A critical analysis of global warming potential of data centers in the digital era

Abstract

The purpose of this research is to evaluate the environmental impacts associated with a theoretical data center in Italy. Through the analysis of four different scenarios that vary the energy mix, the IT attributes (i.e., server, storage, and networking refresh interval) and the physical infrastructure (i.e., power system, UPS mode, annual generator use, power distribution, and cooling system), this research intends to identify the best strategies for reducing the environmental impacts of a data center. This study estimates the environmental impacts of a data center in Italy by focusing on its global warming potential. The functional unit is a theoretical data center of 8650 m 2 , with an IT capacity of 5000 kW, an IT load of 85%, a rack power density of 5 kW, and a lifespan of 10 years. The environmental impact assessment highlights (i) the yearly total CO 2 eq by distinguishing among direct and indirect emissions; (ii) the yearly total CO 2 eq by lifecycle phase (i.e., manufacturing, distribution, installation, use and end-of-life); and (iii) the yearly total CO 2 eq by system (i.e., IT, core and shell, electrical, mechanical and other). Moreover, this research provides insights in the environmental impacts associated with capital goods, fuel and energy, upstream transportation, and waste in operations. In the baseline scenario, the global warming potential of the data center is 677,724 tCO 2 eq, with a cumulative energy consumption of 558,894 MWh and an emission factor of 925 kg/MWh per year. In Scenario 1, which considers a change in the server, storage, and networking refresh interval, the environmental impacts are 602,197 tCO 2 eq, but the cumulative energy consumption is equal to the baseline scenario. In Scenario 2, which implements a more efficient physical infrastructure and a generator use of 8760 h/year, the global warming potential is reduced by 28%, and the emission factor is 719 kg/MWh per year. Last, Scenario 3 considers the average European energy mix. It, other conditions being equal, represents the most impactful scenario from an environmental standpoint (686,575 tCO 2 eq). The implementation of a more efficient physical infrastructure should consider a natural gas power system instead of a diesel one and an annual generator use of 8760 h/year. Environmental benefits can be achieved through intervention on the cooling system, by substituting chilled water with DX systems. In the case of a Tier IV data center, the energy mix does not affect the environmental performance, and Scope 2 emissions are equal to zero.

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