(Eli5) If oil isn’t just from dinosaurs, but from algae and phytoplankton, can oil be renewable?


I recently learned that oil is mostly composed of algae and phytoplankton capturing carbon out the atmosphere thousands of years ago. Later the organisms fall to the bottom of the ocean and through time turn into crude hydrocarbons. So why do we not attempt to create the same crude oil by using alge with waste water from water processing plants?

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Because it took millions of years to turn the algae into oil or trees into coal. We don’t have that kind of time to renew those resources, so even if there was a way to do it, it’s not useful to us.

Trying to accelerate the process would require putting in more energy; since we’re using these as energy sources, it would make the overall process less useful.

In theory, yes. But the ingredient we can’t readily reproduce is time. It takes a long time to degrade in an advantageous way, and making it under lab conditions is more expensive than batteries

Oil requires millions of years of pressure of sediment to convert from organic material to oil. The time scales involved are difficult for humans to comprehend.

We are presently on track to burn through hundreds of millions of years worth of natural oil production in a couple centuries.

It is possible to make synthetic oil, but the amount of energy you need to put in makes it impractical. You require more energy input to make oil than you get out of it.

Combined with the environmental damage that oil causes, and you start to understand why we are better off looking at alternative fuels.

>So why do we not attempt to create the same crude oil by using alge with waste water from water processing plants?

The natural process, i.e. something that would be free takes millions upon millions of years. We don’t really have that kind of time.

Otherwise, you are just talking about creating biodiesel from algae. Which we are already doing but it’s very expensive. (and I think might not even be a net energy gain at all?)

When we say something is “non-renewable” we don’t always mean there no way to ever get more of it. But more that the current methods of getting that thing have a end date that is close enough that we need to worry about it.

Yes, if we use it very slowly, it will naturally be recreated.

Doing it ourselves is possible, too, and would be considered a form of biofuel. We have some fairly cheap biofuel options on the table already though – ones simpler to make.