Meet Sam. Sam is about to buy a car, but he doesn’t know which one. He stands on the dealer’s lot engaged in a host of complex calculations, examining alternatives and weighing the pros and cons of model, cost, fuel efficiency, reliability, and even color. These days Sam has another important choice: gas or electric? With an electric vehicle, Sam must take into account even more variables: When and where will he charge the vehicle? How much will charging cost? Is he willing to pay a premium to own such a car? In 2009, EPRI researchers undertook to gauge how Sam and other consumers view electric cars and what they expect of their electric utilities. Electric vehicles represent a tiny fraction of the vehicles on the road today, but Mark Duvall, director of EPRI’s Electric Transportation Program, expects production to ramp up quickly. “By 2015,” according to Duvall, “it’s quite likely we’ll have more than a million electrics on the road.” As the number of electric vehicles grows, so will demand for power. For an industry accustomed to serving stationary customers, utilities are finding that vehicles present an entirely new set of challenges. “It’s a different business,” said Bernard Neenan, a technical executive at EPRI. “For the first time, our customers are mobile.”
EPRI’s Electric Transportation Program has long focused on understanding how electric vehicles will affect the power grid and how utilities will accommodate the added demand for power. In 2008, the program’s members decided to incorporate another key component of the equation: electricity customers. To prepare for an influx of electric vehicles, utilities need to know when their customers will buy cars, what kinds of cars they will buy, and how those purchases will affect the way they use electricity. Researchers developed an online survey to examine customers’ perceptions of electric cars and the factors that influence electric car purchases. The survey builds on the findings of EPRI’s 2001 national survey of electric vehicle interest, which focused on what consumers want from an electric vehicle. This time, members wanted a survey to help them understand how customers view the utility’s role in electric transportation in their own service areas. “We know electric cars are not going to be adopted uniformly across the county—or even within a utility’s service area,” said Neenan, the project manager. “So it makes sense to gather information specific to the characteristics of the customers in that area.” As Neenan and his colleagues tested the survey to “work out the bugs,” focus group discussions revealed a serious problem: consumers didn’t understand the researchers’ nomenclature. “They thought an electric car was a hybrid car or a hybrid car was an extended-range car,” Neenan said. “That confusion would have been a disaster in the survey.” To address this issue, the researchers added an educational component to outline the differences between standard gasoline vehicles, hybrid electric cars, plug-in hybrid electrics, and battery-only electric vehicles.
In July 2009, EPRI collaborated with Southern California Edison and a third party polling company to administer the survey to SCE’s customers.To qualify, participants had to be at least 18 years old and had to be planning to buy or lease a new vehicle in the next five years. The survey focused on issues critical to the electric power industry: consumer charging preferences; accessibility of at-home charging; at-home charging plan preferences; the consumer’s interest in acquiring an electric vehicle; and the influence of gasoline prices, vehicle price, and the consumer’s friends and family. Of 869 respondents, 292 owned a hybrid and 587 owned a conventional gasoline vehicle. Not surprisingly, interest in plug-in hybrid electric vehicles was highest among people who owned a hybrid. Some 20% of hybrid owners said they “definitely” plan to purchase or lease an electric car, compared with only 8% of non-hybrid owners. Many survey questions dealt with charging, a topic customers identified as important in the 2001 survey. For example, do customers expect that there will be public charging? Where would they be most likely to charge their vehicles? Would they pay a premium for faster charging? Notably, nearly all respondents said they would prefer to charge their electric cars at home. “With a gasoline car, you go to the gas station once a week. With an electric car, you plug in when it’s convenient,” Duvall said. “That’s an incredible benefit to owning an electric vehicle.” Researchers also asked participants when they would charge, if offered three options: an “anytime” plan that would allow them to charge day or night, a “night-time discount” plan that would give participants a discount for charging during off-peak hours, and a “night-time only” plan that would save participants even more money by letting them charge only during off peak hours for a yearly flat fee. In California, participants preferred the “night-time discount” plan over the other two. Half of all non-hybrid owners and nearly 60% of all hybrid owners said they would choose this option. The “anytime” plan was least M The Story in Brief How will consumers react to the auto industry’s rollout of electric vehicles, and how do they expect their power companies to be involved?
