Even in summer in California solar peaks mid-day while demand peaks in early evening. Nevertheless, it appears that the additional costs and efficiency loss fro

Even in summer in California solar peaks mid-day while demand peaks in early evening. Nevertheless, it appears that the additional costs and efficiency loss from cycling fossil plants is dwarfed by the fuel-consumption savings, at least up to modest (33%) penetration of solar/wind: https://www1.eere.energy.gov/wind/pdfs/55588.pdf https://www1.eere.energy.gov/wind/pdfs/55588.pdf In this study, we found that up to 33% of wind and solar energy penetration increases annual cycling costs by $35–$157 million in the West. From the perspective of the average fossil-fueled plant, 33% wind and solar penetration causes cycling costs to increase by $0.47–$1.28/MWh, compared to total fuel and variable operations and maintenance (VOM) costs of $27–$28/MWh. The impact of 33% wind and solar penetration on system operations is to increase cycling costs but also to displace annual fuel costs by approximately $7 billion. The modeling assumptions in that study look pretty reasonable to me. The one significant change I'd make is plugging in a lower natural gas price, e.g. the $3.66/MMBtu from Henry Hub a week ago, compared to $4.60 assumed in the study. Even with that change it looks like fuel savings dwarf cycling costs.