A Broader View on Greening The InterneT

A Broader View on Greening the Internet

In his Perspective “Toward a Green Internet," in Science Magazine (29 March 2013), D.R. Recupero rightly argues for reducing the Internet’s environmental impact, but gives an incomplete picture of the literature, the problem, and potential solutions.  While the article suggests that interest in the topic is recent, widespread recognition of the issue has developed over the past two decades, leading to many new policies, initiatives, technologies, and implementations (1-8).

The analysis does not adequately distinguish between the communications network known as the Internet (now extending to a myriad of device types) and the upstream high-density data centers that deliver content. The importance of emissions from underlying electricity sources is overlooked (9)—efficiency alone is not enough for achieving improved environmental performance. While acknowledging the magnitude of energy use associated with cooling data centers, Recupero’s assessment of applicable efficiency opportunities does not do justice to this topic (10) or to that of downstream networks (11) and IP-connected devices(12), where massive amounts of energy can be saved. Integrated assessments must also account for net energy benefits achieved by information technology in comparison to alternatives (13) and the broader role ICT itself plays in reducing environmental impacts (14).

Avenues for improvement span the gamut from the link (15) to the processor (16) to the customer’s router, the latter of which is responsible for more than 75% of broadband energy use in the case of Telecom Italia noted by Recupero (17). The largest source of potential energy savings is putting devices to sleep—be they servers in data centers or end user devices such as PCs, printers, game consoles and set-top boxes that are functionally on but do not need to be and that can be proxied (12, 18). The great majority of savings are to be found in residential and commercial buildings, though the savings in data centers and telecom facilities are still well worth additional effort (14).


Evan Mills
Energy Technologies Area
Lawrence Berkeley National Laboratory
Berkeley, CA, USA

Jonathan Koomey
Steyer-Taylor Center for Energy Policy and Finance
Stanford University
Stanford, CA 94305, USA

Eric Masanet
McCormick School of Engineering
Northwestern University
Evanston, IL, 60208, USA

Bruce Nordman
Energy Technologies Area
Lawrence Berkeley National Laboratory
Berkeley, CA, USA

Ken Christensen
Department of Computer Science and Engineering
University of South Florida
Tampa, FL, USA



1. Newsham, G. and D. Tiller. “A Case Study of the Energy Consumption of Desktop Computers,” Proceedings of the IEEE Industry Applications Society Annual Conference, pp. 1218-1221 (1992).

2. Gupta, M., and S. Singh, “Greening of the Internet,” Proceedings of ACM SIGCOMM, pp. 19-26, August (2003).

3. Roth, Kurt, Fred Goldstein, and Jonathan Kleinman. 2002. Energy Consumption by Office and Telecommunications Equipment in Commercial Buildings--Volume I:  Energy Consumption Baseline. Washington, DC: Prepared by Arthur D. Little for the U.S. Department of Energy. A.D. Little Reference no. 72895-00.  January (2002).

5.  Masanet, E., Brown, R.E., Shehabi, A., Koomey, J.G., and B. Nordman. “Estimating the energy use and efficiency potential of U.S. data centers.” Proceedings of the IEEE 99, 8 (2011).

6. Blazek, M., H. Chong, W. Loh, and J. Koomey. "A data center revisited:  assessment of the energy impacts of retrofits and technology trends in a high-density computing facility."  The ASCE Journal of Infrastructure Systems 10, 3:98-104. September (2004).

7. Mills, E., G. Shamshoian, M. Blazek, P. Naughton, R.S. Seese, W. Tschudi, and D. Sartor. "The business case for energy management in high-tech industries." Energy Efficiency, 1, 1:5-20 (2007).

8.”GreenTouch.” 2013. URL: http://www.greentouch.org.

9. Shehabi, A., Masanet, E., Price, H., Traber, K., Horvath, A., and W.W. Nazaroff.  “Data center design and location: consequences for electricity use and greenhouse-gas emissions.” Building and Environment 46, 5 (2011).

10.  Koomey, J. "Worldwide electricity used in data centers."  Environmental Research Letters 3, 034008 (2008).

11. Lanzisera, S., B. Nordman and R. Brown, "Data network equipment energy use and savings potential in buildings." Energy Efficiency 5, 2:149-162 (2012).

12. Nedevschi, S., J. Chandrashekar, J. Liu, B. Nordman, S. Ratnasamy, and N. Taft, Skilled in the Art of Being Idle: Reducing Energy Waste in Networked Systems, Proceedings of 6th USENIX Symposium on Networked Systems Design and Implementation (NSDI), pp. 381-394, April (2009).

13. Koomey, J. G., H. S. Matthews, and E. Williams. "Smart everything:  will intelligent systems reduce resource use?"  In press at The Annual Review of Environment and Resources (2013).

14. “GeSI SMARTer 2020: The Role of ICT in Driving a Sustainable Future.” Global e-Sustainability Initiative, 2012.

15. Christensen, K., P. Reviriego, B. Nordman, M. Bennett, M. Mostowfi, and J. A. Maestro. "IEEE 802.3az: The Road to Energy Efficient Ethernet," IEEE Communications 48, 11:50-56 (2010). 

16. Shalf, J. “Beyond petaflops: specialized architectures for power-efficient scientific computing.” SIAM Conference on Computational Science and Engineering, Costa Mesa, CA, February 19 (2007).

17. Bolla, R., R. Bruschi, K. Christensen, F. Cucchietti, F. Davoli, and S. Singh. "The potential impact of green technologies in next generation wireline networks: is there room for energy savings optimization?" IEEE Communications 49, 8:80-86 (2011).

18. Jimeno, M., K. Christensen, and B. Nordman, A Network Connection Proxy to Enable Hosts to Sleep and Save Energy, Proceedings of the IEEE International Performance Computing and Communications Conference, pp. 101-110, December (2008).