As telecom penetration in the country increases, finding reliable sources to power telecom towers is becoming a major challenge for the industry. While diesel generators (DGs) are installed at telecom base stations around the world as either a backup or primary source of power, excessive dependence on diesel can have negative repercussions. In this regard, storage solutions are gaining significance as a viable option for powering telecom sites.

Energy storage solutions can be used both for towers that face long-duration power cuts as well as those that have grid power available for most of the day. While in the former case, these solutions can reduce the use of DGs for long hours, of the latter, they present a possible option to using advanced energy storage systems for completely eliminating DG usage.

Sector need for storage technologies

Energy cost constitutes 40 per cent of the operational costs of tower sites. As such, any reduction in this area can be of significant value to operators. The main factors driving the uptake of energy storage solutions are as follows:

• Lack of reliable electricity infrastructure needed for powering the ever growing number of telecom sites.
• Government policies aimed at reducing diesel consumption.
• Government regulations requiring renewable energy integration for powering telecom towers.
• To ensure that renewable energy is an effective replacement for DG power, the deployment of storage solutions will be needed given the intermittent nature of renewable energy.

Available energy storage technologies

The energy storage market is developing fast, offering a number of solutions for the telecom tower industry. A number of considerations such as cost, performance efficiency and life cycle go into selecting the appropriate technology for a tower site. The most popular solutions available for telecom sites are discussed below:

• Lithium-ion (Li-ion) battery: These batteries represent more than five different kinds of electro-chemistries offering different performances. The life cycle of a typical battery varies from 1,000 to 10,000 cycles. As the capital costs of these batteries have reduced significantly over time, they have emerged as one of the fastest growing energy storage solutions.
• Flow batteries: A flow battery is a hybrid of a battery and a fuel cell. It has a very high life cycle, which is unaffected by the depth of discharge. In a typical flow battery, the power and capacity are decoupled. They are inherently scalable, and appropriate for long-duration applications. For these batteries to become popular, it is critical to achieve increased efficiency through greater research.
• Advanced lead acid: These batteries are the oldest and the most well-established solutions. The easy availability of raw materials for lead acid batteries has been instrumental in keeping battery costs low. However, more research and development efforts need to be focused on these solutions for increasing the battery’s life cycle and depth of discharge tolerance. Lessons from improvement in other chemistries (such as Li-ion) can be applied to achieve better efficiency and applicability of lead acid batteries.

Conclusion

In the past decade, there has been a significant amount of development in the energy storage sector. While Li-ion systems are currently the most widely researched  and much improvement is expected in their life cycle in the coming years, performance improvements are taking place in almost all battery technologies. Lead acid batteries have been available for a long time but most manufacturers are looking at improving their performance by understanding the failure mechanisms, taking a cue from improvements in other types of battery systems. There have been significant advancements in flow battery technologies.

Energy storage systems, coupled with renewable energy sources, can prove to be a game-changing alternative to the business-as-usual scenario of growing diesel consumption. Greater operational and testing experience for addressing operational issues is needed to increase the uptake of these solutions. At the same time, cost reductions are required in all battery technologies to make storage solutions more attractive.

Based on a presentation by Dr Satyajit Phadke, Senior Consultant, Emerging Technologies and Customised Energy Solutions