Achieving a balance between affordable and sustainable electricity while improving reliability is a challenge unlike any the electricity sector has faced since its inception. Technology innovations in key areas such as energy efficiency, smart grid, renewable energy resources, hardened transmission systems, and long-term operation of the existing nuclear and fossil fleets are essential to shaping the future of electricity supplies.
Nothing in human history has been more transformative than electricity. Thomas Edison patented the lightbulb in 1879. Just a half-century later, President Franklin Roosevelt declared electricity a necessity, not a luxury. And in 2012, the National Academy of Engineering named electrification the greatest engineering achievement of the 20th century.
Since its inception, the electricity sector has developed many innovative technologies to improve affordability, reliability, safety, and environmental sustainability. Over the last six decades, even as the power grid has grown dramatically in size and complexity, the price of electricity has remained relatively flat. The average cost of electricity is roughly the same today as it was in the late 1960s, when adjusted for inflation. And the industry has reduced its overall emissions while increasing fossil generation by more than 160% since 1970.
But the industry cannot rest on its laurels today in the face of so much uncertainty and so many challenges. It needs to continue to innovate, to adapt to the changing markets and demands of consumers. At the Electric Power Research Institute (EPRI), we foresee unprecedented change in the industry over the next 10 to 20 years—more change than in the previous 100 years. The drivers are familiar to industry observers:
- The availability of natural gas and its increasing role in power generation. For some months in 2012, gas for the first time matched or exceeded coal for U.S. power generation. And according to the U.S. Energy Information Administration (EIA) Annual Energy Outlook 2012, natural gas–fired plants will account for 60% of U.S. capacity additions between 2011 and 2035.
- The expanding role of renewable generation. The EIA Outlook projects that the aggregate fossil fuel share of U.S. total energy use will fall from 83% in 2010 to 77% in 2035, while over the same period generation from renewable sources will grow by 77%, raising their share of total generation from 10% in 2010 to 15% in 2035.
- Technology challenges to reducing carbon dioxide, mercury, and other emissions. A recent EPRI summary report, Prism 2.0: The Value of Innovation in Environmental Controls, projects the U.S. electricity industry will spend $140 billion to $220 billion for emissions control retrofits, new capacity, and fuel plus operation and maintenance between 2010 and 2035, with more than half of the expenditures occurring by 2020.
EPRI is collaborating with its members, national labs, universities, and other stakeholders to address all of these challenges and continue to provide the power quality and affordability consumers expect. But the projected costs are high. That’s why EPRI is focused on a “no-regrets” portfolio of technologies that would allow utilities to maintain a reliable, environmentally sound, and reasonably priced electricity supply even under the uncertainty of fluctuating natural gas prices, unpredictable electricity supply from grid resources, and potentially increasing environmental regulations (Figure 1).
|1. Balance dispatchable generation with forecastable demand-side resources. The supply side of today’s power system consists of baseload generation plus load-following generation, plus or minus bulk energy storage (left side). All those sources must be continuously balanced to meet customer demand minus interruptible load demand response (right side). The cover photo illustrates a vision of a fully integrated electricity system, where supply and demand are not exclusively on opposite ends of the grid. Source: EPRI
Today, these “no regrets” technologies fall into three broad categories:
- Flexible resources and operations. This category includes the ability to cycle potentially all generation assets, including coal, fossil, nuclear, and renewable generation technologies. It also includes energy storage, demand response, and other technologies located on consumer premises. Employing flexible investment strategies for securing all assets, including an array of alternative supply and demand resources, is another piece of this vision. Fuel flexibility is another component, including the ability to mix fuels for some technologies (for example, biomass cofiring with coal) or combine technologies, such as solar and coal.
- Long-term operations. In the U.S. alone, the industry has an estimated $1.2 trillion invested in assets. As these assets age, significant investment will be required to maintain or replace them and sustain high levels of reliability. The challenge, as it is in the everyday operation and maintenance of assets, is to do the right repair/upgrade/replacement at the right time. That requires a wealth of data provided and analyzed using new technologies.
