first green consulting discussion paper solar rooftop systems

Solar Rooftop Systems: Alternative to Support Growing Energy Need

FIRST GREEN CONSULTING

DISCUSSION PAPER

SOLAR ROOFTOP SYSTEMS: ALTERNATIVE TO SUPPORT

GROWING ENERGY NEED

Author:

DR. SANJAY VASHISHTHA (DIRECTOR, FIRSTGREEN CONSULTING PVT. LTD)

Co-Author:

SAACHI SINGLA (PGPM ENERGY CANDIDATE, GREAT LAKES IEMR)

First Green Consulting Private Limited

U-28 A/3, DLF Phase 3,

Gurgaon, Haryana- 122002. India



TABLE OF CONTENTS

I. INTRODUCTION.............................................................................................04

II. ROOFTOP SOLAR SYSTEMS.............................................................................05

1. Initiatives for rooftop systems under JNNSM...................................................................05

2. Components of rooftop systems....................................................................................06

3. Installing rooftop system over building...........................................................................07

4. Assessment of roof for Solar PV.....................................................................................07

5. Assessment of generation.............................................................................................08

6. Assessment of cost of rooftop Solar PV..........................................................................08

III. FINANCIAL ASSESSMENT................................................................................08

1. Financing of Rooftop Solar PV Systems...........................................................................08

2. Economics of Rooftop Systems......................................................................................09

IV. TECHNICAL ASSESSMENT...............................................................................10

1. Grid Connectivity.........................................................................................................10

2. Net Metering...............................................................................................................11

3. Power Purchase Agreement..........................................................................................11

4. Feasibility Check for rooftop PV system..........................................................................11

V. POLICY INCENTIVES AND SUBSIDIES............................................................12

VI. SOLAR ROOFTOP LEASING AGREEMENT..........................................................15

VII. FUTURE OUTLOOK..........................................................................................15



LIST OF FIGURES

Figure 1: Solar Energy Potential in India............................................................................04

Figure 2: Schematic diagram of Solar Rooftop System.........................................................07

Figure 3: Cost of Generation v/s Interest rates & Average Tariff v/s Variation in load from DG &

HVPNL..........................................................................................................................10

Figure 4: Cost of Generation v/s Subsidy...........................................................................10

Figure 5: Cost of Generation v/s Capex.............................................................................10

Figure 6: Feed-in metering and Net metering.....................................................................14

LIST OF TABLES

Table 1: JNNSM Targets..................................................................................................06

Table 2: Proposed Capacity Allocation under JNNSM............................................................12



I. INTRODUCTION

The current installed capacity of India stands at around 207 GW1. India has been richly endowed with

renewable resources. The existing installed capacity of renewable power in India is around 25.82 GW, which

accounts for about 12% of the total installed capacity. Harnessing of non-polluting renewable energy

resources to control green house gases is receiving impetus from the Government of India. As a part of

National Action Plan on Climate Change, Government of India launched Jawaharlal Nehru National Solar

Mission (JNNSM) in 2009 to promote the development and use of solar energy for power generation and

other uses with the ultimate objective of making solar energy competitive with fossil-based energy options.

The solar photovoltaic device systems for power generation had been deployed in various parts of the

country for electrification where the grid connectivity is either not feasible or not cost effective as also

sometimes in conjunction with diesel based generating stations in isolated places and communication

transmitters at remote locations. With the downward trend in the cost of solar energy and appreciation for

the need of development of solar power, solar power projects have recently been implemented. A significant

part of the large potential of the solar energy in the country could be developed by promoting grid-

connected solar photovoltaic power systems of varying sizes as per the need and affordability coupled with

ensuring adequate return on investment.

While India receives solar radiation of 5 to 7 kWh/m2 for 300 to 330 days in a year, power generation

potential using solar PV technology is estimated to be around 20MW/sq. km and using solar thermal

generation is estimated to be around 35MW/sq. km.

Figure 1: Solar Energy Potential in India

1 http://www.cea.nic.in/reports/monthly/executive_rep/sep12/8.pdf as on 30.09.12

2 http://www.mnre.gov.in/mission-and-vision-2/achievements/ as on 31.08.2012

http://www.cea.nic.in/reports/monthly/executive_rep/sep12/8.pdf

http://www.mnre.gov.in/mission-and-vision-2/achievements/



Considering 300 average clear sunny days and daily average global solar radiation to be around 5.8 kWh/sq

m/day, the capacity utilization factors for various Solar PV based is expected between 15-25% based on

SPV (thin film or crystalline) and upto 35% based on concentrated PV.

The input for the project is the Solar Radiation which is very conducive to setup a Solar PV plant across

country. The economical land is feasible, as India has sufficient deserted space without residential /

agricultural or commercial use and has plenty of Roof Tops. The technology is within reach and most

technology providers have started focusing India, the knowledge base is developed with execution of >1000

MW capacity addition in last 2 years. There is an acute power shortage thus there is strong need for the

user to pay for energy generated. All the elements are available in India, except the big challenge of making

financial sense from the investments.

II. ROOFTOP SOLAR SYSTEMS

While there is a considerable interest in the utility scale grid connected solar power plants, roof top systems

are equally getting attention and the country has about 43 MW of roof top systems connected to the grid.

Rooftop PV systems are much more attractive due to the fact that these systems have potential to reduce

transmission and distribution losses and further reduce additional burden of laying the T&D infrastructure.

Connecting roof top solar PV systems to the grid is a great challenge, specially the rooftop systems which

are in kW capacity; the utilities face tremendous challenge in terms of handling the unstable sources of

electricity at distributed level. While the PV system costs have come down considerably, roof top systems

provide altogether a new market to the urban households who already have an inverter and battery storage

systems as back up source in the event of grid unavailability.

