The advent of fast, unprecedentedly scalable, yet energy-hungry exascale supercomputers poses a major challenge consisting in sustaining a high performance per watt ratio. While much recent work has explored new approaches to I/O management, aiming to reduce the I/O performance bottle-neck exhibited by HPC applications (and hence to improve application performance), there is comparatively little work investigating the impact of I/O management approaches on energy consumption. In this work, we explore how much energy a supercom-puter consumes while running scientific simulations when adopting various I/O management approaches. We closely examine three radically different I/O schemes including time partitioning, dedicated cores, and dedicated nodes. We im-plement the three approaches within the Damaris I/O mid-dleware and perform extensive experiments with one of the target HPC applications of the Blue Waters sustained-peta-flop/s supercomputer project: the CM1 atmospheric model. Our experimental results obtained on the French Grid'5000 platform highlight the differences between these three ap-proaches and illustrate in which way various configurations of the application and of the system can impact performance and energy consumption.