- An interconnected and flexible delivery system. The first energy management system (EMS) was used to balance generation and demand in 1882, when the first of the Pearl Street Station generators was placed in service in New York’s lower Manhattan. Later, the first Supervisory Control and Data Acquisition (SCADA) systems were deployed in the 1950s and evolved into today’s power system, which delivers 3,900 TWh of electricity, generated from approximately 1,000,000 MW of capacity. This electricity is delivered over 2.4 million miles (equivalent to circling Earth 650 times), which includes 200,000 miles of transmission and 2.2 million miles of distribution.
Now EPRI is developing what we call Energy Management System 3.0—a highly interconnected, complex, and interactive network of power systems, telecommunications, the Internet, and electronic commerce applications that can seamlessly and efficiently accommodate variable generation, demand response, electric vehicles, smart meters, distributed generation from thousands or even millions of nodes, phasor measurement units, and electronic communications. It includes:
- Smart energy. Smart energy is more than just the smart grid—an intelligent distribution system, connected at the consumer level in a way that enables seamless integration of resources. Smart energy also includes “big data,” sophisticated analytics to interpret and maximize the value of the tremendous volumes of new data. And it includes “beneficial electrification,” exploring better end uses of energy to improve efficiency beyond kilowatt-hours saved.
- Grid resilience. As “Superstorm Sandy” demonstrated last November, we have to be prepared for the unexpected. Improved resilience includes not only power generation resource and grid hardening but also new/improved recovery and “consumer survival” technologies.
- Consumer-focused technologies. We are seeing unprecedented changes in the ways consumers access and use information. Smart devices and the new controls they provide to consumers will profoundly impact industry and require fundamental changes in the way we provide services and interact with end users.
Flexible Resources and Operations
New tools now under development are expected to lead to better integration of variable generation. Power system flexibility—the ability of the system to respond to changes in demand or variable generation—is crucial to better integrating significant amounts of variable generation. The system will need to manage increased variability and uncertainty over multiple time scales, from seconds and minutes to hours and days. New resources such as battery storage, compressed air energy storage, or demand response enabled by smart grid technologies will also be important sources of flexibility in regions with high variable generation penetration. Additionally, improved variable generation forecasting, new probabilistic operational planning tools, transmission technologies such as high-voltage direct current (HVDC) and flexible alternating current transmission systems (FACTS), and greater coordination among balancing areas can enable smoother integration of variable generation by allowing the system to manage variability and uncertainty more efficiently and reliably.
EPRI is developing processes, with a focus on tools and long-term algorithms, for considering flexibility in resource expansion. Tools will be provided that allow system planners to consider the flexibility needs of the system with high variable generation. They are being designed to enable better planning decisions to maximize the value of flexible resources on the grid. For example, this could lead to metrics to determine the flexibility needs and resources in a system, considering new and existing resources as well as the transmission network in a system.
Changes in demand and increased deployment of renewable generation are forcing coal and combined cycle plants to provide system load-balancing service. Specific operational changes expected for coal and gas plants include two-shifting, high ramp rates, high unit turndown, and reserve shutdown (Figure 2). Guidelines for flexible operations that detail best practices for limiting damage from cycling are under development.
|2. Equipment life extension. Cycling the typical combined cycle plant accelerates damage mechanisms such as creep fatigue, thermal fatigue, and corrosion, thereby increasing the rate of component life consumption. This wear and tear increases the overall costs of generation, including direct costs such as fuel, water treatment, and maintenance. EPRI is studying component and operational changes that will reduce the impact of cycling. Source: EPRI
Owners and operators of fossil power plants need to consider a range of strategies for managing the increasing need for flexible operation. The biggest challenge to mitigating the impacts of power plant cycling is the lack of available data on the impact of flexible operations on plant equipment, damage mechanisms, costs, and mitigation strategies.
An EPRI project is using existing research results of component-level cycling impacts and mitigation, combined with collaborative sharing of lessons learned and strategies used by organizations worldwide, to develop a comprehensive knowledge resource that can guide a successful transition to flexible operation. These Guidelines for Managing Flexible Operations (EPRI document 1023539) are scheduled to be released in DVD format in March and will contain 80-plus EPRI reports plus non-EPRI cycling-related reports.
EPRI also is conducting ongoing flexible operations research and development (R&D) focused on:
- Pulverized coal boiler impacts.
- Improved plant layup practices.
- Selective catalytic reduction and flue gas desulfurization cycling impacts and mitigation.
