How to reduce carbon emissions in telecommunications networks (Reader Forum)

Hoesung Lee, chair of the Intergovernmental Panel on Climate Change, said in a statement to the Climate change 2022: impacts, adaptation and vulnerability report published in February 2022: “This report is a terrible warning about the consequences of inaction, it shows that climate change is a serious and growing threat to our well-being and the health of our planet. Our actions today will shape how people adapt and nature responds to growing climate risks.

The telecommunications industry plays a vital role in helping industries deal with risk by enabling them to operate more sustainably. There can be no green without digital. The digitization of industry and society is key to making industries and communities more productive, less wasteful and more resource efficient. In fact, GSMA research shows that connectivity and digitalization can help other industries and society reduce emissions by up to 10 times more than the mobile industry’s own emissions.

But the growth of digitization will require communications service providers (CSPs) to increase their capacity, which, in turn, focuses attention on how they decouple this from the growth in energy consumption, or specifically, reduce emissions per bit of data transmitted.

One approach is sustainable energy consumption, and several major operators have signed the RE100 commitment to use 100% renewable energy. BT has achieved its 2020 target of purchasing 100% renewable energy, just like Vodafone in Europe in 2021, while also aiming to achieve 100% renewable electricity globally by 2025.

As vital as it is to accelerating the adoption of decarbonized electricity, CSPs want to go further – and can do so by carrying out grid transformation.

Geert Standaert, CTO at Proximus

Access networks

Studies show that the access infrastructure is the most energy-intensive segment of a network. The Radio Access Network (RAN) base station, for example, accounts for between 60 and 80 percent of power consumption, while successive generations of technologies – Global Systems for Mobiles (GSM) to LTE to 5G – are more energy efficient. These 5G upgrades are the perfect opportunity to examine legacy RAN and associated spectrum. In 2017, Vodafone decided to shut down its 3G network in Europe; in 2021, 96% of its traffic was on 4G and 5G, and Vodafone was able to reduce CAPEX as well as OPEX expenditure for energy and spectrum use.

In fixed networks, fiber to the home (FTTH) is much more energy efficient than traditional copper-based digital subscriber line (DSL) connectivity. Since 2007, fixed broadband electricity consumption has been reduced by 38% while speeds have increased 64 times. This trend shows that the explosion in demand for connectivity does not necessarily have to lead to a massive increase in emissions; emissions have declined in recent years since the switch from copper to fiber.

Chipsets are the primary driver of power consumption in an access node, and with more power-efficient chipsets, CSPs can achieve smaller nodes that take up less space, use less power, and require less cooling.

And like mobile technologies, successive generations of Passive Optical Networks (PONs) are improving their energy efficiency. XGS-PON (10 Gigabit Symmetrical PON), for example, consumes twice the power of GPON but provides five times the capacity, so upgrading PON networks by CSPs will also improve the carbon footprint on a basis of bits supplied per watt consumed. Geert Standaert, CTO at Proximus, said their large-scale rollout of fiber in Belgium resulted in a 75% energy saving.

Geert Standaert, CTO at Proximus


The mobile backhaul network must also use the most energy-efficient and sustainable technology. The traditional copper used in city trunks is being replaced by fiber, with the associated improvements in energy efficiency described earlier.

Network convergence has been around as a concept for a long time, and the improved performance characteristics of the latest generations of PONs make it a viable option for mobile backhaul. An urban FTTH network has the ability to support mobile backhaul alongside residential broadband and is advantageously close to where 5G small cells are needed. A single converged network for mobile backhaul, business and residential broadband is more energy efficient than separate networks, as it reduces the number of cables laid and electronic equipment deployed.

Network operations

Recently, AT&T announced that it was testing liquid-cooled base station technology in a live network trial in Philadelphia, which could reduce cooling system power consumption by up to 90% and emissions. base station CO2 reduction by up to 80% compared to traditional active air cooling systems. .

Proximus is also adopting innovative approaches to network operations and business models to accelerate deployments, economic viability and improve sustainability. An example is network sharing, where Proximus shares both mobile and fixed network infrastructure with other CSPs.

Avoiding duplicate networks while maximizing the use of existing assets has enabled Proximus to reduce energy consumption by 20% on its mobile network.

Geert Standaert, CTO at Proximus

Proximus is also exploring innovative deployment techniques. Micro-trenching reduces costs and carbon emissions, with less waste, backfill material and labor. Aerial fiber has the same benefits and uses power utility poles, providing a faster, less disruptive way to route fiber directly to radio cell sites, homes and businesses.

This is just one example of how network optimization offers another path to energy efficiency.

Data centers

Cooling accounts for about half of the energy consumed by data centers. Norwegian construction company MIRIS uses liquid cooling for its data centers and reuses it in a local heating system, creating a clean and energy-efficient process. Similarly, Iliad has adopted adiabatic cooling, a more energy-efficient cooling process that uses a change in air pressure caused by volume expansion in all of its data centers and expects this to reduce the energy consumption.

It is clear that in information and communication technologies (ICT), the line between purpose and profit is disappearing and that commercial and environmental interests must be aligned.

Connectivity and digitalization play a vital role in the sustainable transformation of industry and society, enabling individuals and businesses to reduce their GHG emissions. Every network improvement program is an opportunity to increase sustainability with the network modernization options outlined above delivering tangible results for CSPs. The latest generations of mobile and fixed technologies are giving CSPs more options than ever and helping to make the world a more sustainable place.

Geert Standaert, CTO at Proximus

Melvin B. Baillie