关键词：电力系统；太阳能；风电；能源消耗；发电
摘 要：This study provides a framework to explore the potential use and incremental value of small- to large-scale penetration of solar and wind technologies as a physical hedge against the risk and uncertainty of electricity cost. The idea that adding renewable energy (RE) to a conventional fossil portfolio generates diversity-related benefits is not new and has been discussed by many others (e.g., Bolinger et al. 2002; Awerbuch and Berger 2003; Bazilian and Roques 2008; Roques et al. 2010). Similarly, there may be related benefits from combining RE and natural gas generation (Lee et al. 2012; Weiss et al. 2013) as well as from combining wind and solar within the RE component of the larger portfolio. The core idea behind the value of diversification, of not putting all the eggs into one basket--or in this case electric generation technologies--has widespread acceptance. In finance applications the value of diversification forms the foundation behind the application of mean-variance portfolio (MVP) theory to choose efficient portfolios of stocks and bonds (Markowitz 1952). The related concept of quantifying the value of diversity in the electric sector that may result from reducing the risk and uncertainty of the overall system costs over multi-year to multi-decade time horizons is less well understood or accepted (Stirling 1994; Awerbuch and Berger 2003). Adding RE can be expected to reduce the variability of the overall electric system costs over a variety of timescales as natural gas-fired generation is displaced. However, the direct application of MVP theory to optimize the mix of generation assets within a generation portfolio is problematic for a number of reasons, including the fact that the operational characteristics of some types of generation assets are dissimilar.