I confess that I have not done enough research on this subject to justify a conclusion; nevertheless, I must decide what eMergy should be assigned to energy that will not be available until some known future time in order to compute the net energy associated with the energy technology under investigation. This applies also to objects manufactured by the most efficient methods. As a first step, I would try to discount energy in such a way that the ratio of total energy budget to gross domestic product (E/GDP) is as stable as possible. Thus energy discounting will depend upon monetary discounts. I hope someone will comment on this - perhaps someone who has done serious work on the net energy of alternative energy technologies. The URL http://dematerialism.net/#_Toc172928973 is a portal to the material I have worked on so far.