In India, the application of solar PV has a particular significance, given the condition of its transmission and

distribution infrastructure – high losses, poor power quality and frequent load shedding. Most buildings,

public, private and commercial (for example, malls, hotels, hospitals and nursing homes), have diesel

generators for back-up in case of load shedding by the utility. Given environmental considerations, the use

of diesel should be minimised. There is abundant opportunity to use rooftop or building-mounted solar PV

systems to generate electricity and thereby reduce the consumption of diesel. Due to the intermittent supply

of solar power and grid outages, diesel–solar PV hybrid models could be potential solutions. Generous

subsidies have been offered by the Government (both Central and State). Despite this, widespread

installation of solar PV systems to generate electricity on urban rooftops does not seem like a reality that

will take the shape in the near future.

1. Initiatives for rooftop systems under JNNSM

Government of India launched its National Solar Mission in January 2010 with a targeted installation of

about 20 GW of solar electricity by 2022 under the Jawaharlal Nehru National Solar Mission (JNNSM).



Table 1: JNNSM Targets:

Application

Segment

Target for Phase-1

(2010-13)

Target for Phase-2

(2013-17)

Target for Phase-3

(2017-22)

Utility Grid Power 1,000-2000 MW 4000-10,000 MW 20,000 MW

Off-grid

Applications

200 MW 1000 MW 2000 MW

The first phase has observed a remarkable attention and achieved installations of the order of 950 MW of

solar electricity in the country. The JNNSM also supports small-scale-grid connected systems under the

Rooftop PV and Small Scale Solar Power Generation Programme (RPSSGP). Under this program of JNNSM by

Sept, 2012, 87.803 MW of solar photovoltaic (PV) plants have been commissioned out of 98.05 MW holding

Power Purchase Agreements (PPAs) under the nation’s Rooftop Solar PV and Small scale Solar Power

Generation Program (RPSSGP) program in phase-1, batch-1 (See annexure1).

2. Components of Rooftop System

A typical rooftop system generally comprises of the following equipments:

i. SPV Power Source

ii. Inverter

iii. Grid Charger (only for system with batteries)

iv. Charge Controller (only for system with batteries)

v. Batteries (Optional)

vi. Mounting Structure

vii. AC and DC Cables

viii. Earthing equipment /material

ix. Junction Boxes or combiners

x. Instruments and protection equipments

The solar modules are connected to an inverter to yield 240V AC at medium power levels (2-10kW). This

system is connected to AC power lines (i.e., connected to the grid) as shown in Figure 2. The customer sells

power to the utility during the day and buys power from the power company during the night. Some of the

rooftop systems have inbuilt inverters, also known as micro inverters which convert the electricity generated

by module directly in to AC electricity at the module output itself. The use of micro inverter system greatly

reduces installation labour costs, improves safety, and maximizes the solar energy harvest.

It is possible to integrate the solar module with your existing home inverter system and can reduce the

capital cost significantly. The solar panels are connected to the existing home inverter-battery system

3 http://mnre.gov.in/file-manager/UserFiles/commissioning_status_spv_batch1_phase1.pdf

http://mnre.gov.in/file-manager/UserFiles/commissioning_status_spv_batch1_phase1.pdf



through a hybrid charge controller and can provide relief to the households for additional charging option

apart from normal grid charging of the storage batteries. In the event of non requirement of solar electricity

at the household, this surplus electricity can be fed back to the grid as well. The home owner has to install

this converter along with the existing inverter which also acts as a battery charge controller and connects

the AC mains & load output control system all in one.

Recently NREL has developed a new breed of solar cells which are organic cells, which have been used for

window panes to convert the sunlight in to electricity through the window panes termed as Solar Window.

The research team has developed a conductive wiring grid that is practically invisible, which provides for

more efficient energy harvesting without interfering with the see-through quality of the panel.

Figure 2: Schematic diagram of Solar Rooftop System

3. Installing rooftop system on your building

Installing a solar rooftop solar PV system requires a basic understanding of technical, economic and

regulatory aspects to take a call for the viability of these systems. Installing a rooftop solar PV system is

different than installing a typical solar water heating system as it has many sub systems such as inverter

selection and net metering etc. PV systems have limitations that they produce power intermittently because

they work only when the sun is shining. It is difficult for PV systems to furnish all the power you need, and

are typically used in conjunction with utility-supplied electricity.

4. Assessment of the Roof for Solar PV



The best orientation for a rooftop solar PV system is on a south-facing roof; hence it is important that the

roof has a south facing option available to install solar PV system. A flat horizontal roof is also eligible for

solar PV facing clear sky and having shadow free area. The amount of roof space needed for Rooftop Solar

PV systems is determined on the basis of selection of PV generating capacity. Typically a rooftop system

requires about 100 ft2 area to house a 1 kW power.

5. Assessment of generation

PV systems produce the most electricity during October to March when the sun is shining. Energy production

will vary, of course, depending on geography and climate. A typical 1 kW roof top PV system will produce

about 1600-2000 kWh in a year depending on the location. If we consider a typical household demand of

12000 Units a year, then a typical 5 kW rooftop system will meet about 60-70% of the annual household

electricity demand.

6. Assessment of cost of rooftop solar PV

The electricity generated from rooftop systems are still more expensive than conventional grid electricity,

however it all depends on how much is the opportunity cost of displaced electricity. If the displaced

electricity is a combination of grid and DG based electricity, in that case the cost of displaced electricity is

about 9 Rs/unit which makes solar PV system much more attractive to the roof top installer. Although the

utility grade Solar PV is now costing about 80-90 Rs/Wp, the rooftop PV systems will cost about 120 Rs/Wp

due to economy of scale. Considering a cost of 120 Rs/Wp for a typical roof top system a 10 kW roof top

system will cost about 12 Lac. The building owner is also eligible for 30% capital subsidy (3.6 Lac) and

accelerated depreciation upto 80%. Hence the building owner has to spend about 40% of the total cost of

the systems, which makes PV attractive in terms of low capital cost.

