Gravity storage converts work to potential energy, and back, efficiencies can be 90-almost 100%... heat engines at room temperature generally top out in the 35%ish range. Using the "waste" heat improves that, but nowhere close to 90%.

Gravity storage is not a heat engine, ergo Carnot's rule does not apply.

But the second law of thermodynamics still does. Gravity wells are still a mechanical system, just not a heat engine.

>Not even close. Second law of thermodynamics puts a limit on heat engine. Gravity storage is not subject to such limit.

Emphasis mine. Don't be a pedant.

Well, my important point was that hydrocarbons are fucking terrible but keep focusing on the first part.

Laws of thermodynamics apply to the entire universe, ergo i dont think anyone is claiming to break laws of physics

2nd law of t only applies to mass. Gravity works via gravitons which are massless so the 2nd does not apply..

Because the Carnot limit is particularly pessimistic.

70% vs 40% is a big difference, especially when you consider it from the losses column instead of the wins column. If I gave you a system that was losing 30% of a resource to replace a system that lost 60%, you've cut your losses in half.

If I told you a mechanical system could get that to 15%, you'd replace that again. Anyone who tells you they can get a heat engine down to 15% losses is a charlatan and should be reported for fraud.