AC for the DC

AC for the DC

September is DevPro's month to focus on where IT is heading in 2017 and beyond. One trend of which I'm confident: 2017 will not be the year for wiring data centers (DCs) for direct current (DC) power, at least not to save energy.

DC for the DC is an "evergreen" topic; journalists love to raise it periodically, if only for the chance to introduce sexy names Tesla and Edison as historical context. The bottom line: data centers in the US spend over five billion dollars annually on electricity, and it's likely that 5-15% is avoidable AC conversion loss. The easy conclusion is that it's past time to "flip the switch", rewire DCs for DC, and enjoy the savings.

Higher priorities

Easy and wrong. DC would be a change, and IT managers have higher priorities--starting with reliability and performance--than a potentially de-stabilizing secondary cost saving. I worked on energy efficiency issues for over a decade, and yet I wouldn't risk having to explain an outage that results from excessively-rapid corrosion on high-voltage connectors. DC designs generally involve a new set of vendors and equipment, and most IT departments are better off investing special efforts in security or disaster recovery or governance policies or cooling geometry or a half-dozen other urgencies. DC power provision remains unfamiliar enough to preclude any easy decision in its favor.

We might not be far off. As talent diffuses from the experiments Facebook and other big players are running, and, equally as important, from DC-based marine and military installations, as well as 48 VDC telco centers, it will become easier to select for energy savings.

Before that happens, though--perhaps as early as 2018 for major US operators--I expect DC to win fans for its space savings. A well-designed DC-based power distribution system eliminates a couple of conversions and the equipment to effect those conversions. Energy is too inexpensive now to compel a change to DC in the DC. Real estate, though, especially the secured, climate-controlled real estateof twenty-first century data centers, is pricier.

Within five years, DC-based DCs should become more reliable than their AC-based comparisons. At that point--with components and designs readily available and trustworthy--adoption will accelerate and even saturate. The biggest motivations until then, though, will be real estate and capital expenditure, with energy savings simply insufficient for at least a few years more.

How do your wiring diagrams look? Are you ready to DC power distribution practices? Tell us in the comments below.

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