- Designs for increased flexibility in advanced coal plants.
- Instrumentation and controls to address cycling and turndown.
- Preventive maintenance for combined cycle plants.
- Improving power plant operator situational awareness.
An upcoming EPRI report, Plant Operational Flexibility: Emerging Industry Needs and Research Priorities, will document key cycling challenges and R&D needs for the industry.
The use of robotics to improve asset management is a key technology development area for EPRI. Three autonomous robotic applications deserve recognition: one for concrete, one for underwater component inspection, and one for transmission line inspection (Figure 3).
|3. Robotic assistants. The concrete crawler (left) can climb structures and perform nondestructive tests, avoiding the need for a human to be present in a hazardous location or the necessity of erecting costly support structures. The submersible robotic vehicle (right) is being developed to inspect reactor vessels and spent fuel ponds. Courtesy: Climbing Machines; MIT
Concrete Crawler Allows Real-Time Asset Condition Monitoring. Long-term operation of steam-electric power plants and hydropower facilities requires demonstration of the safety and reliability of concrete cooling, containment, and impoundment structures. Manual inspection is costly and time-consuming, and it exposes personnel to potentially hazardous working conditions. Inspection depth and accuracy are constrained by the capabilities of today’s portable nondestructive evaluation (NDE) systems.
Robots with the ability to climb and navigate irregular, vertical, and curved surfaces of large concrete structures are commercially available. In 2011, EPRI conceptualized a novel application of this technology: as a platform for automated inspection and advanced NDE of major concrete structures at power plants. This concrete crawler employs a commercially available robotic platform to climb the surface of large power industry structures. It applies on-board systems—including simultaneous localization and mapping (SLAM) technology and advanced NDE instrumentation developed for concrete applications—to conduct automated, high-precision inspections and to capture computer-encoded data and images for maintenance decision-making.
The concrete crawler will support long-term operation of generating assets by enabling fast, safe, and in-depth inspection of structures such as cooling towers, hydroelectric dams, and nuclear reactor containments. It will obviate the need to use scaffolding or rappelling for routine structural evaluations, eliminating the associated setup challenges, time requirements, costs, and safety hazards. Its payload of advanced NDE instrumentation will provide unprecedented abilities to examine the interior of concrete structures and locate and characterize voids, rebar corrosion, and other internal defects.
Proof-of-concept testing of a concrete crawler with SLAM capabilities is planned for 2012/2013 at a host site. Follow-on enhancements to the navigation system are anticipated, and the crawler’s desired NDE functionalities and requisite power supply, data collection and processing, communications, and other capabilities will be defined. A fully functional first-generation prototype will be constructed and evaluated in diverse industry settings during 2014, with further refinements and field tests leading to the development of specifications for a commercial inspection robot.
Submersible Mini-Robot Targets Inspection of Nuclear Reactor Internals. Remote-operated vehicles developed for marine applications have proven successful for the visual inspection of submerged components in nuclear reactor vessels and spent fuel pools, but commercially available technologies have several key limitations. EPRI is working with researchers at the Massachusetts Institute of Technology (MIT) to create a purpose-built robot delivering a step-change improvement in the nuclear power industry’s underwater inspection capabilities.
The new robot is being designed to allow safe, reliable, and non-intrusive operation while providing high-fidelity visual inspection across a broad range of components, configurations, and locations. The initial prototype built and tested by MIT features a compact and appendage-free design, a high degree of maneuverability, and wireless operation. Its ovoid form measures about 4 inches by 6 inches, allowing it to nestle comfortably in the palm of a hand. Its innovative propulsion and navigation system applies centrifugal pumps, high-speed valves, and maneuvering jets for precisely controlled motion.
The robot’s shape and umbilical-free operation are critical for successful in-plant applications. Many existing technologies employ propellers, rudders, and other appendages and attachments that limit access to some component locations and preclude certain types of motion. These appendages also may break off during collisions or snag on obstacles, creating the potential for contamination of carefully controlled reactor environments or other operational issues. In prototype testing, the omni-directional robot has demonstrated abilities to navigate through intricate and tight geometries and to conduct inspection-type passes over surfaces. Under joystick control, it can dive and rise, turn in place, and move forward, backward, and sideways.
