The time has come to light your
residence, office/ commercial establishment with the rooftop solar. Adoption of
Rooftop Solar PV is largely associated with the environmental, social and
economic development of the country. It would provide millions of job opportunities
and would also encourage entrepreneurship through the country. Government of India has launched 100 smart
cities and 500 Atal Mission for Rejuvenation and Urban Transformation (AMRUT).
Development of smart cities and AMRUT would encourage renewable energy,
especially rooftop solar PV. Contribute
towards Government efforts to develop smart cities and adopt rooftop solar PV.
Brief on Solar Rooftop PV
Solar rooftop PV is a matured
technology and generates electricity during sunshine. Rooftop PV is a distributed form of
generation of electricity. The rooftop PV is composed of PV modules and the
balance of system (BoS). The PV module is the interconnected array of PV cells.
The items covered under balance of system are structure for installation,
racks, invertors, transformer and misc electrical items. Presently, the capital cost of rooftop PV is
a major barrier in its adoption in India. Generation from RTPV has several
advantages, mainly no additional land, transmission network and water is required.
Potential of Solar Rooftop PV in
India
There is unlimited potential of
rooftop solar PV in India, this potential has been increasing with the economic
and population growth of the country. According to the 2011 census India are
having 330 million houses, 166 million houses electrified, and 76 million uses
kerosene for lighting, 1.08 million using solar for lighting, 140 million
houses with proper roof (concrete or asbestos/ metal sheet) and 130 million
houses having 2 or more than two rooms.
Average house can accommodate 1 to 3 Kwp of solar PV system and large
commercial roof can accommodate larger capacities. If we consider 20% roof of
more than 2 rooms, the potential comes to 25,000 MW (most conservative).
Characteristic of Rooftop PV
The PV works during sun shine of the
day, 9AM to 5PM. Generation from PV varies from season to season, PV generates
25% higher in summer season than winter season and it generates 50% higher in
summer season than monsoon season. The generation from PV is maximum in summer
when the requirement of electricity is at peak, it generates less in winter
when requirement is less. It generates very less in monsoon season when
requirement is very much less. Solar power can effectively used for power
consumption during sunshine hours. There
are 24 hours in a day, and availability of the sun shine is more than 8hours
per day, therefore, 30 % energy requirement of the day (0 hours to 24 hours) is
available during sunshine. The electricity generated may be used during
sunshine or may be fed to the grid when not required.
Capital Cost of Solar Rooftop PV
The capital cost of a rooftop PV
system is composed of PV module cost and balance of system (BoS) cost. The BoS
cost includes items, such as cost of structural system (e.g. structural
installation, racks, site preparation and other attachments), the electrical
system costs (e.g. the inverter, transformer, wiring and other electrical
installations cost). It was only few years ago, PV electricity was four to five
times more expensive than the grid supply. Continuing decreasing cost of solar
rooftop PV and increasing cost of fossil fuels, grid parity have almost
occurred commercial sector in several states of India where high solar resource
is available and prevailing high tariff of electricity. The grid parity is
expected to be achieved in commercial sector within two to three years in the
states where moderate solar resource is available and prevailing lower tariff
of electricity.
Advantage of Solar Rooftop PV
Solar Rooftop PV can be accommodated
on roof or open ground and in variable capacities from few watts to several MW.
When the load is less the power is surplus, this surplus power can be fed to
the grid and in case power requirement is much, the same can be drawn from
grid. The main advantages of Rooftop Solar PV are as under.
• Space for mounting structures
already exists, no additional land is required.
• The distribution network already
exists and no new connection is required.
• A wide range of size can be
accommodated from KW for residential and MW for commercial and industrial
purposes.
• The
cost of residential rooftop PV is within the limit of many home owners.
• The power generated is used at the
same place, therefore, involvement of transmission and distribution is very
much less, the excess electricity generated is fed in the system of utility and
the electricity required can be drawn from the utility. Ultimately, selling the
electricity when not required in day hours of sunshine to the utility and
purchasing when required.
• The arrangement can be made for
backup/ storage when utility supply fails.
• The house owner becomes conscious
about the generation and consumption of electricity.
• It will develop large numbers of
entrepreneurs.
• A large number of jobs shall be
created throughout the country.
Net
Metering
In the day hours the domestic load
is less, therefore, electricity is fed to grid and when the load is more than
the capacity of solar PV, the electricity is drawn from the grid. The grid
supply act as a back up to the rooftop PV, we use the grid supply in night
hours, cloudy days when no sunshine and requirement is more than the capacity
of solar rooftop PV. For maintaining the account of electricity transaction, a
bi – directional meter is installed which can record power flow in both
directions. Thus, the meter gives two readings detailed as under.
•
Electricity
supplied by the utility.
•
Electricity
supplied to the utility
Schematic Arrangement for
Interconnection of Rooftop and Small PV Solar Power Plant with Distribution
Licensee's/Discom's grid.
Abbreviations:
NM: Net Meter, SM: Solar Meter, PCU: Power Conditioning
Thus, the bill is raised for the
electricity supplied by the utility and credited for the electricity supplied
to the utility at the rate decided by respective regulatory commission of the
states.
Now, what to do
Let us come together to encourage
the Government’s efforts in development of smart cities. We should make
planning to support Government efforts. Let us set an example, first adopt rooftop
solar PV to light our residences and commercial establishments (offices,
hotels, restaurant, ware houses) and religious places aware others for
installation of rooftop Solar PV.
