SOLAR ENERGY

Solar energy is radiant light and heat from the sun. It is harnessed using a range of
technologies such as solar power to generate electricity, solar thermal energy and solar
architecture.
It is a crucial source of renewable energy, and depending on how solar energy is collected,
distributed, or converted into solar power, its technologies can be broadly categorized as
either passive solar or active solar.

HARNESSING SOLAR ENERGY

Passive Systems/Passive Solar Energy
Passive systems are structures whose design, placement, or materials optimize the use of
heat or light directly from the sun. It requires no external devices to collect or store solar heat
and takes advantage of the local climate to heat structures.
Passive Solar Space Heating
This system is cost-effective and the simplest way to take advantage of the sun’s free,
renewable energy and displace the need for electricity, natural gas, or other active energy
systems. The inner temperature of a structure may be greatly controlled by careful planning
of the building's location, orientation, and materials. The use of Trombe walls, which are
constructed of absorbent materials that store heat during the day and gradually release it at
night, as well as the installation of big south-facing windows and shade trees, are measures
that may be used in both new and existing structures. Up to 60% of a home's winter heating
can be produced by sunspaces or glass rooms placed on the south side of a structure. As
long as the structure has sufficient insulation and ventilation, solar energy may be used in
any environment.
Solar Architecture- Thermal convection, or the transfer of heat from a hotter area to a
cooler one, is a process that includes solar energy. The Earth's objects and materials start to
warm up as soon as the sun rises. These substances absorb heat from sun rays all day
long. The materials release their heat back into the environment at night when the sun has
set and the atmosphere has cooled. Passive solar energy techniques take advantage of this
natural heating and cooling process.
Oftentimes, passive solar technology is included into building design. To ensure that the
building receives the ideal quantity of sunshine, the engineer or architect could, for instance,
align it with the sun's path during the design stage of construction. This approach accounts
for the local latitude, altitude, and normal cloud cover. Additionally, thermal insulation,
thermal mass, or additional shade can be added during construction or retrofitting of
structures.

Active System/Active Solar Energy

Active systems have devices to convert the sun’s energy into a more usable form such as
hot water or electricity, hence, it is used in solar panels.
Active Solar Space Heating
The thermal energy of the sun is captured by a collector containing a heat-transfer medium,
such as air or liquid, and dispersed throughout the structure by electric fans or pumps in an
active solar space heating system. There are currently no ready-made residential solar
heating systems available, so prospective clients must work with a professional engineering
firm to create a suitable system.
Concentrated Solar Energy- It is another type of active solar technology, also known as
Concentrated Solar Power (CSP). This uses lenses and mirrors to concentrate sunlight from
a large area into a much smaller area. This concentrated region of radiation warms a fluid,
which then powers an additional process or produces electricity.
Solar furnaces are an example of concentrated solar power. There are many different types
of solar furnaces, including solar power towers, parabolic troughs, and Fresnel reflectors.
They use the same general method to capture and convert energy.
Heliostats, flat mirrors that rotate to track the path of the sun through the sky, are used in
solar power towers. Sunlight is reflected by the mirrors, which are positioned around a
central "collector tower," producing a focused ray of light that hits a focal point on the tower.
Photovoltaics – Photovoltaics is a form of active solar technology that was discovered in
1839 by a French physicist Alexander-Edmond Becquerel. He discovered that the platinum
electrodes attached to a silver-chloride generated an electric current when he placed it in an
acidic solution and exposed it to sunlight. Hence, the process of generating electricity
directly from solar radiation is called photovoltaic effect, or photovoltaics.

SOLAR PANELS
One part of a photovoltaic system is a solar panel, also known as a solar module. They are
made up of a panel made of a number of solar cells. Solar panels, also known as
photovoltaic cell or PV panel, is a device that converts the sun's energy into electricity. The
energy generated is then used to charge power stations, which power all your electrical
appliances. They are available in a number of rectangular designs. These panels can be
used to extend a building's electrical supply or offer power in outlying areas.
Large-scale industrial and utility uses of solar energy are in addition to residential and
commercial ones. In this instance, a sizable solar farm, or array, made up of hundreds or
even millions of solar panels, delivers power to sizable metropolitan populations.