Ongoing technology development focuses on the mini-robot’s payload and wireless communications system. The payload is expected to include two cameras. The first will support real-time navigation and visual examination by the robot operator; the second will capture higher-resolution imaging data for subsequent inspection, nondestructive evaluation, and asset management applications.
Optimizing wireless communications for submersed use poses challenges. Water attenuates most frequencies, and systems and components pose complex configurations. A novel system is being explored that combines optical communication capable of high data rates at a distance with radio communication capable of two-way data exchange when line of sight is lost between the mini-robot and its controller.
A next-generation prototype is under development, and experimental testing of its improved visual inspection capabilities is scheduled to begin in late 2013. A fully functional mini-robot could be available by 2015 for in-plant demonstration.
Autonomous Transmission Line Inspection Robot. Managing overhead transmission lines—including towers, conductors, and insulators, as well as corridors—is a costly and challenging proposition. Utilities must meet increasingly stringent reliability and vegetation management standards, but many circuits are approaching the end of their design lifetimes and are located in remote and rugged environments. Fly-by and ground inspections have limitations, and some equipment is extremely difficult to inspect. The autonomous transmission line inspection robot integrates mobility, sensing, imaging, power harvesting, communications, and other innovations to generate the comprehensive, high-fidelity data required for condition-based maintenance. It is capable of crawling over conductor shield wires and carrying a payload to allow autonomous inspection of transmission corridor segments up to 80 miles long at least twice annually (Figure 4).
|4. High wire act. The inspection robot is capable of crawling over conductor shield wires and carrying a payload to allow autonomous inspection of transmission corridor segments up to 80 miles long at least twice annually. Courtesy: EPRI
In 2010, EPRI initiated conceptual development of the transmission line inspection robot, designed to run largely on power harvested from shield wires. High-definition cameras and LIDAR (light detection and ranging) sensors will assess component condition, identify trees that could pose a risk to wires, and measure conductor clearance by comparing images taken over time. Electromagnetic interference detectors will identify discharge activity and other indicators of faulty equipment.
The robot also will be equipped to collect data as it passes instrumentation deployed on towers and wires, such as EPRI-developed radio-frequency sensors for monitoring vibration, lightning strikes, wind-related damage, and corrosive conditions. Data processing, global positioning, and communications systems will analyze and deliver time- and location-stamped data and images to maintenance personnel. High-risk issues and potential problems that require further investigation or immediate action will be flagged, guiding condition-based intervention.
A first-generation technology demonstration platform has been undergoing refinement on a test loop at EPRI’s laboratory in Lenox, Mass., and individual subsystems have been advanced in the field and experimental settings. These activities—conducted in close collaboration with a commercial vendor and member utilities—have informed design and construction of a next-generation robot offering mobility, energy management, imaging, sensing, data management, analysis, alarming, and communications capabilities. A real-world demonstration on a line segment made “robot-ready” by a host utility is planned for this year. Field trial experiences will inform full-scale commercial demonstration on a 40-mile-long transmission circuit.
The transmission line inspection robot is expected to revolutionize transmission asset management by expanding coverage and delivering actionable information while reducing or eliminating the need for helicopter overflights and ground patrols. On-board systems will collect, analyze, and deliver data to enhance compliance with reliability and vegetation management standards and support just-in-time intervention. This technology is expected to improve inspection and monitoring capabilities and worker safety relative to hovering helicopters at cost savings expected to be at least 30%. More importantly, the robot will enable proactive, condition-based maintenance of high-value transmission assets, a smart grid capability supporting long-term operations and leading to significant cost reductions and reliability improvements.
Residential consumption typically represents a significant portion of peak electric loads, but incorporating major end-use technologies such as space conditioning and water heating in demand-response (DR) programs has proven challenging for a variety of reasons. Consumer inconvenience and cost, the diversity of end uses and utility systems, and the incompatibilities between them are among the most significant barriers to DR participation.
Building on years of work to advance interoperability standards across transmission and distribution systems, an EPRI-led initiative launched in 2008 engaged more than 100 product manufacturers, utilities, and other organizations in documenting the need and developing early specifications for a smart grid interface for residential loads. EPRI built the modular DR connector to specification, developed a plug-in communications module with DR capabilities, and integrated them with end-use device controls in coordination with selected manufacturers. Interoperability tests were conducted on space conditioning, water heating, and other modified products, and findings were submitted to the Consumer Electronics Association (CEA) for standardization of a communications interface designed for smart grid integration of residential loads.
