Further, in high wind scenarios where wind makes up 30% and solar makes up 10% of the penetration, the drop in wholesale prices in the regions ranged from 19-37%.
The findings were made in major new technical study by the Lawrence Berkeley National Laboratory (LBNL), funded by the US Department of Energy.
The LBNL scientists simulated wind and solar shares of up to 40-50% in California, the Midwest, Texas and New York in 2030, and contrasted those results with a low penetration rate of renewables.
"High wind scenarios … lead to the greatest increase in irregularity of pricing patterns," across all regions, said the report.
On the other hand, high solar scenarios lead to the largest change in the daily profile of prices and the greatest overall variation in prices.
For example in New York, substantial evening price reductions in the high wind scenario in the winter will lead to a peak price shift from 7pm to 9am.
"Electricity suppliers or various electric-sector programmes may need to be more flexible and adaptable in a high wind future than in a low variable renewable energy or even a high solar future," continued the report.
Volatile
Perhaps the most fundamental changes relate to the timing of when electricity is cheap or expensive and the degree of regularity in those patterns, said LBNL lead scientist Ryan Wiser, one of the co-authors.
Price volatility increases with higher renewables shares, particularly in the high wind scenarios. The researchers found that morning prices in the spring in California can vary between zero and $50/MWh with high wind, but fall in a much narrower range in the low renewables scenario.
The frequency of periods with low prices of below $5/MWh increases to between 3% and 19% of hours in the high variables scenarios depending on the region and mix of renewables.
Price variability was up to three times in the high wind scenario in California relative to the baseline scenario of 2016 with 7% wind.
Higher ancillary service prices could attract new market entrants such as batteries or encourage wind and solar to offer these services themselves, noted Wiser.
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