green solutions for telecom towers part 2 solar photovoltaic applications

8/9/2019 Green Solutions for Telecom Towers Part 2 Solar Photovoltaic Applications

1/21

2013 Intelligent Energy Limited

Green Solutions for TelecomTowers: Part IISolar Photovoltaic ApplicationsJuly 2013

Intelligent Energy


2/21

Green Solutions for Telecom Towers: Part II

2013 Intelligent Energy Limited 2

Contents

1 INTRODUCTION 3

2 SOLAR PHOTOVOLTAIC TECHNOLOGY (SPV) OVERVIEW 32.1 Solar photovoltaic applications 42.2 Components of solar photovoltaic systems 42.3 Efficiency of solar photovoltaic panels 52.4 Geographic considerations for photovoltaic applications 62.5 Advantages and challenges of solar photovoltaic technology 7

3 SOLAR PHOTOVOLTAIC SOLUTIONS FOR TELECOM TOWERS 73.1 Solution design considerations 83.2 Opportunities and challenges of moving to solar technology in the Indian

telecom industry 93.3 Government initiatives 103.4 Green energy mandate for telecom towers 11

4 CASE STUDIES 124.1 Case study 1 12

4.1.1 Site location 124.1.2 Site description 124.1.3 Site economics 14

4.2 Case study 2 164.2.1 Site location 164.2.2 Site description 164.2.3 Site economics 18

4.3 Challenges on the ground 19

5 FUTURE OF SOLAR PHOTOVOLTAIC TECHNOLOGY FOR TELECOM 20


3/21



1 Introduction

Energy saving is a key sustainability focus for the Indian telecom industry today. This is especially true inrural areas where energy consumption contributes to 70% of the total network operating cost 1 . In urbanareas, the energy cost for network operation ranges between 15-30% 2 . This expenditure on energy as aresult of the lack of grid availability highlights a potential barrier to telecom industry growth, especially

regarding the expansion of rural teledensity which sits at 40.81% compared to teledensity in urban areasof 146.15% 3 .

It is estimated that in India almost 70% of telecom towers are located in areas with more than eighthours of grid outage and almost 20% are located in off-grid areas 4 . This uncertainty in power availabilityhas compelled infrastructure providers to use diesel generators to ensure a continuous supply of power.Annually more than 2.6 billion litres of diesel are consumed to operate telecom towers, resulting in theemission of 7 million metric tonnes of CO 25 . Given the deregulation of diesel prices and the need toreduce carbon emissions, it has become imperative for the industry to evaluate all alternative options inorder to improve network operation and to reduce energy costs. Several efforts have been made tooptimise energy costs, such as converting indoor base transceiver stations (BTS) to outdoor ones in order

to eliminate air conditioning on site, installing energy-efficient equipment and also using clean energysources to power the sites. Among them, using clean energy sources for power has the potential toresolve the three key needs of the telecom industry, namely: reduction in diesel usage; expansion of telecom infrastructure to off-grid areas; and reduction in carbon emissions. Clean-energy technologiesare well supported by the Indian Governments subsidy policy 6 . While clean energy technologies such assolar photovoltaic, wind turbines, biomass power and fuel cells have undergone trials at telecom sites,the majority of these trials have been with solar photovoltaic technology.

This white paper discusses two real-time telecom tower sites using solar photovoltaic technology. Thediscussion includes an overview of the solution configuration and the economic case which includes OPEXcomparisons before and after the deployment of the solar photovoltaic solution. The challenges for

large-scale, on ground adoption are also evaluated.

2 Solar Photovoltaic Technology (SPV) Overview

Solar photovoltaic technology uses the light (photons) from the sun to produce DC electricity. As shownin figure 1, a photovoltaic cell is a light-sensitive semiconductor device which, when exposed to sunlight,releases electrons to produce DC current.

