How much of crude oil's stored chemical energy comes from ultimately from uranium?

[nhnifong]

From Wikipedia:

Three conditions must be present for oil reservoirs to form: a source rock rich in hydrocarbon material buried deep enough for subterranean heat to cook it into oil; a porous and permeable reservoir rock for it to accumulate in; and a cap rock (seal) or other mechanism that prevents it from escaping to the surface

Subterranean heat comes from the radioactive decay of Uranium-238, Thorium-232, and Potassium-40. It also came from the gravitational energy from the planet's formation. If this heat is necessary to form crude oil, how much of crude oil's stored chemical energy does it account for?

And maybe this is a bit far fetched, but could we perhaps invent our own oil-formation cycle where we pump oil precursors into old wells, let the earth "cook" them, extract the product, and break it back down into energy and oil precursors?

[IronGremlin]

You'd probably be better off trying to use captured solar energy - Tapping geothermal energy to convert a misc. raw hydrocarbon base is, with current technologies, limited to areas with pre-existing favorable conditions, IE, hot-springs and such. Solar thermal energy is much easier to find in large quantities at present - Maybe someday when we can drill much deeper...

[lajoswinkler]

There's a fourth condition. Time. Lots of it. Chemical reactions that turn organic material into crude oil are extremely slow. Millions and millions of years.

I have no idea how much does nuclear energy contribute to this, though. I'd say not much. Most of the heat came from the planet formation. It's a very good question.

[Seret]

And maybe this is a bit far fetched, but could we perhaps invent our own oil-formation cycle where we pump oil precursors into old wells, let the earth "cook" them, extract the product, and break it back down into energy and oil precursors?

We can already create synthetic hydrocarbon fuels above ground. The only advantage to using geothermal heat would be that it's cheap, but you could just as easily use another cheap source like waste heat from a power plant without all the fuss of having to perform the whole conversion process underground.

Edited November 29, 2013 by Seret

[mossman]

You'd probably be better off trying to use captured solar energy - Tapping geothermal energy to convert a misc. raw hydrocarbon base is, with current technologies, limited to areas with pre-existing favorable conditions, IE, hot-springs and such. Solar thermal energy is much easier to find in large quantities at present - Maybe someday when we can drill much deeper...

You'd be better off using the geothermal energy to directly synthesize fuels (In particular, hydrogenation of CO2 to produce Methanol). A company called Carbon Recycling International in Iceland does exactly that (http://www.cri.is/).

Edited November 29, 2013 by mossman

[IronGremlin]

You'd be better off using the geothermal energy to directly synthesize fuels (In particular, hydrogenation of CO2 to produce Methanol). A company called Carbon Recycling International in Iceland does exactly that (http://www.cri.is/).

Yes, where it's available, geothermal energy is awesome. For example, in Iceland.

The question is simply one of energy, and it's generally easier to produce solar energy in most locations. If you're in Iceland, obviously, geothermal is a better bet, but we don't yet have the technology to 'tap into' geothermal energy wherever we please. Solar thermal, however, is far more widely available.

So, I guess this is a question of whether your raw materials are closer to a hot spring or a desert, more or less. Also important to note is whether or not the source of geothermal energy you're using is located somewhere that it is stable enough that you can actually use it for industrial purposes, and whether or not it's available for said purposes (as in, not a national park / natural monument, etc.)

The size of a solar thermal facility that could do this on any appreciable scale would probably be pretty intense, and variable temperature would be a serious engineering challenge, but I'm guessing that the cost saved by not shipping your raw material half-way across a continent (or the world) to get to the nearest geothermal plant would probably end up making it worth it.

Or you could do it the way most folks do this sort of thing - By burning hydrocarbons as your energy source. Depending on your raw materials, it's actually very possible to come out with a net chemical energy gain from that sort of process, and in fact, there are a number of facilities that can achieve this with simple organic materials, like farm wastes / meat processing by-products. It's not terribly efficient, but again, the question becomes one of logistics - carting around your potential fuel mass gets expensive fast.

[Winter Man]

The most efficient thing to do though would just be to use the nuclear fuel.

[Idobox]

A similar idea, although much easier, is to make charcoal.

Take organic matter (made mostly of water and atmospheric CO2), heat it, and you get coal. It's been done for millennia, usually using fire as a heat source, and is a reasonable way to capture and fix CO2.

Charcoal can then be burned for energy, or turned into gas and oil. An important point would be to retrieve other elements from the organic matter, especially phosphorus, otherwise we might

But as it's been said, it would be far easier to use solar or nuclear energy for that purpose (solar heat is both cheaper and easier than photovoltacis, so I don't think nuclear thermal would be competitive).

Or even better, make transgenic algae that directly produce what you need, and use them to turn solar power into fuel.

[lajoswinkler]

A similar idea, although much easier, is to make charcoal.

Take organic matter (made mostly of water and atmospheric CO2), heat it, and you get coal. It's been done for millennia, usually using fire as a heat source, and is a reasonable way to capture and fix CO2.

Charcoal can then be burned for energy, or turned into gas and oil. An important point would be to retrieve other elements from the organic matter, especially phosphorus, otherwise we might

But as it's been said, it would be far easier to use solar or nuclear energy for that purpose (solar heat is both cheaper and easier than photovoltacis, so I don't think nuclear thermal would be competitive).

Or even better, make transgenic algae that directly produce what you need, and use them to turn solar power into fuel.

NHF, but that's just pure nonsense. Thermal yield of a nuclear fission reactor is incredibly high and the energy is extremely dense compared to solar thermal.

Also, spending money on both sources to fix carbon is extremely wasteful. Plants are very good at fixing carbon and they are equipped with their own solar energy capturing mechanisms. Less deforestation and planting trees on a larger scale would be vastly more efficient than building industrial complexes that fix CO2 and use lots of precious energy to make coal which is then dumped somewhere.

I don't even know why would we use uranium to make coal and then burn the coal. That's incredibly stupid, messy, complicated, wasteful and harmful to the environment because the carbon footprint of such complex would be large than just a simple coal power plant.

[Seret]

NHF, but that's just pure nonsense. Thermal yield of a nuclear fission reactor is incredibly high and the energy is extremely dense compared to solar thermal.

The economics would depend on what sort of timescale you looked at. Nuclear has very high capital costs, high output but high running costs, a long life, then high decommissioning costs. Solar thermal has lower capital cost, very low O&M costs (although this can depend on environmental factors) low or moderate output, and low-end of life costs. You've got to look at these things whole-lifecycle. Nuclear isn't at all cheap.

Energy density is largely irrelevant, I'm not sure I understand why you've mentioned it. The only value fuel energy density has for power stations is fuel transport costs, and the cost of transporting nuclear fuel is high despite it's compact size.

If you had sufficient solar resource then solar thermal might well be more economic, I think dismissing it as "nonsense" is erroneous, unless you'd like to back that up with some actual numbers to prove your point?

As for solar thermal vs PV, that's definitely an interesting question. Solar thermal used to be cheaper for heat, but the cost of PV has nosedived, and it's now competitive even for small scale use like DHW (PV + resistive heating). PV does outperform both flat plate and evacuated tube solar thermal in lower light conditions, and vice versa. I've not seen any recent data on PV verses concentrating systems, but I suspect it's a similar story.