The United States can keep the grid stable at low cost with 100% clean, renewable energy in all sectors despite inaccurate claims.

False Premise Clack et al.’s (1) premise that deep decarbonization studies conclude that using nuclear, carbon capture and storage (CCS), and bioenergy reduces costs relative to “other pathways,” such as Jacobson et al.’s (2) 100% pathway, is false. First Clack et al. (1) imply that Jacobson et al.’s (2) report is an outlier for excluding nuclear and CCS. To the contrary, Jacobson et al. are in the mainstream, as grid stability studies finding low-cost up-to-100% clean, renewable solutions without nuclear or CCS are the majority (3–16). Second, the Intergovernmental Panel on Climate Change (IPCC) (17) contradicts Clack et al.’s (1) claim that including nuclear or CCS reduces costs (7.6.1.1): “. . .high shares of variable RE [renewable energy] power. . .may not be ideally complemented by nuclear, CCS,...” and (7.8.2) “Without support from governments, investments in new nuclear power plants are currently generally not economically attractive within liberalized markets,. . .” Similarly, Freed et al. (18) state, “. . .there is virtually no history of nuclear construction under the economic and institutional circumstances that prevail throughout much of Europe and the United States,” and Cooper (19), who compared decarbonization scenarios, concluded, “Neither fossil fuels with CCS or nuclear power enters the least-cost, low-carbon portfolio.” Third, unlike Jacobson et al. (2), the IPCC, National Oceanic and Atmospheric Administration, National Renewable Energy Laboratory, and International Energy Agency have never performed or reviewed a cost analysis of grid stability under deep decarbonization. For example, MacDonald et al.’s (20) grid-stability analysis considered only electricity, which is only ∼20% of total energy, thus far from deep decarbonization. Furthermore, deep-decarbonization studies cited by Clack et al. (1) have never analyzed grid stability. Jacobson et al. (2) obtained grid stability for 100% wind, water, and solar power across all energy sectors, and thus simulated complete energy decarbonization. Fourth, Clack et al.’s (1) objectives, scope, and evaluation criteria are narrower than Jacobson et al.’s (2), allowing Clack et al. (1) to include nuclear, CCS, and biofuels without accounting for their true costs or risks. Jacobson et al. (2, 21) sought to reduce health, climate, and energy reliability costs, catastrophic risk, and land requirements while increasing jobs. Clack et al. (1) focus only on carbon. By ignoring air pollution, the authors ignore bioenergy, CCS, and even nuclear health costs (22); by ignoring land use they ignore bioenergy feasibility; by ignoring risk and delays, they ignore nuclear feasibility, biasing their conclusions. Fifth, Clack et al. (1) contend that Jacobson et al. (2) place “constraints” on technology options. In contrast, Jacobson et al. includemany technologies and processes not in Clack et al.’s (1) models. For example, Jacobson et al. (2) include, but MacDonald et al. (20) exclude, concentrated solar power (CSP), tidal, wave, geothermal, solar heat, any storage (CSP, pumped-hydro, hydropower, water, ice, rocks, hydrogen), demand-response, competition among wind turbines for kinetic energy, electrification of all energy sectors, calculations of load decrease upon electrification, and so forth. Model time steps in MacDonald et al. (20) are also 120-times longer than in Jacobson et al. (2).