Using a dairy farm to power your server farm

New research out of HP Labs suggests building data centers near dairy farms to leverage the energy that can be derived from the manure cows produce every day.

What do 10,000 cows and diesel generators have in common?

Both have the ability to power a 1-megawatt data center. Diesel generators are already used for this purpose at some data center sites, though the energy source is not very environmentally friendly. On the other hand, 10,000 cows grazing a dairy farm produce 20,000 metric tons of manure each year that can be turned into methane gas and eventually electrical power.

That's according to researchers from HP Labs, who are presenting a paper on these findings at the ASME International Conference on Energy Sustainability in Phoenix on Wednesday.

The idea is this: As our demand grows for computing power and data storage, the capacity to power data centers is not keeping up properly. HP's goal is to use sustainable processes to build data centers that are self-sufficient. That is, build data centers whose power sources are from sustainable energy sources and whose heat output can be recycled and reused within that same data center.

HP Labs

As odd as it may sound, that's where the cows come in. The average dairy cow produces 55 kilograms of manure per day, or 20 metric tons per year. An individual cow's manure can generate 3 kilowatt-hours of electrical energy per day. (That alone could power television usage in three U.S. households on a daily basis.)

And on a farm with 10,000 cows, that amounts to enough energy to power a 1-megawatt data center, according to HP researchers.

"These farms already exist. Some already use the methane and (distribute) it elsewhere for local use," said Chandrakant Patel, one of the HP Labs researchers on the project. "We are suggesting that if you are starting to (look for a place to locate) a data center, now that high-speed networking is starting to extend into other areas, why not look at this opportunity where you cannot only use manure, but capture the energy right at the source?"

The process would work like this: farms already have a manure collection system. The biomass goes into an anaerobic digester, which breaks down the waste like a sewage treatment plant would. At this point in the process, methane gas is released. But in HP's vision, instead of a farm burning off that gas--one of the most dangerous greenhouse gases--the chemical energy in that methane could be converted into electrical energy to power the data center.

To complete the circle, the heat that the data center gives off is then reused as part of the energy needed to break down the biomass.

In India, for example, they are running out of power to keep the data centers that are being built there up and running. "In India they need diesel generators because the power grid can't keep up with the growth," said Patel, and there lies a golden opportunity for a dairy farmer. Patel points out, there could be some money to be made for the enterprising farmer who wants to recycle and use his cows' daily output for this purpose.

The cost to build a 1-megawatt data center is around $5 million. But it could generate around $2 million in revenue per year. So after two or three years, the builder would already make the investment back.

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