4 MAIN TYPES OF SOLAR PANELS

Monocrystalline solar panels - Also known as single-crystal panels, these are made from a
single pure silicon crystal that is cut into several wafers. Since they are made from pure
silicon, they can be readily identified by their dark black color. The use of pure silicon also
makes monocrystalline panels the most space-efficient and longest-lasting among all three
solar panel types.
However, this comes at a cost — a lot of silicon is wasted to produce one monocrystalline
cell, sometimes reaching over 50%. This results in a hefty price tag.
Polycrystalline solar panels - As the name implies, these come from different silicon
crystals instead of one. The silicon fragments are melted and poured into a square mold.
This makes polycrystalline cells much more affordable since there is hardly any wastage,
and gives them that characteristic square shape.
However, this also makes them less efficient in terms of energy conversion and space, since
their silicon purity and construction are lower than monocrystalline panels. They also have
lower heat tolerance, which means they are less efficient in high-temperature environments.
Passivated Emitter and Rear Cell (PERC) panels - PERC solar panels are an
improvement of the traditional monocrystalline cell. This relatively new technology adds a
passivation layer in the rear surface of the cell that enhances efficiency in several ways:
 It reflects light back into the cell, increasing the amount of solar radiation that gets
absorbed.
 It reduces the natural tendency of electrons to recombine and inhibit the flow of
electrons in the system.
 It allows greater wavelengths of light to be reflected. Light waves over 1,180nm can’t
be absorbed by silicon wafers and simply pass through, so they end up heating the
cell’s metal back sheet and reduce its efficiency. The passivation layer reflects these
higher wavelengths and stops them from heating up the back sheet.

PERC panels allow greater solar energy collection in a smaller physical footprint, which
makes them ideal for limited spaces. They are only slightly more expensive to produce than
traditional panels, due to the added materials needed, but they can be manufactured on the
same equipment, and can end up having a lower average cost per watt due to their
efficiency.
Thin-film solar panels - Thin-film panels are characterized by very fine layers that are thin
enough to be flexible. Each panel does not require a frame backing, making them lighter and
easier to install. Unlike crystalline silicon panels that come in standardized sizes of 60, 72,
and 96-cell counts, thin-film panels can come in different sizes to suit specific needs.
However, they are less efficient than typical silicon solar panels.
Thin-Film Solar Panel Variations
Unlike crystalline panels that use silicon, thin-film solar panels are made from different
materials. These are:

 Cadmium telluride (CdTe)

 Amorphous silicon (a-Si)
  Copper indium gallium selenide (CIGS)

Cadmium telluride (CdTe) - CdTe has the same low-cost advantage as polycrystalline cells
while possessing the lowest carbon footprint, water requirement, and energy payback time of
all solar panels types. However, the toxic nature of cadmium makes recycling more
expensive than other materials.

Amorphous silicon (a-Si) - Amorphous silicon panels (A-Si) derive their name from their
shapeless nature. Unlike mono-and polycrystalline solar cells, the silicon is not structured on
the molecular level.
On average, an a-Si cell requires only a fraction of the silicon needed to produce typical
silicon cells. This allows them to have the lowest production cost, at the expense of
efficiency. This is why a-Si panels are suited for applications that require very little power,
such as pocket calculators.

Copper indium gallium selenide (CIGS) - CIGS panels use a thin layer of copper, indium,
gallium, and selenium deposited on a glass or plastic backing. The combination of these
elements results in the highest efficiency among thin-panel types, though still not as efficient
as crystalline silicon panels.

SOLAR PANEL TYPES BY EFFICIENCY

Among all panel types, crystalline solar panels have the highest efficiency.

Monocrystalline panels have an efficiency rating over 20%.

PERC panels add an extra 5% efficiency thanks to their passivation layer.
Polycrystalline panels hover somewhere between 15-17%.
In contrast, thin-film panels are usually 2-3% less efficient than crystalline silicon. On
average:
SOLAR PANEL TYPES BY COST
Monocrystalline panels (or modules as they are technically known) carry a hefty price tag,
due to its energy-intensive and inefficient manufacturing process with only a 50% yield for
every silicon crystal.
Polycrystalline modules are cheaper because they make use of the crystal fragments
leftover from monocrystalline production, which results in a simpler manufacturing process
and lower production costs.
Among thin-film solar panels, CIGS is the most expensive, followed by CdTe and amorphous
silicon. Apart from the lower acquisition cost, thin-film modules can be easier to install thanks
to their lighter weight and flexibility, which lowers the cost of labor.