As a port incorporated in end-use technologies, the modular DR connector is designed to facilitate a “plug-and-play” approach for direct information exchange and interoperability among utility communications systems and the wide array of consumer devices sold in retail outlets. It could enable low-cost engagement of residential consumers in load management programs across a range of end uses. Manufacturers may be able to add grid-interactive features and the communications port to their product lines without being constrained by compatibility concerns. DR-ready devices will be available off the shelf, enabling consumers to enroll simply by inserting a utility-compliant communications module, with no need for an electrician or utility service call. Utilities will be free to develop customized modules or approve third-party products to enjoy both full interoperability with and clear demarcation from customer equipment.
Electricity providers are expected to have the real-time ability to manage residential consumption in a cost-effective manner while offering customers intelligent and flexible approaches for moderating energy use in response to price or other signals. The cost of integrating residential loads with the grid with use of the DR connector is anticipated to be as much as 80% to 90% lower than today’s approaches. As electric vehicles gain market share, the modular DR connector also represents a key enabling technology for transforming batteries into distributed energy resources.
To accelerate adoption of the new standard (CEA-2045), an ongoing EPRI project engages manufacturers, utilities, and their communications technology and load management partners in field deployment and testing of retail products incorporating the modular DR connector. In addition to examining interoperability and efficacy, these studies will address consumer experiences with installing plug-in modules and participating in DR programs.
Common Protocol for Inverters for Grid Integration. In any photovoltaic (PV) and energy storage systems, inverters convert the DC energy output from the PV module or battery cell into AC energy. In addition, inverters ensure that power quality and safety regulations are followed. However, with the increase of distributed energy resources (DER) on the electric grid, especially on distribution circuits, it is expected that inverters will have a more active role in supporting grid stability.
Power electronics incorporated in most inverters are capable of providing reactive power, which can be utilized for voltage regulation and volt-VAR optimization. The voltage fault ride-through capability of inverters allows PV plants to stay online during momentary grid disturbances. Communication-connected inverters, acting on utility commands, can change their operating mode (for example, power factor, active power generation, grid-tied vs. islanded) to match seasonal or load variation needs.
Most of the commercial inverters today, especially the larger utility-scale units, can provide smart grid functionality. The challenge is to integrate hundreds of them from different manufacturers, each with proprietary communication protocols, in the same utility network and operate them in a harmonized manner. Ongoing EPRI research is developing common functions and standard communication protocol mapping for smart inverters.
Another key challenge is to coordinate the operation of these smart DER resources with existing distribution circuit resources like load-tap changing transformers, line regulators, or capacitor banks to optimize grid performance and reliability. Recently, EPRI, working with the U.S. Department of Energy (DOE) and National Institute of Standards and Technology (NIST), launched a new initiative specifically to address the need for utility enterprise integration of DER.
Big Data Challenge. As electric utilities are implementing advanced distribution applications to improve distribution system efficiency, reliability, and performance, a vast amount of data is being generated from sensors, devices, and systems. Utilities are now responsible for data management and analytics to support distribution operations, planning, and asset management For example, going from one meter read per month to hourly reads (720 per month) is a 71,900% increase in kWh data, in addition to potential for volts and VAR data (Figure 5).
|5. Data explosion. The amount of data collected by utilities will continue to increase as more advanced technologies are deployed. Fully taking advantage of this new data by turning it into actionable information with industry standard methods and tools is a significant challenge for utility companies. Source: EPRI
When standardized analytical methods and tools are developed collaboratively, it helps reduce the total cost to procure, implement, and sustain advanced distribution applications. The development of common analytical methods that can be applied across the utility industry can accelerate the ability to process large data sets and translate them into actionable information for common distribution applications. EPRI’s Distribution Modernization Demonstration is addressing these R&D challenges, identified by more than 1,400 industry and public advisors.