III. FINANCIAL ASSESSMENT

1. Financing of Rooftop Solar PV Systems

Government of India has launched a low interest based financing scheme for roof top systems and it is

available from many commercial banks and also through NABARD. The interest rate charged for the roof top

systems is of the order of 5%.

All Commercial Banks (including private commercial banks) and Regional

Rural Banks are eligible to avail refinance facilities from NABARD to refinance the rooftop solar PV systems.

Funds towards meeting the subsidy and refinance requirements under the scheme are provided to NABARD

by IREDA. The rooftop projects eligible for funding support under the Scheme will need prior approval from

the Project Approval Committee of MNRE. MNRE would provide financial support through a combination of



30%4 capital subsidy and/ or 5% interest bearing loans. For the year 2011-12, the benchmark price for

photo voltaic with battery back-up is considered as 300 per Watt Peak (Wp). In respect of the systems

which do not use storage battery such as water pumping systems, the installed PV system cost would be

considered subject to a cap of ` 210 per Wp. Capital subsidy of 90% of the benchmark cost, would be

available for special category states, viz. NE, J&K, Himachal Pradesh, Sikkim and Uttarakhand.

2. Economics of Rooftop Systems

PV power generation has long been considered as a costly technology, due to higher installation cost, use of

rare earth material like Silicon, and low conversion efficiency, etc. Due to higher upfront cost, the roof top

PV installations are globally driven through subsidies in case of off grid systems and Feed in Tariffs (FITs) in

case of grid connected rooftop PV systems. In recent years, the rapid cost reductions in PV module prices

have led PV as one of the alternative technology which is at par with some of the costly conventional power

sources.

The economics of PV plants is generally assessed in terms of cost per watt peak (Rs/Wp) or in terms of

levellised cost of energy (LCOE) and represented in terms of Rs/kWh. While the manufacturing community

assess the cost in Rs/Wp, the investor community assess the economics in terms of LCOE. Since 2004,

regardless of module prices, system prices have fallen steadily as installers achieved lower installation and

maintenance costs. The LCOE for rooftop PV systems has declined by nearly 50% in last three years. Most

important determining factors of the levellised cost as being capital costs, capacity factor, cost of equity and

cost of debt.

Consider a typical 100 kW Solar Rooftop PV Plant compared to the general supply of 70% from grid and

peak 30% from DG sets (Annexure-2). Calculating the return on the savings from the above system i.e.

switching to rooftop rather than following the conventional systems, gives a return of 10% . Working out the

total cost from the rooftop systems, based on Rs. 120/Wp, the Capital Cost of 100kW Rooftop PV plant is

Rs.1.3 Mn with the Capacity Utilization Factor (CUF) of 21%. The equity investment needed is Rs. 1.68 Mn

and the amount funded from Bank loan works out to be Rs. 6.72 Mn. Figure-3 shows that the cost of power

generated by PV exhibit a particularly high sensitivity to the interest variations, followed by variations in

average tariff by changing the %age of power generated from DG and Grid. Figure 4 and 5 also gives the

variation of cost of power generated with the inclusion of subsidy and with the variation of capex

respectively.

Figure 3: Cost of Generation v/s Interest Rates & Average Tariff v/s variation in load from DG and HVPNL

4 http://mnre.gov.in/file-manager/UserFiles/jnnsm_g170610.pdf

http://mnre.gov.in/file-manager/UserFiles/jnnsm_g170610.pdf



Figure 4: Cost of Generation v/s Subsidy

Figure 5: Cost of Generation v/s Capital Expenditure

3.00

5.00

7.00

9.00

11.00

13.00

1 2 3 4 5 6 7 8 9 10

Co

st

of

Gen

erati

on

(R

s./

kW

h)

Cost of Generation

Interest 12% Interest 10% Interest 8%

Interest 6% Average Tariff (70:30) Average tariff (80:20)

Average Tariff (60:40)

3.0

4.0

5.0

6.0

7.0

8.0

9.0

1 2 3 4 5 6 7 8 9 10

Co

st

of

Gen

erati

on

(R

s./

kW

h)

Cost Of Generation

Without Subsidy With Subsidy

3.00

4.00

5.00

6.00

7.00

8.00

1 2 3 4 5 6 7 8 9 10

Co

st

of

gen

erati

on

(R

s./

kW

h)

Cost of Generation

Capex: Rs.100/watt Capex:Rs.110/watt Capex:Rs.120/watt



IV. TECHNICAL ASSESSMENT

1. Grid Connectivity

CERC lays down the guidelines for Rooftop Solar PV and other Small Solar Power Projects to be connected to

the distribution network at voltage levels below 33 kV to be considered eligible for generic tariff

determination.

2. Net-Metering

Net metering allows electricity meter to spin forward when electricity flows from the grid into your building,

and backward when your system produces surplus electricity that is not immediately used. Your excess

electricity is “banked” on the utility grid. Metering helps to measure the solar gross generation, consumer

load consumption, export and import to and from the Grid apart from measurement of AC system voltages

and currents, frequency etc. As per the guidelines of CERC, the metering arrangement requires to

accommodate DG sets and/or battery inverter etc. as per the need of solar developer without affecting the

sealing and security of complete metering system apart from cabling and switchgear from solar panel to

solar meter.

3. Power Purchase Agreement

The recent cost reduction in solar PV has motivated many building owners to use on-site or off site

photovoltaic (PV) generation to hedge against volatile electric utility bills. In case of onsite generation the

building owner has an option of installing himself and owns the PV system. Another option to the building

owner is to do a PPA with the third party for long terms and avoid the high capital investments. Typically in

case of rooftop PV systems, the third party signs a PPA with the building owner and sell the solar electricity

as a part of onsite generation to displace his costly DG based power generation. As long as this system is

completely off grid, there is no problem in terms of meeting the regulatory compliances, however in case of

grid interactive systems, if the solar PV installer at a building installs the PV plant, and go for net metering,

there are no guidelines from Government of India for net metering of solar electricity. Also it is not clear

that the PPA signed by the third party who sell its solar electricity to the building owner as well as to the

grid in the event of non-captive requirement, is he legally allowed to sell the electricity to both parties. The

third party sale can be done under the group captive mode where the buyer should have stake in a Solar PV

at least 26% and should have at least 51% of solar electricity. Rest of the electricity can be sold to the grid.

