RenewElec Book

The integration of renewable energy resources into the electricity grid presents an important challenge. This book, which is part of the RenewElec project, provides a review and analysis of the technical and policy options available for managing variable energy resources such as wind and solar power. As well as being of value to government and industry policy-makers and planners, the volume also provides a single source for scientists and engineers of the technical knowledge gained during the 4-year RenewElec project. The book, published by the RFF press, is now available. You can find more information and pre-order your copoy at the publisher's site or at Amazon.

Some examples of the results from the engineering-economic analysis reported in the book follow.

  • Normally, wind and solar predictions are used by electricity systems operators to determine when and how much the renewable electricity supply needs to be supplemented with conventionally generated power on overcast days or days of low wind. 
  • What the research showed, however, was that wind forecast lows are typically under predicted, while highs are over predicted.  The results of this research can be used to correct wind and solar forecasts, so that systems operators do not over or under compensate with firm generation power.
  • Some wind power studies have envisioned that it would be necessary to cover the country with high voltage electric transmission lines in order to smooth wind’s variability. Importantly from an economic standpoint, the research summarized in the new book also shows that there are significantly less expensive methods that can achieve the same goal, although some transmission will be required.
  • While utility-scale battery storage systems are becoming economically feasible, the research showed that their most profitable applications are to smooth the fast fluctuations of wind power at wind or solar plants in order to better utilize transmission lines. Batteries are not necessary to smooth the strongest variations in wind and solar power; for that slow-responding fossil-fueled generators are generally adequate. Grid-scale storage can provide substantial benefits for renewables integration and can directly benefit consumers by reducing prices in the wholesale energy market and by avoiding the need to keep expensive and rarely used plants on retainer. However, large-scale deployment of storage for energy arbitrage is likely uneconomical for the storage owner under current market rules.
  • Because forecasts of wind power are not perfect, it is necessary to ensure that some other generators are standing by in case of unforecasted lulls in the wind. The research used accurate statistical methods to compute the amount of reserve generation that should be procured each day. The results show that the amount of such generation increases linearly with the amount of wind power.
  • The book also shows how existing large-scale studies of renewable power integration into the electric grid can be significantly improved. Most of the studies implicitly or explicitly assumed that load and wind are uncorrelated and that the data fi t Gaussian (bell-shaped curve) statistical models, neither of which is accurate.
  • The team’s findings also showed that pollution from traditional power sources such as coal and natural gas can be most effectively reduced by introducing renewable energy not into the places where they will generate the most electricity, such as a solar panel in Arizona, but rather into the places like Western PA and the Ohio Valley, where coal emissions are higher than many other places in the nation, so that they can rely less on these pollutants for energy.

Updated by Jeff Easter