We were invited by thealternative.in to conduct a seminar on 'Adopting Solar Energy for Urban Homes' and it was a great experience. It was nice to see that many people are interested and planning to switch to renewable energy for their electricity needs.

1. Sunny Side Up
Switching to Green Homes
By free Spirits Green Labs

2. Have you ever thought that sun can
light up your home for free ?
And by free we mean 0 electricity bill !

3. What to discuss ?
Covering almost everything you need to know
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5
7
Solar Energy for Home
What is it ?
Advantages/Disadvantages
All the pros & cons you need to know
Is your home solar friendly ?
Requirements to adopt solar energy
Some other products
Products that can be used in daily use
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4
6
8
Why switch to solar ?
Need of the hour
Types of Solar Systems
Various systems you can adopt
Electricity bill savings
How solar system makes your e-bill 0
Solar around us
How others are utilizing solar energy

4. Solar Energy for Home
What is a Solar Power System ?
A solar power system uses solar
energy to produce electricity for
your home.
• Whether you’re powering up your
computer, running your
dishwasher or brewing a pot of
coffee, the energy comes straight
from the sun – not from burning
fossil fuels.

5. Why switch to solar ?
What is the need to switch from fossil fuels to solar energy ?
• Converting to solar energy is the biggest
personal change you can make to fight
global warming.
• India is blessed significant amounts of
land areas having good sunshine for over
300 days a year. If solar (either in the form
of PV or thermal) becomes cost effective,
the entire country’s electricity needs can
be fully met from solar alone!

6. What can one solar system change ?
Impact of single solar system installed
• Here are some ways to think about
the environmental impact that an
average (5 kW system) solar home
can have on the planet over the life
of the panels.

7. Advantages/Disadvantages
You must know the pros and cons before deciding
ADVANTAGES
• Emissions - Solar has a clear advantage
over traditional electricity generation in its
effect on the environment.
• Fuel Costs – Solar produces electricity
with no fuel or ongoing costs, and will do
so for the life of the installation. Even for a
small panel installation to supplement your
home's power needs, you will be able to
see the benefit on your monthly power
bills.
DISADVANTAGES
• Installation - generating power with
solar cells is essentially free, purchasing
and installing those panels is not.
• Installing solar power for your home can
be an expensive proposition, especially if
you are attempting to derive all your
power from solar electricity
• Reliability - only works when the sun is
up. Hence you will need to have a backup
power source or use storage batteries to
provide power at night or during
inclement weather.

8. How does a solar system works ?
How is the system installed ?

9. Is my home good for solar ?
Available Roof Space Determines How Much Power Your Home Can Produce

10. Comparison based on location
Which location best suits the solar power generation.

11. Sizing the solar power system
Steps to sizing your rooftop PV plant
• Scoping the project
• Calculating the amount of solar energy available
• Surveying the site
• Calculating the amount of energy needed
• Sizing the solar system
• System size
• Panel size
• Inverter size

12. Scoping the project
Clearly laying out what you wish to achieve with your rooftop solar PV
installation is critical to designing a plant that fits your needs. Examples of
different kinds of needs we encounter in our work include
• Completely supports your daytime electrical needs
• Supports lighting loads
• Supports critical loads during power cuts
• Provides power for night-time use

13. Amount of solar energy available
• We expect about 4-7 kWh/m2/day of solar insolation in India.
• That means we can generate 4 kWh of power per day from a 1 kWp panel. This is
an average measure that can vary across different regions in India.
• To have accurate calculations, we find out the exact insolation level for a
particular home.

14. Surveying the site
• Already been discussed before.
• Space available – 1 kW of panels would require 100-130 SF (about 12m2)
of shade-free roof area
• Orientation – A south-facing roof is ideal

15. Calculating the amount of energy needed
• Calculating the amount of energy
needed
• This home would require 10 kWh
of power per day to satisfy the load.
• At this point the plant designer
might wish to identify
large/variable loads that need not
be supported by solar power or
that can be operated through some
other power source to reduce the
investment in the solar system.

16. Sizing the solar system
• System size - This load requires
1.8 kWh/day. Adding a 30% safety
margin to this, and assuming the
insolation to be 4kWh/m2/day, we
get
System size = (Energy
Requirement*1.3) /insolation
level
= 1.8*1.3/4 = 0.585 or 585 Wp.
• Panel size –
No. of panels = System size/Panel
Rating
• Inverter size
We use a 45% safety margin when calculating the inverter size.
Required Inverter size = Total Wattage of all
appliances*(1+45%)

17. Saving on electricity bills
How much can be saved on electricity bill if using solar systems ?
• Having solar panels can reduce your
electric bills by a significant amount.
• Every watt-hour of electricity your
panels produce is one less watt-hour
you have to buy from your utility
company.

18. Some other products
Other solar powered products that you can use around you.

19. Solar around us
Who is already using solar power systems to power up their buildings
• Jungle Lodges and Resorts - Five of the 20 cottages at Bidar, five of 18 cottages at Bandipur and
five of 22 cottages at Bhadra have been connected to solar panels and batteries.
• Greenpeace Office, Wilson Garden - A 15KW grid comprises the solar rooftop system. With solar
panels, inverter and a battery back-up for six to eight hours, this system generates 70-80 units of
electricity per day, slicing their electricity bill by Rs 15,000 per month.
• Max Mueller Bhavan, Indiranagar - The institute started putting solar panels in place in 2008 and
installed 35 solar modules with a total capacity of 7.8 kilowatt during peak hours so far.
• Karunashraya, Marathahalli - This hospice has a solar water heating system in place too.
Streetlights on the campus and along the driveway are also enabled by solar energy.

20. free Spirits Green Labs
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