A growing number of third-party solar power providers are looking to rent roof surfaces from the home

owners and install PV systems and sell the power generated to the home owner/local utility through the

different available scheme of solar rooftop policies of government of India. Even commercial building owners



can also lease their rooftop on rent to the solar PV developers and can do a long term PPA to use the

electricity generated through the PV system.

4. Feasibility Check For Rooftop PV System

Before performing a detailed site survey, a client prefers to do the feasibility check by considering the

following parameters:

Shadow Test: To collect the maximum sunlight during the day, the panels should be faced to the South as

much as possible. The roof must be checked from the shadow of the trees and of the neighbouring roofs and

walls. In case there is some shadow on the roof, a detailed analysis of time and direction of sunlight needs

to be evaluated to estimate the energy received by the rooftop.

Rooftop Type: The load carrying capacity of the roof should be checked. Solar panels with structure typically

weigh 15 kg per sq. meter. This weight varies with technology and type of structure.

Sizing of Solar system: Size of the solar system depends on the available rooftop area for installation of

panels. This can be calculated by dividing the entire roof area by each panel area and multiplying it by the

panel’s rated output. For estimate purposes, 70% of rooftop area can be used for panel’s installation.

Size of the solar system = Panel’s rated output* (rooftop area/ each panel area)*70%

System Output: The panel output and hence the system output is defined by the Capacity Utilization Factor

which defines the panel efficiency and the solar radiation incident on the panel. Typically, for India the CUF

for solar plants is estimated at 19%.

Number of units generated = Installed capacity* 365*24* CUF

V. POLICY INCENTIVES AND SUBSIDIES

MNRE launched a program referred to as “ Rooftop PV and Small Solar Power Generation Programme” for

the small solar power plants connected to distribution network at voltage levels below 33 kV and envisaged

under Phase I of the JNNSM . The programme envisages developing about 100 MW of solar capacity.

Table 2: Proposed Capacity Allocation under JNNSM

S.No. Project Category Proposed Capacity Limit

1. Projects connected at HT Level with installed

capacity of 100 kW to 2 MW

90 MW

2. Projects connected at LT Level with installed

capacity of less than 100 kW

10 MW



Various states have also taken individual rooftop initiatives which are summarised in annexure 3.

MNRE offers 3 types of financial incentives for the solar rooftop systems:

Capital Subsidy: MNRE provides 30% capital subsidy on capital expenditure for rooftop solar PV system.

For commercial and non-commercial entities in grid connected area, subsidy can be granted to a plant size

upto 100kW. However, entities setting up solar plant for rural electrification can claim a subsidy for upto 250

kW plant size.

Interest Subsidy: The government provides soft loans at 5% per annum on 50% of the capex amount for

5 years tenure for solar projects by both commercial and non-commercial entities. Commercial entities can

claim any of interest or capital subsidy but the non-commercial entities can claim both subsidies

simultaneously.

Accelerated Depreciation: For solar system, a company can claim 80% depreciation in the first year itself

leading to savings on income tax on overall profit. This benefit can be claimed by both commercial and non-

commercial entities. The procedure for the availing the financial incentive includes the following process:

To claim the financial incentive, an application needs to be written to MNRE in the prescribed application

form for project approval. A commercial entity seeking to avail incentive needs to specify its preference for

capital or interest subsidy. Once approved, in case of interest subsidy, the MNRE forwards the application to

the commercial bank for the soft loan. In case of capital subsidy option, MNRE provides subsidy money in 3

phases: start of project, mid-way through the project and after the successful completion of the project.

Apart from MNRE, the entities can avail of commercial loans from organizations such as SIDBI at 15%

interest rate typically for 7 years with 1 year moratorium period.

SOLAR ROOFTOP POWER IN GUJARAT

Currently Feed-in-Tariff is only available in Gujarat .Similar solar feed-in-tariff policies are under process of

being released in Delhi and other states. It is a means of promoting solar power and will serve to meet peak

demand in the cities of India.

Kilowatt –scale photovoltaic power plants, which are mounted on rooftops and directly feed electricity into

the grid, are typically connected to the grid on one of the following philosophies:

1. Feed-in metering (two-meter) philosophy

The two-metering interconnection scheme is applicable where a separate feed-in-tariff is allowed for feeding

of solar electricity into the grid, and hence will be applicable in Gujarat. Energy is easily accounted for in this

case through a dedicated feed-in-meter. Such schemes are applicable in several European countries

including Germany.



2. Net metering philosophy

Net metering is applicable where the conventional electricity and solar electricity are traded at the same

tariff. As the cost of solar electricity is higher compared to the conventional electricity, such a net- metering

scheme requires has to be supported with additional subsidies to the developer. Such schemes are quite

popular in countries including USA and Japan.

Figure 6: Feed-in Metering and Net Metering

Gujarat has also recently announced to install 5 more Rooftop Solar Projects of 25 MW capacity. The

five projects are divided into three packages. The first is for putting up 5 MW plant each in Vadodara and

Mehsana. The second is for 6.5 MW project in Rajkot and 3.5 MW in Bhavnagar. The third is for 5 MW plant

at Surat. These projects would be grid-connected where a developer would rent a roof, build the plant and

sell power to the state electricity distribution company, GUVNL. The discoms would purchase power for 25

years from these developers.

