We are discussing growth again in India and it is also the buzz word in the telecom industry in the country. Per person, data services usage in India grew by over 30 % in 2014, which has led to a renewed interest in investments in the sector.
The next level of investments will be aimed at the improvement of teledensity in rural India, which has currently reached around 46% against 147 % in urban parts of the nation. Investments will also be aimed at optical fiber network expansion and setting up of new telecom towers for all 2G, 3G, and 4G services. Operators have been facing capacity issues in the 3G spectrum with only around 20% penetration of 3G services in the Indian metros. 3G penetration at pan India level is just over 6% and is likely to increase in leaps and bounds by 2020 due to the high demand for internet services over cheaper smartphone handsets.
However, the high growth in the sector may not translate into high profitability due to increasing operating costs. Telecom tower operators have registered extraordinary energy bills that are in the range of 25 to 40% of their overall operational costs. This is due to the unreliable nature of electricity supply at tower sites. To mitigate the risk of unreliable electricity supply, the industry is undergoing a structural transformation where more and more towers are operated by ESCOs, O&Ms or Energy Management Service providers who are owning, maintaining and operating the passive energy infrastructure. These companies are providing energy at a contracted fixed cost basis.
Some of the key trends which are driving the need for better alternate energy storage solutions are mentioned below:
The poor State of Electricity in Rural India
Fast saturating urban voice markets and the government’s plan to significantly improve teledensity in villages to over 70% by 2017 has led telecom companies to comprehensively focus in rural lands. The challenge here lies in providing services with power availability less than 10 hours per day. Over 17,000 tower sites are not at all connected to the grid and they run entirely on diesel-Genset (DG) backup. Telecom industry claims that over 450,000 towers have been installed in the country with 70% of the towers running on the DG back-up of over 8 hours.
In many such sites, DG optimization has been achieved by the usage of Li-ion batteries. These batteries have certainly demonstrated fast charging capabilities, superior efficiency and higher depth of discharge. Such advanced properties have given them an edge over existing dominating VRLA technologies which under severe operating conditions have reported less than 800 cycles.
RET Mandate and Limitation of Lead Acid Battery
The industry is of opinion that DOT (Department of Telecommunications) mandate to power 50% of rural towers and 20% of urban towers from hybrid sources (renewable energy technology + grid power) by 2015 is unrealistic. As reported by telecom industry participants, carbon emission reduction targets can be met with the use of advanced energy storage technologies and implementation of RET is not required at over 20% of urban towers by 2015. Till 2014, approximately only 10,000 towers were powered by solar PV based hybrid system and more than 70,000 are operating without the use of diesel. The installation of hybrid energy solutions at the telecom towers site can be a practical issue due to the unsuitability of the site for solar PV installation.
In this case, tower companies are not willing to spend more on capital expenditure after heavy spending at spectrum bidding. Advanced energy storage technologies are likely to make inroads in either case of PV getting installed or not. Current installations of a lead-acid battery are not good enough for replacing diesel as they require long charging duration and will have a shorter life if regularly discharged to the depth. On top of it, lead-acid batteries are not monitored and the site operators are not aware when they would need a replacement.
Evolution in Telecom Infrastructure and Technologies
Telecom tower owners are switching over to outdoor BTS (Base Transceiver Station) from indoor BTS as they have realized more than 50% power consumption is a reduction. Indus Towers, the leading telecom tower company in India, has claimed that half of its sites are outdoor BTS. For outdoor telecom sites, storage technologies with better performance at extreme temperatures are preferred. In this scenario, Li-ion and Flow Battery have shown better results than even VRLA Gel batteries which are more resistant to temperature fluctuations than any other lead-acid technology currently available in the market. And with the reduction of prices of Li-ion to less than $400 per kWh, the Levelized Cost of energy in case of Li-ion + AC/DC generator installation is much lesser than that for Lead Acid + AC/DC generator.
Secondly, in the coming years, 3G and 4G technology penetration will increase and these technologies will have a smaller power requirement than 2G technology. Current 4G BTS installations are known to consume 800W of power. The next generations of BTS: Smart cells, picocells, and femtocells will be mostly in-house installations with power requirements less than 500 W. Such connections will be installed in millions across the country and their smaller structural design will demand a back-up solution with high energy density. In this scenario, Li-ion will be an advantage over technologies like flow batteries, as they are much bigger in size.
Conclusion
In recent times, more and more operators and ESCOs are looking to optimize energy costs by limiting usage of diesel gensets and also by increasing DG efficiency by running it at maximum loading. These companies have tried many alternative options like flow battery, Li-ion battery, hybrid energy sources (including solar PV and also wind). However, Li-ion has come out as the preferred technology until now because of its fast charging ability, high efficiency, deep discharge, and high energy density. Lone competence of Li-ion which is yet to be demonstrated at a telecom site is their long cycle life. However, Li-ion manufacturers are very confident of this property and are even ready to offer longer warranties than that offered with lead-acid batteries.
There are challenges in switching over from lead-acid to Li-ion as they require better charging and monitoring infrastructure. Each of these Li-ion (from different companies) may require a unique set of BMS (Battery Monitoring System). So unlike VRLA, where it is easy to switch between the vendors, in Li-ion batteries, one has to be aware of the compatibility of charging and battery monitoring set up before ordering Li-ion batteries from a particular vendor. In this case, an advanced lead-acid battery may replace an existing set of VRLA much easily than Li-ion.
