Powering Human Civilization beyond the Fossil Fuels Era

In approximately four decades, extracting a barrel of oil or a cubic foot of gas will cost as much energy as they contain. Thereafter, the net contribution of fossil fuels to the humanity’s energy budget will be negative. Meanwhile, over 80% of that budget currently comes from fossil fuels, despite five decades of substantial investment in renewable alternatives. Production of cement, steel, plastics, and fertilizer, as well as nearly all of transportation, construction and agricultural machinery still completely depend on fossil fuels. Within the lifetimes of billions of people already born, these fundamentals of human civilization will become unavailable, unless human civilization accelerates replacing fossil fuels with sustainable alternatives two-to-eleven-fold, depending on the chosen approach. If it fails to decisively and strategically invest its remaining net-energy-positive fossil fuels into this transition, human civilization appears likely to collapse. Making this transition on time and on (energy) budget presents an unprecedented challenge. All earlier energy transitions (dung to firewood, firewood to coal, etc.) involved minuscule energy fluxes compared to the current global human energy consumption. Still, their global completion took much longer than the four decades available now. Accelerating the transition calls for focusing efforts and investment on the best available options. This study presents a coherent set of criteria to determine what “best” means, along with a comparative review of the options based on that set. The criteria include technology maturity and scalability of both the total resource and its flux (power). From this analysis, solar energy (coupled with either local thermal energy storage or with global electric grid) appears to be the most realistic option for the energy transition. Either local storage or the global grid can mitigate the intermittency of solar energy so it can be used as a reliable baseload power source. However, the estimated investment needed to complete the global transition is $701 trillion for local storage vs. $127 trillion for the global grid. The collaborative global grid approach is far more affordable than energy separatism. In turn, constructing global power infrastructure will increase demand for international cooperation and human labor, helping resolve many of humanity’s immediate problems: geopolitical rivalry, the risk of resource wars, technological unemployment etc.