Kerala Rooftop Policy

Kerala State Nodal Agency, ANERT, recently launched 10,000 Solar Rooftop Power Plants Programme 2012-

13 . The programme envisaged the installing of 1kW*10000 Solar Roof-top Power Plants during the year

2012-13 with a total of 10MW capacity. One system with 1kWp is allowed to each individual beneficiary,

with Central and State financial support. The minimum requirement for installation should be 15sq meter of

shade-free area and appropriate space for putting the batteries and inverters. The system would be in the

off-grid mode generating approx. 4 units per 1 kWp system per day. This electricity is to be used for internal

combustion. Central financial assistance from state would be minimum of either 30% cost of the project or

Rs. 81,000/ per system. Apart from the Central subsidy, the state subsidy of Rs. 39000/per system is also

available for the approximate cost of the plant of Rs. 2.5 lakh.

Feed-in metering interconnection scheme Net metering interconnection scheme



VI. SOLAR ROOFTOP LEASING AGREEMENT

Most rooftop solar developers require an option to lease the rooftop. The option will permit the

operator to have access to inspect and test the rooftop and do such other investigations as it

deems necessary to satisfy itself that the location is suitable for a solar PV array and that the

building owner is in a position to grant a lease to it. The option will be open for exercise by the

operator for a period sufficient to enable the operator to conduct such inspections and

investigations and to apply for and obtain a Feed in Tariff (“FIT”) program approval or enter into

a power purchase agreement (“PPA”) with the local electrical utility. The option agreement will

provide that if the developer exercises its option, the parties will enter into a lease of the rooftop

area on the terms set out in the option agreement.

Generally the rooftop lease is signed for 20 years (to match the term of the FIT or PPA) and the

tenant/installer will most likely ask for the exclusive option to renew the lease. Renewal rights

are potentially important, as it is anticipated that the productive life of the solar photovoltaic

(“PV”) array equipment may be substantially longer than 20 years. Rent can be structured in

several ways. Usually, it will be a fixed, all-inclusive “gross” rent, but it may be calculated based

on the size of the roof area or the portion of the rooftop utilized, the wattage produced by the

facility, a percentage of the revenues received by the tenant, or on some other basis. In addition,

the lease may provide for the tenant to pay for its electricity consumption and for any realty

taxes associated with the solar PV array.

VII. FUTURE OUTLOOK

To enhance the energy capture from each solar panel, Sun Power came up with Sun Power T10 Solar Roof

Tile to tilt a 10-degree angle. These non-penetrating solar roof tiles interlock for security and rapid

installation. The durable, light-weight materials and the patented design resists high winds and corrosion.

Uniquely flexible, the Sun Power T10 Solar Roof Tile adapts to the size and requirements of virtually any flat

rooftop. For facilities trying to achieve the maximum power density from their solar solution, the Sun Power

T5 Solar Roof Tile may be a better option. However, for facilities where space constraints are not a primary

consideration, the T10 is the ideal solution as it will increase the total energy production from each solar

panel.

On the whole, if we consider 30% captive power generation in commercial buildings, the average cost of

power to the consumers is about 8.5 Rs/kWh, this is the point where the roof top systems make commercial

sense. But do they really have roof top space to accommodate the solar power at their roof. The vertical

high rise glass buildings which are energy guzzlers hardly have any rooftop space for solar power systems.

The buildings in tier 2 and tier 3 cities have much more horizontal spread which makes good case for

accommodating the rooftop systems. Although the glass facade in case of high rise buildings can be of solar



PV as building integrated PV systems, however they extract very less energy due to the limitation of solar

energy falling in a perpendicular fashion on them. Our limitation is that we design buildings and then think

of solar to integrate with the existing design.

In-order to achieve its solar portfolio obligations New Delhi Power Limited has already proposed a rooftop PV

programme with a target of 50 MW for 10,000 customers in the first phase of JNNSM. The experiences in

Germany and California on roof top systems show a great relief to the distribution losses. Adopting the

rooftop system in India as well is likely to provide a great relief to the Indian utilities as well in terms of

reduced distribution losses. While the cost of utility scale projects have already come down to about Rs. 8

cr./MW, it is important to develop market based mechanisms through which the cost of roof top systems can

be brought down. Current rooftop systems cost almost Rs. 12-13 Cr./MW, due to the higher labour,

transaction and implementation costs. The economics of rooftop systems makes sense only to the

consumers who have high dependency on the captive DG sets, which they use in the event of grid failure. It

is important to have more generic guidelines for grid integration, connectivity, net metering, etc for large

scale deployment of roof top systems.



ANNEXURES

Annexure 1: Commissioning Status of Roof Top Solar PV Projects under Batch-I, phase-I of

JNNSM under RPPSGP Scheme

S.No. Name of project commissioned State Solar PV capacity

commissioned (MW)

1 Sri Power Generation (India) Private Limited Andhra

Pradesh

1.0

2 Amrit Jal Ventures Pvt. Ltd. Andhra

Pradesh

1.0

3 Andhra Pradesh Power Generation

Corporation Ltd.

Andhra

Pradesh

1.0

4 Ramakrishna Industries Andhra

Pradesh

1.0

5 Singhal Forestry Private Limited Chhattisgarh 2.0

6 Chhattisgarh Investments Ltd. Chhattisgarh 2.0

7 Chandraleela Power Energy Private Limited Haryana 0.8

8 Zamil New Delhi Infrastructure Private

Limited

Haryana 1.0

9 SDS Solar Private Limited Haryana 1.0

10 Sukhbir Solar Energy Private Limited Haryana 1.0

11 C&S Electric Ltd. Haryana 1.0

12 Dr.Babasaheb Ambedkar Sahakari Sakhar

Karkhana Ltd.

