Refining light crude is essentially the same process as heavy crude with fewer steps. US refineries are designed to handle virtually any kind of crude and are highly configurable. That flexibility is part of what makes their refinery business so successful. US refinery capacity is ~50% larger than their domestic oil production; it is a major export business for the US.

The real cost to not processing heavy crude oil is that many refinery assets will be sitting idle because they aren't needed to process light crude.

It may be a bad idea (for various reasons), but it is one already being floated. Here is a press release just today from a California congressman who is proposing a bill to this effect.

https://sherman.house.gov/media-center/press-releases/congre...

If you agree with the parent that Americans are going to feel more energy market pain in the coming months I would imagine the pressure for this will only increase.

> An export ban wouldn’t really help much

It could help in the long term by underwritig refinery retooling. The problem is you'd almost certainly need public support for those investments, given they could be undone by the lifting of such a ban. (An export ban would also trash America's reputation with our import partners.)

> US refinery capacity is oriented towards heavy crude from the gulf or Venezuela.

Or from Alberta.

> An export ban wouldn’t really help much: US oil production is (now) predominantly light crude, while US refinery capacity is oriented towards heavy crude from the gulf or Venezuela.

That's not too much of a problem. A refinery tooled for heavy sour crude technically can process light, heavy, sour and sweet crude - the other way around would be an issue because you'd need to construct hydrocracker and desulfurizer stages first.

The issue is a financial one. A refinery is often a multi-billion dollar asset, and having significant parts of its value sit around unused for prolonged times means write-offs which means stonk number go down, and as we all know there is nothing more important for the economy than the stonk market.

Another, but smaller, problem is that running a refinery on different crude compositions means that the volume ratio of the various oil products changes, and the refinery may find itself sitting on more, say, heavy fuel oil than it can store, sell and ship. And once the tanks are full, production has to stop.

Fake numbers, but I have heard it is something like the US produces 100 units of light crude -exports it all, and imports 50 units of heavy. Net exporter, but the stuff we use domestically for gas refineries comes from elsewhere.

Technically, the refineries can be retooled to take a different blend, but it is expensive to do.

It’s actually harder (requires more advanced technology) to refine heavy and sour crude. The US refining industry process this type of oil mainly because it’s more profitable not because of some limitation.

American oil on the other hand (As in extracted out of the ground) is actually too high quality for domestic consumption therefore gets shipped overseas and sold at a premium. The weird economics of this are made possible by globalization. While it’s not fungible on a dime it’s easy to solve and the US really does hold all the cards when it comes to the petroleum industry.

US crude oil is exported to foreign refineries for blending purposes. By blending low-quality crude with high-quality crude it can reduce the total costs to the refiner even after accounting for the fact that you had to buy high-quality crude to improve the properties of the domestic crude.