One of the main claims of the energy decline movement is that oil is somehow an irreplaceable source of energy. Oil somehow has remarkable energy density or other properties which render it a special source of energy that cannot be replaced by anything else.
That point of view is badly wrong, in my opinion. Oil has many easy, obvious substitutes which cost about the same or less. Oil has obvious substitutes for all of its uses. Some of those substitutes would take several decades to implement (we can't all switch to EVs tomorrow, for example). However, all of the substitutes are easy and straightforward for an industrial economy.
In this article I will outline the substitutes for oil, for all of its uses.
Right away, I must point out that more than 60% of oil usage is for light-duty vehicles (cars and SUVs) which can be easily replaced by EVs[1]. Another 15% is used for delivery vans and heavier trucks which travel less than 300 miles per day, which can also be easily electrified. Thus, we can simply use battery-electric vehicles for more than 75% of oil usage. Thus, most of the problem has an extremely obvious solution which is already widespread.
Railroads and long-haul trucking can be electrified using overhead wires. Most of the railroad tracks in the world already have overhead wires. Similar wires could be installed over a few key highways in the United States and elsewhere, thereby placing every populated location within 300 miles of an overhead wire, and therefore within the range of battery-electric heavy trucks such as the Tesla Semi. Railroads and long-haul trucks represent another 10% of oil usage, bringing the total for electrified transport to 85% so far.
The remaining terrestrial vehicles include buses, ferries, construction equipment, agricultural machinery, and mining equipment. All of those vehicles travel back and forth to the same location throughout the day or operate in a small area continuously throughout the day. As a result, they can all use battery swapping.
Finally, ships and airplanes can use synthetic methane. Methane is the main component of natural gas. It is easy to make methane using renewable electricity, water, and the Sabatier process. This has already been done on an industrial scale for many decades and was first discovered more than a century ago. It has always been easy to make methane. This one thing by itself is an obvious substitute for all uses of oil. Vehicles like ships, trucks, and so on, can just use a compressed methane tank and their existing internal combustion engines (with slight modifications). Where I grew up, in the SF Bay Area, there have been methane-powered garbage trucks, taxis, and buses for decades.
There has always been an easy, drop-in substitute (synthetic methane) for all uses of oil. We could have switched to synthetic methane at any point. It was not price-competitive with diesel until recently, but if we were willing to pay today's higher fuel prices then we could have switched to synthetic methane at any time. Thus, the idea that oil is somehow irreplaceable is clearly not correct. The transition to synthetic methane would have been easier than the transition to EVs because existing car designs and production lines could have been used.
Thus, there are multiple, overlapping substitutes for all uses of oil. Almost all of the substitutes are a similar price or lower than oil is at present.
[1] https://www.otherlab.com/blog-posts/us-energy-flow-super-sankey
