ENERGY MANAGEMENT IN TELECOM INFRASTUCTURE INDUSTRY

[Mr. M. GOVINDARAJAN]

Telecom towers

The increase in the number of mobile phones within 18 years is very high.  For the purpose of mobile phones telecom towers have been installed by the service providers. At present India has about 4,25,000 telecom towers with total tenancies of 7,50,000. The technology in mobile sector is increasing. The industry switched to 3G technology from 2G technology.  The telecom operators continue to expand their 3G networks and also to roll out 4G technology.  The number of towers that are required to provide adequate coverage for these technologies is high.  This rise further increase in the Telecom industry’s energy demands additionally.

Types of towers

Based on the installation the towers can be classified as Ground Based Towers and Roof Top Towers. Ground based towers are erected on open ground with foundations.  The height of these towers is normally 30 to 200 meters.  Roof top towers are erected on top of the roof of the existing buildings with raised columns and tie beams. The height of these towers may be 9 to 30 meters.

Energy for Telecom towers

The Telecom industry is the second largest consumer of energy after transportation.  The total electricity required for these telecom towers is approximately 12 billion to 14 billion units of electricity per annum.  Grid connection is better than any other alternative energy solution in terms of cost efficiencies.  Availability of grid connection is the question of the day.  The infrastructure providers are required to ensure 24 x 7 power availability at the base transreceiver stations irrespective of the site conditions and grid outages

In a number of villages in India and around the world, electricity is either not available or is available only in limited quantities. As a result, even if battery backup is provided for the Base Transceiver Station (BTS), the batteries do not get fully charged. Further, due to frequent interruptions in the power supply, the life of these batteries gets shortened, which in turn increases the operational cost to run services in rural areas. Unavailability of reliable power in semi-urban, rural and remote areas increases operational costs further because sufficient backup systems have to be maintained.

At present 40% of the towers across the country have access to electricity for less than 15 hours. Most states are still facing a power shortage. The situation is likely to improve.  To face the energy crisis the telecom operators have to go for alternative energy solutions.

 The following are the further challenges:

• The towers in remote areas are characterized by highly uncontrolled and unpredictable environments.  Therefore the energy requirements of each telecom towers site needs to be looked at their multiple angles to overcome the challenges that arise in energy management;
• The poor quality of power;
• The outage cycles are highly varied across regions.
• The operational efficiency that assets should bring in, which often does not match up to the ideal due to various factors such as improper maintenance;
• The manpower and its efficiency deployment;
• Every location and tower has different characteristics and different requirements.

Therefore the three components, energy, assets and people are to go hand in hand along with other process for achieving energy optimization.

Green Telecom

The Telecom Regulatory Authority of India (TRAI) recommendations on Green Energy applications have been approved by Government. Following directives have been issued to the licensees/all ILD service providers to adopt measures to green the Telecom sector setting broad directions & goals:

1. At least 50% of all rural towers and 20% of the urban towers are to be powered by hybrid power (Renewable Energy Technologies (RET) + Grid Power) by 2015, while 75% of rural towers and 33% of urban towers are to powered by hybrid power by 2020.
2.  All service providers are required to evolve a carbon credit policy in line with carbon credit norms with an ultimate objective of achieving a maximum of 50% over the carbon footprint levels of the base year in rural areas and achieving a 66% over the carbon foot print levels of the base year in urban areas by the year 2020. The base year for calculating all existing carbon foot prints would be 2011, with an implementation period of one year and the first year of carbon reduction would be the year 2012.
3. All service providers to declare the carbon foot prints of their network twice in a year. Further based on the details of footprints declared by all service providers, service providers should aim at carbon emission reduction targets for the mobile network at 5% by the year 2012-2013, 8% by the year 2014-15, 12% by the year 2016-17 and 17% by the year 2018-2019.

The Telecom operators are to comply with the above.  The green telecom policy requires mobile operators to migrate 75% of all cell towers in rural areas and 33% in urban areas to hybrid power by 2020.  The Department of Telecom (DoT) wants these towers converted to green energy sources like solar, biomass or wind.  The roadmap to encourage green energy in the telecom sector, prepared by the DoT, says at present 80-90 per cent of power requirements for rural towers are met by diesel generator sets, each of which consumes 8,760 liters of diesel a year if it runs eight hours a day. It is estimated that 5.12 billion liters of diesel is consumed by telecom towers annually, and total emission due to this is around 10 million tonne of carbon dioxide.

Alternative energy solutions

The telecom companies are evaluating new solutions and alternative sources of energy such as solar, wind, hybrid solutions etc., and also for less power intensive telecom equipments.

Diesel Generator Sets

The first alternative solution is using diesel generator sets for which diesel consumption is required. According to ICF International the utilization of diesel is expected to 4.8 billion liters to 6.3 billion liters by 2015 and 2020 respectively.  It was expected due to deregulating diesel prices by the Government the cost towards diesel consumption will rise further.  But now the diesel price is on the decline.  This will result some economy in the usage of diesel.

Due to lack of reliable power in rural areas, there has been a substantial increase in the usage of diesel for running engine alternators to keep telecom exchanges, transmission equipment and BTS s up and running. This increases costs substantially.

In spreading the reach of telecommunications in remote areas, renewable energy should be used to power relay towers in remote areas. By replacing diesel generators with solar panels in cell phone towers, more than 5 million tons of carbon emissions could be prevented from entering the atmosphere.

