Monday, March 9, 2009

Fuel Cells and Data Center Backup Power

Everything that moves or works needs energy and the same is true ranging from human beings to inanimate matter in the form of computers and servers. Needless to say the power requirements for a data center necessarily include a continuous supply of power which isn’t interrupted by the elements of weather, climate, power grid or anything under the sun for that matter.

Since the dependence on grid power for 24/7 supply would be bit risky despite the best available infrastructure in any part of the globe, alternative sources of energy have been used to provide back up power in the event of main power failure. These sources include battery back ups, electrical generators etc and have been providing back ups to systems despite certain practical drawbacks of each of these sources. Scientists have been struggling to develop better power back ups and fuel cells offer one such source of back up which would be discussed in this article.

What is a Fuel Cell?

Most of us know what fuel means and also what is meant by a cell! But have you ever heard or have you got a clue as to what a fuel cell means? Well, to put it simply in the terms as described by Stanford University , a fuel cell is a “static device that converts the chemical energy in natural gas into electricity and hot water through an electrochemical process”.

If we go back in time we will discover that although the concept of a fuel cell was demonstrated as long back as 1839 by Sir William Grove, it was not converted into a practically usable device until half a century ago when NASA used fuel cells in her missions.

Comparison to a Battery and a Combustion Engine

People have many questions and doubts regarding the use of fuel cells especially their comparison vis-à-vis batteries and IC engines as source of power. Actually a fuel cell can be said to contain the best of both worlds namely batteries and engines. Batteries produce energy (i.e. electrical energy) from chemical energy via reactions that take place inside the battery without having to carry out combustion of the electrolyte thereby making the process a lot easier and clean. Engines on the other hand produce energy by burning fuel combined with oxygen in the air and producing energy in the process, while releasing a lot of heat and polluting leftovers as well.

A fuel cell burns fuel like an engine but does so without the emissions associated with an engine, more like a battery. Most commonly used fuel for fuel cells is hydrogen apart from other substances such as natural gas and methanol.

Let me elaborate on a very important point at this stage that fuel cells are currently in their development state only and are not mass produced commercially unlike batteries which are available in plenty. Obviously they are bit costly to find and install at the present times but the situation will certainly become better as their potential for various uses including data center back up is realized and they become more commercially viable in the coming future.

Types of Fuel Cells

Fuel cells come in various types and are mainly classified based upon the electrolyte that they use. It would not be possible to elaborate on different fuel cells in detail, in this relatively short report but a brief description would suffice the purpose at the moment. Based on the electrolyte description, the various types of fuel cells are as follows;

Proton Exchange Membrane fuel cells contain a solid polymer as the electrolyte and offer several advantages such as the absence of corrosive fluids from the cell, better durability. They only use hydrogen and oxygen for operation but then the continuous supply and storage of hydrogen could be problematic especially from the safety point of view. However PEM fuel cells are costly initially due to the presence of platinum catalyst which not only adds to the cost but also gets poisoned easily from CO2 emissions. They are less efficient than other types of fuel cells and their output capacity is limited to a couple of hundred kilowatts of power at the most which make them suitable for smaller sized data centers.

Phosphoric acid fuel cells use phosphoric acid as the electrolyte and a platinum catalyst in the electrodes which makes the cell a bit costly. The upside includes less sensitivity to poisoning by external agents unlike the PEM cells described above. Moreover these cells are highly efficient and can be used upto power requirements ranging upto a couple of megawatts thus making them suitable for large installations.

Apart from these two types there are several other types of fuel cells as well which include but not limited to Molten Carbonate, Alkaline, and Direct Methanol fuel cells, each of them having their own unique features, power range and advantages as well as drawbacks.

Suitability for Data Center Power Supply Back up

We have already seen that fuel cells provide a source of clean, noise free and high quality electric power which can be produced continuously provided the fuel supply is maintained. This makes them more suitable for power back up applications in data center situations where the use of batteries would be limited in their time for back ups, while engines would produce a lot of noise, heat and pollution which would have to be taken care of as well. Data centers consist of sensitive and important machines and equipment and hence fuel cell provide an ideal medium of power supply back up in case of main power failure.

The future of fuel cells certainly seems bright not only in typical applications involving power supply for data centers but also in general as well. Given the increasing environmental concerns related to production of energy via conventions sources and the advantages that fuel cells have to offer, they certainly offer a very promising source of non-conventional energy. Data centers on the other hand also are becoming more power hungry by the day and these two factors combined together would go a long way in promoting fuel cell technology.


Recent Posts