Green batteries

From TheStudentWiki

1 Introduction
2 Organic batteries
3 Bacterial batteries
4 Beer batteries
5 Fuel cells
6 See Also
7 External links/references
8 The Group

Introduction

With the effects of global warming now becoming more apparent, we in the computer industry realise the need for serious consideration as to how we power today’s computers and the plethora of portable electrical devices we own. Almost all of us own a mobile phone, many of us own a portable music player, and many of us own a digital camera – all these devices require power from a battery, and many batteries currently in widespread use contain harmful materials such as mercury. This wiki is intended to evaluate the alternative battery technologies available at the moment and being developed.

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Organic batteries

Microbial Fuel Cell (MFC) batteries cost around £10 each to manufacture. They produce electricity by using E.coli bacteria to produce enzymes which break down carbohydrates in food, producing hydrogen. A chemical reaction then removes electrons from the hydrogen, and uses them to produce an electrical current sufficient to power a pocket calculator, MP3 player, mobile phone, or even a low-energy lightbulb. This process allows leftover food waste to be converted into useful electricity, instead of being thrown away.

Currently, the battery is approximately the size of a portable CD player, but may become smaller as the technology improves and becomes more efficient.

If put into widespread use, these batteries would reduce the need for hazardous materials to be used in manufacturing conventional batteries, which are put into landfill sites when they reach the end of their life, poisoning wildlife and damaging the environment.

In principle, the batteries currently being developed can use 50 grams of sugar to power a 40-watt lightbulb for eight hours, however the rate of conversion is currently so slow that the current produced is hardly enough to power a pocket calculator.

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Bacterial batteries

Bacterial batteries are very similar to the organic batteries described above, however they use Rhodoferax ferrireducens bacteria to convert simple sugars found in fruit into electricity. These batteries have an 80% efficiency, as opposed to 10% efficiency of organic batteries, making them suitable for use in remote places where mains electricity is not available. The US Department of Defence has expressed an interest in using them to power underwater devices.

The bacteria is capable of feeding from glucose (the main type of sugar found in the environment), fructose (found in fruit), sucrose (found in sugar cane), and xylose (found in wood and straw).

In principle, a cup of sugar can power a 60-watt lightbulb for seventeen hours, however the rate of conversion is so slow that the current produced is hardly enough to power a pocket calculator.

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Beer batteries

Australian brewer Foster’s has made the world’s first beer-powered battery, using bacteria to convert sugars present in waste water from the brewery into electricity, with clean water being the only by-product produced. It is to be installed at their brewery near Brisbane.

As brewery waste water is highly concentrated and easily bio-degradable, the battery operates with a much higher efficiency and conversion rate than other organic and bacterial batteries, and is capable of producing two kilowatts of power (enough to power a small house). The electricity produced can be fed into the power system of the factory, reducing the amount of mains electricity used, therefore reducing CO2 emissions by requiring less electricity to be produced from burning fossil fuels in inefficient power stations.

Once the patent on the technology has been finalised, it is expected that many other food and beverage factories could make use of the technology to reduce their electricity consumption.

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Fuel cells

Toshiba has developed a fuel cell battery capable of powering a laptop computer for approximately ten hours from a 100 millilitre cartridge shaped similar to an inkjet printer cartridge. The battery breaks down methanol to provide electricity.

The cartridge fits into a device which is designed to be placed underneath and at the back of a laptop computer. It has a volume of one litre, and weights about the same measure of water.