Solar energy has experienced phenomenal growth in recent
years due to both technological improvements resulting in cost reductions and
government policies supportive of renewable energy development and utilization.
This study analyze the overview landscape, trends of PV technology, challenges
and potential globally and within the economic and technology constraints. It
is also discussed about the 3rd generation high efficiency solar cell with
advanced concepts and new approach of breaking the 31 % efficiency limits.
Lastly, it is described the opportunity of solar PV in the realization of solar
energy’s access and affordability to ensure continuous growth of solar green
energy as an affordable renewable energy source.
1.0 An overview landscape
The Sun is a dependable,
non-polluting plus infinite source of energy. From the time when the beginning
of life on world, the energy that was received by all living forms was
transmitted from the sun. It is the period now when the mankind is on a
perspective to again depend and rely upon the sun as the primary source of
Solar energy is the utilization of the radiant energy as of
the Sun. Solar power is frequently utilized traded by way of solar energy but
refers extra particularly towards the conversion of sunlight into electricity,
either by photovoltaics as well as concentrating solar thermal devices, or by
one of several investigational technologies such as thermoelectric converters,
solar chimneys and solar ponds.
Solar energy plus shading are essential considerations in
building design. Thermal mass is utilized in the direction of conserve the heat
that sunshine delivers towards the entire buildings. Daylighting strategies
optimize the utilize of light in buildings. Solar water heaters heat swimming
pools and provide domestic hot water. In agriculture, green houses extend
rising seasons and pumps powered by solar cells (also known as photovoltaics)
provide water for grazing animals. Evaporation lakes are used to harvest salt
and clean waste streams of contaminants. Solar energy is the speediest
developing form of energy production.
In the midst of fast increase in energy costs, concern over
pollution, reduction of resources and environment degradation the consciousness
for inadequate resources around the earth has increased dramatically. Utilize
of fossil fuels which causes green house emissions, ineffective use of energy
and let go of dangerous pollutants towards the environment causing threat such
as acidic rain necessity be addressed critically in new buildings. Governments
by way of vision comprise come to realise that generation of electrical power
through non renewable sources of energy is not enough. The power of the future
must be ecologically friendly as well.
Solar refining as well as sanitization methods create
potable water intended for millions of population around the world.
Family-scale solar cookers plus larger solar kitchens concentrate sunlight
intended for cooking, drying in addition to pasteurization. Clotheslines are a
common application of solar energy.
Further sophisticated concentrating technologies enlarge the
rays of the Sun designed for high-temperature material testing, metals melting
as well as manufacturing chemical production. A vary of prototype solar
vehicles give ground, air plus sea transportation.
Photovoltaic is a method by which energy commencing the sun
can take place directly utilized for power generation. This technique for
electricity generation causes no environmental pollution, has no rotating or
moving parts, in addition to causes no material running down. Photovoltaics are
also multifunctional. It can produce and operate lights, pump water, operate
any house hold equipments and appliances, can manage a few electrical gadgets plus
communication equipment. The photovoltaic finds its wide application in rural
community electrification in the developing countries and electricity
generation for the buildings, commercial regions and industrial zone in cities.
Around the world development of photovoltaics has been an
exponential curve between 2007–2017. At some stage in this period of phase,
photovoltaics (PV), also recognized as solar PV, advanced from a niche market
of minor range applications to a standard electricity resource. While solar PV
systems were primary recognized as a capable renewable energy innovation,
programs, such as feed-in tariffs, were executed by a number of governments in
order to supply economic incentives for investments. Intended for a few years,
development was principally focused by Japan and pioneering European countries.
As a result, cost of solar declined radically due to Experience curve impacts
like enhancements in innovation and economies of scale.
Experience curves illustrate so as to the cost of a thing
diminishes by the sum-total ever produced. PV development expanded even more
fast after production of solar cells in addition to modules begun to incline up
in the USA with their Million Solar Roofs project, and after renewables were
included to China’s 2011 five-year-plan for energy production1.From the time
when , deployment of photovoltaics has picked up momentum on a worldwide range,
especially in Asia but as well in North America and other regions, where solar
PV by 2015–17 was progressively competing among conventional energy sources as
grid parity has already been come to in about 30 countries2.
Projections intended for photovoltaic progress are
complicated as well as burdened with a lot of instabilities. Official
organizations, such as the International Energy Agency reliably expanded their
estimates above the years, but still knock down short of actual
Historically, the United States was the pioneer of installed
photovoltaics designed for many years, and its total capacity summed to 77
megawatts in 1996—more than several other country in the globe at the phase.
Then, Japan was the world’s leader of produced solar electricity in
anticipation of 2005, after Germany took the lead and by 2016 had a capacity of
more than 40 gigawatts. In any case, in 2015, China became world’s largest
manufacturer of photovoltaic power.789 China was expected to remain its
quick progress and to triple its PV capacity to 70 gigawatts by 20171011.
