eBay says its data center infrastructure is now able to process 18% more online-auction transactions per 1kWh of power than it did one year ago.

The company released Digital Service Efficiency (DSE) numbers for the first quarter of 2013 on 24 May, announcing the efficiency improvements and a refined approach to measuring that efficiency. eBay created DSE (first announced in March) as a tool to measure efficiency of its data centers and to share those metrics externally.

Sri Shivananda, VP of platform, infrastructure and engineering systems at eBay, attributed the increase in efficiency primarily to the company's infrastructure team's efforts to run more efficient servers and facilities. “Compared to the first quarter of last year, we’ve reduced the power consumed by an average of 63 watts per server,” he wrote in a blog post.

The company has increased its total server count by 37% since the first quarter of 2012, but the power consumption of its data centers went up only 16%, or by 2.69MW, according to Shivananda. Its 54,000 servers require 19.08MW of power to support 116.2m users, according to the Q1 DSE dashboard.

This infrastructure processes slightly more than 32,000 transactions per 1kWh. For eBay, a transaction is a Uniform Resource Locator (URL) and an associated web page generated when “buy” or “sell” requests come in from users.

The company has revised the way it calculates the total number or transactions its servers process, which resulted in a substantial decrease in the total amount of transactions. The revision – from 7.3tr down to 4.3tr – was due to a better assessment of what transactions are actually customer-facing, as opposed to being directed inward.

Another metric DSE provides is the cost to run a server and to serve a user. It also shows how much revenue eBay generates from running a server and serving a user.

In Q1, eBay generated $14 in revenue per user and about US$30,000 per server. Its cost per user went down 8% and cost per server went down 24%.

Revenue from its data centers consuming 1MWh of energy was about $39m in Q1.

Through DSE, eBay also publishes the carbon footprint of its data center infrastructure. In Q1, the level of associated carbon emissions was 17.3 grams of CO2 equivalent gases (g CO2e) per 1,000 transactions – down 7% from one year ago.

The company's goal for the year is to decrease its carbon footprint by 10%. The installation of fuel cells by Bloom Energy at its Salt Lake City, Utah, data center is slated for completion this summer, and Shivananda said he expected the fuel cells to contribute to that goal significantly.