Solar energy has proven to be a dependable and economical method of powering telecommunication systems in topographic points where conventional electricity is unavailable or impractical. It provides an first-class beginning of clean, dependable power to maintain un-interrupted power supply to telecom towers. This paper contains a brief description of Indian telecom towers and photovoltaic ( PV ) cells used in telecommunication systems. Because solar energy systems are robust and cost effectual, the demand for solar power in telecommunications will go on to turn.
Key Words-insolation, irradiance, photovoltaic, solar cell, solar energy
Introduction
India is now in the 2nd largest of the Global telecom markets and is projected to get the better of China. Our state presently has about 400,000 telecom towers around the land and poised to increase to 450,000 towers over the following 2 old ages ( 2 ) . A big part of these towers is non connected to the electricity grid or does non hold entree to dependable electricity connoting they have to put in backup power systems in order to run without breaks. Diesel Generators have been the pick of telecom operators despite their high C imprint. Telecom Towers are estimation to fire 2 Billion Liters of Diesel ( around 500 million barrels ) yearly at a cost of 10000 crores. On an norm, about 260,000 is being spent yearly to carry through the Diesel demands of a individual telecom tower. These high input costs besides result in high pollution. While the authorities has been seeking to change over these towers to renewable energy signifiers, most of the tower operators have been really slow to implement this alteration. The renewable energy ministry had asked telecom companies to cut down their dependence on conventional fuels and see options for partially powering telecom towers. While some tower Godheads are looking at tight natural gas and piped natural gas to power towers, Indus Towers, the largest with over 1 lakh towers in India, planned to put up 2,500 solar towers by terminal of this twelvemonth. Viom Networks, which operates more than 38,000 towers across India, plans to run more than one-quarter of this figure on alternate energy within the following two old ages. It plans to run 2,000 towers on solar power entirely by 2013. For the GSM Technology, it requires an norm of 6 BTS to run one tower. Each shelter has two ( 1.5 ton ) air conditioners for the cardinal care of the temperature for the shelter 's electronic systems. The DG set is typically 15 kVA capacity, which consumes an norm of 3 liters of Diesel per hr [ 4 ] .
Each tower requires energy from 1000 W to 3000 W ( older installing consumes more power as comparison to new one because of technological promotion ) . Each 1000 W consequences in the 22 tonnes/hr of emanation of CO2 if running on the province electricity and in instance of the gensets this figure is many times more. Assuming mean power ingestion of each tower is 1200 W so entire CO2 emanation is 105.6 lakh metric ton per hr by all these towers if we assume that all are running on province electricity. In India about 70 % telecom towers are in rural countries. Soon 40 % power demands are met by grid electricity and 60 % by Diesel generators [ 2 ] . The Diesel generators are of 10-15 KVA capacity and devour about 3 litres of Diesel per hr and bring forth 2.63 kilogram of CO2 per litre. For every kWh of grid electricity consumed, 0.84 Kg of CO2 is emitted. Entire CO2 emanation is around 5 million tones of CO2 due to diesel ingestion and around 8 million dozenss due to power grid per annum. The move from Diesel to solar and other alternate beginnings of energy will ensue in a decrease of 5 million dozenss of CO2 emanations every bit good as a nest eggs of immense sum in operating disbursals for telecom tower companies. Move to renewable energy beginnings can bring forth 1000000s of C credits that could countervail the opex on their towers. Therefore by replacing diesel generators with solar panels in cell phone towers, more than 5 million dozenss of C emanations could be prevented from come ining the ambiance and cut down the opex of telecom towers. India has approximately 500 million nomadic phone endorsers, more than even the population of any state except China India is expected to hold one billion mobile phone endorsers by 2015 which would intend about 250,000 more Mobile towers which, in bend, would duplicate the C emanations. Even if the solar panels supply a portion of the entire power required, it would still salvage significant sums of money, fuel and C emanations.