Maharashtra 1.0

13 Sepset Constructions Limited Maharashtra 2.0

14 Citra Real Estate Limited Maharashtra 2.0

15 MGM Minerals Ltd. Orissa 1.0

16 Raajratna Energy Holdings Private Limited Orissa 1.0

17 S N Mohanty Orissa 1.0



18 Molisati Vinimay Pvt. Ltd. Orissa 1.0

19 Soma Enterprise Limited Punjab 1.0

20 AEW Infratech Pvt. Ltd. Rajasthan 1.0

21 Asian Aero- Edu Aviation Private Limited Rajasthan 1.0

22 Basant Enterprises Rajasthan 1.0

23 Zamil New Delhi Infrastructure Private

Limited

Rajasthan 1.0

24 Navbharat Buildcon Pvt. Ltd. Rajasthan 1.0

25 Lanco Solar Private Ltd. Rajasthan 1.0

26 B&G Solar Private Limited Tamil Nadu 1.0

27 RL Clean Power Pvt. Ltd. Tamil Nadu 1.0

28 Great Shine Holdings Pvt. Ltd. Tamil Nadu 1.0

29 RV Akash Ganga Infrastructure Ltd. Uttarakhand 2.0

30 Technical Associates Ltd. Uttar

Pradesh

2.0

31 Kijalk Infrastructure Pvt. Ltd. Jharkhand 2.0

32 Metro Frozen Fruits & Vegetables Ltd Uttrakhand 1.0

33 Andromeda Energy Tech. Pvt. Ltd. AP 0.75

34 Vivek Pharmachem Rajasthan 1.0

35 Ecoenergy Inc Punjab 1.0

36 Sovox Renewables Private Limited Punjab 1.0

37 G S Atwal & Co.(Engineers) Pvt. Ltd. Punjab 1.5

38 Amson Power Private Ltd. Tamil Nadu 1.0



39 SunEdison Energy India Private Ltd. Rajasthan 1.0

40 Kishore Electro Infra Pvt.Ltd. Andhra

Pradesh

1.0

41 Harrisons Power Pvt Ltd. Tamil Nadu 1.0

42 Gajanan Finacial Services Pvt. Ltd. Andhra

Pradesh

1.0

43 Dhruv Milikose Pvt. Ltd. Uttar Pradesh 1.0

44 Photon Energy Systems Limited Andhra

Pradesh

1.0

45 Dante Energy Pvt. Ltd. Uttar Pradesh 2.0

46 Tayal & Co. Haryana 1.0

47 VKG Energy Pvt. Ltd. Haryana 1.0

48 H.R. Minerals And Alloys Pvt. Ltd. Haryana 1.0

49 Cartill Energy Pvt. Ltd. Punjab 1.5

50 Abacus Holdings Pvt. Ltd. Orissa 1.0

51 Bhavani Engineering Andhra

Pradesh

1.0

52 PCS Premier Energy Pvt. Ltd. Jharkhand 2.0

53 Jay Ace Technologies Ltd. Uttarakhand 2.0

54 Sovox Renewables Private Limited Rajasthan 1.0

55 Andhra Pradesh Industrial Infrastructure

Corporation Limited

Andhra

Pradesh

1.0

56 New Era Enviro Ventures Private Limited Jharkhand 2.0

57 Premier Solar Systems Pvt Ltd. Jharkhand 2.0

58 Conflux Infratech Private Limited Rajasthan 1.0

59 Enertech Engineering Private Limited Jharkhand 2.0



60 Pantime Finance Company Private Limited Odisha 1.0

61 Shri Mahavir Ferro Alloys Private Limited Odisha 1.0

62 KVR Constructions Jharkhand 2.0

63 AKR Constructions Ltd. Jharkhand 2.0

64 Saimeg Infrastructure Pvt. Ltd. Jharkhand 2.0

65 Priapus Infrastructure Ltd. Uttar Pradesh 2.0

66 Adora Energy Private Limited Madhya Pradesh 2.0

67 JSR Developers PVT. Ltd. Madhya Pradesh 1.25

68 Shiv-Vani Energy Limited Madhya Pradesh 2



Annexure- 2 Typical 100 kW Rooftop PV Plant

Financial and Tariff Assumptions

Assumptions supporting Financial Projections Input Value Units

Project Capacity 100 kW

Cost/Watt 120 Rs.

Total Project Cost 1.2 Crores

Subsidy 30%

Actual Investment 0.84 Crores

Debt 80%

Equity 20%

Debt Amount 0.67 Crores

Equity Amount 0.17 Crores

Interest rate 12%

Loan Tenure 10 Years

Return on Equity 12%

Plant Load Factor 19%

Tariff Increment 3%

O&M Expenses 3% of project cost

Escalation in O&M 5%



Cash Flow and Returns Calculations

Years 0 1 2 3 4 5 6 7 8

Power generation 166440 164776 163128 161497 159882 158283 156700 155133

30% Load on DG 49932 49433 48938 48449 47964 47485 47010 46540

70% Load on HVPNL 116508 115343 114189 113048 111917 110798 109690 108593

5% Cost of DG supply (5% sc) 15 15.75 16.54 17.36 18.23 19.14 20.10 21.11

5% Cost of HVPN Supply 6 6.30 6.62 6.95 7.29 7.66 8.04 8.44

Average Tariff 8.70 9.14 9.59 10.07 10.57 11.10 11.66 12.24

Energy charges (INR) 1448028 1505225 1564681 1626486 1690733 1757517 1826938 1899103

Finance cost 1,008,000.0

962,048.0

910,581.7

852,939.5

788,380.2

716,073.8

635,090.6

544,389.4

12% Return on equity 201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

12% Debt Interest portion (10 year loan)

806,400.0

760,448.0

708,981.7

651,339.5

586,780.2

514,473.8

433,490.6

342,789.4

2% Operating cost 240,000 244800 249696 254689.92 259784 264979 270279 275685

2% Escalation in Operating Cost

` Total costs 1,248,000.0

1,206,848.0 1,167,777

1,107,629.4

1,048,163.9

981,053.2

905,369.6

820,074.0

Cash flow - 8,400,000 200,028.0

298,377.1

404,403.8

518,857.0

642,568.7

776,463.4

921,568.9

1,079,028.6

IRR 10%



9 10 11 12 13 14 15 16 17 18 19 20

153582 152046 150525 149020 147530 146055 144594 143148 141717 140299 138896 137508