1 Adoption of Green Technology and Safety of Wireless Network by Milan Jain (Sr. Research Eng. Converged

Network, TRAI)2 Adoption of Green Technology and Safety of Wireless Network by Milan Jain (Sr. Research Eng. Converged

Network, TRAI)

3 http://www.indiatelecomonline.com/topics/telecom-statistics/4 http://www.gsma.com/mobilefordevelopment/wp-content/uploads/2012/05/Energy-for-the-Telecom-Towers-India-Market-Sizing-and-Forecasting-September-2010.pdf 5 Assumption 2.1 litres. Diesel usage per hour and 8 hours of outage per day for 4,25,000 towers6 http://www.solar-apps.com/Revised-Capital-Subsidy-and-Benchmark-cost-of-the-SPV-system.pdf


4/21



Figure 1: Electricity generation in a solar photovoltaic cell

2.1 Solar photovoltaic applications

Solar photovoltaic technology can be used as either a stand-alone, grid-connected or hybrid solution. Thetable below summarises the description of each type of application.

Table 1: Three types of solar photovoltaic applications

Solar photovoltaicapplications

Description

Stand-alone This type of application requires the equivalent level of backupenergy storage to ensure power supply when sunshine isunavailable.

Grid-connected In this application, energy is fed back from the photovoltaic moduleto the grid.

Hybrid This is a combination of photovoltaic arrays and other energysources such as hybrids with wind turbines, biomass power, fuel cellsand diesel generators.

2.2 Components of solar photovoltaic systems

Solar photovoltaic cells, modules, panels, strings and arrays

Solar photovoltaic cells are the building blocks of a solar photovoltaic system. Each photovoltaic cellcircuit is packaged in a protective laminate to avoid moisture and corrosion.

Solar photovoltaic modules consist of photovoltaic cell circuits and are connected in series and/orparallel to produce the required currents.

Solar photovoltaic panels are the assembly of modules and are wired in series to form an installableunit.

A number of panels are connected in series and are termed as a solar photovoltaic string .

Solar photovoltaic arrays are a group of strings which form the complete power generation unit. Figure2 illustrates a solar cell, module, array and string structure.


5/21



Figure 2: Structure of a photovoltaic system 7

Charge controller

A charge controller regulates the voltage and current output from the solar panels as required by thebattery and the load. It also keeps the batteries protected from overcharging and discharging.

Battery bank

The battery bank is used as storage providing the source of power during non-sunshine hours. Battery

capacity is measured in Ampere-hours (Ah) at a constant discharge rate. A wide range of batteries can beused in solar photovoltaic configurations. Lead-acid and valve-regulated lead-acid (VRLA) gel batteriesare most commonly used across telecom sites in India.

2.3 Efficiency of solar photovoltaic panels

The efficiency of a solar photovoltaic system varies and depends on the grade of the photovoltaicmaterial used. The table below summarises the various types of solar photovoltaic materials and theirrespective efficiencies.

Table 2: Current range of efficiencies for different solar photovoltaic technologies 8

Wafer-based c-Si Thin films

SingleCrystalline(sc-Si)

MultiCrystalline(mc-Si)

Amorphous Silicon(a-Si); Micro-morphSilicon (a-Si/c-Si)

Cadmium-Telluride (CdTe)

Copper-Indium-Diselenide (CIS) /Copper-Indium-Gallium- Diselenide(CIGS)

14-20% 13-15% 6-9% 9-11% 10-12%

7 http://www1.cooperbussmann.com/pdf/9df1f7ec-8c62-4210-8cf8-9504927394f0.pdf 8 http://www.iea.org/publications/freepublications/publication/pv_roadmap.pdf


6/21



2.4 Geographic considerations for photovoltaic applications

Geographic parameters including daily average energy incidents, the duration and availability of sunshineand also solar power density across different geographic locations, influence the scope of solarphotovoltaic deployment. Table 3 provides facts on solar radiation in India.

Table 3: Geographic considerations of solar photovoltaic applications in India 9

Parameters Availabilities

Daily average energy incidents 4-7kWhr/m2

Solar power density across India See solar map of India (figure 3)

Duration of quality sunshine per day Approximately 5 hours

Number of days with quality sunshine 300

The figure below shows the solar power density across India which maps the performance anddeployment feasibility of solar photovoltaic solutions.