Electricity Generation Through Solar Cells
In India the one-year solar radiation is about 5 kWh/ sq thousand per twenty-four hours with about 1500-2000 sun-shine hours per twelvemonth. Solar radiations represent the Earth 's most abundant energy beginning. The perennial beginning of solar energy provides limitless supply, has no negative impact on the environment. The solar photovoltaic ( PV ) modules convert solar radiation from the Sun into electrical energy in the signifier of direct current ( DC ) . Converting solar energy into electricity is the reply to the mounting power jobs in telecom towers peculiarly in the rural countries. PV or solar cells are semiconductor devices that convert sunlight into direct current electricity ( Fig.1 ) . When light photons of sufficient energy work stoppage a solar cell, they knock negatrons free in the silicon crystal construction, coercing them through an external circuit and so returning them to the other side of the solar cell to get down the procedure all over once more.
Fig. 1. ( a ) photovoltaic consequence ( B ) how a PV cell plants ( degree Celsius ) a crystalline Si panel
The electromotive force end product from a individual crystalline solar cell is about 0.5 V with an amperage end product that is straight relative to the cell 's surface country ( about 7 amperes for a 6-inch-square multi crystalline solar cell ) . Typically, 30 to 36 cells are wired in series ( + to - ) in each solar faculty. This produces a solar faculty with a 12-volt nominal end product ( ~17 Vs at peak power ) that can so be wired in series and/or parallel with other solar faculties to organize a complete solar array. Solar cells used in telecom towers are shown in Fig 2. Solar cell is cosmopolitan and will work virtually anyplace ; nevertheless, some locations are evidently more suited than others. Irradiance is a step of the Sun 's power available at the Earth 's surface, with power peaking at about 1,000 Wattss per square metre ( W/m2 ) . With typical crystalline solar cell efficiencies about 14 to 16 per centum, approximately 140 to 160 Wattss can be generated per square metre of solar cells placed in full Sun. Insolation, which is a step of the available energy from the Sun, is expressed in footings of `` full Sun hours '' ( i.e. , 4 full Sun hours = 4 hours of sunshine at an irradiance degree of 1,000 W/m2 ) [ 1 ] .
Fig.2 Solar cells used in telecom tower for United Nations interrupted power supply.
Tele Density
Telephone introduced in India in 1882. The entire figure of telephones in the state stands at 885.99 million, while the overall tele-density has increased to 73.97 % and the entire Numberss of nomadic phone endorsers have reached 851.70 million as of June 2011. Himachal Pradesh has become the first province in India to accomplish 100 per cent tele-density. The province has about seven million nomadic clients [ 5 ] . The province population is 6.8 million as per the Census 2011 much lower than the nomadic subscriber population of seven million. While the urban tele denseness reached 150.67 per cent, the rural tele denseness reached 32.11per cent. Experts have pointed out that the grounds for this rapid growing are lowest call rates, big market base due to bigger population, well ample untapped market and robust economic growing of the state. In add-on factors like rapid technological acceptance, better service criterions, advanced merchandise offerings and competitory pricing amongst the service suppliers has besides contributed in a major manner to increase the tele-density of the state.
Energy Management in Telecom Towers
A Telecom tower enables telecom operators to supply web connexion to mobile users.
Fig. 3 Standard Telecom System
Telecom being an indispensable service requires the web to be ever available. In order to accomplish this, the tower substructure that has 2 operators uses 6-8 kilowatt ( avg. ) of electricity per hr ( Fig.3 ) . Energy demands of a telecom tower in India are presently met through:
Electricity Mains
Diesel Generator and
UPS / Battery Racks
Diesel Consumption in Telecom Towers and Environmental Pollution
The telecom operator spends 3 billion ( USD 67.42 million ) every month towards running Diesel generators in distant locations where grid base power is limited. This translates to an operational energy disbursal of around 65 billion yearly to run web towers, particularly in off-grid locations ( 4 ) . Since, Electricity supply is fickle and is non available through out the twenty-four hours in many parts, Diesel Generators ( DG ) are used to power the telecom web, as a dorsum up for power supply.
DG 's are operational for 15-20 hours ( avg. ) in rural countries and 3- 7 hours in urban countries ( Table 1 ) seting a emphasis on the environment by manner of C emanations and noise pollution
One liter of Diesel emits 2.63 kilogram of CO2 emanations.
Hence telecom webs contribute to carbon emanations and planetary heating.