ADVANTAGES OF SOLAR PANEL

Solar panels are a clean and renewable energy source for homeowners and outdoor
enthusiasts. Below are the benefits of using a solar panel and power station to charge your
appliances.
Clean & Green Energy: Solar panels do not emit toxic fumes while converting the sun's
energy into electricity. Hence, they are a clean, green energy source that reduces your
carbon footprint.
Zero Maintenance: Solar power panels are easy to clean and maintain. All you need to do
is wipe the dust off with a soft, clean cloth to improve its efficiency.
Safe: Unlike gas generators, solar panels do not require coal or gas to generate electricity.
Hence, they are pretty safe for indoor use.
Diverse Uses: Solar energy is extremely versatile, and can provide power not only to our
homes and appliances but to places where channelling power from a grid is impractical or
impossible, such as remote, off-grid regions, satellites and boats.
Benefits the Community: A process known as net metering allows consumers to sell
excess electricity their panels produce back to the utility company, further reducing utility
bills. This often reduces a community’s reliance on fossil fuels, as well.
Technology Is Improving and Prices Are Decreasing: Technology has improved
tremendously since the early days of solar power and advancements continue to be made
every day. Better yet, despite these advancements, solar’s ubiquity appears to have driven
its cost down, making solar more accessible to more consumers. Many state incentive
programs and a federal tax credit can also help consumers minimize the out-of-pocket
amount they spend on a new solar system.
Reduces High Electricity Bills: You can power all your home appliances with solar panels
and a portable power station. Thus, renewable energy helps reduce high electricity bills and
save money.
Eco-friendly: Solar panels reduce the emission of greenhouse gases like carbon dioxide,
nitrogen oxides, sulfur oxides, etc., into the atmosphere, making them an environment-
friendly power solution.

DISADVANTAGES OF SOLAR PANEL

High Cost of Solar Panels: Despite decreases in the cost of solar panels over the past ten
years, a complete solar installation still requires significant investment. On average, a
consumer can expect to pay around $18,000 on a complete solar setup for a home before
accounting for any incentives and the federal solar tax credit.
Sunlight Dependent: Without sunlight, a system reliant on solar energy cannot produce
power. This can pose a problem for consumers in areas with less-than-ideal levels of sun
exposure or poor weather. Solar batteries to store excess energy can help mitigate this issue
and even under constant-clouds the best solar panels will still remain cost and energy
efficient enough to be worth the installation.
Installation Can Be Difficult: Although most of the components in installing solar panels
are relatively simple, if you’re not a fan of being on a roof or not comfortable working with
electricity, solar panel installation can be complicated. For instance, tying the panel wiring
into the home can be complex for the average DIYer and should be left to the professionals.
Space Constraints: Solar panels and the associated wiring take up space. Depending on
the number of solar panels needed, finding enough space with adequate exposure can be
difficult, especially in less-spacious residential areas.
Solar Energy Storage Is Expensive: Since solar batteries store the excess energy
generated by your solar panels, they are essential to your solar panel system. However, they
can be costly depending on the type and size of the battery. For instance, a single lead-acid
battery can cost between $200 and $800, while a residential lithium-ion solar system can
cost $7,000 to $14,000.
Environmental Impact of Manufacturing: The production of solar technology has its
environmental downsides, as the mining of materials and manufacturing of solar panels
creates a considerable amount of greenhouse gas. The Office of Energy Efficiency &
Renewable Energy issued a report revealing that solar panels pay for themselves in terms of
greenhouse gas emissions within one to four years of use, so while certainly still a downside,
much of the issue can be mitigated.
Difficulty with Relocation: Uninstalling a solar system and moving it can be difficult, time-
consuming and expensive, so the semi-permanence of the structures means panels are not
often something you’ll take with you from house to house. They’re often best considered an
investment in the structure or property they’re added to.
Scarcity of Materials: Sunlight may be unlimited, but the materials required to manufacture
solar technology are not. The availability of the raw materials required to produce solar
products may not be sufficient to meet future demand and the options for mining these
materials can have a significant environmental impact.
Disposal or Recycling Options: Solar technology contains some of the same
environmentally-harmful substances in many consumer and industrial electronics, so proper
disposal is critical. At present, recycling options for solar panels remain limited.