Figure 3: Solar power density in India 10,11

9 http://en.wikipedia.org/wiki/Solar_power_in_India10 http://en.wikipedia.org/wiki/File:Solar_Resource_Map_of_India.png11 Map presents annual average of solar power density


7/21



2.5 Advantages and challenges of solar photovoltaic technology

Solar photovoltaic technology has some limitations which make its mass adoption challenging. Theseinclude high initial levels of capital investment, the requirement for large deployment areas, dependencyon sunshine availability and configuration of storage capacity. Table 4 provides a broad overview of someof the basic advantages and challenges of solar photovoltaic applications.

Table 4: Advantages and challenges of solar photovoltaic technology

Parameters Advantages Challenges

Emissions Zero None

Space requirement None Footprint requirement @10 squaremeter/kW.

CAPEX Recent drop in panel pricedue to mass manufacturing andtechnology innovation

Requires high storage capacity,hence the additional battery costincreases the CAPEX.

OPEX No fuel required Regular panel cleaning is required tomaintain optimum efficiency.

Sunshine availability Average 300 days annually Some geographic locations in Indiahave a prolonged monsoon seasonand hence less availability of sunshine.

Solution configuration Easily integrated intohybrid solution

Intermittent sunshine availabilityrequires equipment automation tooptimise solar photovoltaic usage. Ahigher capacity solution leads to ahigher CAPEX investment.

Storage Enough sunshine to charge thebattery in high solar density (4-7kWh/m 2 ) areas

High battery capacity is required inareas with less solar power density(less than 4 kWh/m 2 ).

3 Solar Photovoltaic Solutions for Telecom Towers

Enabling distributed power generation and emission-free operation makes solar photovoltaic technology adesired option for backup power. However, the dependency on sunshine and the average spacerequirement of 10 square metres for a 1kWp panel 12 limits the scope of deployment.

In recent trials, the two types of applications deployed at telecom tower sites are stand-alone and hybridsolar photovoltaic. The application types were chosen based on the site load profile, grid outagescenarios, space availability at the site and other configuration aspects including average sunshineavailability throughout the trial and the power storage configuration for non-sunshine hours.

The illustration in figure 4 describes the stand-alone system and figure 5 details the hybrid applicationusing solar photovoltaic technology. Hybrid applications can be developed by combining solarphotovoltaic technology with various energy sources such as wind turbines, biomass gasifiers, fuel cellsand diesel generators. Using an augmented battery bank is not considered to be a hybrid solution;instead it is a part of the solar photovoltaic solution.

12 Solar Opportunities in Telecom by Sai Ram Prasad, CTO, Bharti Infratel, Solar Directory 2012


8/21



Figure 4: Stand-alone solar photovoltaic application

Figure 5: Hybrid solar photovoltaic application

3.1 Solution design considerations

The solution design is based on the availability of sunshine in a particular geographic region. Table 5provides a theoretical approach to solution design and describes the parameters for solution design

consideration.


9/21



Table 5: Factors influencing solar photovoltaic solution design

Parameters Description

Load A detailed site load profile is required to design the total panelcapacity.

Efficiency losses Efficiency losses of the various tower site equipment influence

solar panel capacity. Solar photovoltaic technology as an energysource needs the capacity to support the BTS load afterconsidering the losses of the battery, charge controller and otherauxiliary loads.

Energy incident The availability of daily average energy incidents of 4-6 hoursduration largely impacts the energy output per panel. Thisdetermines the panel capacity at the site.

Efficiency of solar photovoltaicpanels

Panel capacity

Panel size

The efficiency of different panel sizes influences the total solutionfootprint. Also the number of panels required to meet the energydemand is determined by panel efficiency.

Battery configurationCharging current limitationBattery output voltagerequired (Ah)

The charging current limitation of a given battery is fixed andbased on its specification. Battery capacity is designed accordingto the duration and availability of sunshine and charging currentlimitation, especially when solar is the only source of batterycharging.

