I came across a couple links that may be of interest.
First is a company called FCE, They have 3 products which are generators that run on pure hydrogen and range from 250kw to 2mw.
http://www.fce.com/site/products/stationary.html is their link to their products.
APC has released a new UPS system that runs on hydrogen as well. These are fairly small units that are rack mounted by the looks of it. You can stack 3 of the 10kw units together to get 30kw per cabinet.
http://www.apcc.com/solutions/displa...B5B8E4E3CA5BF8 is a link to the information on their Fuel cell UPS.
APC has also published a white paper that gives information regarding the implementation of an "Energy Efficient" datacenter which is, from my eyes, another part that should be factored in to a green datacenter.
http://www.apcmedia.com/salestools/N...XSHX_R0_EN.pdf is a link to their white paper.
Sorry if it appears that I am partial to APC. I have become very interested in some of their InfraStruXer product line...well parts of it atleast.
Last year, they did an hour long seminar on "Going Green" in a datacenter. I believe this is the seminar I watched before...
https://event.on24.com/eventRegistra...epage=register is the link for the seminar if you are interested.
It still makes me wonder about the desire to go green while all these products are relatively new to the market. The technologies just havent been proven to me that they will last the lifetime of your datacenter. The topics we are discussing are related to power which is by far the most critical component to any data center. Additionally, from what I understand, processed hydrogen in mass quantities that will be needed to run a 2mw generator is not the easiest to find all around the country. I could be wrong as I have honestly not researched this that much.
Good luck!
--Keith