By the end of 2016, cumulative photovoltaic capacity come to
concerning 302 gigawatts (GW), approximate to be enough to provide between 1.3%
and 1.8% of worldwide electricity demand.79 Solar contributed 8%, 7.4% and
7.1% to the respective yearly domestic consumption in Italy, Greece and
Germany.5 Installed worldwide capacity was proposed to additional than double
or even triple to more than 500 GW between 2016 and 2020.2 By 2050, solar
power was predictable to turn out to be the world’s main source of electricity,
with solar photovoltaics and concentrated solar power contributing 16% and 11%,
correspondingly. This would necessitate PV capacity to grow to 4,600 GW, of
which more than half was prediction to be conveyed in China and India.2
1.3 Challenges and potential globally and within the
economic and technology constraints
The greatest challenge to Solar Energy faces nowadays is the
substitute conventional energy sources that are cheaper in conditions of
utilization measures (dollar per KWh).Electricity produced from Solar Energy is
costlier compared to that created commencing coal-fired power plants.
Government and enterprises are functioning on creating cheaper solar cells to
decrease cost of utilization. Even though the price of Solar Photovoltaic
technology has diminished in the last years, it is still not a possible
resolution for huge range power generation purposes. In US, the average cost of
Photovoltaic modules is around 0.0311553USD lc/KWh and the price of electricity
generation of electricity from Solar Photovoltaic and Solar thermal route is
within the range of 0.186933USD—0.311565USD per kWh and 0.155684USD –
0.233527USD per kWh correspondingly. The electricity produced this manner is
four-five times costlier as of that produced from conventional sources.
Progression in innovation is necessary to decrease this space.
The manufacturing procedure requirements to be extra cost-
effective from the time when the Solar Photovoltaic conversion of electricity
is a high-technology procedure insistent high rank of abilities and skill.
Companies are designating exclusive reserves for investigation and expansion in
the industry to persuade innovations to make better the process. From the time
when the field is a generally new one with less knowledge in the field, new
companies face challenges in adapting up by the existing players in the field.
There are a small number of places which do not obtain an adequate amount solar
energy all over the year, which influences the cost of production. Regions
which receive huge amounts of rainfall and are clouded for the majority parts
of the year, automatically acquire ruled out as prospective sites for Solar
One more main challenge so as to solar energy faces is
storage space of the generated power. Electricity from Photovolatic cells
cannot be generated during the night and during cloudy days and therefore
appropriate way have to be adopted to store up the energy created during the
other times of the day. One more major inconvenience is that approach on a
short term basis cannot be predicted. Away from each other of this readily
available are seasonal variations which cause the supply and demand to expand
out of phase. It is consequently necessity that Solar Energy cannot be depended
upon as the only source of electricity for potential uses like space heating,
till proper storage measures are invented. It is also hard to store energy as
it also increments the price of manufacture and installation. Only in the past
this issue gets resolved can solar energy actually compete with other existent
sources of energy.
Due to lack of proper government control ,native government
and people are skeptical concerning the effect that setting up of big solar
power plants will have on the individuals and environment. A big scale solar
power plant ordinarily requires about one square kilometer for each 20-60MW
RAW MATERIAL AND WASTE PRODUCTS
A number of the materials ( like Cadmium) utilized meant for
creating Solar PV cells are dangerous and other raw materials like plastics
utilized for the packaging of the cells are non-biodegradable, subsequently
affecting the environment. Even though some of the waste created at some stage
in the manufacturing process is biodegradable (silicon), not all other
materials are biodegradable and disposal of the same is a challenging process.
AESTHETICS AND DESIGN
An additional obstacle to more extensive selection of solar
cell and solar module products and systems in the middle of commercial and
housing consumers is aesthetics and design. Consumers have stood up to solar
products for aesthetic reasons. Built up solar products are heavy, rigid,
easily broken and non-modular. Solar cell and solar module manufacturers can
make better aesthetics by creating products that can be more attractively
incorporated into building structures, and so as to lighter, flexible and modular and hence more
2.0 3rd generation high efficiency solar cell with advanced
concept and new approach breaking the 31% efficiency limits
Third generation photovoltaics (PVs) endeavor to radically
decrease the price of solar energy lower than the current level of approximately
$1/Watt to a lesser amount of$0.20/Watt 14. Worldwide power generation of PVs
is more than 5 GW as well as the whole industry is developing over 25% per year
15. A combination of expanded energy prices and fears above global warming
are approaching up demand for PVs. PVs propose a near boundless source of
carbon neutral energy that might ease both problems at the same time 16.
The huge mainstream of solar cells lying on the market are
single junction silicon devices acknowledged collectively as first generation
devices. Thermodynamics on a very basic level limit their energy conversion
efficiency among 31% and 41% depending on the concentration of incoming
sunlight 15. This is acknowledged as the Shockley-Queisser efficiency limit.
