On-Site Renewable Energy and Backup Power Solutions for Telco Infrastructure Applications

According to Nokia, 93% of CO2 emissions related to telecom networks come from equipment operation, with 80% of the network’s energy consumption accredited to base-station sites. Equipment manufacturers are implementing power-saving technologies in the latest generation network equipment, although since the equipment still requires vast amounts of power to operate, finding the most sustainable energy sources will reduce not only energy-related Operating Expenditure (OPEX) but also the carbon footprint of the network.

The Global System for Mobile Communications Association (GSMA) estimates that energy costs now account for 20% to 40% of telco OPEX due to energy-intensive radio units and the network densification required for 5G coverage. This is set to increase with the introduction of 5G and beyond as the new technologies require still more energy to provide the same network coverage compared with previous generations.

Aradatum, a “21st century tower company” that provides renewable energy solutions for telco infrastructure, has recognized that the current grid infrastructure—developed as far back as the late 1800s—cannot support the modern demand for energy. The company is developing innovative renewable energy-powered telco tower solutions to alleviate this stress on the grid. Aradatum has noted that there have been over 180 large-scale outages in the U.S. national grid during the last 20 years; if this infrastructure isn’t supported and some of the power demand is sourced from elsewhere, then the grid will become overwhelmed, and more outages will occur. Aradatum estimates that 300,000 new cell towers will need to be deployed across the United States to support the rollout of 5G networks—meaning that grid energy demand for network equipment will significantly increase if no alternative energy solutions are implemented.

In remote areas that are considered either off-grid (no energy supply from the grid) or poor-grid (limited, inconsistent energy supply), alternative power solutions must be utilized to provide stable network coverage. Solar panels, wind turbines, hydrogen fuel cells, and battery storage technologies enable a more sustainable cell site. Battery technology exists in many applications already; the technology allows rechargeable cells to provide a safety net or to be a primary power source for a wide array of technologies and allows network operators to reduce or eliminate the reliance on diesel generators.

Diesel generators at poor- or off-grid sites are a popular choice as a backup power source, though to reduce the carbon footprints of 5G network deployments, mobile network operators need to replace these generators with more energy-efficient and greener solutions. Ryse Energy, a renewable energy company, observes that over 1.5 million telco sites are powered entirely by inefficient diesel generators, with telco industry purchase estimates at over US$19 billion of diesel per year for these generators.

Outages can occur in even the most stable grid situations; inclement weather, earthquakes, equipment failure or damage, and surging energy demand can disrupt power distribution to important telco infrastructure. While diesel generators have been the go-to backup system, mission-critical applications need security in power for networks and other applications. Battery storage can provide this security, though it is only recently that the technology has become more accessible due to vast research and development efforts into Electric Vehicle (EV) technology.

Lithium-Ion (Li-ion) batteries are far more efficient than lead acid batteries, and some can be discharged to 100% without damage. Lead acid batteries are often “oversized” for their applications because they cannot be discharged beyond 30% to 40%, since this will cause damage and further reduce capacity. Li-ion batteries are estimated to have three-to-four times more energy density than lead acid, meaning a smaller sized Li-ion battery can deliver a significantly larger power output than a lead acid battery of the same size. The lifetime of Li-ion batteries means an additional three years’ worth of lifetime extension compared with lead-acid, making Li-ion the more sustainable choice.

EVs have long used Li-ion battery technology—more specifically, Lithium Nickel Manganese Cobalt Oxide (NMC)—though over the last few years the use of Lithium Iron Phosphate (LFP) battery technology is on the rise, growing from 8.9% in 2020 to approximately 20.6% to 21.5% in 2022, turning LFP from a niche technology to an energy storage staple. This increase in research and development in LFP technology has enabled wider adoption of the technologies outside the EV sector.

