With each passing year, more organizations seek out green service providers. Both for the sake of reducing overhead and as a reflection of corporate environmental responsibility (CER) values. Data centers, though indispensable to organizations in every conceivable industry, are voracious energy consumers. This fact has generated interest in sustainable facilities – which raises an important question: What is a green data center?

Green data centers an illusion?
Globally, data centers consume around 3% of the total energy generated and that amount increases every day. The carbon footprint of a medium 10MW data center can range from 3.000.000 to over 130.000.000 KG of CO2. Reducing that carbon footprint through efficiency and renewable energy use has an immense effect. PUE (Power Usage Effectiveness) improvements can eliminate millions of KGs of CO2 emissions.

Energy Source
As a customer it is worth asking where the energy comes from. A data center that is using green energy (hydroelectricity, wind or solar) minimizes its carbon footprint. Fossil fuels are widely used in the data center industry. One problem with fossil fuels is the up and down nature of costs. Renewable energy costs are 'stable', because there is virtually no recurring cost. Wind and sun are free.
Data centers are always prepared for power outages / GRID failures and have batteries and generators on-site. Data centers can use diesel aggregates on GTL (Gas To Liquid). GTL is a replacement for diesel fuel and is produced on the basis of natural gas. It has the advantage that it is highly biodegradable and is almost clear of Sulphur and aromatics.

Power Usage Effectiveness
As described data centers consume 3% of the total energy and astonishing one-fifth of the World's energy by 2025, according Data Economy. A green data center endeavors to conserve energy by using as little as possible on non-IT functions such as cooling. The Power Usage Effectiveness (PUE) metric is central to this effort. To calculate PUE, divide the total amount of electricity entering a data center / rooms by the amount specifically powering the IT load. A perfect PUE rating of 1 would mean all a facility's energy goes to the IT load. This is more wishful thinking than a reality at this point; however, some of the most efficient data centers in the world boast an average annual PUE in the 1.1 range.

Cooling method
Cooling-related energy-saving methods will be captured in the average annual PUE, but they're worth examining, because they illuminate the types of efforts that go into managing a green data center. IT equipment generate heat. Heat must be abducted by a fluid (typically air), with that fluid treated and circulated in the most efficient manner possible like described in our blogpost: Cabinet Airflow Management Done Right. The cooling unit used in the data center, which should be selected based on the climate, are an important factor of the PUE. Indirect evaporative cooling, for instance, is a highly efficient process in moderate-to-dry climates that have abundant access to water. It involves adding water to the air to lower its temperature. Datacenter.com is using Indirect Adiabatic cooling without use of any compressor to reduce to power usage overhead. More about our Indirect Adiabatic Cooling platform is described in our earlier blogpost: Adiabatic cooling.