An anonymous reader writes: The Guardian reports of a recent paper, published in the journal Energy and Environmental Science, that helps explain how wind and solar energy can power most of the United States: “The authors analyzed 36 years of hourly weather data (1980-2015) in the U.S. They calculated the available wind and solar power over this time period and also included the electrical demand in the U.S. and its variation throughout the year. With this information, the researchers considered two scenarios. In scenario 1, they imagined wind and solar installations that would be sufficient to supply 100% of the U.S. electrical needs. In the second scenario, the installations would be over-designed; capable of providing 150% of the total U.S. electrical need. But the authors recognize that just because a solar panel or a wind turbine can provide all our energy, it doesn’t mean that will happen in reality. It goes back to the prior discussion that sometimes the wind just doesn’t blow, and sometimes the sun isn’t shining. With these two scenarios, the authors then considered different mixes of power, from all solar to all wind. They also included the effect of aggregation area, that is, what sized regions are used to generate power. Is your power coming from wind and solar in your neighborhood, your city, your state or your region?
The authors found that with 100% power capacity and no mechanism to store energy, a wind-heavy portfolio is best (about 75% wind, 25% solar) and using large aggregate regions is optimal. It is possible to supply about 75-80% of U.S. electrical needs. If the system were designed with excess capacity (the 150% case), the U.S. could meet about 90% of its needs with wind and solar power. The authors modified their study to allow up to 12 hours of US energy storage. They then found that the 100% capacity system fared even better (about 90% of the country’s energy) and the optimal balance was now more solar (approximately 70% solar and 30% wind). For the over-capacity system, the authors found that virtually all the country’s power needs could be met with wind, solar, and storage.”
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