I enjoyed “The Evolution of Robotics” in the winter issue [p. 7] on current progress in robotics at Hopkins. Just wanted to call out one inaccuracy in the article where it assumes robotics at the Whiting School traces back to the 1990s.
Assuming the Applied Physics Laboratory at Laurel is considered part of the Whiting School, there may be a longer history for robotics than indicated in the article. When I was working on my master’s in computer science at APL back in 1981–85, I had the opportunity to work with Dr. Sigilito at APL. He related to me the history of the “Hopkins Beast”, which was a robot that looked a bit like R2D2 from Star Wars and inhabited the basement of a laboratory building. This early robot had a limited vision capability that allowed it to identify specially designed electrical outlets in the basement area. This allowed the robot to move about on its own and when its charge fell below a certain level it would look for an outlet to recharge itself. After charging it would continue to wander about the basement using its limited artificial intelligence and vision capability.
Greg Chirikjian’s robot is certainly lightyears ahead of the “Hopkins Beast.”
Rod Summerford, MCS ’85
What About Nuclear?
I want to compliment “The Terawatt Challenge” by Mike Field in the winter issue, and especially the [sidebar] “Dead Calm, Dark Night.” I found the article to be technically interesting, but it failed to state (except indirectly) that a major part of the energy supply problem requires meeting the demand for electricity on that single peak day of the year. The article did discuss the problems of storing electricity during off-peak hours, but it did not state that meeting the expected peak demands of the future will certainly require the installation of new power plants to carry the electric load when the wind is not blowing and the sun is not shining. For me, this omission had a negative effect on the value of the article.
There was no mention that Hopkins might also support the idea of installing the most environmentally friendly type of power plant: nuclear. Hopkins alumni have been supporting nuclear power plants in the past—why not the future? I, for one, studied under Professor A.G. Christie and was awarded the master of science in engineering from Hopkins in 1950, and was a key member of the team that designed and built the Calvert Cliffs Nuclear Power Plant, which has been supplying huge quantities of reliable and safe electricity since 1973, and hasn’t emitted a single ounce of carbon dioxide during the entire period (except, of course, CO2 from the small heating boiler). In addition, Hopkins professor of environmental health and sanitary engineering John C. Geyer provided material support during the design phase.
Robert W. Davies, MS ’50
Fuel for Thought
I would like to congratulate Mike Field and Johns Hopkins Engineering magazine on the thoughtful and interesting article “The Terawatt Challenge” [Winter, 2009].
While fuel cells have potential efficiencies of 60 percent as noted, current generation cells require ultra-pure hydrogen to avoid rapid cell deterioration. This exacerbates the efficiency losses inherent in the current hydrogen production technology. Over 90 percent of deliberately produced hydrogen in the U.S. comes from steam reforming of methane (SMR). Almost all is used in petroleum refining and fertilizer (ammonia) manufacture and is typically produced at 95–99 percent purity level, with a thermal efficiency of 60–65 percent. This leads to an overall efficiency of 35–40 percent in a fuel cell system. Raising hydrogen purity to the five-nines level likely would reduce production efficiency. The entire energy train deserves attention.
Mr. Field noted that improvements in fuel cell electrode catalysts that greatly reduce platinum requirements are generally seen as central to bringing fuel cell costs into an economically viable range. This seems an area where the broader resources of the university, particularly in surface chemistry, may be critical to the prospects for any breakthrough advance in technology.
The effort by Professor Meneveau and others to understand the subtle, but potentially troublesome, environmental consequences of large-scale wind turbine deployment is to be applauded. Early coal-based power plants were not a major environmental concern; they were few and sparsely distributed. Massive deployment of wind turbines has the potential for unfortunate and unforeseen environmental consequences. Seeking to understand such phenomena early on is a very worthwhile endeavor.
In addition to the “Dead Calm, Dark Night” dispatch issues raised, transmission remains a major impediment to both wind and solar-based electric power. While this has been largely viewed as dominated by rights-of-way and financial constraints, EPRI, DOE, and others have noted that major improvements in transmission efficiency and grid management are needed to facilitate the economic transmission of power from the remote areas favorable for generation to the densely populated areas that are the major load centers. It is unclear whether grid and transmission technology match interests and expertise within the Whiting School, but it is clearly part of the enabling technology suite for solar and wind power.
The transition from the power system we have, both in the U.S. and globally, and the more sustainable system we hope to have is fraught with challenges. Central generation stations are some of the longest-lived and most expensive infrastructure we possess. I remember visiting the BG&E Wagner Station as an undergraduate in the early 60s. It was then a young, but not new, facility. With environmental add-ons, it is still in service; such longevity is not atypical. Carbon management that can both de-rate existing plants and reduce their efficiency, and a possible PHEV automotive fleet could have major impacts on the electrical grid and the need for new generating capacity, whatever the technology employed. This area is deserving of far more attention than it has received and could be a fruitful arena for joint work between the Whiting School and the business school.
David K. Schmalzer ’64, MS ’65, PhD, PE
Director Fossil Energy Program
Argonne National Laboratory (retired)