Energy, Health, and Climate Costs of Carbon-Capture and Direct-Air-Capture versus 100%-Wind-Water-Solar Climate Policies in 149 Countries.

Air pollution, global warming, and energy insecurity are three major problems facing the world. This study first examines whether 149 countries can transition 100% of their business-as-usual (BAU) all-sector energy to electricity and heat obtained from 100% wind-water-solar (WWS) sources to solve these problems. WWS eliminates energy-related air pollution deaths and CO2-equivalent emissions while reducing end-use energy needs by ∼54.4%, annual energy costs by ∼59.6%, and annual social (energy plus health plus climate) costs by ∼91.8% among nations, giving energy- and social-cost payback times of 5.9 and 0.78 years, respectively. Conversely, "all-of-the-above" policies promoting carbon capture (CC) and/or synthetic (as opposed to natural) direct air carbon capture (SDACC) to reduce or offset CO2 emissions trigger, with full penetration of CC/SDACC across 149 countries, $60-80 trillion/y in social cost, or 9.1-12.1 times the WWS social cost and only 1.1-25.6% lower social cost than BAU. Even when all CO2 is stored, CC and SDACC increase air pollution, CO2-equivalent emissions (due to capture inefficiencies and not capturing non-CO2 greenhouse gases), energy needs, and equipment costs relative to WWS. Sensitivity tests reinforce this finding. Although full penetration is extreme, any CC/SDACC level increases social cost and emissions substantially versus WWS. Thus, policies promoting CC and SDACC should be abandoned.