3.2 Opportunities and challenges of solar photovoltaic technology adoption in the Indiantelecom industry

Solar photovoltaic technology has come to be economically viable for different applications over the lastfew years as a result of technology maturity, the scale of adoption, mass manufacturing and innovation.Solar photovoltaic prices have reduced by 65% since 2001 and 73% since 2007 13 . The trend in price fallis represented in figure 6 below.

Figure 6: Price trend of solar photovoltaic modules, 2001 to 2012 14

13 http://thisisxy.com/blog/the-rise-of-green-mobile-telecom-towers14 GTM Research, X&Y Partners analysis


10/21



This significant price reduction has redefined the economic viability of solar photovoltaic solutions fortelecom applications and could accelerate the speed of adoption. According to the Telecom RegulatoryAuthority of India (TRAI), switching to solar will save $1.4 billion in operating expenses for telecom towercompanies compared to the current diesel solution 15 .

The table below shows solar photovoltaic deployment statistics by different telecom operators andinfrastructure providers as of May 2013 16 . A few recent examples/initiatives of solar photovoltaic adoptioninclude Bharti Airtels plan for deploying 3000 solar photovoltaic sites, Idea Cellulars intention for 200solar hybrid installations and Vodafones target of deploying 150 solar photovoltaic sites (in addition tothe 390 sites currently deployed by Vodafone) 17 .

Table 6: Adoption of solar photovoltaic applications for telecom towers 18 (as per GSMAs GreenDeployment Tracker)

Company Solar towers

Bharti Infratel Ltd 1350

Vodafone Essar 390

Idea Cellular 100Indus Towers 650

GTL Infrastructure 80

Total 2570

Though government subsidies, lower interest rates on loans and the significant reduction in solar panelprices are encouraging, there are more challenges that need to be addressed including optimal solutiondesign for various energy management scenarios, seamless integration with other renewable energytechnology (RET) solutions and optimal configuration of solar photovoltaic panels as well as appropriatestorage and space requirements.

3.3 Government initiatives

The Indian government is taking a multifaceted approach to accelerate energy security and to reduce thecountrys dependency on fossil fuels. A few of the solar initiatives by various government bodies areoutlined below:

Jawaharlal Nehru National Solar Mission (JNNSM):

This programme provides a comprehensive framework of solar power development in India. The Missionenvisions 200 MW capacity of off-grid solar applications by the end of Phase-I (2013) and an overall

installation of 2,200 MW by 2022. Under this scheme, systems of up to 100 kWp will receive fundingsupport from the government.

Ministry of New and Renewable Energy (MNRE):

To encourage the usage of alternative and renewable energy sources, the MNRE provides the followingsupport under the JNNSM scheme:

The MNRE announced its support for 400 telecom towers using solar photovoltaic technology 19

15 http://www.ccaoi.in/UI/links/fwresearch/conceltation%20paper%203.pdf

16 http://www.gsma.com/mobilefordevelopment/programmes/green-power-for-mobile/tracker17 http://www.gsma.com/mobilefordevelopment/wp-content/uploads/2013/01/GPM-Bi-Annual-Report-January-2013.pdf 18 http://www.gsma.com/mobilefordevelopment/programmes/green-power-for-mobile/tracker19 http://panchabuta.com/2011/08/22/400-telecom-towers-supported-in-pilot-project-for-use-of-solar-photovoltaic-power-systems-by-mnre-for-fy11-in-india/


11/21



Operator and infrastructure provides wide distribution of 400 MNRE-supported towers acrossIndia

The MNRE provides up to INR 81.00/Wp to offset the project cost

In April 2011, the MNRE revised the capital subsidy and benchmarked the cost of solarphotovoltaic systems 20 to account for solar panel cost reduction in recent years

Table 7: Statistics of 400 solar powered towers supported by the MNRE in India

Operators States Number of solar-powered towers

Airtel Bihar 100

Indus Andhra Pradesh 100

GTL Infrastructure Uttar Pradesh 100

BSNL Across 12 states of India 100

Total 400

Universal Service Obligation Fund (USOF):

To evaluate the viability of using renewable energy sources in the USO Fund projects, the USO Fund hascollaborated with The Energy and Resources Institute (TERI) for the latters Lighting a Billion Lives initiative. The aim is to provide additional mobile charging facilities for rural areas. The project will cover5,000 villages across India over two years 21 .

