Mobile network operators and tower companies are exploring ways to minimise or eliminate the use of diesel generators (DGs) at telecom sites. Since the majority of the sites today operate with multiple tenancies, they function at very high loads. This load coupled with low/unpredictable grid power availability is increasing site opex significantly. Energy optimisation and pilferage management challenges have become the top priority of mobile network operators and tower companies in order to remain competitive.
The changing market scenario and growing data adoption have led to a rise in new tower roll-outs as well as the addition of new base transceiver stations (BTSs) at the existing tower sites, which, in turn, will increase the energy requirements.
In such a scenario, looking at energy storage solutions as potential green energy alternatives is a step in the right direction to address the techno-commercial challenges at telecom sites as well as ensure 24×7 power backup for sustainable telecommunications in India.
Currently, both valve-regulated lead-acid (VRLA) and lithium-ion (Li-ion) batteries are well-proven and acceptable storage solutions that also meet the Indian Operational and Environmental conditions at telecom sites. The integration of these two solutions, Li-ion batteries for cyclic application and advanced VRLA for stationary application, can help provide intermittent power backup, as the combined unit offers a high energy density (25 kWh and 40 kWh) that is sufficient to manage <2 kW loads and >2 kW loads respectively. The high intelligence controller switch is available for automatic charging and discharging functions, controlling the usage priority for Li-ion or lead-acid batteries.
Case for TESU
A telecom energy storage unit (TESU) is designed to utilise the cyclic capability of Li-ion batteries. In an intermittent grid supply scenario, this is achieved by using a maximum of one cycle from VRLA batteries and up to three cycles from Li-ion batteries on average per day. This solution provides an optimum and efficient usage of both VRLA and Li-ion batteries for fulfilling the energy requirements. The overall life expectancy of the system also increases significantly.
TESU offers a reliable backup solution in intermittent grid outage and long grid outage conditions. In case of an intermittent grid outage, Li-ion will discharge and VRLA will act as a standby battery bank, and in case of a long outage, the VRLA battery will provide a long backup. This means the system is suitable for both types of grid scenarios.
The system can be designed with autonomy of 12 to 16 hours. Depending on the load requirement and grid availability, TESUs can be used to meet the power needs of more than 75 per cent of telecom sites in India where the grid is available for more than eight hours.
Evolving policy framework
Go-green has become a popular theme and has been discussed at length in almost every telecom industry forum over the past few years. However, the adoption rate of renewable energy technology (RET)-enabled solutions has been slow due to large-scale capex requirements and operational challenges. Moreover, most of these solutions need to be accompanied with appropriate energy storage technologies to fulfil the power backup requirements, which further adds to the capex. In such a scenario, TESU can transform a telecom site into an energy efficient and DG-free site. In addition, it can provide benefits like high autonomy of 16 hours, fast charging, low opex, remote monitoring and a reduced carbon footprint.
The following policy initiatives will help in building a sustainable telecom network:
- There is a strong possibility of achieving the Department of Telecommunications’ objectives of rural coverage and higher teledensity if all projects funded from the Universal Service Obligation Fund are powered by TESUs besides the grid/RET.
- Operators and tower companies can adopt TESU as a green alternative to eliminate the use of DG sets at sites where the grid is available for more than eight hours, which will help them align with the DoT targets.
- The Ministry of New and Renewable Energy needs to extend subsidy to tower companies in line with other RET objectives and technologies to promote faster adoption of TESUs.
In sum, energy storage solutions can be suitably adopted as green alternatives for meeting the distributed energy demand at telecom sites. The industry needs to start thinking beyond just batteries and switch to energy solutions for supporting green telecom as well as helping customers reduce their operational expenses.
By Manoj Gupta, Vice-President, Strategy and Business Development, Coslight India