New EPRI developed surveys gather regional information on the public’s interest, assumptions, wants, and needs. 16 EPRI JOURNAL desirable. The survey also presented an optional discount of $10 a month if customers would allow the utility to interrupt their charging occasionally. More than half of non-hybrid owners and 70% of hybrid owners were extremely or very likely to choose this option.
What holds true for California customers may not hold true in other regions. “We looked at their (SCE’s) results and said, we don’t think that’s our typical customer,” said Bryan Coley, a research engineer with Southern Company. In 2010, EPRI researchers helped Southern Company in Atlanta implement its own survey of 500 customers. Atlanta is a city with long commute times and notoriously bad traffic, where residents might be inclined to purchase electric vehicles to cut their gasoline bills. “This was a great opportunity to benefit from a market research study already started by EPRI,” Coley said. EPRI also launched a 1,000-person survey in collaboration with the Tennessee Valley Authority (TVA), which provides electricity to Tennessee and parts of Kentucky, Alabama, Georgia, Mississippi, North Carolina, and Virginia. Responses to these surveys are strikingly similar, but differ substantially from California responses in two key areas. First, the percentage of Californians who said they would buy an electric car in the next five years was much higher. “That’s not unexpected,” Neenan said. “California consumers are more inclined to be early adopters’.” Second, California respondents would be more willing to charge at night if the price of electricity were cheaper. That’s important because drivers who come home from work and plug in their cars could be charging during peak demand and increasing stress on the electricity grid. “Charging behavior is kind of the wild card in all of this,” said James Ellis, senior manager of transportation and infrastructure at TVA. So utilities would like to offer customers an incentive for agreeing to charge when loads are lowest. The survey suggests that might work in California, where 66% said they would charge only at night or late at night, but that strategy might be more difficult to implement in the Southeast. When the survey offered Southern Company’s and TVA’s customers the same discounts, two-thirds of the respondents said they wanted to be able to charge at any time. This may reflect cultural differences or the Southeast’s relatively cheaper electricity. “It really just shows that low cost energy economics is more of a driver here than the environmental benefits,” Ellis said. While responses differed among surveys, most differences were subtle. “One of the things we’re finding is how alike people are,” Neenan said. “That may mean we can administer surveys over regions rather than just in utility service territories.” Participants from all three surveys said that faster charging would influence their decision to buy an electric car, but few participants indicated that they were willing to pay extra for faster charging options. Similarly, few participants were willing to pay a premium to purchase the car itself. In all three regions, respondents who said they would be likely to buy an electric car tended to be young, male, educated hybrid owners. One section of the survey explored customers’ expectations of their utilities. Responses indicate that consumers think that electric utilities will play an important role in the transition to electric vehicles. Between 50% and 70% expect the utility to offer home charging installation services and provide car readiness audits to tell them what upgrades they need to prepare their homes for an electric car. Many customers think that utilities should provide public charging stations. “Under the traditional model, a utility delivers power no further than the electric meter,” Ellis said. But the survey results suggest that some consumers may like to see power providers The GM 2011 Chevrolet Volt is a plug-in hybrid. It has an unlimited driving range with its gasoline engine and an EPA-rated range of 35 miles on its battery. It will recharge from “empty” in about 8–10 hours using a 120-volt portable charger or in 3–4 hours from a dedicated 240-volt charger. Photo courtesy of Chevrolet. Ford plans to release the battery electric version of the Ford Focus in late 2011. The Focus Electric is powered by a lithium ion battery that can recharge from either 120 or 240 volts. Using the wall-mounted 240-volt charger can completely recharge the battery in as little as 3–4 hours. Photo courtesy of Ford. The 2011 Nissan Leaf is a 100% battery electric vehicle with an EPA-rated range of 73 miles. It can