Julian Sanchez, Marco Sanchez
Recent data shows that the release of CO2 emissions is having a meaningfully disruptive impact on the climate of our planet. Although the totality of the consequences of climate change is still unknown, there are examples in regional ecosystems that raise serious environmental and economic concerns. Designers have an opportunity to make a positive contribution to the challenge of reducing emissions through research and innovation that helps affect the energy-consumption behavior of humans. Here, we discuss four domain-specific examplesdriving, aviation, home energy consumption, and personal computer usewhich help highlight opportunities in this area.
Historically, our professional community has been proactive in identifying critical areas that can benefit from our expertise. Researchers and practitioners in design, human factors, and HCI have made important contributions in domains such as aviation, medical systems, the Internet, software development, and military applications.
Our planet's climate is an exceptionally complex system, and much like any complex system, it is difficult to discern the causal nature of its internal mechanisms. However, as the efforts of scientists around the world yield more data on this issue, there are emerging, abnormal trends in the temperature of the planet . For example, on average, the planet has experienced unusually warm temperatures in the past 50 years, and especially in the past 10 (e.g., the two warmest years ever, as far as scientific records show, were 1998 and 2005). Also, records from Mauna Loa Observatory in Hawaii show that CO2 levels have risen from approximately 335 to approximately 385 parts per million (ppm) or 1.6ppm/year over the past 30 years . Comparatively, records from ice cores show that over the previous 6,000 years, CO2 levels rose from approximately 185 to approximately 265ppm or 0.013ppm/year . That is an increase of more than two orders of magnitude in recent history. Basically throughout the existence of humanoids, the planet has never experienced current CO2 levels . This accelerated rate of CO2 released into the atmosphere is driven by the 30 gigatons/year that are currently generated by the burning of fossil fuels.
There are two ways to approach the issue of CO2 emissions: generation and consumption of energy. On the generation side, the solution path needs to spur cleaner methods to produce energy. Some scenarios predict that by the year 2050, approximately 60 percent of the world's energy will come from renewable resources . However, the amount of energy generated with coal is also expected to double by 2030, mainly as a function of the industrialization of China and India. Therefore, while cleaner energy generation is critical, it is only part of the equation.
The other side of the equation is lowering our energy consumption, while minimizing the impact on our lifestyle. One way to work toward less consumption is through technology solutions such as hybrid automobiles and energy-efficient appliancesbasically, making technology more efficient. But the most immediate and highest-payoff approach in terms of tailoring energy consumption can be accomplished with the application of creative problem solving.
To date, an emphasis of the creative design communities has been the development of user-centered products, processes, and systems. Through research and innovation, HCI and human factors professionals have aimed to understand human behavior and interaction with technology to optimize the performance of human-machine systems and improve the user experience. Understanding how a technology works (i.e., how it uses energy) could become a key feature of the user experience with most technologies, especially if the economic consequences of energy consumption are easily accessible and intuitive. Energy consumption is not a variable that has been given much consideration in terms of affecting human performance and behavior in human-machine systems.
Consider the following research vignettes of subtle changes that illustrate the potential for design to make a difference in the study of energy usage.
As gasoline prices were approaching record highs in the summer of 2008 ($4/gallon), we noticed several mainstream media features on how to alter driving behavior to save gas and money. The basic message was intuitive: Ease off the accelerator as much as possible, and use the brakes as little as possible. An automobile with a real-time, miles-per-gallon (mpg) gauge was used as the experimental platform to test the impact of driving behavior on fuel efficiency. For eight straight workdays (Monday-Thursday), our morning commute was conducted under "normal" driving behavior, and the mpg of each trip (15.1 miles) was recorded. The commute always began within the same 10-minute window in the morning, and total driving time was recorded. The process was repeated for the subsequent eight workdays under a gassaving driving behavior, following the suggestions offered by media experts.
After four weeks, the average mpg under "normal" driving behavior was 25.5 (SD = 1.4), and it took an average of 21.6 minutes (SD = 2.5) to complete the morning commutes. Under the gas-saving behavior, the average mpg was 30.7 (SD = 1.2) and the average commute time was 23 minutes (SD = 2.8). An increase of 5 mpg, with an average delay of 1.4 minutes, was deemed as a positive trade-off. More important, having the real-time mpg indicator and coupling it with driving behavior provided valuable insight about the types of situations that have the most impact on fuel efficiency.
Imagine applying the same principle behind gas-saving driving behavior to flying airplanes. The space may be a lot more complicated, but the change is not unrealistic. Airplanes typically descend and ascend in a stepwise fashion to accommodate crossing traffic. Leveling off in the middle of a descent requires additional power from the aircraft, and therefore more fuel. However, a concept that is gaining traction in the aviation community is the design of arrival procedures into airports such that airplanes can execute Continuous Descent Arrivals (CDAs). During a CDA, the aircraft descends without leveling off (see Figure 1). The potential benefits of implementing these types of arrival procedures across major U.S. airports could amount to annual reductions in CO2 emissions of approximately 850,000 metric tons . Some CDA-like procedures have already been implemented at some airports, like Hartsfield International Airport and Louisville International Airport.
Admittedly, implementing CDAs is not trivial, and it requires a great deal of testing and evaluation to ensure that safety and efficiency standards are met. However, for CDA-like procedures to gain prevalence, a number of HCI and design issues require attention. Air-traffic controllers are accustomed to stepwise descents, which give them full control and awareness of the location of airplanes since they issue the level-off commands as necessary. CDAs introduce uncertainty and make it more difficult for a controller to estimate the future location of an aircraft that is continuously descending. This added uncertainty may affect the controller's performance, especially if there is a need to cross an ascending aircraft anywhere near the projected descent path of the CDA aircraft (the controller can ignore CDA procedure and level the aircraft off at any point). Therefore, it is critical to isolate the variables that lead to additional controller workload when managing CDAs and understand their impact on the controllers' performance. This will facilitate the development of interventions (procedural, automation, and/or training) to help controllers overcome the new workload introduced by CDAs.