The project will employ “learning by doing” in developing and demonstrating data management and analytics. It will explore new and existing distribution applications that have value to utility members for uses such as early identification of incipient faults, increased accuracy of outage location, and online validation of geographical information system (GIS) maps. It is expected to define the detailed functional requirements for each application, along with the associated data management and integration requirements. And it will demonstrate these applications in a practical approach, preserving legacy systems, as appropriate, while developing an architecture that leverages emerging standards such as the Common Information Model.
Electrification to Enhance Productivity. Businesses are facing intense economic pressures to improve productivity, enhance quality, and lower costs to remain competitive. Utilities are seeking to add value for their customers and promote local economic development. And society seeks to curb emissions to improve quality of life while growing jobs and stimulating the economy. Electrification through the application of novel, efficient electrotechnologies can address all of these needs.
Electricity offers inherent advantages of controllability, precision, versatility, and efficiency compared to fossil-fueled alternatives in many applications. However, a lack of familiarity and experience with emerging technologies impedes many enterprises, particularly small- to medium-sized businesses and civil institutions, from pursuing electrification measures that improve productivity and efficiency of operations. Utilities also must reconcile electrification strategies with mandated energy efficiency goals that are usually narrowly defined in terms of kilowatt-hour reductions. Moreover, the lack of an analytical framework to quantify the net benefits of electrification strategies—from the customer, utility, and societal perspectives—hinders development of utility-business partnerships to facilitate beneficial electrification.
A new EPRI project is exploring “beneficial electrification” by working with the industry; leading industrial collaborative organizations such as the American Iron & Steel Institute, Water Research Foundation, and the Institute of Paper Science and Technology; and with the DOE’s Advanced Manufacturing Office and NIST’s Advanced Manufacturing Partnership. The project will develop an analytical framework to quantify electrification potential in a given region or service territory, establish a valuation framework to enable business case analysis of electrification programs, and identify the most suitable and highest impact electrification applications for each utility’s unique service territory and customer composition. Special consideration will be afforded to applications ubiquitous to most service territories, including community infrastructure, such water/wastewater treatment plants and transportation ports.
EPRI is developing innovative technologies to enable grid damage prevention, recovery, and customer “survivability” during and after major emergencies.
On average, U.S. electricity consumers can expect to lose power for more than 100 minutes annually due to outages from major storms. The majority of outages result from damage to the millions of miles of distribution lines. According to a 2008 Edison Electric Institute Reliability Report, 67% of electrical outage minutes were weather-related, typically due to wind, ice, or snow either directly affecting distribution assets or bringing vegetation into contact with utility lines, poles, and transformers. And restoring service after storms can be costly. A survey of 14 U.S. electric utilities identified 81 major storms between 1994 and 2004, costing those utilities more than $2.7 billion. These direct costs represent only a fraction of a region’s wider economic losses resulting from extended outages.
Natural disasters are not the only outage threat. Increased use of computers and wireless communications also means heightened concerns about cybersecurity—an added complication in the resiliency equation. Distribution systems may be particularly vulnerable to cyber attack with the increased role of automation, as automation is one of the strategies to reduce the impact of outages resulting from other causes.
As storms and cybersecurity threats increase, so do customers’ expectations of service reliability with the evolution of the 24/7, digitally connected society. Even with enhanced response and heroic efforts by crews, restoration that stretches to days, and in some cases weeks, is no longer acceptable. At the same time, consumers expect electricity to be affordable.
EPRI and electricity sector stakeholders are developing innovative technologies to address these challenges and make the distribution system more resilient to storms and terrorist attacks. It’s a multi-pronged approach: prevention, recovery, and survivability. Damage prevention refers to the application of engineering designs and advanced technologies that harden the distribution system to limit damage. System recovery refers to the use of tools and techniques to quickly restore service to as many affected customers as practical. Survivability refers to the use of innovative technologies to aid consumers, communities, and institutions in continuing some level of normal function without complete access to the grid.
Prevention: Hydrophobic Coatings. New advances in material science have resulted in the development of a family of nanostructured polymer coatings that can be engineered to provide surfaces with specific desirable properties. These so-called nanocoatings have found application in the aerospace industry to keep surfaces ice free and in architecture to provide self-cleaning properties for windows. Nanocoatings can provide scratch, corrosion, and chemical resistance, as well as super hydrophobicity.
