 Energy storage is accomplished through the use of high-capacity springs, as well as simply transporting food to feed either "megodonts" (bioengineered elephants) or human laborers.His writing deals with the ethics and possible ramifications of genetic engineering and western dominance, as well as the nature of humanity and a world in which, despite drastic changes, people remain essentially the same.Similar themes run through his book "The Water Knife", where a future American Southwest is reduced to a dystopian Dust Bowl where water is a guarded commodity for the wealthy and powerful interests.