many biophysical economic thinkers are trained in ecology and evolutionary biology, fields that do well at breaking down the natural world into a few fundamental laws and rules, just like physicists do. Though not all proponents of the new energy-centric academic study have been formally trained in economics, scholars coming in from other fields, especially ecology, say their skills allow them to see the global economy in a way that mainstream economists ignore.

Central to their argument is an understanding that the survival of all living creatures is limited by the concept of energy return on investment (EROI)

For instance, if a squirrel burns energy eating nuts, those nuts had better give the squirrel more energy back then it expended, or the squirrel will inevitably die. It is a rule that lies at the core of studying animal and plant behavior, and human society should be looked at no differently, as even technologically complex societies are still governed by EROI.

Source: here

In January 2007 a blog post titled Black Google Would Save 750 Megawatt-hours a Year proposed the theory that a black version of the Google search engine would save a fair bit of energy due to the popularity of the search engine. Since then there has been skepticism about the significance of the energy savings that can be achieved and the cost in terms of readability of black web pages.

We believe that there is value in the concept because even if the energy savings are small, they all add up. Secondly we feel that seeing Blackle every time we load our web browser reminds us that we need to keep taking small steps to save energy.