>The palm oil land is being cleared from rainforest and has a limited growing range.

I don't know where people got the idea that oil palms are limited to a tropical rainforest climate, but it's not true. Palms are dry-weather crops; that's why they're all over California. Historically, the largest oil palm producer was Nigeria; only a small fraction is a rainforest climate and those areas are urbanized anyway:

https://en.wikipedia.org/wiki/Nigeria#/media/File:Koppen-Gei...

It simply happens that Indonesia and Malaysia hold a significant fraction of the world's rainforests and are developing high-productivity food crops in response to rapid population growth on the shores of the Indian Ocean and of course a popular will that demands economic growth.

There are thousands of different palm species, not all of which produce the oil palm fruit, which is the starting point for palm oil. The main palm tree species that produces oil palm fruit is Elaeis Guineensis. This species can only grow within 5-10 degrees of the equator.

There are many palm species in California, but they do not produce oil palm fruit.

Perhaps it would be efficient to to GMO palm tree that grows in wider range. Or make a yeast that can produce oil from garbage, that would be pretty useful.

So where the sugarcane for oil's land comes from? Current land for sugarcane is to produce sugar.

A substantial part of the global sugarcane crop is used to make ethanol for fuel. The world's biggest producer, Brazil, uses the majority of its crop for ethanol. (65% as of 2019, the most recent number I could find [0]).

Wikipedia's "Sugarcane" article quotes a 2005 source to claim "solar energy-to-ethanol conversion efficiency is 0.13%". It might be slightly better now, but it's not going to match the 20% or more of a modern photovoltaic system, which could be used to power electric vehicles instead (an ideal use of solar energy, because electric vehicles need batteries anyway so there's no base load problem).

[0] https://www.reuters.com/article/cofco-sugar-ethanol/cofco-ex...