Abstract
Global 2021 energy flows indicate sectors with the greatest opportunities for efficiency improvements and emissions reduction. Analysis of the International Energy Agency's 2050 Net Zero Emissions (NZE) Scenario with respect to the 2021 energy profile as a reference point provides a model for changes in energy efficiency, emissions reduction, cost, and land use resulting from substitutions of fossil fuels with renewable options at the levels required for net zero emissions by 2050. Even with optimized outcomes, the probability of such widespread changes occurring over the next 30 years is reduced by the need for large investments, infrastructure changes, and the successful deployment of technologies still under development. Achievement of the technical potential outcomes for alternative solar energy to fuels conversion technologies, including cultivated microalgae biomass and biofuels and photocatalytic and photobiological hydrogen, would reduce reliance on mature renewable technologies and provide increase in net energy ("power to wheels") to help meet the demands of a growing population while reducing cost and CO(2) emissions compared to the baseline 2050 NZE scenario. Such technical potential performance along with those for solar and wind represents 4 billion tons of CO(2) removal (a 28% increase) over the baseline 2050 NZE Scenario but still requires another 9.5 billion tons of carbon capture and removal (CCR) to achieve NZE.