Quantifying The CO2 Of A CDN

Consumer awareness about the impact of video streaming is increasing and broadcasters are more willing to choose environmentally friendly solutions. However, they also expect image quality to continue to rise. At the same time content streaming services are hitting a processing bottleneck to achieve high quality at the lowest possible bitrate. Does something have to give? Saving the planet versus streaming the planet seems like an obvious choice but there are ways that carbon reduction can happen at the same time as our entertainment experiences can get richer.

Streaming’s carbon footprint is based on the electricity usage of data centres, data transmission and devices, plus the CO2 emissions associated with electricity generation. The overall footprint of streaming video is also inextricably linked to how the electricity is generated. While the energy efficiency of digital technologies has improved rapidly, more investments in renewable energy to power data centres and networks means the environmental impact of streaming isn’t growing as fast as it has in the past.

The 2021 Carbon Trust report estimated that one hour of video streaming emitting a total of 50-60g of Co2. Petrol cars emit many times that amount but the climate emergency is such that M&E needs to do more to eliminate carbon in the system.

“The industry is late to the party when it comes to sustainability,” says Remi Beaudouin, CSO, ATEME. “The initially pure broadcast landscape is now turning into a multi-screen playground where much of the focus goes to optimizing performance. The first challenge is to change the mindset and take into account the carbon footprint of all the various services.”

Hybrid CDNs utilise a mix of on-prem hardware and cloud-based infrastructure operated by major cloud services providers. Carbon costs can be quantified in terms of their energy consumption and associated carbon emissions using real-time analytics, hardware manufacturer data, and carbon footprint calculator tools.

Remi Beaudouin, ATEME.

Remi Beaudouin, ATEME.

“We all need to contribute to changing the paradigm: that is, choose and adopt standards whose first driver and priority are not engineering performance, but carbon footprint reduction,” says Beaudouin. “The more our solutions are optimised, the less CPU they need, the lower the carbon footprint is by channel/content. Lower bitrate means less storage, less bandwidth required to stream, and reduced consumption on the display device.”

Broadpeak estimate that about 70% to 80% energy consumption savings can be achieved in a multicast Adaptive Bit Rate (ABR) during popular live events.

Based on its analytics, Ateme says it can dynamically adjust compression and streaming to match what is strictly needed and optimise accordingly on the end-user device. The firm is also involved in VVC, an MPEG codec expected to divide the bitrate by half.

Many companies have embraced important sustainability programmes like the DPP’s Committed to Sustainability scheme and the Science Based Targets plan.

“This momentum is likely to grow as OTT services and pay TV companies increasingly prioritise investment toward vendors that can demonstrate their commitment to the environment and carbon reduction,” says Jim Brickmeier, Chief Product & Marketing Officer at Velocix.

“CDN carbon emissions rise in relation to traffic demand, but there is also a baseline cost. CDN deployments are often sized for peak demand levels, for example to support major live sporting events. If CDN capacity is fixed, this can leave servers idling and generating carbon costs whenever traffic volumes are lower than peak levels. These costs can be readily calculated and used to drive optimisations.”

In response, Velocix is evolving all its streaming applications towards hybrid-cloud architectures that feature carbon cost measurement and flexible on-demand scaling. This enables CDN capacity to flex according to consumer demand, explains Brickmeier.

“Resource utilisation scales-up rapidly as audiences grow, and then spins down once the surge is over, thereby minimising the use of compute resources and the associated carbon footprint. Using analytics, operators can also better understand their emissions and seek out strategies to improve.”

Quantifying and tackling the environmental impact of streaming is complex. There are multiple visible and hidden contributors to the global energy consumption in video streaming networks, including devices, CDN servers, head-ends, and networking equipment.

“Making progress as an industry depends on recognising that we can be competitors in a market without making it a zero-sum game - sharing values, innovations and techniques which benefit us all - while holding each other to account as a result,” says Antonio Corrado, CEO, MainStreaming.

“With switching costs between streaming services so easy and points of differentiation increasingly slim on a technological level, green issues will increasingly become a point of significant competitive advantage. From our inception we’ve built consideration of environmental impact directly into the technological choices we make.

He explains that MainStreaming’s technology is geared around minimising power consumption. “Our adoption of algorithms to manage adaptive demand and flow and move functions to the Edge where possible doesn’t just serve to make our services more reliable, efficient and effective, but also - by design – it is better for the environment. Indeed, energy consumption with MainStreaming technology is up to 50% lower than standard streaming operations.”

Many players have good intentions and a real ambition, but they lack guidance, best practices, tools, and technologies to react and keep energy consumption under control.

“Networking equipment is agnostic to the type of data it carries,” says Yann Begassat, Business Development Manager at Broadpeak. “The only fact we know is that video is the dominant traffic. Virtualization is also a challenge. Multiple applications and network functions will increasingly run on same hardware infrastructures, making it difficult to determine how much energy the CDN is consuming.”

Velocix CDN.

Velocix CDN.

If the industry is serious about moving to carbon cleaner CDN solutions while maintaining viewers’ quality expectations it might follow one or mix of the following [in ideas supplied by Synamedia Software Architect, Gwendal Simon].

Elastic CDN - The infrastructure adjusts to the traffic volume in real-time. AI predicts next-hour traffic load to either boot up new edge servers or shut down existing ones, without impacting QoE.

Smart edge - This reduces the number of video files per title to reduce the infrastructure footprint. Analysis finds the sweet spot between the number of profiles (resolutions, bitrates, formats, etc), the number of variants (A/B watermark), and the number of copies (cache group).

“Unlike today’s proprietary CDN logging systems, future standardized end-to-end log collection should include data to calculate energy consumption with full transparency,” says Simon.

We can expect regulators to set CO2 requirements for streaming providers but measuring consumption is a first step; quotas for the use of renewables and SLAs that cap energy may follow. We might also anticipate the launch of streaming services with green credentials for those consumers willing to tolerate lower quality video.

As Beaudouin put it, “Content consumption is a carbon consumer. Reducing the environmental footprint of our consumption in this area is one piece of a larger puzzle: a small effort for an individual; a giant one for planet Earth.”

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