3.4 Green energy mandate for telecom towers

TRAIs mandate requires that telecom companies should use renewable sources of energy to power atleast 50% of rural telecom towers and 20% of urban telecom towers by 2015. By 2020, the telecom

companies have to convert 75% of rural towers and 33% of urban towers to run on hybrid power22

. TheMNREs recent mandate to convert a minimum of 50,000 towers to solar photovoltaic technology 23

immediately is another step towards ensuring compliance for the adoption of clean energy. Severalproposals from the government have been rolled out for solar powered telecom sites such as BharatSanchar Nigam Limiteds (BSNLs) tender for 15 telecom towers in Bihar 24 and the Department of Telecommunications proposal for 2,200 telecom towers for security networks 25 .

The Tower and Infrastructure Providers Associations (TAIPA) initiative of forming Renewable EnergyService Companies (RESCOs) provides a simplified ecosystem of energy management for telecom towers,whereby infrastructure providers have to pay a fee based on the actual usage of power with no upfrontinvestment in capital. Thus far, high levels of capital investment and inability of a single renewable

energy technology to provide a full range of solutions across all geographies in India make it a challengefor RESCOs to be successful 26 .

Due to these varied energy management scenarios, the Indian telecom industry is yet to benchmark thecost of operation for telecom towers.

20 http://www.solar-apps.com/Revised-Capital-Subsidy-and-Benchmark-cost-of-the-SPV-system.pdf 21 http://www.tele.net.in/telefocus/item/11111-telecom-outreach-key-role-of-the-uso-fund

22 http://www.igovernment.in/site/telecom-towers-be-powered-renewable-energy23 http://www.energynext.in/at-least-50000-mobile-towers-should-switch-to-solar-mnre/24 Tender No.-25068/MS-O&M/CSPS/Non BSNL s ites/12-13/0625 http://www.ciol.com/ciol/news/187289/dot-seek-cabinet-approval-200-green-towers26 Intelligent Energy Ltd, Green Solutions for Telecom Towers: Part I, March 2013


12/21



4 Case Studies

The two case studies below provide an insight into the practicalities and economics of solar photovoltaictechnology implementation by providing actual data at the live sites. The discussion includes details of the solution configuration and economic comparisons of the before and after solar hybrid solutioninstallation at both sites.

4.1 Case study 1

4.1.1 Site location

Table 8: Site description of case study 1

Site location

Geographic location District: KolarState: Karnataka

Distance from Bangalore 72 km

Average daily temperature 35C

4.1.2 Site description


Site description Units Values

Site type - Outdoor

Base transceiver station (BTS - Outdoor

Number of BTS - 1

BTS load kW 1

Grid electricity panel kVA 15

Grid power availability hrs/day 9

Battery bank Ah 300

Diesel generator kVA 15

Energy management before the solar photovoltaic hybrid installation

Before the installation of the solar photovoltaic solution, the 15 hours of grid deficit was backed up byrunning a 15kVA diesel generator for 12 hours and the remaining 3 hours using a 300Ah battery. Figure 7illustrates the power supply schematic at the site.


13/21



Figure 7: Power supply schematic of backup power with diesel generator prior to solar hybrid installationof case study 1

Energy management after the solar photovoltaic hybrid installation

In February 2012, a solar photovoltaic solution was installed at the site. The solution includes 3kW solarpanels, a central controlling unit (CCU) and a 600Ah VRLA battery bank that supports the (on average)14 hours of grid power outage per day. The static power conditioning unit (PCU) which replaces theearlier power interface unit (PIU) provides the additional hour of grid utilisation by managing grid voltagefluctuation. This turnkey solution is provided by ALTA Energy, India.

