Just Released! “Energy, Biology, Climate Change”

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Our newest book just Released! “Energy, Biology, Climate Change” and available at Amazon.com for $19.95.

The focus of this book is the interactions between energy, ecology, and climate change, as well as a few of the responses of humanity to these interactions. It is not a textbook, but a series of chapters discussing subtopics in which the authors were interested and wished to write about. The basic material is cutting-edge science; technical journal articles published within the last year, selected for their relevance and interest. Each author selected eight or so technical papers representing his or her view of the most interesting current research in the field, and wrote summaries of them in a journalistic style that is free of scientific jargon and understandable by lay readers. This is the sort of science writing that you might encounter in the New York Times, but concentrated in a way intended to give as broad an overview of the chapter topics as possible. None of this research will appear in textbooks for a few years, so there are not many ways that readers without access to a university library can get access to this information.

This book is intended be browsed—choose a chapter topic you like and read the individual sections in any order; each is intended to be largely stand-alone. Reading all of them will give you considerable insight into what climate scientists concerned with energy, ecology, and human effects are up to, and the challenges they face in understanding one of the most disruptive—if not very rapid—event in human history; anthropogenic climate change. The Table of Contents follows: Continue reading

Wearable Supercapacitors: Making Devices More Flexible

Flexible supercapacitor

 

by Emil Morhardt

Maybe someday you will be able to recharge your gadgets by plugging them into your jacket, which you charged up in a few seconds from a convenient wall plug. I wrote earlier about storing energy in wires that were configured to be capacitors. Now Yu et al. (2014), at the School of Chemistry and Chemical Engineering, Nanjing University, in China, have fabricated experimental sheets of flexible layered conductive and non-conductive materials (diagram above is from their paper) that they envision as eventually wearable. We all get tired of waiting around for batteries to charge, but supercapacitors charge almost instantly. They don’t usually have much energy storage capacity though—you don’t get as much energy storage per unit weight or volume as you presently can from batteries—but if they are built into something that you need to carry around with you anyway, that might not be so important. A good example is the plug-in electric boat I wrote about on October 11. Boats don’t care much about how large or heavy something is, but they need to be fueled rapidly. So if you could store all the energy you need quickly in your jacket, your battery-powered devices could recharge in your pocket, wherever you are. Continue reading

Flywheel Versus Supercapacitor for Running a Small Electric Ferry

by Emil Morhardt

When we think of all-electric cars, we think lithium-ion batteries because they are lightweight and have a high power density. For ships, light-weight doesn’t matter so much, and it turns out there are types of shipping routes that don’t need very much energy storage: think ferries, specifically the plug-in ferry Ar Vag Tredan (the “electric boat” in Breton), a zero-emission passenger ferry crossing the Lorient roadstead 56 times a day. When parked between trips it can recharge its supercapacitor more-or-less instantly (that’s a main feature of supercapacitors—that and their ability to discharge their power equally quickly to meet any need for power the ship may have.) How would a flywheel energy storage system work compared to the existing supercapacitor? That’s the question asked in a new paper by Olivier et al. (2014). Continue reading

Hybrid Energy Storage for CubeSats

by Emil Morhardt

CubeSats are cool. No, actually very cold, since they’re out in space. But they are reproducing like rabbits. There are well over 200 of these little 10 cm X 10 cm X 10 cm cube satellites have been launched into orbit by tucking them into the nooks and crannies in the launch vehicles around much larger satellites. (Some are multiples of cubes, 10 cm X 20 cm, or 30 cm.) They need energy. Until now they have been powered in the main by lithium ion batteries like those in your computer, and charged by the photovoltaic panels that make up a CubeSat’s skin. The thing is that these batteries don’t work very well when they are cold; the speed of electrochemical reactions, just like those of every other chemical reaction, are modulated by temperature—the colder the slower. The current Li-ion batteries don’t work at all below –10°C, yet CubeSats headed for deep space are expected to encounter temperatures of –40°C some of the time. So if you have a CubeSat process that needs power at low temperatures or a short-term burst of power faster than the batteries can provide, you need help. Continue reading

Supercapacitors save Windpower Batteries

Supercapacitor

by Emil Morhardt

Windpower, because it is intermittent, works best on the electrical grid if it has some energy-storage facility connected to it. Batteries are the simplest approach, and the low cost of lead-acid batteries makes them good candidates, but they resent being randomly charged and discharged (especially deeply discharged) at the will of the wind, and die prematurely. Enter the supercapacitor; it can be charged by wind turbines much faster than a battery, can deliver its stored energy to the grid much faster as well, and doesn’t resent it at all, even being deeply discharged at every cycle. Engineers at Kocaeli University connected a supercapacitor in parallel with a battery (see diagram above) so that it would buffer transient current surges, saving the battery to do what it does best. The system worked just like one might expect, but there are some graphs in the paper showing just how the current flowed, and I think it is a nice example of an experimental setup to look into these types of hybrid energy storage systems. (The diagram is from their paper. There’s a link to it below.)

Erhn, K., Aktas, A., Ozdemir, E., 2014. Analysis of a Hybrid Energy Storage System Composed from Battery and Ultra-capacitor, 7th International Ege Energy Symposium & Exhibition, June 18-20, 2014, Usak, Turkey   http://bit.ly/1neZfey

Please send suggestions for other recent papers appropriate for this blog to emorhardt@cmc.edu.