46074 45614 45158 44706 44259 43816 43378 42944 42515 42090 41669 41252

107507 106432 105368 104314 103271 102238 101216 100204 99202 98210 97228 96255

22.16 23.27 24.43 25.66 26.94 28.28 29.70 31.18 32.74 34.38 36.10 37.90

8.86 9.31 9.77 10.26 10.78 11.31 11.88 12.47 13.10 13.75 14.44 15.16

12.85 13.50 14.17 14.88 15.62 16.41 17.23 18.09 18.99 19.94 20.94 21.98

1974117 2052095 2133152 2217412 2305000 2396047 2490691 2589073 2691342 2797650 2908157 3023029

442,804.1 329,028.6

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0 201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

201,600.0

241,204.1 127,428.6

281198 286822 292559 298410 304378 310466 316675 323008 329469 336058 342779 349635

724,002.4 615,850.8

494,158.7

500,009.8

505,978.0

512,065.6

518,274.9

524,608.4

531,068.6

537,657.9

544,379.1

551,234.7

1,250,114.7 1,436,243.9

1,638,993.8

1,717,402.1

1,799,021.7

1,883,981.7

1,972,416.2

2,064,465.0

2,160,273.2

2,259,991.9

2,363,777.9

2,471,794.5



Cost of generation 7.50 7.32 7.11 6.86 6.56 6.20 5.78 5.29 4.71 4.05

1 2 3 4 5 6 7 8 9 10

Yearly Installment 1189334 1189334 1189334 1189334 1189334 1189334 1189334 1189334 1189334 1189334

Interest 806,400

760,448

708,982

651,339

586,780

514,474

433,491

342,789

241,204

127,429

Principal Repayed 382,934

428,886

480,352

537,994

602,553

674,860

755,843

846,544

948,129

1,061,905

Balance 6,337,066

5,908,181

5,427,829

4,889,835

4,287,281

3,612,422

2,856,579

2,010,034

1,061,905

0



Annexure-3

Rooftop Subsidy scheme

With the success of JNNSM policy for the projects of grid connected MW capacity and continuous

declining movement of panel cost will make the rooftop systems economically more viable option. The

Government’s policy will act as a catalyst for the same. Here the First Green is providing you a gist of

the policy for off grid Roof top system (programme on “Off-grid and Decentralized Solar Applications”,

8th June 2012)

• Government of India (MNRE) provides 30% of capital subsidy on the roof top systems (off grid).

Based on the benchmark cost for solar photovoltaic panels (revised on 01/04/11 by MNRE) the

available subsidy is of Rs 81/Wp with battery and Rs 57/Wp without battery storage system.

• Promoters’ equity contribution should be at least 20% of the project cost

• Rest of the amount can also be financed by MNRE by a soft loan @5% will be available.

• 80% accelerated depreciation benefit is available as per Section 32 of Income Tax Act.

• Rs 100/Wp for SPV modules used subject to a maximum of 40% of the cost of the system to non-

profit making organizations only

• Support will be available for systems capacity varying between 25 to 100kW.

• Proposals in prescribed format will be considered on first-cum-first basis through SNAS by MNRE

• Capital subsidy would be released to the banks upfront, on receipt of sanction of loan by the bank

to the borrower.

• The loan amount is repayable in monthly instalments within 5 years.

Boundary Conditions

The policy also defines maximum boundary conditions to avail subsidy and incentives for the projects

under this programme on “Off-grid and Decentralized Solar Applications”

Individuals: Capital Subsidy & Soft Loan

• Pumps for irrigation and community drinking water – up to 5 kWp

• All except above – up to 1 kWp

Non Commercial Entities: Capital Subsidy & Soft Loan

• Mini grids for rural electrification – up to 250 kWp


Industrial / Commercial Entities: Capital Subsidy or Soft Loan

• Mini grids for rural electrification – up to 250 kWp




Gujarat Solar Rooftop Policy

Gujarat Government, after the successful installation of about 605 MW of Solar Power plant in

Charanka in Patan district, now plans to introduce Rooftop Solar Power Plant Policy. Gandhinagar, as

of now , already has about 1.39 MW of solar rooftop systems covering about 2 acres of roof-top area.

The Gujarat State , recently, also envisaged a 5 MW rooftop programme on the PPP model in the

capital which is now extended to about 5 more cities and towns. The entire solar power project is

expected to produce about 30 lakh units of clean energy daily, which is capable of electrifying about

10 lakh households and save about 10 lakh tonnes of CO2 emissions. The advancement and growth

in the technology has reduced the cost of solar plants significantly from about Rs.15 to Rs. 8.5 per

unit in the past years, thus making it comparable with the gas-based power.

Rooftop policy of Haryana

The Haryana Renewable Energy Development Agency (HAREDA) recently launched the Solar Rooftop

Scheme to motivate commercial and industrial establishments like hotels, hospitals and housing

complexes to replace DG sets installed for captive requirement during load shedding. Under this

scheme, HAREDA approved 2 standalone solar PV projects of 100 kW each in Gurgaon to demonstrate

applications of solar PV for industry power back-up. The State Government has agreed to offer

financial assistance of Rs 75 lakh for each project.

Solar City Program of MNRE

In February 2009, MNRE announced a scheme on ‘Development of Solar Cities to promote the usage

of Renewable Energy in urban areas by providing support to Municipal Corporations for the

preparation and implementation of a road map to develop their cities as Solar Cities. An indicative

target of 60 cities/towns, with atleast one in each State, has been set for the 11th Plan period (2007-

2012). In a major development under this scheme, the Government of Andhra Pradesh has recently

(December 2009) announced the development of a solar farm cluster called Solar City on a 10,000

acre land at Kadiri in Anantapur district. Solar City is expected to attract investments worth Rs. 3,000

Cr in the first phase. Four firms – Sunborne, Lanco Solar,

AES Solar and Titan Energy – have signed a Memorandum of Understanding with the state to set up

establishment in Solar City. These companies will be the anchor units in Solar City and have a

proposed combined capacity of 2,000 MW.