The formula for using less energy in our homes seems easy: Consume less energy. One could draw a parallel to dieting, where the formula for weight loss should be fairly evident: Consume fewer calories. However, medical research shows that by itself, motivation to lose weight does not predict weight loss ; while methods such as counting calories, tracking fat, and using a weight scale regularly correlate strongly with successful weight loss . The relevance of these findings in the medical/nutritional field is that tracking and learning the high-payoff behaviors of consumption appear to be the catalyst for efficient consumption behavior.
Can counting watts have a similar impact on energy consumption to that of counting calories on dieting? Figure 2 shows an energy-bill comparison of three years for a three-person family living in a 2,100-sq.-ft. house (three bedrooms, two bathrooms, one story, no natural gas, southern region of the U.S.). The meaningful aspect of this chart is that in mid-June 2008, one of the house members measured the energy consumption of all of the electrical devices, along with the estimated cost of using each device per month. We shared this information with members of the house, and discussed and implemented behaviors for reducing consumption. The downward trend observed in 2007 is simply a function of the seasonal change, which always leads to a reduction in air conditioner use. The most compelling aspect of Figure 2 is the difference between 2007 and 2008 during July, August, and September.
This particular family took a fairly aggressive approach in their energy-consumption behaviors (e.g., air conditioner during summer went from 74°F to 81°F, water-heater breaker was turned on only for one hour in the morning, Direct TV/cable boxes were disconnected when not in use). However, their change in energy-consumption behavior reduced the electric bill by more than half in some months. This simple, anecdotal example suggests there is an opportunity to develop solutions that improve energy consumption awareness in homes. Much like weight loss, it may be a simple matter of having information that allows an individual to formulate efficient strategies of energy consumption tailored to their personal constraints. Consider the potential impact of a real-time meter that shows rate of consumption inside homes with data about the sources of energy usage, and decision-support information about opportunities for savings . If someone is shown the monthly dollar impact of changing the temperature settings of their AC by two degrees, would the individual be more or less likely to implement that change?
By the year 2020, personal computers (laptops and desktops with LCD monitors) will account for approximately 42 percent of the carbon footprint of all information and communication technologies . One interesting fact about personal computers is they are designed with the capability to operate at higher levels of energy efficiency than their common/default configurations. For example, the city of Miami recently implemented a power savings initiative for approximately 2,000 desktops and 800 laptops, which was purely based on the power configurations of computers. This effort resulted in an estimated reduction of 828 tons of CO2 emissions per year (equivalent to a midsize automobile's emissions over 250,000 miles). The city of Miami's solution automatically sent computers into a sleep mode when inactive for a specific number of minutes.
While conceptually simple, this solution took a significant amount of effort to develop since it had to account for a wide range of computer models, operating systems, etc. The results highlight the potential benefits of taking advantage of capabilities that already exist in most personal computers. There are potential "low hanging fruit" solutions, which include making energy-consumption settings more accessible and meaningful for users than they are today. For example, a user with the intention of saving energy might take the time to turn off his or her computer before going out for a one-hour lunch. However, rebooting a computer actually consumes the equivalent of putting it on sleep or standby mode for approximately three hours. It is likely that a considerable percentage of PC users do not even know there is a power options control nested in the control panel, and even if they know it is there, they would not get much value out of looking at it. As another example, most laptop users probably assume the brightness of their display impacts battery life, but by how much? Once again, the challenge for our design communities is to develop and research simple, intuitive solutions that can help users turn energy management into part of their interaction with a computer. Imagine an energy-management function that is easy to access and provides transparent information about the energy-consumption settings of the computer.
The problem of climate change is real and serious. The approach to overcoming this challenge should be multifaceted but in many cases will not be simple or easy. Our creative communities can have a meaningful impact on this issue by investigating interventions to make technologies' energy consumption part of the user experience. The benefits are not just for the planet, but are economic as well. Perhaps the term "appropriate reliance" can acquire a broader meaning, one that encompasses an energy-efficient use of technology . Concepts like automation transparency can also be expanded or adapted to represent technologies/automation that share their energy-consumption behavior with the human. To date, many of us may have dismissed ideas about energy conservation because we did not find them practical, or because we thought that not enough people really cared for such ideas to work. However, as we move forward, the issues related to climate change will start to become sobering realities. Now is the time to start working on solutions.
2. Scripps CO2 Program. http://scrippsco2.ucsd.edu/
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8. Kruger, J., Blanck, H. M., and Gillespie, C. "Dietary and Physical Activity Behaviors Among Adults Successful at Weight Loss Maintenance." Journal of Behavioral Nutrition and Physical Activity 3 (2006).
9. See http://www.google.org/powermeter/ for an example
10. SMART 2020; http://www.smart2020.org/
Julian Sanchez is a senior human factors engineer at the MITRE Corporation in the Center for Advanced Aviation System Development (CAASD). He received his Ph.D. in the engineering psychology program at the Georgia Institute of Technology in 2006.
Marco T. Sanchez is the Network IT Administrator for the city of Miami. He received his M.S. in industrial and systems engineering and his B.S. in electrical engineering at La Universidad del Valle (Cali, Colombia). Sanchez is a Microsoft Certified Systems Engineer.
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