use a portable 120-volt charger, but most drivers will likely opt for a dedicated wall-mounted 240-volt charger that can completely recharge the battery from “empty” in less than 8 hours. Photo courtesy of Nissan. WINTER 2011 17 think beyond that model. “It gives us more insight into what tools TVA can help our power distributors build in order to better meet consumers’ needs,” Ellis said. Utilities may not be able to provide the services that customers expect for the prices they want to pay. Coley was surprised at how little customers offered to pay for conveniences such as 240-volt charging stations and faster charging. Purchasing and installing a 240-volt charging station, for example, can cost as much as $2,000, but more than 90% of customers said they wouldn’t pay even $1,000. “Consumers always want the best value at the best price,” Coley said. But the survey results make Coley suspect that customers need more education. Ellis agrees and added that consumers may not be taking into account the benefits of fuel switching. “The upfront costs of hardware and plug-in vehicles are more expensive right now,” he said, “but there may be future financing models that can help make buying an electric car and supporting charging infrastructure more like buying a conventional vehicle.” “These surveys help utilities understand what their customers expect from them, but they also help EPRI understand what our research agenda needs to look like to be able to meet some of these requests,” Duvall said. For example, given that people who have relatively cheap electricity seem to want the convenience of charging at any time, EPRI researchers might explore other incentives that could entice customers to charge their cars during off-peak hours; EPRI could then develop the technologies needed to deploy those incentives.
The Road Ahead
EPRI researchers plan more surveys, some of which may cover an entire state and allow several utilities to share the data. Once EPRI has data from several regions, it plans to create a national database of the survey responses. “The more data we have, the more we can learn,” said Duvall. Coley would like to see the survey repeated in a few years. “At that point, our customers will have had some hands-on experience with the vehicles,” he said. Neenan calls the survey a first step. “This is an early market, so not everyone who wants an electric vehicle can get their hands on one,” he said. “But as more automakers enter the market and the volume ramps up, we’ll quickly get to a point where more people will think about buying electric vehicles. Because the current survey doesn’t look at decision tradeoffs, the data can’t be used to calculate a true adoption curve.” Neenan and his colleagues hope to start working on a new survey in 2012 specifically designed to address those decision factors. “Through this more probing research,” he said, “researchers can look more closely at the decision to purchase an electric car and the impacts of the car’s price, gasoline costs, and other factors.” And knowing how many consumers will buy electric cars is the first step in preparing the electricity grid for this new fleet. “The industry is trying to anticipate how electric vehicles will change the demand for electricity,” Neenan said, “so we don’t get caught unprepared.” With better information, both Sam the car buyer and his utility power supplier may expect to arrive at the same plug at the same time for a successful “refueling.”
Utility Robots, Rise Of The Machines
They don’t look like the Terminator or come from the Forbidden Planet. But robots are becoming important allies to the power industry, performing tasks that are too risky, remote, or complex for humans to handle efficiently.
The industry is starting to pay attention to the possibilities: in October 2010, the first International Conference on Applied Robotics for the Power Industry brought together robotics experts and power company representatives from 22 countries to facilitate the development of suitable machines. EPRI has long recognized that robots can perform critical functions and has been developing robots for power plant and high-voltage environments since the 1970s.
One early power line robot, TOMCAT (Teleoperator for Operations, Maintenance, andConstruction using Advanced Technology), featured a large remotely operated arm for work on live transmission wires. EPRI designed TOMCAT to be an all purpose machine, but robotics trends now call for smaller equipment to perform specific functions. EPRI’s current work covers a wide range of applications and makes use of the knowledge of research and industry partners to investigate promising technologies while lowering development costs.