Solar

Solar energy has been used since 1960 in India. India has a solar power capacity of over 3GW. It is economical and commercially viable if the power cut is more than eight hours and with up to two tenants at the towers site in the case of out door sites. In respect of indoor sites it is dependent on the grid failure of more than 16 hours and with one tenant. The limitation of this technology is that the viability is highly dependent on the radiation and temperature and space availability at the sites.  Solar is a clean and effective way of harnessing energy. Also, the maintenance cost for the operation of solar equipment is comparatively lower as compared to diesel generators operated BTS towers. Solar generators have no carbon emissions and also help in preserving the environment for sustaining life on earth. It reduces global warming, as carbon emissions are null in solar devices. The manpower needed for the operation and maintenance for solar equipment do not require extra skill.

The solution of this type is emerging as the most preferred by the industry. Many of the operators are to deploy solar power solutions at 5% to 10% of their towers by 2015. Solar Photo voltic (PV) units have a higher upfront cost than DG sets and depends on battery back when day light is not available. If one wants to configure a solar PV installation for a tower, a detailed evaluation of the loan profit of the site, weather conditions throughout the year, battery efficiency, charge controller efficiency, power loss due to dust accumulation and available area for installing are to be considered.

Biomass

 It is economical and commercially viable for sites with an average load of more than 5 KW and grid outage of more than 8 hours. The high dependency on biomass feedstock and its logistics is the main limitation of this solution. There are several challenges in dealing with fuel security during large scale deployments.

Wind energy

This requires less space. It can be easily installed on telecom towers. However the quality of wind energy generation is highly dependent on the wind speed and duration. It requires equivalent

VRLA (Valve Regulated Lead Acid batteries)

By using VRLA significant cost savings can be achieved. This can reduce diesel operation hours by 12 hours at an off grid site and by 8 hours in a site with poor grid availability thereby resulting in 60% and 52% cost savings. The solution brings maximum cost savings about 80% of a solar hybrid site where diesel generator set use can be eliminated and towers can be operated through a battery, solar energy and grid electricity. It can bring annual opex savings of ₹ 2,90,000/- to ₹ 4,60,000/-. Using an advanced VRLA conventional energy solution along with other conventional energy solution at an off grid site could result in annual open savings of ₹ 4,40,000/-.  For a poor grid site it will be ₹ 2,90,000/-.

Fuel Cell

This has several advantages.  It also results in complete elimination of diesel generator sets.  It is green energy which is suitable for any site type.  It is compact. It requires low maintenance and is easily scalable.  An advanced VRLA battery is used primary back up while a fuel cell is used for providing extended back up. It is opt for sites located in the vicinity of hydrogen source.  The sites with erratic and discontinuous grid availability and those having ground based towers can also apply fuel cell solutions for energy storage.  It is an expensive solution.  The unit cost is around ₹ 24/- which includes both fuel and logistics costs. It is a very recent technology and lacks the skilled manpower required for its operation.  The total cost of ownership (TCO) is the highest when compared to the other hybrid solution. The challenge in using this is the lack of development of hydrogen infrastructure, including its storage and logistics.

The technology is new and still evolving.  The issues like fragmented hydrogen and methanol supply chain persist.  Its feasibility needs to be tested on a larger scale.  The telecom operators consider implementing fuel cell solutions for meeting their power needs.

Lithium Iron Battery

It also results in the complete elimination of a diesel generator set from a site. These are used for cyclic application. It is much helpful for sites with power and erratic grid supply. It is also suitable for both the ground based tower and roof top sites. It is a highly cost effective solution. It occupies lower space; lower maintenance requirements; provides improved performance and offers higher reliability.

Flow batteries

These allow the rate of electricity flow to be separated from the total of energy held.  This allows faster charging and longer discharge capacity independent of each other without significant impact on the cast. Dr. Vishal Mittal, Director, Engineering and Principal Scientist, Imergy Power Systems found that these technology is suited for telecom towers and micro grids which have a requirement of 5 kw to 10 kw.

Energy storage system

Managing energy costs is the important area for telecom tower operations. The telecom operators began to adopt energy storage technologies in a big way to address the challenge of unpredictable power to a great extent.   Therefore the operators are having energy storage systems installed. These technologies required to be financially and commercially viable to be considered as standalone services. These solutions are more flexible in supplying power or charging. The storage systems are based on adhesive batteries that are very temperature sensitive and have reliability problems in terms of charging.  The energy storage systems are expected to provide over 15% of the required power at telecom sites.  Lead acid based systems with storage capacities of 15KWh is the majority storage system. 

Financing

An attempt to push telecom companies to invest more in green energy technology, now DoT plans to provide easy bank financing, by way of softer interest rates and longer loan tenures, since telecom towers enjoy infrastructure status. Telecom tower companies will also be eligible for higher overseas borrowing limits, lower import duties and excise exemptions on telecom infrastructure equipment, said a DoT note.

Conclusion

Going forward the industry should look for new technologies and solutions for the better energy management. A cluster based energy generation approach can be adopted for rural areas. The storage technologies will definitely play a vital role in increasing improving the efficiencies of telecom network. The return of investment for such technology is very important.  Grid parity needs to be achieved to ensure the sustenance of renewable solutions over a longer horizon.

References:

www.dot.gov.in

www.trai.gov.in

tele.net journals