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Solar photovoltaics (PVs) and wind constitute more than 60% of global annual net new capacity additions. Balancing an electricity system with 30-100% variable PV and wind is straightforward using off-the-shelf techniques comprising stronger interconnection over large areas to smooth out local weather, storage, demand management, and occasional spillage of renewable electricity. The overwhelming dominance of PV, wind, and hydroelectricity in new renewable energy deployment means that renewable electricity is tracking toward near equivalence with renewable energy. A global survey of off-river (closed-loop) pumped hydro energy storage sites identified 616 000 promising sites around the world with a combined storage capacity of 23 million GWh, which is two orders of magnitude more than required to support 100% global renewable electricity. This is significant because pumped hydro storage is the lowest cost storage method and is available off-the-shelf in large scale. Australia is deploying PV and wind at a rate of 250 W per year per capita, which is four to five times faster than in the European Union, the USA, Japan, and China. This is significant because it demonstrates that rapid deployment of PV and wind is feasible, with consequent rapid reductions in greenhouse gas emissions.

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Electronic structure calculations have the potential to predict key matter transformations for applications of strategic technological importance, from drug discovery to material science and catalysis. However, a predictive physicochemical characterization of these processes often requires accurate quantum chemical modeling of complex molecular systems with hundreds to thousands of atoms. Due to the computationally demanding nature of electronic structure calculations and the complexity of modern high-performance computing hardware, quantum chemistry software has historically failed to operate at such large molecular scales with accuracy and speed that are useful in practice. In this paper, novel algorithms and software are presented that enable extreme-scale quantum chemistry capabilities with particular emphasis on exascale calculations. This includes the development and application of the multi-Graphics Processing Unit (GPU) library LibCChem 2.0 as part of the General Atomic and Molecular Electronic Structure System package and of the standalone Extreme-scale Electronic Structure System (EXESS), designed from the ground up for scaling on thousands of GPUs to perform high-performance accurate quantum chemistry calculations at unprecedented speed and molecular scales. Among various results, we report that the EXESS implementation enables Hartree–Fock/cc-pVDZ plus RI-MP2/cc-pVDZ/cc-pVDZ-RIFIT calculations on an ionic liquid system with 623 016 electrons and 146 592 atoms in less than 45 min using 27 600 GPUs on the Summit supercomputer with a 94.6% parallel efficiency.

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