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

by Dr. Mark Z. Jacobson
Low-Cost Solution to Grid Reliability

Low-Cost Solution to Grid Reliability

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 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.

The 2050 delivered social (business plus health and climate) cost of all WWS including grid integration (electricity and heat generation, long-distance transmission, storage, and H2) to power all energy sectors of CONUS is ∼11.37 (8.5–15.4) ¢/kWh in 2013 dollars (Table 2). This social cost is not directly comparable with the future conventional electricity cost, which does not integrate transportation, heating/cooling, or industry energy costs. However, subtracting the costs of H2 used in transportation and industry, transmission of electricity producing hydrogen, and UTES (used for thermal loads) gives a rough WWS electric system cost of ∼10.6 (8.25–14.1) ¢/kWh. This cost is lower than the projected social (business plus externality) cost of electricity in a conventional CONUS grid in 2050 of 27.6 (17.2–54.4) ¢/kWh, where 10.6 (8.73–13.4) ¢/kWh is the business cost and ∼17.0 (8.5–41) ¢/kWh is the 2050 health and climate cost, all in 2013 dollars (22). Thus, whereas the 2050 business costs of WWS and conventional electricity are similar, the social (overall) cost of WWS is 40% that of conventional electricity. Because WWS requires zero fuel cost, whereas conventional fuel costs rise over time, long-term WWS costs should stay less than conventional fuel costs. In sum, an all-sector WWS energy economy can run with no load loss over at least 6 y, at low cost. As discussed in SI Appendix, Section S1.L, this zero load loss exceeds electric-utilityindustry standards for reliability. The key elements are as follows: (i) UTES to store heat and electricity converted to heat; (ii) PCM-CSP to store heat for later electricity use; (iii) pumped hydropower to store electricity for later use; (iv) H2 to convert electricity to motion and heat; (v) ice and water to convert electricity to later cooling or heating; (vi) hydropower as last-resort electricity storage; and (vii) DR. These results hold over a wide range of conditions (e.g., storage charge/discharge rates, capacities, and efficiencies; long-distance transmission need; hours of DR; quantity of solar thermal) (SI Appendix, Table S3 and Figs. S7–S19), suggesting that this approach can lead to low-cost, reliable, 100% WWS systems many places worldwide.

Mark Z. Jacobson’s career has focused on better understanding air pollution and global warming problems and developing large-scale clean, renewable energy solutions to them. Toward that end, he has developed and applied three-dimensional atmosphere-biosphere-ocean computer models and solvers to simulate air pollution, weather, climate, and renewable energy. He has also developed roadmaps to transition states and countries to 100% clean, renewable energy for all purposes and computer models to examine grid stability in the presence of high penetrations of renewable energy.

Learn more about Dr. Jacobson

The authors received no external support for this work.