(681c) Characterizing Excess Energy Availability and Value

Solar and wind energy technologies are increasingly being deployed in an effort to mitigate climate change.¹ However, solar and wind energy resources are inherently variable, and as reliance on these resources grows, additional technologies and strategies will be needed to ensure that energy demand is met.² Commonly discussed options include energy storage, backup generation, demand-side management, and transmission expansion. However, some of these options might continue to be costly or difficult to deploy. If the costs of solar and wind energy technologies continue to decline³ while complementary technologies remain more costly, another approach to lowering the overall cost of meeting energy demand could become increasingly economical: overbuilding solar and wind power capacity. Such overbuilding has already been identified as a potential cost-reducing strategy in models of cost-optimal energy systems that rely heavily on renewable resources.^2,4

Overbuilding of solar and wind power capacity can lead to the production of considerable quantities of excess energy. Increasingly, proposals have suggested that this energy could be stored in chemical fuels or used to synthesize materials. If technologies could be developed that effectively use this excess energy, the utilization of renewable resources could be increased, reducing the costs of transitioning to low-carbon energy resources. However, the opportunity provided by this excess energy has not yet been well-characterized.

In this work, we characterize the temporal and spatial availability of excess energy in cost-optimized systems that combine solar and wind resources with energy storage to reliably provide electricity. We use high-resolution data on weather and electricity demand, renewable energy technology models, and an energy system model to identify characteristics of systems that minimize levelized energy costs. We then examine the quantity and timing of excess power produced by these least-cost systems at diverse locations. We demonstrate how excess energy availability and characteristics depend on the ratios of wind-to-solar power capacity, the cost characteristics of energy storage technologies, and the overall reliance on a combination of renewable resources and storage to meet demand. Our results provide insight into how chemical technologies and processes could be designed to effectively utilize excess energy to produce fuels and materials, and can inform future engineering research strategies and financial investments.

References

(1) Key World Energy Statistics 2019; Key World Energy Statistics; International Energy Agency, 2019.

(2) Ziegler, M. S.; Mueller, J. M.; Pereira, G. D.; Song, J.; Ferrara, M.; Chiang, Y.-M.; Trancik, J. E. Storage Requirements and Costs of Shaping Renewable Energy Toward Grid Decarbonization. Joule 2019, 3 (9), 2134–2153.

(3) Taylor, M.; Ralon, P.; Al-Zoghoul, S.; Epp, B.; Jochum, M. Renewable Power Generation Costs in 2020; International Renewable Energy Agency: Abu Dhabi, 2021.

(4) Jenkins, J. D.; Luke, M.; Thernstrom, S. Getting to Zero Carbon Emissions in the Electric Power Sector. Joule 2018, 2 (12), 2498–2510.