LFP batteries typically have a life expectancy of 2,000–3,000 depletion cycles before hitting 80% of their original capacity, compared with 500–1,000 cycles of NMC batteries. NMC batteries have a higher energy density (i.e., more energy transferred per weight); however, the depth of discharge available (i.e., how much of the stored energy can safely be depleted without causing damage and reduction in capacity) in NMC batteries is in the 80% to 90% range. LFP batteries can be safely discharged by 100%. LFP batteries have a wider safe-operating temperature range than NMC and are generally regarded as a safer option as there is no ignition or explosion risk with LFP batteries. The cobalt present in NMC batteries not only is a highly sought-after element with links to unsustainable and unethical mining but also can result in toxic emissions during and after the battery’s operational lifetime. LFP batteries are seen as the more sustainable choice, and with limited space available for deploying battery storage solutions as a viable backup option, smaller, more energy-dense solutions are needed.

Battery storage is a sustainable backup solution only when the power stored in them comes from renewable sources. Charging batteries using “dirty” fuels is no greener than taking electricity straight from a fossil-fuel-powered grid. Many vendors offer small and local deployments of renewable energy solutions, such as wind turbines and solar panels, to power cell sites and charge batteries when the wind is blowing and sun is shining; they then switch to backup battery power when needed.

Switching to renewable energy solutions will greatly reduce the carbon emissions and long-term OPEX for cell site deployments. The capital expenditure for sites with diesel generators is low because these generators are cheap to purchase—though the OPEX for the fuel required to meet the demand for maintenance and for fuel delivery costs are very high. The initial associated costs for deploying renewable energy technologies at cell sites are high, but in the long term, the savings in energy costs, reduced maintenance costs, and reduction in greenhouse gas emissions make the overall lifetime of the cell site more sustainable than one that is connected to the grid or one that relies solely on a diesel generator. After all, the sun and wind cost nothing!

The GSMA stated in their report Going Green: Benchmarking the Energy Efficiency of Mobile that “46% of total energy consumption was supplied by renewables, 43% from traditional grid and 11% from diesel.” While this is a significant portion of renewable energy sources being used at cell sites, there is scope to increase the usage of greener power sources in order to enable more sustainable networks.

Solar panels are a viable alternative to diesel generators for poor- or off-grid sites, and over the last decade prices have come down to a comparable rate. However, the sun doesn’t always shine, so without efficient energy storage solutions or another supplementing renewable energy source (e.g., wind turbines), solar panels may have inconsistent power delivery. Hybrid solutions are ones that combine multiple energy sources (e.g., wind and solar) to generate energy.

Ryse Energy advocates for rightsizing renewable and hybrid energy solutions for cell sites and suggests that by switching to solar, wind, and battery storage solutions, diesel backup generator dependency can be reduced by up to 90% to 95% under the right conditions. Bladon Micro Turbine has recently joined forces with Ryse Energy to provide micro turbines that have combustion efficiencies of 99.9%. These turbines can be run on diesel, kerosene, paraffin, or low-carbon hydrotreated vegetable oil fuel that can be blended to reduce costs and emissions by up to 95% or can be run on hydrogen to provide a zero CO2 emission solution.

GenCell offers hydrogen and ammonia fuel cells and battery storage solutions for off-grid sites. Hydrogen fuel cell generators emit only water vapor, meaning that they can be deployed in almost any environment with no detrimental effect.

Advanced energy management software, implementing Artificial Intelligence (AI) to manage power usage on site, is being more widely adopted in renewable energy solutions. Green Cubes Technology provides modular, rack-mounted Li-ion (LFP and NMC) battery storage solutions to reduce or eliminate reliance on diesel generators where possible. Green Cubes offers a remote monitoring software to optimize the power distribution and to monitor battery performance in order to reduce the need for in-person maintenance site visits.

Huawei Digital Power has developed renewable energy solutions—mainly solar photovoltaics and energy storage solutions—for a range of applications. Huawei has implemented AI software in the Huawei Power Solutions energy management platform to monitor power supply and to improve efficiency by up to 20%.

Multiple vendors are offering a wide range of renewable energy solutions for off- or poor-grid areas. However, in cases where the grid can provide sufficient and stable power to cell sites, long-term renewable energy power purchase agreements for grid power are aiding network operators in achieving their net-zero ambitions. Companies that invest in renewable energy solutions for cell site deployments sooner rather than later will see a quicker return on investment, and this is especially true as fossil fuel prices are climbing to all-time highs, ultimately reducing the energy-related emissions at cell sites. Harnessing renewable energy solutions will lead to greener, more sustainable networks.