Intermittency of renewable power sources is a growing concern for grid reliability in the United States and it has not been properly addressed by public policy for very long. One simple way to mitigate this problem is to diversify the renewable energy portfolio. This work studies the case of Texas, a state that not only is the largest wind power producer in the US, but that also has faced considerable diversification in its renewable energy portfolio in the past ten years. A dispatch model is proposed to simulate how thermal generators respond to changes in the intermittency of renewable sources. Additionally, since higher renewable output usually means higher intermittency and vice-versa, a mean–variance analysis is used to study this trade-off. Results indicate that although intermittency decreases the reliability of the grid, reducing it can have adverse effects as increasing the dispatch of polluting power sources and decreasing the revenues of thermal generators, what can decrease important investment in dispatchable power sources in the long-term. Also, results show that the subsidy design adopted by the federal government is an obstacle to portfolio diversification.

中文翻译：

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通过投资组合多元化减少可再生能源间歇性的影响

可再生能源的间歇性问题日益引起人们对美国电网可靠性的担忧，而且公共政策长期以来一直没有妥善解决这个问题。缓解这一问题的一个简单方法是使可再生能源组合多样化。这项工作研究了德克萨斯州的案例，该州不仅是美国最大的风力发电生产国，而且在过去十年中其可再生能源投资组合也面临着相当大的多样化。提出了调度模型来模拟火力发电机如何响应可再生能源的间歇性变化。此外，由于较高的可再生能源输出通常意味着较高的间歇性，反之亦然，因此使用均值方差分析来研究这种权衡。结果表明，虽然间歇性会降低电网的可靠性，但减少间歇性会产生不利影响，如增加污染性电源的调度和减少火力发电机的收入，从长远来看，这会减少可调度电源的重要投资。此外，结果表明，联邦政府采用的补贴设计是投资组合多元化的障碍。