The central controlling unit controls and monitors solar power utilisation, grid power utilisation andbattery utilisation, as well as battery charging and discharging. The central controlling unit is

programmed to prioritise the solar photovoltaic technology as a primary power source over all the otherpower sources. Hence, solar power is used when sunshine is available even if the grid power is available.The solution has an inbuilt data transfer unit (DTU) to store and transmit data for remote monitoring andsends SMS alerts through GPRS when service is required.

Since installation, the diesel generator has not been in use. Figure 8 below illustrates the power supplyschematic at the site.

Figure 8: Power supply schematic, with solar photovoltaic installation for case study 1


14/21



Table 10: Solution configuration of case study 1

Components Units Value

Solar panel capacity kWp 3

PCU kVA 15

Solar maximum powerpoint tracker controller(MPPT)

kW 5

SMPS kW 6

Battery capacity Ah 600

4.1.3 Site economics

OPEX comparison

Table 11 shows the monthly savings over the traditional diesel solution for backup power for the telecom

tower after the solar photovoltaic solution was installed. Evaluated in the comparison are cost of the grid,cost of fuel for the diesel generator and operation and maintenance of the hybrid solution.

Table 11: OPEX comparison of the before and after solar photovoltaic hybrid installation for case study1 27

Components Units Before solar hybrid After solar hybrid

Cost of grid consumption INR/day 99 69

Diesel cost INR/day 1186 0

Maintenance cost INR/day 159 37

Total OPEX INR/day 1444 116

Per unit OPEX INR/kWh 60 5

Savings per kWh is calculated to INR 55.00

Payback period calculations

The solution costs INR 13,60,000. If the solution is financed for 120 months at 14% rate of interest, themonthly pay out for CAPEX is INR 21,116 which adds INR 5 per kWh.

The graph in figure 9 compares the cost of energy of the solar photovoltaic solution with the dieselsolution, considering an annual expenditure for diesel at various price points, installed capacity and

operation and maintenance.

27 All numbers are presented as actuals from site


15/21



Figure 9: Cash-flow projections in case study 1

The graph summarises the time frame of the realised return on investment for the installed solarphotovoltaic solution in comparison with the yearly expenditure for the diesel solution. Considering theplausible price points of diesel at INR 52.25 per litre 28 , INR 60 per litre and INR 70 per litre, therespective payback periods, including CAPEX investment, are plotted. The chart demonstrates that, atINR 52.25 per litre of diesel, the return on investment on solar photovoltaic can be realised afterapproximately 2.5 years of deployment. When the price is at INR 60 or 70 per litre, the return oninvestment of solar photovoltaic technology will be much faster, that is between 1 and 2 years. In thiscase, for every INR 10 increase in diesel price the time frame of the return on investment for the solarphotovoltaic solution is reduced by approximately 6 months.

The savings resulting from the deployment of the solar photovoltaic system will result in an increase infree cash flow of INR 4,81,737 on an annual basis. In other words, the investment in the system willyield an IRR of 33% which is significantly higher than cost of capital (14%) and implies viability of thesolution.

This site has not received any capital subsidies for solar photovoltaic systems and hence such subsidieshave not been used in the calculation.

28 Delhi diesel price in June 2013 INR 50.25 per litre, plus INR 2.00 logistic cost

Year0

Year1

Year2

Year3

Year4

Year5

Year6

Year7

Year8

Year9

Payback period analysis for case study 1

Diesel @70.00 INR/ltr

Diesel @60.00 INR/ltrDiesel @52.25 INR/ltr

Solar Photovoltaic


16/21



4.2 Case study 2

4.2.1 Site location

Table 12: Site location of case study 2

Site location

Geographic location District: TumkurState: Karnataka

Distance from Bangalore 150 km

Average daily temperature Minimum 18CMaximum 35C

4.2.2 Site description


Site description Units Value

Site type - Outdoor

BTS - Outdoor

Number of BTS - 3

BTS load kW 3

Grid power availability hrs/day 6

Energy management before the solar photovoltaic hybrid installation

Before the installation of the hybrid solution, the sites backup power requirement of 18 hours a day onaverage was fulfilled by a 20kVA diesel generator running for a minimum of 10 hours per day and theremaining 8 hours by three batteries each of 400Ah capacity, with one for each of the service providers BTSs. The diagram below represents the diesel generator power supply schematic at the site.

