Thomas Gold Was Right and Wrong
Astrophysicist Thomas Gold died in 2004. During his long career he made many contributions to physics and astronomy. Unlike many scientists, Gold was willing to risk being wrong. Many of his ideas turned out to be right. When pulsars were discovered by Jocelyn Bell in 1967, some thought they could be signals from ET's. Gold and Fred Hoyle identified them as rapidly spinning neutron stars. The source of neutron stars' rotating beams has remained a mystery, but they could be explained by internal Black Holes.
Gold and Hoyle also promoted a "Steady State" universe. This model universe did not expand--redshift of distant objects was usually explained by a slowing speed of light. The steady state was an alternative to what Hoyle derisively named a "Big Bang." Who knew that this insulting name would catch on? Discovery of the cosmic microwave background in 1965 discounted the steady state. The 2.7K radiation showed that the Universe evolved from a hotter, denser state.
Note that a modern theory of R = ct predicts a Big Bang. Redshifts would indeed be caused by expansion. Change in c would not cause redshifts, but would make high redshifts curve upward. That might lead a naive person to think that the universe was accelerating due to "dark energy."
We were taught in school that petroleum is produced from decomposing fossils, hence the term "fossil fuel." Gold, following some Soviet scientists of the 1950's, took the maverick view that petroleum is abiogenic. Under this theory oil forms deep within the Earth, cooked by Earth's internal heat and aided by bacteria living many kilometres underground. Bacteria would explain the organic compounds found within oil. Under this theory, Earth contains far more petroleum than previously thought and is still producing it.
Was Gold right or wrong about oil? The abiogenic theory is still a minority view, but recent discoveries lend support to Gold. The deepest hole ever dug, the Kola Superdeep Borehole, found bacteria living at depths of 6.7 kilometres. We have found "extremophiles" living in all sorts of inhospitable environments. Moons such as Titan and possibly the planet Mars are still producing methane due to some mysterious process. Earth herself produces an unknown amount of methane, which leaks into Space through volcanic and oceanic vents. Production of these hydrocarbons is indirect evidence supporting Thomas Gold.
The amount of energy produced by Earth's interior is only a guess. The old hypothesis of "radioactive decay" is not adequate to explain even Earth's known heat production. If Earth leaks a large amount of methane, that is even more energy that must be accounted for. Something else is keeping Earth's interior hot, producing vulcanism and also hydrocarbons.
The first stars did not form until hundreds of millions of years after the Big Bang origin. In the early Universe of quasars and active galactic nuclei, the primary source of energy was Black Holes. Hidden from sight, they may still be producing energy. Thomas Gold thought that Earth's internal heat is still producing oil. The petrol in your tank may be energy from a tiny Black Hole.
UPDATE: This doesn't imply that we should waste hydrocarbons. Even if Earth is still producing oil, humans have been using it far faster.