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5G Power: Creating a green grid that slashes costs, emissions & energy use

2020.07.29 By Chen Dongxu, Senior Engineer, China Tower and Ye Wanxiang, Chief Engineer of Site Power Facility domain, Huawei

In 2019, the 5G Power solution won ITU's Global Industry Award for Sustainable Impact. For operators, it provides a replicable power solution that can slash site retrofitting costs.

5G Power is based on intelligent technologies like peak shaving, voltage boosting, and energy storage. These capabilities make it possible to deploy sites without changing the grid, power distribution, or cabinets during 5G evolution.

5G Power was designed to address the energy challenges of 5G deployment and improve investment efficiency for operators. In the future, 5G energy solutions will need to meet the demands of simplified deployment, rapid construction, efficient energy saving, and smooth evolution.

5G construction: Energy and emissions

China Tower is a world-leading tower provider that builds, maintains, and operates site support infrastructure such as telecommunication towers, high-speed rail, subway systems, and large indoor distributed systems. As of June 2019, China Tower boasted a combined 1.954 million sites with a value of 315.36 billion yuan (US$44.3 billion). 

On June 6, 2019, the Ministry of Industry and Information Technology issued 5G licenses, and since then Chinese carriers have been ramping up large-scale 5G deployment. By the end of the year, more than 130,000 5G sites are expected to be put into operation nationwide. Hangzhou in Zhejiang Province is aiming to build China's first "5G City", having already achieved contiguous 5G network coverage.

5G network construction differs significantly from 4G in terms of networking modes, product forms, and performance parameters. The power consumption of 5G hardware is between two and four times greater than 4G, posing unprecedented challenges for site infrastructure construction. It calls for systematic research and innovative 5G energy solutions to meet the energy challenges brought by 5G.

The 5G era will be a fully mobile, fully connected smart era. It will see the growth of connections and communication between people, between people and things, and between things and things. With the number of global connections set to exceed 100 billion by 2025, 5G will engender a greater diversity of scenarios and service requirements. 3GPP defines three main 5G scenarios:

  1. eMBB: Enhanced Mobile Broadband at 10 Gbps. 
  2. uRLLC: Ultra Reliable and Low Latency Communications at 1 ms.
  3. mMTC: Massive Machine Type Communications at 1 million/km².

Energy consumption per unit of data (watt/bit) is much less for 5G than 4G, but power consumption is much higher. In the 5G era, the maximum energy  consumption of a 64T64R active antenna unit (AAU) will be an estimated 1 to 1.4 kW to 2 kW for a baseband unit (BBU).

Communicate

Base stations with multiple frequencies will be a typical configuration in the 5G era. It's predicted that the proportion of sites with more than five frequency bands will increase from 3 percent in 2016 to 45 percent by 2023. In a site with multiple frequencies, maximum power consumption for the whole mobile tower will exceed 10 kW. At 10 or more frequency bands, site power consumption surpasses 20 kW. And in scenarios where multiple operators share a site, power consumption is doubled.

Communicate

This trend will require significant retrofitting of existing site infrastructure, because grid capacity, battery capacity, cabinet heat dissipation, and power distribution will be insufficient, leading to a huge amount of wasted resources.

In scenarios where power has to be supplied to remote 5G high-power AAU, excessive cable loss will lead to excessive voltage drops, and in some remote locations, voltage may even fall below hardware operating requirements and stop AAUs from working.

Power supply systems at more than 30 percent of tower sites may need to be retrofitted, according to Chinese site surveys and engineering surveys. The average cost of increasing grid capacity for a single site is around US$2,800. As there are currently 2.5 million mobile towers in China, retrofitting costs will total around US$2.1 billion. 

The growth of power consumption by 5G networks will trigger growth in energy consumption in general. In China, for example, total power consumption by telecoms networks exceeds 50 billion kWh. Once 5G networks are deployed, the power consumption of telecoms networks in China will exceed an estimated 100 billion kWh, generating annual carbon emissions of 27.2 billion kg.

Smart functions with 5G Power 

In Hangzhou, the 5G Power solution deployed by China Tower and Huawei supports one cabinet for one site and boasts smart features like intelligent peak shaving, intelligent voltage boosting, and intelligent energy storage.

1. One Cabinet for One Site

The 5G Power solution has a fully modular design and leverages advanced high-density technology, delivering a fourfold increase in power density compared with traditional power supplies, and a 1.7x increase in lithium battery energy density. It supports a 24 kW rectifier, 600 Ah lithium battery, and 3.5 kW cooling system in a single cabinet. 5G Power meets power supply and backup demands for co-deployed 2G/3G/4G and 5G hardware using a One Cabinet for One Site solution. Traditional solutions, on the other hand, require more cabinets.

Modular rectifier, power distribution, and temperature control components can also be deployed according to requirements. With the same initial investment, the solution delivers 5G evolution capabilities and CAPEX savings of 50 percent when deploying 5G. 