Figure 10: Power supply schematic of backup power with diesel generator prior to solar hybrid installationin case study 2


17/21



Energy management after the solar photovoltaic hybrid installation

In May 2009, a solar hybrid solution was installed to meet the 18 hours of outage. The solar hybridsolution includes a 10kW solar photovoltaic panel, a 5kW wind turbine, a 22kW SMPS and a 2500Ahbattery. The 400Ah battery bank also remains at each BTS. The battery was designed to ensuremaximum energy storage and utilisation of solar hybrid power at the site. Figure 11 illustrates the powersupply schematic at the site.

Figure 11: Power supply schematic after the solar hybrid solution installation in case study 2

As depicted in the diagram, both solar and wind power generators are connected to their respectivecharge controller units (CCUs) for optimal power transfer. The following table provides configurationdetails of the solar hybrid solution.

Table 14: Solar photovoltaic hybrid configuration in case study 2

Components Units Value

Solar panel capacity kWp 10

Solar charge controller andmaximum power pointtracker

kW 10

Wind turbine and chargecontroller

kWp 5

Switch mode power supply kW 22

Battery capacity Ah 2500

On certain days, due to prolonged grid failure, lack of sunshine or total absence of wind, the diesel

generator supports the backup power need. According to the site records, of the 18 hours of daily outage,


18/21



on average almost 16 hours of backup power is provided by the solar hybrid solution and the remaining 2hours by the diesel generator 29 .

In comparison with case study 1, since the load is higher here, the possibility of using the solar hybridsolution as a stand-alone option reduces.

4.2.3 Site economics

OPEX comparison

Table 15 shows the monthly savings after the solar hybrid solution was installed. Evaluated in thecomparison are the cost of grid consumption, cost of fuel for the diesel generator and the operation andmaintenance of the hybrid solution.

Table 15: Comparison of OPEX for the before and after solar photovoltaic hybrid installation for casestudy 2 30

Components Units Before solar hybrid After solar hybrid

Cost of grid consumption INR/day 263 269

Diesel cost INR/day 1138 354

Maintenance cost INR/day 379 441

Total OPEX INR/day 1781 1064

Per unit OPEX INR/kWh 25 15

Savings per kWh is calculated to INR 10

Payback period calculation

The solution which includes solar panels, wind turbine, battery bank, two charge controller units andSMPS of capacities described in table 13 costs a total of approximately INR 27,00,000. If the solution isfinanced for 120 months at the rate of 14% interest 31 , the monthly pay out for CAPEX is INR 42,200which adds INR 25 per kWh. It should be noted that the solar solution design has not been optimised atthis site. With optimisation, there is an opportunity to reduce the CAPEX investment.

The graph below compares the cost of providing backup power using the solar photovoltaic solution incomparison with a diesel-only solution at the various points of diesel price projection.

29 Based on site average actual data30 All numbers are presented as actuals (March 2013) from site31 60 months contract duration already completed and contract duration of 60 months likely to be extended as per discussions withBSNL


19/21



Figure 12: Cash-flow projection in case study 2

The graph summarises the time frame of the realised return on investment for the installed solarphotovoltaic solution against the yearly expenditure of the diesel solution. At the time of this evaluation,the price of diesel is INR 52.25 per litre 32 . Given that the deregulation of diesel prices is expected at anytime, diesel at INR 60 per litre and INR 70.00 per litre is used in this analysis chart. From the chart it canbe determined that with an increase of every INR 10 per litre in the price of diesel, the solar photovoltaicpayback period reduces by approximately 2.5 years. However, for this 3kW site, at the current price of

INR 52.25 per litre and without any subsidy from the government, the time frame of solar photovoltaicpayback period is approximately 9 years.

The savings resulting from the deployment of the solar photovoltaic system will result in an increase infree cash flow of INR 2,61,456 on an annual basis. In other words, the investment in the system willyield an IRR of -1% which is significantly lowers than cost of capital (14%) and implies non-viability of the solution over the contract duration of 10 years.

