More than 90% of the world's primary energy currently is supplied by fossil fuels, while more than 8% comes from nuclear power and hydroelectricity. Thus, despite the recent publicity for energy sources such as wind, solar, geothermal or biofuels, they provide only a tiny fraction of the world's energy, and even then mainly as a result of subsidies. On the positive side, large-scale energy production from non-hydroelectric renewable sources has at least become technologically feasible. One of the commonly cited reasons why new energy technologies have had difficulty gaining commercial viability is the so-called “valley of death". According to Markham et al. (2010), the phrase “valley of death" was first used in 1995 to refer to the challenges of transferring agricultural technologies to Third-World countries. It was later applied to describe a paucity of funding for the commercialization of new technologies relative to the funds available for more basic R&D.
