Can oil be used as a fuel source without contributing to global climate change?

Question

I just posted this other question regarding oil, and as a follow-up, I would like to ask if oil can be used as a fuel source for energy without contributing to global climate change?

Answer 1

There are two ways oil can be used as a fuel source for energy without contributing to global climate change.

The first is carbon capture and storage. However, part of the allure of oil is that it's very volumetrically dense, meaning a liter of oil contains a lot of energy at 1 bar pressure. Not so with natural gas, you have to have at least 700 bar pressure and even then a litre of compressed natural gas won't contain much energy. The problem is the burning product, carbon dioxide, is a gas and therefore not volumetrically dense. You'd have to compress it to very large pressures, meaning a pressure vessel is needed, and still it would take a lot of volume. If you have an oilfield and extract a liter of oil, and then burn it into carbon dioxide, you can't store the carbon dioxide in the liter of freed space on the oilfield. Gasfields are different: extract a given volume of gas, burn it to carbon dioxide (and water), and store the carbon dioxide in the freed space. The carbon dioxide fits in there. So if oil is being used at great rate, it usually means we need energy-dense fuels and that eliminates carbon capture and storage.

The second is making oil from renewable sources. Renewable oil is exactly the same compounds. Finland plans to have 30% biofuel energy content requirement in 2029 for all fuels. We already have reached 19.5% in 2022. And the 2029 target was made before the accelerating adoption of electric cars that reduce oil use. So with the accelerating adoption of electric cars, it probably would be realistic to raise the target for 2029 to 35%.

So most users of oil can use renewable oil. It's a bit more expensive, but not by much. It can't be produced at the rates oil is being used today, but if light road transportation only (the main user of oil) switches to electric vehicles, the remaining oil users which constitute only a small percentage of oil use can still continue to use oil, only using renewable oil instead. It's chemically the same compounds.

Answer 2

Not of itself. Using oil as fuel means burning it and that means producing carbon dioxide.

There are a lot of things we can do after burning oil to avoid releasing the CO2 to the atmosphere, but none of those things are specific to CO2 from oil. For example, we can plant trees to absorb the CO2, but that works for any CO2.

(edit) I'm focussing on CO2 and the atmosphere to make my language simpler and hopefully easier to understand, when I mean "CO2 equivalent" and "global ecosystems", ignoring the diffence between money and resources, as well as indirect contributions to climate change (if an oil spill kills an ecosystem that contributes to climate change, but that's hard to discuss in the context of "is it theoretically possible to..."). At heart this is an economic argument, "by taking resources from here to use there, you're making climate change worse".

But: we burn oil, we get CO2. How do we stop that contributing to climate change?

At the simplest level, we can capture the CO2 and store it forever ("carbon capture and storage"). Let's ignore what "forever" means, and just accept that it can be done. There are companies that say they can do it. They charge money for doing that.

So we ask: is spending that money the cheapest way to reduce the amount of CO2 in the atmosphere?*

The answer is no. Not now, and there doesn't seem to be any prospect of that changing. The various CCS experiments around the world have all been very expensive to build and operate, and many have been shut down or are running at minimum capacity.

What does that mean? It means that for a given amount of money, we can reduce climate change by a small amount using CCS (is, burning oil without adding to climate change), or by a much larger amount by spending the money somewhere else - usually by planting trees.

Well, why don't we just plant trees so we can burn oil without making climate change worse?

That's because we don't have to burn oil for energy, so that's an easy thing to stop doing. At least compared to breathing which is very difficult to stop doing. But we do need to reduce CO2 emissions, and things are so bad we need to be actively taking CO2 out of the atmosphere (and oceans).

• this is the basis of carbon taxes: by having a "free market" in CO2 reduction we spend resources most efficiently