SOLAR PANEL CALCULATION

There is no single accurate answer to how many solar panels a home needs. Every home is
different, and so are its power needs. Using a solar panel calculator and understanding
various variables gives an accurate estimate of how many panels you'll require. Some
essential factors you'll need to consider are load wattage, energy usage, solar panel backup
time, efficiency, etc. Let us discuss each aspect in detail.

Solar Panel Output Calculation

Generally, solar panels produce a few hundred watts to 400 watts per hour. However, there
are several external variables that affect the actual output of the panels.Some important
factors include how many hours of sunlight the solar panels receive, your location, and how
many watts your panels can produce in an hour.
Formula:
Daily watt hours = Average hours of sunlight × solar panel watts × 85%.
(As not all the sunlight is converted into electricity, we tested to determine that the Jackery
solar panels are 85% efficient.)
Example:
Suppose you live in an area that receives 4 hours of peak sunlight, and your panel has a
200-watt rating. In this case, the solar panel output will be:
Daily watt hours = 4 × 200 × 0.85 = 680Wh.
That means one solar panel with a 200-watt capacity can produce around 680 Wh,
depending on its efficiency.
For instance, if you purchase Jackery SolarSaga 200W Solar Panels, you can enjoy a high
conversion rate and efficiency. Along with the portable power station, these solar panels can
convert sunlight into electricity and power appliances.

Load Wattage Calculation

The load wattage is the next important thing you'll need to keep in mind while buying a solar
panel system. In simple words, load wattage involves analyzing your power requirements by
understanding how many appliances you wish to charge and for how much time.

Formula:
To calculate the total load wattage of the electrical appliances, you need to multiply the
power used by each device by the number of usage hours per day. This will give you the
total kWh per day of one appliance.
Example:
For instance, if you wish to run a refrigerator for 6 hours and it consumes 300 watts per hour,
here is how to calculate its load wattage.
Load Wattage = 300 × 6 = 1800 Wh.
Similarly, you can calculate the load of all other home appliances. Add them up, and you will
get the total power you need for one day.

Energy Usage Calculation

The next crucial step for solar panel calculation is to determine your home's average
electricity consumption and energy usage. The amount of energy an appliance uses in an
hour is termed energy usage.
To get an estimated energy usage value, you need to figure out daily kWh usage, peak sun's
hours, etc.
Formula:
Step 1: Calculate the kWh usage: First, you need to gather the kilowatt-hour usage
from your electricity bills. Next, determine the average monthly kWh by adding 12
months of kWh usage and dividing it by 12. Divide the resulting number by 30 to
calculate daily kWh usage.

Step 2: Determine peak sun hours: Note down the peak sun hours you receive.
Remember, not every location gets the same amount or intensity of sunlight. To
make the most of solar power, calculate the average sun hours you receive and
move to the third step.

Step 3: Calculate Solar System Size: The last step is to determine the size or
capacity of the solar system you'll need to power appliances. You can simply divide
the daily kWh by the average sun hours. Then, multiply the result by the panel's
efficiency to get an estimated solar system size.
 Kitchen
Living Room Outdoor
Appliance Watts Watts Watts
Appliances Appliances
s
150-200
500 W 1100 W
Blender TV W Band Saw

1000 250-1000
Coffee 10-30 W
W LED Bulb Drill W
Machine
1200-
Dishwashe 1500 Video Game 150 W 200 W
W Electric Blanket
r Console

1200
Electric 100 W 1500 W
w Laptop Hair Dryer
Kettle

850 W 100 W 280 W

Toaster LCD Monitor Dehumidifier

1200
Electric 100 W 1100 W
W Printer Circular Saw
Oven
Note: Always use highly efficient solar panels with a power station to charge appliances.
Instead of connecting hundreds of solar panels, you can purchase a combination of powerful
power stations with high battery capacity and connect them with solar panels.

