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Variance of Renewable Generation

February 1, 2012

Title: Variance Analysis of Wind and Natural Gas Generation under Different Market Structures: Some Observations
Authors: Brian Bush, Thomas Jenkin, David Lipowicz, and Douglas J. Arent, NREL; Roger Cooke, Resources for the Future

Does large-scale penetration of renewable generation such as wind and solar power pose economic and operational burdens on the electricity system? A number of studies have pointed to the potential benefits of renewable generation as a hedge against the volatility and potential escalation of fossil fuel prices. Research also suggests that the lack of correlation of renewable energy costs with fossil fuel prices means that adding large amounts of wind or solar generation may also reduce the volatility of system-wide electricity costs. Such variance reduction of system costs may be of significant value to consumers due to risk aversion. The analysis in this report recognizes that the potential value of risk mitigation associated with wind generation and natural gas generation may depend on whether one considers the consumer's perspective or the investor's perspective and whether the market is regulated or deregulated. We analyze the risk and return trade-offs for wind and natural gas generation for deregulated markets based on hourly prices and load over a 10-year period using historical data in the PJM Interconnection from 1999 to 2008. Similar analysis is then simulated and evaluated for regulated markets under certain assumptions.

—Jim Leyshon