The self-cleaning and super hydrophobicity properties are particularly attractive for application on insulators in contaminated environments, and coatings with ice-repelling qualities may reduce the risk for flashovers in winter storms. Ice-repelling coatings also may have applications in conductors in areas where there is a risk for mechanical overload due to ice accretion in winter months.
An EPRI project is working to develop performance requirements and potential degradation modes and determine if there are any “fatal flaws” that may prevent the application of these new technologies. It also seeks to gain experience and identify appropriate test methods that can be used to evaluate and specify nanocoatings for use on electrical insulators and conductors.
Recovery: Airborne Damage Assessment. EPRI recently completed preliminary tests showing that both small piloted aircraft and unmanned aerial vehicles (UAV) or drones equipped with high-resolution cameras, global positioning systems (GPS), and sensors can be valuable tools for damage assessment. UAVs equipped with EPRI’s Airborne Damage Assessment Module (ADAM) can be small and light enough to be handled by a technician and can quickly survey devastated areas that are difficult to reach by roads blocked by downed trees or other obstacles. The use of ADAM-equipped aircraft could substantially reduce costs and cut response time by hours, if not days. It could also aid in assessing system conditions in normal situations. EPRI research will also assess the accuracy of the sensors and cameras to determine if it is sufficient to assess equipment such as insulators.
EPRI is working with utilities to conduct test flights with manned and unmanned aircraft to clarify how the module should be configured and deployed to handle different terrains and weather conditions as well as meet other requirements. This project will also look at different cost models to determine the level of value for investment in ADAM and aircraft.
Survivability: Using PEVs as a Power Source. Plug-in electric vehicles (PEVs), both all-electric and hybrid, could be used to supply energy to a home during an outage. Hybrid electric vehicles also could operate as a gasoline-fueled generator to provide additional standby power. Automakers are interested in the concept, but the technologies require further development.
Nissan Motor Co., Ltd. recently unveiled a system that enables the Nissan Leaf to connect with a residential distribution panel to supply residences with electricity from its lithium-ion batteries. The batteries can provide up to 24 kWh of electricity, sufficient to power a household’s critical needs for up to two days. EPRI is investigating potential uses for both gas-powered and electric automobiles as a power resource during extended outages (Figure 6).
|6. Rolling electricity storage. EPRI is investigating how plug-in electric vehicles may be used to supply electricity during a system outage or emergency. This graphic shows the evolution of battery storage technologies. Source: EPRI
New Materials for Safer Nuclear Fuel. Improved grid resilience includes innovations in power generation. The 2011 accident at the Fukushima Daiichi nuclear plant in Japan illustrated the operational and safety challenges associated with a loss of cooling capability, which can lead to a nuclear fuel meltdown. Current light water reactor fuel designs and materials have limitations that constrain their ability to maintain integrity under accident conditions. EPRI is investigating a variety of alternative fuel design concepts aimed at making fuel safer and increasing operational flexibility and reliability. While complete mitigation of fuel degradation in a severe accident may not be possible, improved materials that can withstand higher temperatures in these scenarios could give operators more time to act before significant damage occurs.
Existing light water reactors rely on zirconium-based alloys for fuel cladding and channel materials. These alloys perform well under normal operating conditions, but when the temperature spikes during a loss-of-coolant accident, they can weaken, corrode, and generate hydrogen. The hydrogen buildup can reach combustible levels, where an explosion is possible, which is what happened at the Fukushima plant.
The technologies EPRI has examined include:
- Cladding made from refractory metals, such as molybdenum and niobium
- Cladding and fuel channels made from silicon carbide
- Cladding made from iron-chromium-aluminum
- Fully ceramic micro-encapsulated fuel pellets
To date, EPRI has focused most of its efforts on molybdenum cladding and silicon carbide channels. Molybdenum alloys have a higher melting temperature than zirconium-based alloys, so they retain their shape even at high temperatures. Molybdenum also exhibits high wear resistance, high dimensional stability, low thermal expansion, and high thermal conductivity. The metal is chemically stable up to 2,000 degrees Celsius. EPRI research suggests a duplex or triplex fabrication approach to make the cladding compatible with current light water reactor coolants. Duplex cladding would have a thin layer of zirconium or other alloy on the outside of the molybdenum tube, while triplex cladding would have thin layers on both the inside and outside. Such fabrication techniques are challenging, but the industry already has experience fabricating duplex and triplex zirconium cladding.
