Greenprint Your Home: U Solar CEO Harinarayan presents the various solar technologies available in the market today for homes. More at www.thealternative.in/greenprint-your-home
2. The Sun offers more energy in a quarter of
an hour than the entire world can use in a
whole year….
2
3. Tapping Solar Power…
Solar Photo Voltaic Systems (LIGHT)
– Use for generation Electricity
– The fastest growing power generation technologies in
the world
– Worldwide penetration in over 100 countries
Solar Thermal Systems (HEAT)
– Used for Heating applications
– A sustainable and most economical way to heat water
for residential or commercial purposes
3
7. Technology Options (Residential)
Flat Plat Collectors
Insulated plates under one or more
glass polymer covers
More robust and longer life
Evacuated Tube Collectors
Rows of transparent glass tubes and
inner metal tubes
Not as rugged as flat plate collectors
More expensive due to copper
content
Efficiency of 40%
Less expensive
Performance is affected in overcast
conditions
Lower Absorber gross area
Performance is not affected in
overcast conditions
Higher absorber gross area
Efficiency of 45%
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8. Additional Options
Re-circulating Pump
– Useful for getting instant hot-water
– Important if tap to water tank distance is significant (eg: flat is in the
lower floor of complex, or tank serves multiple apartments)
Heating Element
– Heating element for days when sunshine is poor or water usage is very
high
– Heating element fitted in the water-tank with a manual turn on/off
switch (can be automated with some logic for large installations)
Hard Water – heat exchanger option
– If water is hard (> 200ppm), then life of Solar Water Heater is affected
– Better to have a “heat exchanger” where the heating fluid is different
from the water that is finally used
8
11. Working of a Solar PV system –
Off Grid
Electrons in upper
layer of wafer
substance get
excited, causing
voltage difference
from lower layer of
wafer
Sun’s rays light up the
upper layer of wafer
substance in Solar PV
cell module
e
In the event the Solar
Power runs out, the
AC Mains /GRID
takes over
AC
The
Sun
GRID Power
+
The batteries
supplies power to
the inverter, which
supplies AC to the
loads
-
Inverter
Voltage difference
between wafer layers in
module cause s electric
current to be
generated, which is
sent through cables to
charge controller
AC Loads
Charge
Controller
Charge controller charges
the batteries during
sunlight and controls the
charging levels
Solar Power from the
batteries is used as a
“first priority”
DC Loads are
directly powered
from the batteries
11
12. Working of a Solar PV system –
Grid Tied
Electrons in upper
layer of wafer
substance get
excited, causing
voltage difference
from lower layer of
wafer
e
Sun’s rays light up the
upper layer of wafer
substance in Solar PV
cell module
The
Sun
+
-
AC
GRID Power
Voltage difference
between wafer layers in
module cause electric
current to be
generated, which is
sent through wiring to
inverter
AC Loads
Inverter synchronized
with the grid Grid and
reduces Grid power usage
to the Loads
Inverter
12
13. Key Differences between Two Systems
Feature
Grid Tie System
Working
Pumps directly into grid Manager Solar, Battery, Load
and Grid
Storage
None - Separate Home
Inverter System needed
Battery Bank to store extra
power
Costs
Cheaper due to simpler
inverter and no storage
Higher due to more
sophisticated solar inverter
and storage
Maintenance Less (no batteries)
Backup
Power
August 2012
Off Grid System
Higher (due to batteries)
Must be another UPS or Part of the system
DG
Presentation to BESCOM by U-SOLAR
13
14. Working of a Solar PV system –
Hybrid System
Electrons in upper
layer of wafer
substance get
excited, causing
voltage difference
from lower layer of
wafer
Sun’s rays light up the
upper layer of wafer
substance in Solar PV
cell module
e
In the event the Solar
Power runs out, the
AC Mains /GRID
takes over
AC
The
Sun
+
GRID Power
Excess Power is
fed back to the
grid
-
The batteries
supplies power to
the inverter, which
supplies AC to the
loads
Inverter
Voltage difference
between wafer layers in
module cause s electric
current to be
generated, which is
sent through cables to
charge controller
AC Loads
Charge
Controller
Charge controller charges
the batteries during
sunlight and controls the
charging levels
Solar Power from the
batteries is used as a
“first priority”
DC Loads are
directly powered
from the batteries
14
15. System Components: Solar Panels
•
•
•
•
•
These are normally located on the
roof of the building mounted on MS
/ Stainless Structures
They can also be mounted on
sloping roofs (tiled or otherwise)
Ideally they should face the South,
but East or West is also possible
Approximate space is about 130
sqft / kw of installation
They are interconnected to a
certain voltage using special DC
cables. The voltage depend on the
configuration
15
16. System Components: Inverter
• The inverter is the “brains” behind the
system and manages power from different
source
• A hybrid inverter marries different sources
of power – solar, battery and grid and
feeds the load
• It senses the load requirements, the
available Solar and Grid Power and feeds
the load
• The inverter must be rated to support the
peak load of the facility
• It can be programmed to maximize the use
of solar power as well as provide backup
16
power
17. System Components: Battery Bank
• These are special Solar Lead Acid
Batteries with special charging /
discharging characteristics
• These store the solar power for
usage
• The size of the storage is
determined by the duration of
backup power that is required
• These need to be maintained
with regular checkup (4 – 6
months)
17
19. Thrust on Solar Energy in India
Jawaharlal Nehru National Solar Mission ( JNNSM)
Key Highlights
Key Highlights
- Targets 20 GW of Solar Power generation by 2022
- 1st phase of JNNSM includes 200 MW of Roof top PV &
- Targets 7 Mn. sq.m. of SWH installations by 2013
- 30% capital subsidy and/or soft loan option @5% interest rates
*Generation Based Incentive
19
20. Rooftop Solar: Net Metering is the Key
Generate while the sun-shines
and earn revenue.
Draw from the grid when you
need it
20
21. The Importance of Net Metering
• Zero liability on the Utility… ie. Government does
not need to do anything other than define the
specifications and framework No Revenue
outflow
• Solar Power at Utility scale cannot compete with
Coal / Hydel w/o government support… however..
• Solar Power at Retail level is now “grid competitive”
– Commercial tariff in Karnataka @ 7.5 / kwh
– Rooftop Solar can be made available at similar rates
21
22. Urban Vision for Solar – “Net Zero” Homes
• All Residential rooftops can have solar PV systems
ranging from 1kw upwards
• Simple Math:
– 100,000 homes in Bangalore install an average of 2 kw
each (total space per 2kw ~ 300 sqft)
– Total installed capacity 200 MW
– This is about 20 – 30% of Bangalore’s residential
requirement
• These generators will supply power to the grid
during the day and draw back
22
23. What is required from the Government
• Enable net-metering policy
– Define the standards and safety mechanisms
– Define the process (who reads the meters, how, etc)
– Define the billing mechanism
[ No Cost to the Government]
The rest will be taken care of by the citizens !
23
24. Net Metering Policies in India
• Tamilnadu has allowed Net Metering since 2012
– However standards notified only in Nov ‘2013
– Applicable for residential customers
• Andhra has allowed net metering now
– Subsidy for residential customers
• No proper news from Karnataka
24
25. Capital Subsidy Info
• For residential, only upto 1 kw, 30% subsidy was
available (for commercial this is 100kw)
• However, NO new projects have been approved
since April 2013
• Some developers were offering system net of
subsidy.. But that is now being withdrawn
25
The mission consists of broadly three schemes:
Grid connected solar power projects
Roof-top and other small solar power plants
Off-grid and decentralized solar applications
The first 2 schemes involve generating electricity from solar and being evacuated to the grid
