In the current economic climate, most CIOs are more focused on taking out operational costs than on being green, writes Steve O'Donnell, head of technology research at CleanAnalysis. However, a significant but unrecognised cost of IT is the amount of electricity consumed by data centre systems.

McKinsey and Co reports that most CIOs are not held financially accountable for the power consumed by IT operations and this is leading to sub-optimal investment decisions. CIOs will find they can improve both their green credentials and their company's bottom line by dealing with unnecessary electrical load in the data centre.

Corporate IT departments typically have poor asset management controls, driven by the perceived low return and high risks involved in cleaning things up. Shutting down unused assets and decommissioning old, unused data is hard work and can be risky, but if we measure the full benefits the financial return can be significant.

£3.8m annual savings at BT

A single high-performance enterprise disk can consume as much as 1MW-hour of electricity in its lifetime, so we need to adopt the principle that the cheapest and greenest data is deleted data. Corporate data centres contain between 10 and 20 per cent of equipment that can be switched off with no business impact. In my time running IT Operations at BT, we saved over £3.8m per annum in one project, just by shutting down systems that were not required.

A successful outcome is more certain if we start from the right place, and data management is no different. Ensure each piece of new data has a default retention period and be ruthless about ensuring that the deletion process is complied with. Start investigating data de-duplication products that can remove or prevent the creation of multiple replicas of the same data.

For current data with no retention policy set, set one now and even if it is six years out, the data will get deleted eventually. Challenge the laziness that results in old data being held on disk "because we might need it". If you can't delete it now, swap it to tape.

Small outlay, big results

Poor maintenance and management of the data centre infrastructure can also burn huge quantities of unnecessary electricity. The measure of efficiency in data centres is power usage efficiency (PUE) and the difference between the best (1.2 times equipment power) and worst (3.5 times equipment power) is vast.

Simple, repeatable measures can be taken to move the PUE in the right direction and at modest cost.

Paybacks in the order of three months can be achieved by paying attention to detail. For example, increasing the set point for data centre air-conditioning units a few degrees higher can make a major impact on how long the chiller units run for and the cost of the electricity consumed.

Separating hot and cold air with curtains can improve air handling efficiency by as much as 17 per cent - for an outlay of just a few pennies. Much of our infrastructure is under-utilised and inefficient. Virtualisation and consolidation can dramatically improve efficiency and reduce costs.

Steve O'Donnell is head of technology research at CleanAnalysis, which provides analysis of cleantech companies, technologies and legislation.

Part 2 of this debate features a viewpoint from Rodolphe D'Arjuzon, managing director of analyst firm Verdantix.