Monday, July 28, 2008

Quick Energy

ZBB Energy Corporation has developed a regenerative zinc bromide aqueous flow storage system:
Unlike the lead acid and most other batteries, the ZESS uses electrodes that cannot and do not take part in the reactions but merely serve as substrates for the reactions. There is therefore no loss of performance, unlike most rechargeable batteries, from repeated cycling causing electrode material deterioration. During the charge cycle metallic zinc is plated from the electrolyte solution onto the negative electrode surfaces in the cell stacks. Bromide is then converted to Bromine at the positive electrode surface of the cell stack and is immediately stored as a safe chemically complexed organic phase in the electrolyte tank. When the ZESS discharges, the metallic zinc plated on the negative electrode dissolves in the electrolyte and is available to be plated again at the next charge cycle. In the fully discharged state the ZESS can be left indefinitely.

The ZESS offers 2 to 3 times the energy density (75 to 85 watt-hours per kilogram) with associated size and weight savings over present lead/acid batteries. The power characteristics of the ZESS can be modified, for selected applications. Therefore, the ZESS has operational capabilities which make it extremely useful as a multi-purpose energy storage option. _ZBB_HT_NextEnergyNews
The ZESS is said to be compatible with solar recharging, and ZBB plans to install a combined ZESS/Solar energy system at LifeVillage in Cote d'Ivoire.

Also on the energy front, Brian Wang gives an excellent presentation on the efforts to approach Carnot efficiency from heat engines--the source of 90% of the world's power production. Read the article and follow the links to expand your knowledge of this important and growing area of energy technology.

Toyota is taking a close look at "metal-air cells" for the next generation of their hybrids.
In this type of battery, electricity is generated by a reaction between oxygen in the air and a metal like zinc at the negative electrode. The battery does not require the use of a combustible liquid electrolyte, so there is no danger of ignition as is the case with lithium-ion batteries. Moreover, an air battery has over fives times the energy-storage capacity of a similarly-sized lithium-ion battery...It may take some time before air batteries reach the practical stage, but Toyota believes that they will ultimately become the next-generation battery technology of choice. _GCC
The problems with the technology include a poor scaling to large sizes, and complex recharging requirements (as discussed here previously). More work at the drawing board, and in the lab.

Brian Westenhaus at New Energy and Fuel continues looking at new LED technology, and its potential to significantly reduce power consumption across the developed world.

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