Today’s projects put robots inside major plant components, on suburban streets, and on high-voltage transmission lines. Taking the Heat Robots make good detectives, and they are particularly adept at performing work that involves squeezing into tight spaces, such as the vertical and horizontal tubes of a heat recovery steam generator (HRSG). In a combined-cycle plant, these tubes transfer heat from the combustion turbine’s exhaust gas to water flowing through the tubes to generate additional steam for electricity production. The closely bundled tubes are typically 50–70 millimeters (2–2.75 inches) in diameter and extend 12–18 meters (40–60 feet) between the upper and lower headers.
Physical limitations pose big challenges for close inspection. When the tubes perform poorly or fail altogether, the causes can be complex and difficult to uncover. So inspection requires something flexible and agile. Accessing the tubes inside the bundle presents a particular challenge for nondestructive evaluation (NDE) because the ultrasonic and eddy-current equipment used to detect problems must be in contact with the tubes. Robots are good candidates, and a so-called “snake” robot has been developed to crawl around in the tight environment. EPRI is working with Carnegie Mellon University to improve the robot’s agility, speed, and efficiency and to add capabilities to perform NDE. The goal is to improve the robot’s ability to inspect the hard-to-access center of the tube bundle. Designers also hope to be able to introduce the robot for a complete inspection through a single entry point in the HRSG header, avoiding the time and cost of cutting and closing multiple entries. Other modifications would allow the robot to climb vertical tubes more easily and to direct its inspection camera straight down the tube bundle. The team plans to alter the robot’s “gait” so that it can maneuver through different tube configurations and remain stable when encountering obstacles.
To increase its range of motion and prolong its operation in the field, researchers are looking to reduce the weight of the robot’s tether while adding other safety features. Over time, EPRI plans to add more NDE capabilities for a wider range of problems and solutions. Seeing the Light Light-emitting diode (LED) technologies use energy more efficiently than conventional lighting and promise a longer lifespan, resulting in lower operation and maintenance costs. Since 2009, EPRI has been conducting an LED energy-efficiency demonstration to assess the technology for street and area lighting. EPRI designed a robot, called Scotty, to help researchers collect data from the 20-plus U.S. demonstration sites. Scotty takes precise measurements of light levels on the street so that researchers can determine, among other things, how much and how fast the light intensity deteriorates over time. It’s not an easy job. Researchers want to collect photometric data near the ground and to do so in a precise grid.
The Story in Brief Robots are the power industry’s allies for complex inspection and data collecting missions. the past, researchers manually inspected the equipment, made light measurements, and recorded the data. Scotty, a four-wheeled, remote-controlled robot, is proving to be a faster, more exacting surveyor. Guided by a global positioning system (GPS), Scotty traces designated paths, measures lighting levels, and transmits the readings to a remote computer five times per second. The robot completes a job in minutes rather than hours. It can measure all types of lighting, allowing direct comparisons of LED systems with more conventional options. Thanks to Scotty’s precision, researchers are making measurements at a 2-foot (0.6 m) spacing, providing much more detail than the conventional 10-foot (3.1 m) spacing. The robot also keeps human inspectors off the streets, where they may be exposed to speeding cars and other hazards. Living the High(-Voltage) Life Transmission lines present a substantial and expensive challenge for human inspection and maintenance. They stretch hundreds of miles, often through remote areas. As the technology is refined, momentum is growing to use robotic inspection for transmission line components. In a survey conducted during last year’s robotics conference for the power industry, 32% of the respondents said they used robots for live line work, most often for replacing parts or cleaning insulators. Inspection and preventive maintenance applications could greatly increase the use of robots on the high wires.