Table 1 Power Availability at Tower Sites
Grid Power Availability Cell Sites
10 % : & gt ; 20 hour Chiefly metro metropoliss of Mumbai, Kolkota,
Chennai, some metropoliss of Gujarat, State of
Chattisgarh, some metropoliss of Punjab
20 % : 16-20 hour Covers most other major metropoliss and towns in the
remainder of the state
30 % : 12-16 hour All semi-urban and little urban towns in all
provinces
25 % : 8-12 hour Mostly rural countries
15 % : & lt ; 8 hour Mostly parts of Bihar and some towns of
Assam, NE provinces, UP and J & A ; K
The Power Problem
A speedy analysis of telecom web runing costs indicates power and fuel are the primary operating costs, consisting over 30 % of entire operating cost. This is because grid power ( Electricity Board or EB power ) is extremely undependable and in a batch of instances, non available in rural countries. BTS sites require changeless and uninterrupted power for the safe operation of the web. As a consequence, BTS sites have utilized onsite Diesel generators to either supply backup or primary power in the absence of EB power. Uninterrupted operation is achieved through a battery bank. The typical constellation of DG sets is 10-15 KVA with a fuel burn rate of 2-3 liters per hr ( depending on full or half load operations ) . Assuming seven hours of DG operations in urban countries and 20 hours in rural countries, estimated use of Diesel fuel is 2-4 billion liters per twelvemonth across the 400,000 towers in India. Fuel demand is increasing with each new tower. India, with its first-class irradiance, has the chance to work Photovoltaic ( PV ) solar power to run into this challenge of onsite power coevals. Coupled with a battery backup, PV systems are a feasible and exciting option to cut down the power cost and entire operating outgo ( OPEX ) , thereby supplying a sustainable and dependable strategic solution to the fuel job. The operating cost of Diesel and solar PV system is shown in Table-2 which shows that solar PV system is economical ( 14.08/kWh ) than Diesel DG sets ( 16.19/kWh ) and besides eco friendly and can market their C recognition to cut down farther the opex of the telecom tower.
Table 2. Comparative analysis of solar PV and diesel generators ( DG ) uses in telecom tower.
Strictly DG sets
Strictly PV system
Annual ingestion of 15 kVA DG sets @ 3 litres/h, liters
26280
Assumed capacity, Wp
15000
4 % shut down period i.e.for 96 % operation, liters
25229
Annual sunshine hours
1650
kWh produce @ 3.5 kWh/litre
88301.5
10 twelvemonth output, kWp
247500
Diesel cost @ 42/litre,
1059618
Capital investing
@ 200/Wp,
30,00,000
Cost of machine etc,
300000
Operating cost, ( including depreciation, involvement, care ) , /10 old ages
49,80,000
Operating cost ( including depreciation, involvement, housing/rent, care ) , /year
1429918
Operating cost/kWh,
16.19
Operating cost/kWh,
20.12
After 30 % subsidy
14.08
Telecommunication Companies and Their Role
ECIndia has the fastest turning telecom web in the universe with its high population and development potency. India 's public sector telecom company BSNL ( 11.41 % ) is the seventh largest telecom company in universe. The entry of new participants into the telecom industry has made competition intense, in peculiar over the last four old ages. The dominant participants in the market presently include Bharti-Airtel ( 20.09 per cent of the Indian market ) , Reliance Communications ( 16.70 % ) , Vodafone ( 16.54 % ) , Tata Tele Services ( 11.08 % ) , Idea ( 10.97 % ) and Aircel ( 6.76 % ) ( Table 3 ) .
Table 3. Share of telecom companies in Indian market and stairss taken to utilize renewables
Companies
Market portion, %
Stairss taken for usage Renewable energy in teletowers
Bharati Airtel
20.09
Targeted for solarizing 2000 towers by 2010-11. No latest information on accomplishment.
Reliance Communication
16.70
Stairss taken to utilize renewable to cut down opex by 50-60 %
Vodafone
16.54
23 % of its planetary operation by renewables
BSNL
11.41
Taken pilot undertakings under Jawharlal Nehru Solar Mission for solarizing towers.
Tata Teleservices Ltd
11.08
Deployed 31 cell sites powered by solar power and fuel cells.
