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Book Review

Sustainable Electricity

A Look at the Green Azores Islands

One book is reviewed in this issue, which looks at the energy sustainability in the Azores. The mission of the book, according to the reviewers, “is to make the electric energy systems of two islands—Flores and São Miguel in Azores archipelago, Portugal—as green as possible without increasing the long-term service cost.”

Engineering IT-Enabled Sustainable Electricity Services: The Tale of Two Low-Cost Green Azores Islands

Engineering IT-Enabled Sustainable Electricity ServicesMarija Ilic´, Le Xie, and Qixing Liu, editors

As the primary energy source, coal is widely used for power generation, which causes serious concerns related to the environment and sustainability. Thus, renewable energy sources have been developed significantly over the past decade. Unfortunately, renewable energy tends to be variable and uncertain because of the prime movers (i.e., wind and solar) and the dependence on natural and meteorological conditions. The motivation of the book, Engineering IT-Enabled Sustainable Electricity Services: The Tale of Two Low-Cost Green Azores Islands, published by Springer in 2013, is to make the electric energy systems of two islands—Flores and São Miguel in the Azores archipelago, Portugal—as green as possible without increasing the long-term service cost. Based on the study of the electrical network, energy resources, and demand characteristics of the Azores islands, especially Flores and São Miguel, a systematic deployment of an IT-enabled method and automation is proposed to transform their ­current electric energy systems into sustainable, low-cost systems. There are at least six major strengths in this book.

  • Real-world data are used in the simulation and study, which is an excellent resource for those who are interested in gaining more thorough research in developing a stronger, cleaner, and more intelligent electric energy infrastructure. Based on the book, Flores is one of the smallest islands of the Azores archipelago, with a population of about 4,000 inhabitants. The island is powered by a fleet of diesel generators, a reservoir hydro plant, and synchronous wind turbine-generators. São Miguel Island is the capital and the largest island with 140,000 inhabitants, powered by geothermal, hydropower, and heavy fuel oil. As for the wind data in the Azores archipelago, the missing data is corrected and the wind turbine hub height is derived based on the raw meteorological wind speed data. Then, the wind turbine manufacturer’s data sheets are used to convert wind speed to wind power.
  • Look-ahead dispatch for the efficient use of available resources is proposed for wind and load power prediction for the islands of Flores and São Miguel. Due to the presence of major new uncertainties in power systems (e.g., high penetration of variable ­generation and responsive loads), the operation and planning of electric power systems have become more challenging than in the past. In this book, look-ahead generation dispatch is subject to ramp constraints with wind power and load forecasts. The proposed model can obtain the dispatch of less expensive and less polluting generation. To design the right demand response program for the islands, the ability of different types of loads to participate in adaptive load management is assessed. For instance, since there are many automobiles in Flores, electric vehicles can be used to adjust their energy needs to support high penetrations of wind and solar power.
  • The recommendations for minimizing power delivery losses are pointed out for the Azores archipelago, which is important to obtain economic and environmental sustainability. Strategically locating the new wind power plants and optimally utilizing them and other generators can dramatically reduce the distribution losses. Since voltage optimization is also critical to reducing delivery losses, the use of extended ac optimal power flow (ac XOPF) is suggested to compute the most effective schedules as conditions may change during operations, to assess the potential value of new plant candidates, and to reinforce power delivery systems to enable the efficient use of newly added resources.
  • To balance the wind power deviations in a longer time range (especially on a minute-by-minute basis) and to obtain acceptable mid- and long-term frequency, a quasi-static control method for cost-effective intra-dispatch real power balancing is proposed for the two islands. Based on the book, the governor control or energy storage such as flywheels can be used to reduce small, fast fluctuations. Also, the rotor excitation in conventional power plants, the doubly fed induction generator, and flexible ac transmission systems (FACTS)-based voltage control in wind power plants can be used as fast voltage control to stabilize the very fast wind power fluctuations. Moreover, structure-based dynamics with a coupled model of real power and voltage is introduced for assessing small signal stability when there is a high penetration of renewable energy resources in the Azores archipelago.
  • The proof-of-concept implementation of differentiated reliability of service by remote distribution system reconfiguration is proposed to minimize cost and reserve margin. The optimal placements of normally closed switches and normally opened switches are carried out to reconfigure the distribution systems to minimize the switches combined with the infrastructure cost paid to customers by utility. Considering increasingly unpredictable renewable energy sources, it is very important to analyze transient stability problems in networks with high wind penetration. In the book, the FACTS devices and flywheels are proposed to help improve stability and reliability.
  • A stochastic dynamic optimization model is proposed to analyze the optimal expansion decisions considering the uncertainty of wind power generation and future loads. In the book, the impact from the variability of wind power and load on optimal, long-term expansion decisions is investigated on São Miguel Island. It is shown that wind power is a cost-efficient expansion alternative, but some dispatchable generation is also needed to compensate for the uncertainty in wind power.

In addition to the merits discussed above, this book provides a comprehensive suite of operational support tools for the Flores and São Miguel islands, which can be applicable to other interconnected power grids such as those found in the United States, Europe, and China. It also has an easy-to-follow monograph, which provides a holistic view of the multiscale challenges of future power and energy systems. Moreover, it provides open-access simulation data for the Azores archipelago, which can serve as a test case for the community at large for quantifying the benefits of innovative technologies in future systems. Finally, the book is easy to understand, and readers with undergraduate education in electrical engineering should be able to comprehend and follow.

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  • November/December 2017
    Renewable Integration
  • January/February 2018
    Societal Views of the Value of Electricity
  • March/April 2018
    Controlling the Unpredictable Grid