the high estimate presented in this report...In the long term, it is possible to implement a low-carbon ICP. The energy requirements of heating are likely to not be sensitive to intermittency, because of the high heat capacity of the large mass of shale and the long heating time. Thus, intermittent renewables could be used in off-peak times.

Second, the reuse of waste heat seems feasible, given that the hot, depleted production cells will need be flushed with water to meet the water quality requirements in any case. However, these low-carbon ICP options are costly and, therefore, are unlikely without regulation of carbon emissions.

Large-scale oil shale development could result in significant additional emissions. If we produce, refine, and combust fuel equal to 10% of the 2005 US gasoline consumption (~1.8 x 1018 J) using the ICP instead of conventional oil, full-fuel cycle emissions increase from ~45 million tonnes of carbon (MtC) for conventional oil to 55-67 MtC. This approximate increase of 10-20 MtC can be compared to total emissions from the state of Colorado, which were 24 MtC in 2001.

The wide range of potential impacts of the ICP and its inherent flexibility underscore the importance of deliberately and consciously choosing our path as we transition to oil substitutes. Finding an environmentally responsible path to secure domestic fuel supplies will be dependent not only on developing new alternatives to oil, but also on implementing policies and programs to guide the responsible deployment of these technologies.

—Brandt (2008)

Separately, a recent report from MIT’s Laboratory for Energy and the Environment concluded that a 10% oil sands component in US petroleum fuels would increase fuel cycle greenhouse emissions approximately equal to the loss of one to three MPG in new vehicle fuel economy in 2035.

In other words, in order to make up for the additional emissions from fuel cycle [with a 10% oil sand component], the cars and light-trucks will have to attain higher levels of fuel economy to keep the well-to-wheels emissions from getting worse. This loss is equivalent to the fuel use reduction achieved through a 7.5 % market penetration of hybrid vehicles by 2035 in case of low oil sands share and up to 20% market penetration of hybrid vehicles by 2035 in case of high oil sands share.

—On the Road in 2035


  • Adam R. Brandt (2008) Converting Oil Shale to Liquid Fuels: Energy Inputs and Greenhouse Gas Emissions of the Shell in Situ Conversion Process. ASAP Environ. Sci. Technol., doi: 10.1021/es800531f

  • On the Road in 2035 (MIT 2008)



A difficult and dirty industry. I wonder how far the oil price would have to fall before the Sands are put on hold - probably far higher than the $60 they were saying 3-5 years ago.
I guess improved tech and sequestration can't get here fast enough.


The reason why these shales will stay in the ground is in the fisrt sentence of this araticle : "in situ conversion process produces an energy output 1.2 to 1.6 time greater than the primary energy input" in clear an EROI of 1.2 to 1.6, not better than corn ethanol and totally hopeless, economical viability is impossible with an EROI below 3 and barely viable below 5.

When you think that they need to dedicate a nuclear power plant (that will produce its own waste) to heat the rock during 4 years, better work on eletric car.

Reality Czech

1.6:1 or even 1.2:1 may be economical if it trades cheap energy inputs for high-price products. However, if an electric vehicle gets 60% generator-to-wheels and the ICP-fueled ICEV gets 1.6 * 0.2 = 32%, the EV is going to go twice as far per unit of electricity and much farther per dollar invested.

There may be an upside. Large wind farms built to heat Colorado shale with their off-peak production will sell their peak production directly to consumers. If DSM or storage can bid up the off-peak price, the ICP process may not be able to afford the power.


Nuclear Oil is an antidote to the Peak Oil Blight

Nuclear Oil is a name for oil produced using nuclear power. Pebble bed reactors and other nuclear reactors are good sources of heat. The high temperatures reactors can provide process heat to conversion plants that heat oil shale, oil sludge, or tar sands to extract oil. The overall productivity of the conversion plants would be increased and CO2 emissions eliminated by not burning the end product for heat.

Nuclear reactors can be built at the production sites, such as the Alberta tar sands pits, the Colorado shale oil lands, the West Virginia coal mines, the Qatar gas fields, or the eastern Venezuela sludge oil fields. The oil extraction and production processes can take place more efficiently, using nuclear heat, without creating even more CO2.

The website has much more about peak oil and the opportunities to use nuclear power to reduce CO2 contributions and extend the availablility of fossil fuels. It is comprehensive, and filled with links to explore the subject.



The EROI of nuclear is already low ~ 5-10 so I am not sure the whole things make any sense. Anyway given the difficulties to get a permit to build a nuclear plant and store the waste for a purpose that is highly questionnable from an environmental point of view as well as economical seems very unlikely to happen. This nuclear oil concept seems very shaky to me

Red Gun

Please differentiate between CO2 and pollutants. The term "greenhouse gas" is as helpful as a hole in the head, given that water vapor is 95% of greenhouse. Try to keep it scientific.

d burgdorff

The headline on this article is misleading. Oil shale MAY increase GHG depending on where the energy to process the shale comes from. The author admits that because of long heating times, renewables could be used. This would result in no increase in CO2.