Idea Cellular
10.97
Solar-DG loanblend in some nomadic towers
Aircel
6.76
No information available
Stel
0.34
Cringle
0.39
Eti Salat
0.08
HFCL
0.18
Uninor
2.73
Videcon
0.83
MTNL
0.69
Siestema
1.21
Beginning: Telephone Regulatory Authority of India ( as on 28th Feb, 2011 )
As per the directives of Ministry of New and Renewable Energy, some companies have taken inaugural stairss to utilize renewable energy beginnings to power their telecom towers. Some major are:
Bharti Infratel has set a mark of deploying 2000 renewable energy sites by the fiscal twelvemonth 2010-11. The undertaking is besides expected to ensue in an estimated decrease of 58,170 metric tons of CO2 emanations per twelvemonth.
BSNL has taken up pilot undertakings for 10 kilowatts solar workss at 14 sites and Wind power undertaking at 6 USO funded sites in Rajasthan, Gujarat, Tamil Nadu, Karnataka and Maharashtra.
Indus Towers, the largest with over 1 lakh towers in India, will put up 2,500 solar towers by September this twelvemonth.
Viom Networks, which operates more than 38,000 towers across India, plans to run more than one-quarter of this figure on alternate energy within the following two old ages. It plans to run 2,000 towers on solar power entirely by 2013.
There are around 5,60,276 Base Transceiver Stations ( BTS ) in the state. It may be noted that BTS is different from towers as one tower may hold more than one BTS. In India the tower companies portion the tower sites with all telecom operators. While the tower is erected by the tower substructure companies, the BTS is installed by the telecom operators. A nomadic tower is an aerial where electronic communications equipment are placed on a wireless mast or tower to make a cell in a cellular web. A nomadic tower is composed of a tower or other elevated construction for mounting aerial and one or more sets of transmitter/receivers transceivers, digital signal processors, control electronics, a GPS receiving system, regular and backup electrical power beginnings, and sheltering. Circle wise interruption up of BTS is given below [ 3 ] .
Metro
DelhiA A A A A A A A A A A A A A A A A A A A A A A A A A 20,715
MumbaiA A A A A A A A A A A A A A A A A A A A A A 21,038
KolkottaA A A A A A A A A A A A A A A A A A A A A 14,018
TotalA A A A A A A A A A A A A A A A A A A A A A A A A A 55,771
A Circles
MaharashtraA A A A A A A A A A A A A A A 42,998
GujaratA A A A A A A A A A A A A A A A A A A A A A A 31,852
Andhra PradeshA A A A A A A A A A A 43,661
KarnatakaA A A A A A A A A A A A A A A A A A 39,093
Tamil NaduA A A A A A A A A A A A A A A A 52,075
TotalA A A A A A A A A A A A A A A A A A A A A A A 2,09,679
Fig 4. A roof top Mobile tower in Bhubaneswar utilizing intercrossed grid-DGB Circles
KeralaA A A A A A A A A A A A A A A A A A A A A A A A 27.156 Fig.3 A BTS system
PunjabA A A A A A A A A A A A A A A A A A A A A A A A 19,575
HaryanaA A A A A A A A A A A A A A A A A A A A A 13,883
UPA A A A A A A A A A A A A A A A A A A A A A A A A A A A A 68,487
RajasthanA A A A A A A A A A A A A A A A A A A 28,694
Madhya PradeshA A A A A A A A A A A 31,665
West BengalA A A A A A A A A A A A A A A 24,532
TotalA A A A A A A A A A A A A A A A A A A A A A A 2,13,992
C Circles
Himachal PradeshA A A A A A A A A 5,425
BiharA A A A A A A A A A A A A A A A A A A A A A A A A A 35,086
OrissaA A A A A A A A A A A A A A A A A A A A A A A A 18,095
AssamA A A A A A A A A A A A A A A A A A A A A A A A A 9,610
North EastA A A A A A A A A A A A A A A A A A A 5,490
Jammu & A ; KashmirA A A A A A A A 7,128
TotalA A A A A A A A A A A A A A A A A A A A A A A A A A 80,834
Grand TotalA A A A A A A A A A A A A A 560,276
Decision
To cut down CO2 emanation and planetary heating due to telecom towers, Govt. should do it compulsory to telecom companies to utilize renewable energy.
Govt. should halt subsidy on Diesel for telecom companies.
More inducements should be given to those who use renewable energy for their towers.
