<p>Mostly the sun. All fossil fuels are essentially carbon stores derived from ancient plant and/or animal remains that got the energy to concentrate said carbon from the Sun. The energy that fuels their transition from raw remains to coal, gas, and oil is primarily chemical, and internally derived, with a side order of mechanical alteration. Mechanical compression causes heating without any separate input; thus as other material buries the carbon rich remains and they are compressed by the overlying weight and heated. The combination of heat and pressure alters the stable chemical forms liberating certain chemicals such as sulfur and nitrogen oxides, these chemicals further alter the material they are leaving and the mechanical and chemical energy released when they are liberated becomes more heat. Very deeply buried material may be subjected to heat rising from the mantle but this is not essential.</p>

CC BY-SA 4.0
2024-09-16T00:34:37.653Z
The question says this is the narrative. But the transformation from plankton to oil is an energetic process as well, which has an energy balance including other sources. At least that's what I glean from Kerogen story
Dan Getz
CC BY-SA 4.0
2024-09-16T00:21:23.287Z
2024-09-16T05:23:36.427Z
2024-09-16T05:23:36.427Z
Ash
<p>Famously, fossil fuels are claimed to contain the energy from the sun collected over thousands of years by photosynthesis in the deep past. But, having looked into it a bit, it turns out, that photosynthesis is a first step in the origin of fossil fuels. After dying ancient plankton sink and are transformed over thousands, or millions, of years to <a href="https://en.wikipedia.org/wiki/Kerogen" rel="nofollow noreferrer">Kerogen</a> and later to oil and gas. The transformation depends on the heat gradient of the Earth. This heat gradient and the pressure are a result of other factors such as the residual heat from Earth's formation (essentially Earth's gravitational potential energy) and radioactive decay. What is a good way to attribute the energy content of oil/gas to each of those sources of energy. Specifically, the sources in the &quot;pie chart&quot; can be:</p>
<ol>
<li>Earth formation heat.</li>
<li>Radioactive decay.</li>
<li>Solar / photosynthesis</li>
</ol>

CC BY-SA 4.0
2024-09-23T14:11:26.417Z
Since asking this question, I've found this source: https://www.geochemsoc.org/files/6214/1261/1770/SP-2_271-284_Sato.pdf
which may provide information to potential responders. It also states that most energy is from photosynthesis, but perhaps someone more experiences can clarify it for me.
Dan Getz
<petrology><geothermal-heat><radioactivity><energy>
What are the energy source(s) for the transformation(s) of fossil fuels?
Dan Getz
# What are the energy source(s) for the transformation(s) of fossil fuels?

(Asked by: username_0 on 2024-09-15)

Famously, fossil fuels are claimed to contain the energy from the sun collected over thousands of years by photosynthesis in the deep past. But, having looked into it a bit, it turns out, that photosynthesis is a first step in the origin of fossil fuels. After dying ancient plankton sink and are transformed over thousands, or millions, of years to [Kerogen](https://en.wikipedia.org/wiki/Kerogen) and later to oil and gas. The transformation depends on the heat gradient of the Earth. This heat gradient and the pressure are a result of other factors such as the residual heat from Earth's formation (essentially Earth's gravitational potential energy) and radioactive decay. What is a good way to attribute the energy content of oil/gas to each of those sources of energy. Specifically, the sources in the "pie chart" can be:

1. Earth formation heat.
2. Radioactive decay.
3. Solar / photosynthesis

**Tags:** petrology, geothermal-heat, radioactivity, energy

> **Comments:**
> **username_0**: Since asking this question, I've found this source: https://www.geochemsoc.org/files/6214/1261/1770/SP-2_271-284_Sato.pdf which may provide information to potential responders. It also states that most energy is from photosynthesis, but perhaps someone more experiences can clarify it for me.  

---

## 1 answers

### Answer by username_1 on 2024-09-16. Score: 1

Mostly the sun. All fossil fuels are essentially carbon stores derived from ancient plant and/or animal remains that got the energy to concentrate said carbon from the Sun. The energy that fuels their transition from raw remains to coal, gas, and oil is primarily chemical, and internally derived, with a side order of mechanical alteration. Mechanical compression causes heating without any separate input; thus as other material buries the carbon rich remains and they are compressed by the overlying weight and heated. The combination of heat and pressure alters the stable chemical forms liberating certain chemicals such as sulfur and nitrogen oxides, these chemicals further alter the material they are leaving and the mechanical and chemical energy released when they are liberated becomes more heat. Very deeply buried material may be subjected to heat rising from the mantle but this is not essential.

> **Comments:**
> **username_0**: The question says this is the narrative. But the transformation from plankton to oil is an energetic process as well, which has an energy balance including other sources. At least that's what I glean from Kerogen story  

---