As a proof-of-concept site, this deployment received around 80% subsidy from the government, makingthe solution economically viable from the date of installation as shown in figure 12.

4.3 Challenges on the ground

Due to the diversity of energy management scenarios, viability of the technology and maturity of thesolution, adoption of renewable energy technology has multiple challenges before it can be adopted atlarge scale across the country. Table 16 captures a few of the major challenges encountered by both testcase sites.

32 Delhi diesel price in June 2013 INR 50.25 per litre, plus INR 2.00 logistic cost

Year0

Year1

Year2

Year3

Year4

Year5

Year6

Year7

Year8

Year9

Pay back period analysis for case study 2Diesel @ 70.00INR/ltr

Diesel @ 60.00INR/ltr

Diesel @ 52.25.00INR/ltr

Solar photovoltaic witharound 80% subsidies


20/21



Table 16: List of challenges faced by telecom infrastructure providers and RESCOs in deploying RETsolutions at large scale

Parameters Challenges

Technologychallenges

Seamless integration with other energy sources such as wind turbines, biomassand fuel cells

Configuration of off-grid applications

Complex system integration (configuration is not optimised for consumption)

Design andconfigurationchallenges

Prioritisation of solar photovoltaic technology among other available energysources for frequent outages

Optimisation of solution configuration in terms capacity installed

Deploymentchallenges

Higher foot print requirement

Optimum exposure to sunshine for the solar panel

Poor operation and maintenance services

Scalabilitychallenges

Capital intensive

Geographical limitation

Variety of energy management scenarios and flexibility of solution integration

Economicchallenges

High CAPEX

Replacement of batteries further increases the capital investment

Not enough encouragement by government to overcome the tipping point in theadoption of the technology at large scale

5 Future of Solar Photovoltaic Technology for Telecom

In telecom, solar photovoltaic technology has experienced a better rate of adoption to date in comparisonwith other RETs. Achieving optimal configuration is still a barrier for large-scale adoption of the solution.As shown in the case studies, telecom sites with lower load profiles benefit from solar photovoltaictechnology installations from day one whereas for telecom sites with higher load profiles, it is difficult to

justify the cost of capital investment required. The growing cost of diesel and relevant subsidies may tipthe balance in favour of solar investment in some of these cases. For higher load profile sites, batterycapacity is high thereby increasing capital investment and maintenance requirements. At times, thesesites have to fall back on diesel generators to supplement the gap left by the solar solution.

With innovative business models like the OPEX model solution where the initial capital investment is

financed and the telecom tower owner pays only for the usage, the solar adoption rate can increasesignificantly.

While solar offers a good solution for many telecom towers with lower load profiles, the deploymentconstraints at other towers make it necessary to evaluate the capabilities of alternative renewable energytechnologies aside from solar, such as biomass power and fuel cells. The next edition of this whitepaperwill discuss the practical and economic viabilities of these alternative technologies.


21/21


Intelligent Energy acknowledges the contribution of ALTA Energy India and all others, for sharing information andconducting primary research used in the development of this white paper.

A special thanks to Mr P.K. Panigrahi, Sr. Dy. Director General (BW), DOT and Mr V.K. Hirna, Dy. Director General(Electrical), DOT for their support.

About Intelligent Energy

Intelligent Energy delivers efficient and clean energy technology for the global consumer electronics, automotive andstationary power markets from compact energy packs for mobile devices, to power-trains for zero-emission vehicles,and stationary power units for the always-on infrastructure.

Our unique technology architecture is used by global blue chip companies to create differentiated, cost-efficient fuelcell power systems for mass market applications. It enables Intelligent Energy and our industry partners to solve thechallenges of continuous power and productivity, by creating convenient everyday energy solutions to power your life.

Intelligent Energy operates globally, with offices in the Americas, Europe and Asia.

www.intelligent-energy.com

green solutions for telecom towers part 2 solar photovoltaic applications

Documents