The same thing can be said for converting coal to liquid which would probably be more economical.

Unless we are worried about running down the entropy of the universe, energy efficiency doesn't matter. All that matters is profit and environmental impact.

David Ahlport

==The term "greenhouse gas" is as helpful as a hole in the head, given that water vapor is 95% of greenhouse. Try to keep it scientific.==

The catch of course being that watervapor rapidly cycles out of the greenhouse layer, such that it doesn't accumulate.

Water vapor is also rather temperature sensitive, so the temperature of the greenhouse layer determines the amount of watervapor present. (Warmer, more water vapor. Colder, water vapor condenses and less water vapor)

Whats more, the real figure is closer to 80%. 95% is an unscientific figure given by Richard Lindzen in an informal interview.

BFD - shell is destined to become its name.


Let me ask you Red Gun, what is the best way to increase the amount of this powerful greenhouse gas called 'water vapor'?


It would be far more efficient to turn nuclear into electricity to run your car than it would be to use nuclear to extract tar sands and turn that into oil then turn that into electricity or refine it for gasoline to move your car. But in each step of this ineficient process is another billionaire with his lobbyists who can get rich cheating the government or consumers.

@ Treehugger

I am a member of the alternate nuclear movement which supports small, high efficiency, high temperature production line built PBMR Gen IV reactors. I use an EROI for this type of nuclear of 11% in cost estimates.



Well said.

Why don't we convince our politicians and other powers to be to do it?

To stop buying Hummers (and similar vehicles) is the first step.

We could take the second step and stop buying any vehicles doing less than 35 mpg average.

We could even take the third step and stop buying vehicles doing less than 45 mpg average, etc

Will we do it?


you wouldn't be part of the quasi religious, cult of La-rouche style fundamentalist trippers?
Their politics seem very familiar to readers of Greencarcongress.
If you havent met them before:


To whoever wrote me,

What do you mean an EROI of 11% ? you mean 10 ? that is quite good indeed for nuclear, but anyway the well to wheel efficiency of this nuclear electricity would be like 3 times higher using electified transportation than using it to extrat these crap of oil shale and burning them in an ICE. Plus it would be something like 10 times cleaner, so ?


Treehugger: yes, if electrical vehicles would have existed. If efficient batteries would have existed, if the lead those batteries would have been environmentally friendly, etc. "would"


47% is not as bad I thought that it would be.


I like the sound of oil shale. Grow algae on the extra CO2 from the Shell oil shale process, and it's a win-win situation!



MIT has just invented a new fuel packaging for light water nuclear reactors that will increase the output of existing nuclear plants by 50%. The return on investment for nuclear will rise to about 22–27%. Good news!


Harvey, we're you ever in a 12 step program? No need to answer;)

Henry Gibson

From the begining of life on earth, all life forms must ingest radio-active potassium in order to live. We are all radio-active, and the radio-activity lives on, even if we are cremated, as radio-active waste. Every visit to the W.C. releases radio-active wastes.

A published figure of 10,000 pounds of coal being required to produce the same electricity as one pound of fabricated nuclear fuel means that during operation there will be about 30,000 pounds of CO2 released and as much as 1000 pounds of ash, but the used fuel rods weigh one pound. In theory one pound of Uranium can generate about the same heat as 3,000,000 (three-million) pounds of coal. A CANDU reactor could actually have its daily requirement for fuel delivered in a taxi.

The "USED" fuel rods still have 95% or more of their energy left, so they are not waste. If the high speculative price of uranium remains, they will be reused. Without any modification US reactor "used" fuel bundles could be loaded into a special heavy water reactor to be used for another year or so, and most of the energy value will still remain unused. The proposed Energy-Amplifier could use it all.

There is no economic logical reason to protect humans more from fuel rods than they are from their own built in radiation. They must be protected just as people are protected from the sun or molten steel in a steel mill or laser light.

If you only need heat from a nuclear reactor, the high pressure steam parts can be eliminated along with most of the cost. This makes heat-only nuclear reactors the cheapest fuel cost form of heat, including solar.

Using electricity to heat the ground is at least ten times the expense of natural gas heat. Pumping oxygen and methane into a deep combustion chamber could not have been too difficult to arrange. Cooling the ground is very expensive too. Why would any body trust the efforts of an oil company to produce oil from oil shale. They can just pump water into existing fields and pump out a few more gallons of oil.

Compared to gasoline, It may be cheap enough now to use nuclear electricity to recycle CO2 into methanol. ..HG..

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