Mary A. Cameron

Low-cost solution to the grid reliability problem with 100% penetration of intermittent wind, water, and solar for all purposes

Significance The large-scale conversion to 100% wind, water, and solar (WWS) power for all purposes (electricity, transportation, heating/cooling, and industry) is currently inhibited by a fear of grid instability and high cost due to the variability and uncertainty of wind and solar. This paper couples numerical simulation of time- and space-dependent weather with simulation of time-dependent power demand, storage, and demand response to provide low-cost solutions to the grid reliability problem with 100% penetration of WWS across all energy sectors in the continental United States between 2050 and 2055. Solutions are obtained without higher-cost stationary battery storage by prioritizing storage of heat in soil and water; cold in water and ice; and electricity in phase-change materials, pumped hydro, hydropower, and hydrogen. This study addresses the greatest concern facing the large-scale integration of wind, water, and solar (WWS) into a power grid: the high cost of avoiding load loss caused by WWS variability and uncertainty. It uses a new grid integration model and finds low-cost, no-load-loss, nonunique solutions to this problem on electrification of all US energy sectors (electricity, transportation, heating/cooling, and industry) while accounting for wind and solar time series data from a 3D global weather model that simulates extreme events and competition among wind turbines for available kinetic energy. Solutions are obtained by prioritizing storage for heat (in soil and water); cold (in ice and water); and electricity (in phase-change materials, pumped hydro, hydropower, and hydrogen), and using demand response. No natural gas, biofuels, nuclear power, or stationary batteries are needed. The resulting 2050–2055 US electricity social cost for a full system is much less than for fossil fuels. These results hold for many conditions, suggesting that low-cost, reliable 100% WWS systems should work many places worldwide.

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

The premise and all error claims by Clack et al. (1) in PNAS, about Jacobson et al.’s (2) report, are demonstrably false. We reaffirm Jacobson et al.’s conclusions. 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 … [↵][1]1To whom correspondence should be addressed. Email: jacobson{at}stanford.edu. [1]: #xref-corresp-1-1

An intercomparative study of the effects of aircraft emissions on surface air quality

This study intercompares, among five global models, the potential impacts of all commercial aircraft emissions worldwide on surface ozone and particulate matter (PM2.5). The models include climate-response models (CRMs) with interactive meteorology, chemical-transport models (CTMs) with prescribed meteorology, and models that integrate aspects of both. Model inputs are harmonized in an effort to achieve a consensus about the state of understanding of impacts of 2006 commercial aviation emissions. Models find that aircraft increase near-surface ozone (0.3 to 1.9% globally), with qualitatively similar spatial distributions, highest in the Northern Hemisphere. Annual changes in surface-level PM2.5 in the CTMs (0.14 to 0.4%) and CRMs (−1.9 to 1.2%) depend on differences in nonaircraft baseline aerosol fields among models and the inclusion of feedbacks between aircraft emissions and changes in meteorology. The CTMs tend to result in an increase in surface PM2.5 primarily over high-traffic regions in the North American midlatitudes. The CRMs, on the other hand, demonstrate the effects of aviation emissions on changing meteorological fields that result in large perturbations over regions where natural emissions (e.g., soil dust and sea spray) occur. The changes in ozone and PM2.5 found here may be used to contextualize previous estimates of impacts of aircraft emissions on human health.

Reply to Bistline and Blanford: Letter reaffirms conclusions and highlights flaws in previous research.

Bistline and Blanford’s (1) (hereinafter BB16) comments about Jacobson et al. (2) (hereinafter J15) are incorrect or unsubstantiated, and thus affect no conclusion in J15. However, their remarks highlight the failure of previous decarbonization studies to treat many existing storage options, load reduction upon electrification, accurate wind power, and true nuclear and carbon capture costs. [↵][1]1To whom correspondence should be addressed. Email: jacobson{at}stanford.edu. [1]: #xref-corresp-1-1