EPRI is refining a prototype, called Ti, to develop an inspection robot that can reside permanently on a transmission network, traveling up to 40 miles (64.4 km) on a line in four months. The robot will then reposition itself on another wire or be moved by a line crew. Along the way, the robot will identify right-of-way encroachment and any vegetation that threatens the performance of the line, plus monitor and report problems with transmission line components. EPRI researchers are now analyzing data from laboratory tests to improve Ti’s design. The current prototype can run at up to 3 miles (4.8 km) per hour and inspect, on average, 15 segments of 138- kV line each day. Ti incorporates high-definition infrared cameras and image-processing technology and can compare images taken at different times to track equipment deterioration well before failure. Researchers expect to add a light detecting and ranging (LIDAR) sensor to provide close measurements of the relative positions of the conductor, vegetation, and other structures.
Ti’s use of GPS technology enables utility operators to quickly pinpoint trouble spots. Ti will also transmit data collected from sensors already installed along the transmission lines to check on the performance of insulators, conductors, and compression connectors. This use of sensors can be critical, particularly in regions that experience strong winds or frequent lightning. Creating inspection robots for the nation’s transmission network will continue to be a key focus. EPRI will unveil a new transmission robot at the Utility Products Conference and Exhibition in San Antonio, Texas, in January 2012. Nuclear Reactor Drain Line The interior surfaces of carbon steel drain lines in a boiling water reactor (BWR) are susceptible to corrosion by the deoxygenated water that flows through the pipes. If not detected early enough, corrosion can thin pipe walls and cause failures that could lead to an unscheduled shutdown or other problems. EPRI is developing a series of robots to inspect and evaluate reactor drain lines for various BWR designs. Drain line examination presents key challenges. The lines are surrounded by extensive hardware at the bottom of the reactor, making access difficult. Moreover, the configuration of drain lines and adjacent equipment differs by BWR plant design.
In 2007, EPRI conducted a field test to demonstrate the first robot’s ability to remotely assess the wall thickness of a BWR drain line. The reactor’s piping configuration was typical of BWR reactor Models 5 and 6. The robot used two rotating ultrasonic transducers to measure the thickness of the drain line pipe. Data analysis showed that the drain line was in good condition. Since then, three other reactors have deployed the same robot design to inspect drain lines. A second-generation robot was designed for a drain line configuration typical of BWR Model 3 reactors. In these reactors, the drain line follows a complex path on top of an I-beam and through pieces of hardware, such as a control rod drive mechanism and in-core flux-monitoring tubes. The complexity of the operation prompted researchers to build a detailed, full-scale mockup of the piping configuration, including obstructions.
Testing the robot 8 EPRI JOURNAL Scotty, a mobile light-measurement robot, performs accurate, timely, and repeatable measurements of LED light levels. Ti, a transmission line inspection robot, can traverse 60 miles (96.6 km) of line at least twice a year, collecting high-fidelity information that utilities can act on in real time. WINTER 2011 9 on the mockup allowed engineers to fine tune the robot, identify likely problems, and train the inspection team. In 2011, after two years of development, the new robot was put to use during a reactor’s planned maintenance shutdown. The EPRI–utility team encountered a navigation problem because the mockup did not correctly reflect a spacing gap, but after some modification, the robot completed its mission and provided the data necessary for the plant owner to certify that the drain line was in good operating condition. Inspection of Concrete EPRI is also designing a robot to facilitate the inspection of large concrete structures.
The “concrete crawler” will have to be able to move over curved concrete wall surfaces, be rugged enough to withstand outdoor use, and run on a battery that can last three to four days. Why? Because the crawler will be checking large structures such as cooling towers, containments for nuclear reactors, and hydropower dams, said Maria Guimaraes, a project manager in EPRI’s Nuclear Sector. Currently, inspectors assess the integrity of such concrete structures with manually applied NDE equipment, using scaffolds that must be moved around the structure to gain access. As concrete structures age, the need for evaluation increases. “Right now, it takes a long time to inspect a cooling tower,” Guimaraes noted. “With a robot, it could be safer, simpler, and less expensive.” The concrete crawler will carry test equipment and collect data for later analysis in the lab. Forty companies responded to a request for proposals for the concrete crawler projects this past summer. EPRI is evaluating the proposals and plans to conduct field tests next year.