As a ceramic material, silicon carbide has favorable high-temperature characteristics as a potential cladding material, but it also faces significant technical obstacles, such as fabrication. A more feasible goal may involve the use of silicon carbide to fabricate “channels,” the enclosures found between each fuel assembly in boiling water reactors. In 2008, EPRI began investigating the use of silicon carbide as a replacement for zirconium alloys to prevent channel deformation, a problem called bowing. By replacing zirconium in the channels with silicon carbide, less hydrogen would be produced in an accident, thereby increasing safety. Channels represent about 40% of the zirconium mass in a boiling water reactor core. EPRI has developed silicon carbide channels and has begun testing their viability.
Implementing nuclear fuel cladding at commercial nuclear power plants will require an extensive testing and evaluation program involving the fuel vendors, nuclear plant owners, research entities such as EPRI and the DOE, and other international organizations such as the International Atomic Energy Agency and the Nuclear Energy Agency. Given the resource commitment required and high-risk nature of this research, no single entity or group can succeed alone. Collaboration will be critical in conducting the necessary laboratory and field testing, and in assessing whether these new technologies are commercially viable.
Leveraging Consumer Technologies
Consumers are using smart devices—primarily phones and tablets—in ways that are profoundly impacting society and the electric industry. Consider the smart phone, which was introduced in 2007. In 2011, manufacturers shipped 500 million of them. Apple introduced the iPad in April 2011 and built more than 100 million of them last year. This profusion of devices has fueled an explosion in the development of applications and uses. In 2007, a little-known network called Twitter carried 340 “tweets” a day. By 2012, the volume had increased a million-fold, and many of Twitter’s users also were among the 900 million active Facebook users. On an average day, more than 200 billion e-mails are sent worldwide.
EPRI is developing a variety of apps, primarily for utility staff, that enable use of smart devices for tasks that include operating valves, navigating robots, providing field force data visualization for utility engineering and operations professionals, finding and analyzing stray voltage, analyzing power quality, and finding the locations of electric vehicle charging stations.
The data visualization technology combines tablet and smart phone technologies, real-time data from the internal magnetometer, and 3-axis gyroscopic to stabilize and provide a more accurate “compass” when a user points the mobile device at a distribution pole or at transmission and distribution conductors. GPS and Common Information Model messages serve to locate and retrieve segmented GIS data from a utility GIS database, and the device renders the GIS data segments on screen as a map information overlay from the camera image. An example of this would be seeing a pole structure symbol through the camera while the screen displays the camera image with the one-line circuit drawing overlaid.
EPRI’s iCV Analyzer Application is a contact voltage detector app that is used in concert with a commercially available probe (antenna) and amplifier (wand) that allows users to identify metal objects that may have become inadvertently energized. The iCV Analyzer app can be downloaded from iTunes. There is now interest from commercial manufacturers to manufacture and sell the add-on wand device for contact voltage detection. E-mailing datasets, user site info, and GPS location features are included capabilities of this app.
Utility companies are finding more and more ways to enhance their points of contact with consumers. Of the companies responding to a recent buildnetwork.com survey, 40% said smart devices have changed how they communicate/connect with their customers, and 24% said they have impacted their products and services and how they are delivered.
EPRI recently surveyed a number of its utility members to find out how they are using mobile platforms, both internally to support transmission and distribution (T&D) operations and to provide services to end-use customers. Of the 24 companies that had responded as of this writing, two-thirds currently are using mobile devices for utility operations (not including mobile terminals used by utility crews). The main uses are inspection and assessment, followed by work order management and workforce deployment (Figure 7).
|7. Want to get closer to utility customers? There are apps for that, and the industry is using them. In a survey of 24 major utilities, 67% said that the company is currently deploying and using mobile devices in its T&D operations, but often in different ways. Source: EPRI
On the consumer side, 63% of the responding utilities are sending text messages to customers and 38% are connecting via downloadable apps. For both T&D and consumer purposes, cyber security concerns and support costs were listed among the top barriers.
— Arshad Mansoor is senior vice president, research & development for the Electric Power Research Institute.