Fibre: The sustainability driver in broadband
Fibre: The sustainability driver in broadband
16 July 2021 | Filip De Greve
Today the Information and Communications Technology (ICT) industry accounts for more than 2% of global greenhouse gas (GHG) emissions, according to the European Commission in 2020.
For comparison, that’s about the same as all air traffic. However, ICT technologies have the opportunity to help other industries reduce that and become more sustainable.
Digitalisation in general, and broadband in particular, contribute to this reduction by cutting transportation, creating gains in productivity and efficiency. They also boost economic growth for individuals, countries, cities and society as a whole. Because of this, despite its own carbon footprint ICT actually carries a 7-fold net positive effect on emissions — reducing global CO2 emissions by up to 15%.
That said, climate change is by far the greatest challenge of our time, and we need to do whatever we can to reduce GHG emissions as much as possible. Within the broadband industry, the track record is good. Initiatives like Science-Based Targets and the Code of Conducts for Broadband Communication Equipment from the European Commission are helping develop pathways, set targets, and encourage commitments from stakeholders. And it’s working: since 2007, home broadband power consumption has been reduced by 38% while speeds have increased by a factor of 64. How? Through fibre networks.
The introduction of full fibre-to-the-home (FTTH) networks, replacing copper-based digital subscriber line (DSL) connections, has broken the link between bandwidth demand and power consumption. Subsequent generations of Passive Optical Network (PON) technology and additional innovations in chipset technology are driving a 120-fold improvement in energy efficiency.
How? Here are a few reasons:
- Very high-speed digital subscriber line (VDSL) requires many more active components in the network than PON, and so it consumes more power. But when you also consider the far greater bandwidth of GPON compared to VDSL, the net gain is a 12-fold improvement in Bits delivered per Watt consumed.
- Many FTTH operators are upgrading networks from GPON to XGS-PON. Because XGS-PON delivers five times the bandwidth of GPON for the same power consumption, it lends another positive impact for energy efficiency.
- The power consumption of fixed network telecom equipment is mostly driven by the chipsets used, so any efficiency gains here can make an impact. For example
- Power-optimised line cards with higher port density, integrated energy-saving features (such as powering down unused optics and fan tray control) and higher throughput per watt work toward building a more sustainable infrastructure.
- More power-efficient chipsets lead to smaller power-optimised nodes, which occupy less space, use less energy and can be passively cooled. When installed in street cabinets, nodes also require less grid protection equipment, smaller power supplies and only “heatwave days” fan ventilation backup.
Because of these elements, fibre’s future-proof scalability clearly makes it the broadband technology of the future. As a result of this shift to fibre and passive power splitting, fewer ports and active electronics will be needed to serve customers — requiring less power provisioning in the network.
Fibre also has extremely low attenuation (0.2 dB/km) due to the purity of the glass and the confinement of light emitted by the laser inside the core of the fibre cable. Because of this, passive fibre networks deliver the lowest ecological footprint. Point-to-point fibre technologies like GigE and 10GigE are competitive in power per bit, but they cannot benefit from the same infrastructure sharing efficiencies. This makes PON technologies the ideal fit to deliver mass-market enterprise services and robust fibre transport for many 4G and 5G cell sites.
Reduced energy consumption and increased network reliability (through the absence of active network elements in the field) also mean that the FTTH network costs less to run and operate. Here’s how: in short, moving to a full-fibre network means central offices can be consolidated, which reduces energy consumption further. Additionally, the network has a longer lifespan, and a more reliable network requires fewer field support staff, which means less travel to network locations to carry out maintenance and repairs. Ultimately, this results in a better customer experience in the form of superior service quality (bandwidth, latency, etc.), higher reliability and lower operating costs. Fibre-to-the-home essentially combines low energy requirements and greenhouse gas emissions with superior scalability and bandwidth evolutions to 25G, 50G and beyond.
There is one challenge for fibre, however, in that it is generally quicker and cheaper to upgrade a DSL or cable access network than it is to install new fibre. Nevertheless, customer demand for bandwidth is relentless and nearly every telco and cable operator recognises that fibre is inevitable in the long run. So with fibre, broadband is one of the rare industries where increased demand and consumption are directly driving improvements in sustainability.
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