2. Intelligent peak shaving

Intelligent peak shaving is used for the Hefeng village base station in Hangzhou. The site's average load is 1.4 kW, with peak loads of 2.7 kW. However, the AC power limit is 1.6 kW. When 5G services were added in tests, peak loads exceeded the power limit.

5G Power's intelligent peak shaving technology leverages smart energy scheduling algorithms of software-defined power supply and intelligent energy storage. That means at peak loads, the smart lithium battery can power the load, support site peak shaving, and reduce the need for the grid to allocate capacity at the typical power levels.

It requires no changes to grid power, cutting retrofitting costs for a single site by more than US$1,800 and lowering the initial investment costs of 5G evolution.

3. Intelligent voltage boosting

The Xiaoshan site in Hangzhou uses smart voltage boosting technology, with the 5G AAU and power source more than 50 meters apart. When the 5G service was added in tests, a drop in voltage after the 5G AAU was mounted on the tower led to insufficient power supply voltage. This meant the security of the power supply couldn’t be guaranteed and the AAU power cabling had to be changed. Moreover, the increased power consumption of the hardware increased line loss and energy wastage.

With intelligent voltage boosting, the 5G power module and 5G Power BoostLi lithium battery work in tandem to support power supply to the system at a constant voltage. The original configuration could only provide 48V, but intelligent voltage amps this up to 48V–57V, without having to replace AAU cabling. Real-world test results of site performance show that DC output voltage reaches 56.9V–8.9V, higher than the traditional 48V power supply.

Intelligent voltage boosting reduces the need for retrofitting power cables and can prevent issues such as fines for 5G sites going offline or increased cable loss when cabling is not replaced. Intelligent voltage boosting can reduce energy consumption of the whole site by 1 percent.

4. Intelligent energy storage

5G Power supports the smart mixing and matching of lithium batteries, including new and old batteries and different capacities, manufacturers’ products, and materials. For the true on-demand configuration of batteries, balanced charging and discharging of new and old batteries helps to reduce battery deployment costs.

5G Power builds a green energy grid

China Tower and Huawei conducted joint pilot verification in 2018 and found that the 5G Power solution could support effective 5G site deployment without changing the grid, power distribution or cabinets. This in turn could cut retrofitting costs for a single site by more than US$1,800, save 4,130 kWh of electricity per site per year.

China Tower planned to build or retrofit about 2 million 5G sites between 2019 and 2022. An estimated 800,000 of these sites will adopt Huawei's 5G Power solution, eliminating 900 million kg in carbon emissions every year, helping to realize targets for green power grids for the 5G era.

The 5G Power solution is underpinned by breakthroughs in hardware and software and site-wide coordination. It supports simplified smart and green solutions, helping build a sustainable and green target power grid for the 5G era.

1. Simplified

5G Power supports up to 24 kW in power supply capacity and is only 4U high – 3U  for the power source and 1U for the tower that operators share for power distribution. So, existing sites and cabinet space capacities can house the solution. In contrast, a traditional embedded power supply module typically needs to be 7U to 9U in height to achieve the same capacity. This makes it difficult to use existing cabinets and requires new cabinets, increasing the strain on site resources.

5G Power also adopts fully modular architecture, with modular power supply, energy storage, temperature control, and power distribution components. This allows on-demand evolution and supports intergenerational networks. Traditional power supply systems lack the capability for end-to-end evolution. As they cannot be modularly expanded, the entire cabinet has to be replaced if the site's temperature control and cooling capacity is inadequate.

2. Intelligent 

5G Power boasts a raft of intelligent features, including intelligent peak shaving, intelligent voltage boosting, and intelligent energy storage.  Intelligent functions remove the need to retrofit the mains grid, support on-demand battery configuration, and reduce voltage drop, slashing site retrofitting and O&M costs. Traditional power systems only provide power supply for the site and lack these intelligent features, and sites that use them will require a significant amount of retrofitting to support 5G rollout.

3. Green

5G Power focuses on improving energy and E2E efficiency at the component, site, network, and service level, consuming zero watt when there are zero bits. 

Traditional power systems only enable site-level efficiency and cannot coordinate with changes in service power consumption. During service troughs, the power supply cannot sleep or shut off, making altering energy consumption in line with changing service levels and maximizing energy-saving impossible.

5G Power's innovative technology cuts the cost of 5G network evolution and enhances energy efficiency by around 9 percent. Moreover, the solution's energy storage modular expansion capability supports China Tower's power operations services, and the frequency and peak shaving services for the power grid give an additional 8-percent return.

China Tower and Huawei's joint innovation on 5G Power will serve as an important reference for future 5G network deployment and evolution around the world. It will help global operators save on site retrofitting and power costs and boost energy conservation and emissions reduction in sites, helping build a sustainable and green target power grid for the 5G era.