Prospects of wind solar load and storage

Accelerating energy transition towards renewables is central to net-zero emissions. However, building a global power system dominated by solar and wind energy presents immense challenges. Here, we demonstrate the potential of a globally interconnected solar-wind system to meet future electricity demands.

When solar-wind generation within a grid exceeds its net power demand (i.e., total demand minus baseload), surplus power is first transferred to interconnected grids experiencing shortages, with the remaining surplus stored until capacity is reached. Any surplus beyond storage capacity is curtailed.

High penetration of solar-wind generation is invariably associated with increased curtailments and system-wide costs, with pronounced marginal cost effects. For instance, the cost increase required to raise penetration from 78% to 80% is more than four times that of raising it from 72% to 75%.

Under the S-G scenario, the decline in solar-wind electricity supply caused by the complete outage of a single regional grid averages only 2.6% (ranging from 0.7% to 11.7%), compared to declines of 5.8%, 15.1%, and 26.4% under the S-C, S-A, and S-I scenarios, respectively (Fig. 4b).

As the degree of interconnectivity increases, solar-wind development gradually shifts towards regions with distinct resource advantages, such as the midwestern United States for superior solar resources, and coastal or high-altitude areas for high wind energy potential (Fig. 2a, b).

Two key technical parameters of energy storage are considered: the maximum operational power and the average storage duration. The round-trip efficiency of energy storage is set to 90%, referencing commercial storage technologies 63.