Tamil Nadu has launched India’s largest solar rooftop programme for providing Solar powered Green

Houses (3 lakh houses by 2015-16) under Chief Minister’s Solar powered Green Houses scheme, with

provision of solar powered Home lighting systems with battery backup in 60,000 Green Houses in

2011-12. Another 60000 green houses will be provided with solar lights during 2012-13 at a cost of

Rs.180 crores. This scheme is also first of its kind in India with grid back up.



The Govt. of Orissa has declared Orissa Renewable Energy Development Agency (OREDA) as the

Nodal Agency (State Competent Authority) to pre-register the proposals from the prospective

developers for holding RPSSGP under JNNSM.

In order to enable the project proponents to get registered with IREDA, the Commission determined

the following generic tariff for Rooftop PV and other Small Solar Power Plants to be commissioned in

the State of Orissa under JNNSM

According to Maharashtra Electricity Regulatory Commission, Regulation 68 of the RE Tariff

Regulations specifies, that the tariff for Solar Rooftop PV projects and other small solar projects will

be Rs 0.50/kWh higher than the Tariff specified for Solar PV projects in the Regulations.

Accordingly, the Tariff for such Projects in FY 2012-13 shall be as follows:

The above Tariff shall be applicable for Solar Rooftop PV and other small solar Projects wherein PPA

are signed after March 31, 2012 and projects are commissioned during FY 2012-13, and the same

shall be valid for a tariff period of 25 years from the Commercial Operation Date (COD).

For the state of Karnataka, the policy is structured as follows

Roof Top Solar Tariff: The Roof Top Grid connected solar KWp level projects of 5 KWp to 100 KWp

will be allowed connecting at 415 V, 3 phase, 11 KV level of distribution system of the licensee in

such a manner that the maximum energy injection will not be more than 70% of the consumption

from the distribution licensee‘s source by the Solar Roof Top consumer. Any injection in a billing

period exceeding 70% of the consumption will be treated as inadvertent and will not be considered

for commercial purpose; neither the deficit is carried forward to next billing period. Such injection will

be settled on Net Basis with the consumption of the said consumer from the distribution licensee’s

source in each billing period.

Particular

Tariff

Period

Levellised Total

Tariff (FY 2012-13)

(Rs/kWh)

Benefit of

Accelerated

Depreciation

(if availed)

(Rs/kWh)

Net Levellised Tariff

(upon adjusting for

Accelerated Depreciation

benefit)

(if availed)

(Rs/kWh)

Solar rooftop PV

and other Small

solar power

Projects

25 11.66 1.65 10.01



Roof Top Grid connected solar power quantum fed to the Grid will be eligible for a Tariff of Rs 3.40

per KWh along with Net Metering facility. If any incentives available from Ministry of New and

Renewable Energy Government of India, it will be passed on to the Developer. However, Roof Top

systems will be additionally eligible for any other subsidies extended to the Roof Top Projects.

Solar Photo Voltaic systems below 2 KWp will be battery backed isolated stand alone systems.

Isolated Solar Photo Voltaic sources up to 200 KWp will be for Rural Applications

Roof Top small scale Solar PV Installations will be encouraged with Net Metering facility to feed

surplus power generated to the Grid.

Under Solar Karnataka Programme it is targeted for 25000 Solar Roof Tops of 5 to 10 kwp with

Net Metering will be taken up with a 250 MW potential during next 5 years with a generation potential

of 350 MU.

Regulatory bodies responsible for Rooftop systems:

Karnataka Electricity Regulatory Commission: Concurrence for Solar Tariff and Roof Top Net

Metering. Energy Department, Government of Karnataka: Approval is required to take up MW

scale and Roof Top Solar projects.

The multi-storey buildings in the state of West Bengal will have the obligation to install solar panels

on the rooftops for power generation, according to a new policy approved by the state government on

May 23, 2012, regarding power generation from renewable energy sources. The policy was cleared by

the state cabinet committee on infrastructure and industry.

The new policy mandates the multi-storey buildings to have solar panels installed on the rooftops.

Power generated has to be transferred to grid and residents will draw electricity from it. The

additional amount will be adjusted in their monthly bills.



Annexure 4

System Sizing of a typical rooftop system



Annexure 5: Technical Specifications of PV Modules and Inverter Systems

The Rooftop PV and Small Solar Power Projects deploying PV modules and Inverter systems should

comply with the IEC/ BIS standards and the standards specified by CERC to be considered technically

qualified.

The equipment quality to be used should meet the guidelines for engineering design included in the

standards and codes listed in the relevant ISI and other standards, such as:

i. IEEE 928: Recommended Criteria for Terrestrial PV power systems.

ii. IEEE 929 Recommended practice for utility interface of residential and intermediate PV systems.

iii. IEEE 519 Guide for harmonic control and reactive compensation of Static Power Controllers.

iv. National Electrical NFPA 70-1990 (USA) or equipment national standard.

v. National Electrical Safety Code ANSI C2 (USA) or equipment national standard.

vi. IEC : 61215 (2005)- Crystalline silicon terrestrial photovoltaic (PV) modules – Design

qualification and type approval

vii. vii. IEC: 61730 -1, -2 Photovoltaic (PV) module safety qualification Part 2: Requirements

for testing

viii. IEC: 60904-1(2006) Photovoltaic Devices- Part-I: Measurement of Photovoltaic current-

Voltage Characteristic

ix. IS 9000 Basic environmental testing procedure for Electronic and electrical items.

first green consulting discussion paper solar rooftop systems

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