Refer to the table to determine the energy needs of different appliances.

Solar Panel Backup Time Calculation

The backup time of the inverter or solar power station determines how long it can provide
power during outdoor adventures or power outages. The backup time of a solar energy
system depends on the solar battery size and charge consumed by the appliance.
The battery capacity is generally measured in AH (ampere-hour). The most common battery
type is 12V, which provides 80% efficiency. The more the solar panel backup time, the
longer you can run your devices.

Formula:
Battery Backup Time = (Battery AH × 12V × battery efficiency) ÷ Total power consumption.
Example:
Suppose you are running an appliance that consumes 100W of energy. In this case, the
backup time will be: (100 AH × 12 V × 0.8) ÷ 100 watts = 9.6 hours.
Hence, you can run the appliance for 9.6 hours with a 100 AH battery capacity solar power
system.

Solar Panel Cost Calculation

With the increasing popularity of solar panel systems, many homeowners are planning to
harness solar energy. However, the cost associated with solar panels before switching to
renewable energy is worth noting.

The main factors that affect the overall cost of solar panels include the type of panels you
wish to install. For instance, if you're planning to install monocrystalline solar panels that are
highly efficient, you'll need to pay a few extra bucks. Other factors influencing solar panel
calculation include size, conversation rate, and other relevant features of solar power panels.

Alternatively, you can use the solar panel cost calculator to determine the overall expenses.

Solar Panel Paycheck Period Calculation

The solar panel payback period is the estimation of the time it takes for the solar panel
system to generate enough energy savings so you can offset the initial investment.

Formula:
The simple formula to calculate the payback period is the total cost of the system divided by
the average yearly energy savings.
Payback Period = Total cost of solar panel system ÷ Average yearly energy savings.

Example:
Suppose you've purchased a solar system of $20,000 that helps you to reduce your
electricity bills by $70 per month.
In this case, the average yearly energy savings will be $70 × 12 = $840.
Payback period = $20,000 ÷ $840 = 24 years.
Hence, solar panel systems will take 24 years to completely offset the initial investment.

Solar Panel Efficiency Calculation

Solar panel efficiency, in simple words, represents the amount of sunlight a solar panel can
convert into usable electricity. It is calculated by dividing the amount of electricity produced
by the solar panel by the amount of the sun that strikes the solar panel.
Formula:
 Efficiency (%) = [(Pmax ÷ Area) ÷ 1000] × 100%.
Where
Pmax = Maximum solar panel power (measured in watts).
Area = Length × Width of solar panels (measured in sq. M).
1000 = Conversion factor to convert power output per unit area from watts per sq. M to
percent.
Example:
Suppose you have a solar panel with a maximum power output of 200W and a surface area
of 1.6 m2. The efficiency of solar panels would be:
Efficiency = [(200 W ÷ 1.6 m2) ÷ 1000] × 100% = 12.5%.
In this case, the solar panel efficiency is 12.5%. That said, it can convert 12.5% of the
sunlight that hits the panels to electricity.

Fraction of Incident Radiation

Surface Color
Absorbed
Dark blue to black 0.80-0.90

Dark brown to blue 0.70-0.80

Green, red, and brown 0.50-0.70

Grey to dark grey 0.40-0.50

White smooth surfaces 0.25-0.40

Solar Panel Insolation Calculation

Solar panel insolation is the amount of solar energy that falls on the surface area in a
specific amount of time. It is measured in kilowatt-hours per square meter per day
(kWh/m2/day).

Formula:
I=E/A×t
Where
I = Solar insolation (kWh/m2/day)
E = Total solar energy that falls on the panel (kWh/m2)
A = Surface area (m2)
t = Length of time (day)
Example:
Suppose a 1 square meter of the surface area receives 5 hours of peak sunlight and 5 kWh
of energy in a day. In this case, the insolation would be calculated as follows:
I = 5 kWh / 1 m2 × 1 day = 5 kWh/m2/day.

Note: The actual insolation will depend on multiple other factors, including but not limited to
location, atmospheric conditions, time of year, etc.