I think oil and cellulose and chitin are on the cusp of earning their place as feedstocks(at various rates). As these values rise, they will compete with use as

I think oil and cellulose and chitin are on the cusp of earning their place as feedstocks(at various rates). As these values rise, they will compete with use as combustion inputs and one by one aspects of combustion will become marginalised and supplanted by higher uses. Cellulose is also known as viscose (AKA Rayon) and it one of the best higher uses of cellulose. Chitin is insect shell protein. Oil is depleting with time. Cellulose and chitin are made in huge volumes. Various chemical treatments/additions etc have a huge potential range of products that can be made with them. We grow trees = wood, many types. It should be possible to make a 'wood' from cellulose and chitin used in composite fiber/foam compound to create a wood that can be engineered in many ways. Wood is long fibers of cellulose with cells strung like beads along these fibers all glued with lignin into a solid. Grown wood is cheaper, but it should be possible to make an engineered cellular wood, based on viscose chemistry in time as wood prices climb.