## 3 The Third Industrial Revolution (TIR) and Energy Internet  
Many vital building blocks, organizations, and activities of today's society depend on the continued operation of various large and widespread critical infrastructures, including telecommunications networks and transportation systems. In particular, energy generation and distribution systems play a crucial role. Electrical power grids represent one of the most important critical infrastructures of our society. Current power grids with their aging infrastructure become increasingly unreliable and are poorly suited to face increasingly frequent outages, e.g., the three-day blackout due to trees falling on power lines in the Washington, DC area early July 2012, the lengthy power blackout in the states of New York and New Jersey due to hurricane \"Sandy\" in October 2012, or more recently in February 2013, the power outage during Super Bowl 2013, which lasted for 34 min. In coming years, power grids in the United States, Europe, and other regions worldwide are expected to undergo major paradigm shifts. Today, Internet technology and renewable energies are beginning to merge in order to create the infrastructure for the TIR economy, which has been officially endorsed by the European Commission as economic growth roadmap toward a competitive low carbon society by 2050 and has been implemented by several early-adopting countries such as Germany, England, and Italy, as well as cities such as San Antonio, TX, USA, among others [43]. It has been receiving an increasing amount of attention by other key players, e.g., the Government of China most recently. In the coming era, millions of consumers will produce their own renewable energy and share it with each other via an integrated and seamless _Energy Internet_, similar to the way we use to create and share information online nowadays. The future Energy Internet aims at not only addressing the reliability issues of current power grids but also offering several additional major benefits. The Energy Internet will be instrumental in realizing the vision of the _smart grid_ by incorporating sophisticated sensing, monitoring, information, and communications technologies to provide better power grid performance, engage customers to play an interactive role, and support a wide range of additional services to both utilities and consumers. Potential smart grid applications include substation and distribution automation, advanced metering infrastructure (AMI), wide-area situational awareness (WASA), home energy and demand response management, outage management, distributed generation and renewables, and grid-to-vehicle/vehicle-to-grid (G2V/V2G) electricity storage and charging applications for plug-in electric vehicles (PEVs) [44]. The authors also quantified the communications requirements of the aforementioned smart grid applications in terms of latency, bandwidth, reliability, and security, and concluded that a _reliable_ and _fast_ smart grid communications infrastructure is necessary to enable real-time exchange of data among distributed power grid elements, e.g., power generators, energy storage systems, and users. Recently, a number of major telecommunication service providers such as KT and Telecom Italia have started to move into the energy market. An interesting example is Deutsche Telekom's new offering of virtual power plants, where homes deploy combined heat and power plants (CHPPs) on site to locally supply both hot water and power, thereby reducing the load on the power grid and avoiding transmission line losses. \"Deutsche Telekom delivers virtual power plants\". Importantly, note that business models, arguably more than technological choices, play a key role in the roll-out of smart grid communications infrastructures. According to [45], utilities along with municipalities are responsible for 22% of households passed with fiber-to-the-building/home (FTTB/H) in Europe.