Fig. 1 shows the origin of the majority of the efficiency
losses. Appearing in this case, (14) represents photons with energies less than
the bandgap of the device that are not absorbed (“red losses”) and (15)
represents photons with energies more than the bandgap which lose this overload
energy as heat (“blue losses”). Since the sun is a polychromatic source of
light, fixing the bandgap gives a tradeoff between these two losses. Efficiency
capacity are usually obtained under AM 1.5 solar conditions that recreate the spectral
distribution of sunlight below a specified atmospheric condition.
Third generation PVs are intended to combine the advantages
of both the primary and subsequent generation devices. Specifically, this
assessment paper will concentrate on attempts to get better the efficiency of
PVs more than the Shockley-Queisser efficiency limit throughout the subsequent
four methods: multi junction cells, intermediate-band cells, hot carrier cells
and spectrum conversion. A number of these concepts are as of now obtainable in
commercial products while some have only scant experimental proof. They all
ultimately contribute to the same promise of reducing the price per watt of PVs
to a point where they can form a large portion of the world’s energy supply.
Figure 1 (online color at: www.lpr-journal.org) A diagram
showing the primary losses in solar cells adopted from 1. (14) Incoming
photons with energies below the bandgap (labeled as Eg) are not absorbed. (15)
Incoming photons with energy in excess of the bandgap are absorbed but the
electrons and holes will relax to the conduction band minimum (CBM) / valence
band maximum (VBM) by producing phonons (represented by dashed lines). (16)
Electrons and holes can recombine with the help of electronic states within the
bandgap. These states are typically defects or impurity atoms and the
recombination event produces phonons. (16) Electrons and holes can also
recombine radiatively and produce a photon with an energy equal to the bandgap.
Unlike 1, 2, and 3, this radiated energy is not necessarily lost as these
photons can be reabsorbed. However, photons emitted from the front of the cell
back towards the incoming sunlight are lost forever and ultimately restrict the
maximum efficiency of the cells.
Figure 2 (online color at: www.lpr-journal.org) The AM 1.5
spectrum is the standard used to determine the efficiency of solar cells. The
spectrum represents, for a given location and atmospheric conditions on earth,
the intensity and spectral distribution of incoming sunlight. Also displayed
are the bandgaps of a select number of solar cell materials. For a single
junction, the most efficient cells have a bandgap between 1.1 eV and 1.4 eV
that includes Si, InP and GaAs. A wide array of bandgaps is available by
alloying different semiconductors with each other.
Multi-junction solar cells as of now have produced
efficiencies over 40% and are commercially produced. The main hold-up for
expanding production of these cells is their restrictive costs. Nevertheless,
new technologies combined with concentration technology might overcome this
issue. Intermediate-band solar cells as well as hot carrier cells assure
similar efficiency enhancements and yet lower costs than multi-junction cells.
In any case, no cells have to this date exhibited efficiency surpassing the
Shockley-Queisser efficiency boundary. Finally, spectrum conversion
technologies propose a simple way of improving efficiencies that is compatible
with existing solar cell technologies.
3.0 Opportunity of solar PV in the realization of solar
energy’s access and affordability .
One of the majority
common systems utilized to harness solar energy is a small-scale rooftop-based
solar photovoltaic system. Solar capturing panels are located on top of the
roof of a house, building, or business, and then feeds collected energy to a
conversion system. Even just a small system used to be incredibly costly, but prices have declined significantly over
the past few years. As of 2010 to 2013, prices for rooftop-based V systems
retain dropped more than 9%, and this includes installation costs7
When you combine falling installation costs with the assure
of tax credits and money saved on energy bills, you have no deficiency of
reasons to get included10. The majority states offer tax credits, discounts,
grants, and more that could decrease the total cost of a rooftop-based PV
system to below $10,000. In addition, consumers are able to finance these costs
through leasing agreements and power purchase contracts, the latter of which
requires them to continue using the system for an expanded interval of time at
At the same time as this is all great information for
consumers who are looking to power their homes, it doesn’t offer to a great
extent for business owners who for the most part have larger structures with
higher demands. The good news is that large-scale PV systems have also dropped
in cost, more so than household ones. In fact, large-scale systems are an
average of 60 percent lower in price than residential solar systems if you take
a look at the per-wattage costs15.
Concentrated solar power systems (a way that uses mirrors to
direct thermal energy) are to a great extent more costly and have not seen the
similar reduction in prices, but they have one particular benefit over the
other two types. CV systems can be utilized to store the sun’s energy as they
collect heat, which implies they are still capable of creating electricity
while there’s no sunlight.
Solar energy’s accessibility makes is an fundamental tool in
developing countries, where 1.3 billion population do not have grid access. For
these communities, stand-alone solar systems are single method of accessing
electricity in rural areas.
They allow remote villages to benefit from groundwater
pumping for drinking water and irrigation, telecommunications systems such as
radio, television and cell phones, and appliances like refrigerators and sewing
It can be very useful to combine solar with other sources of
energy in countries that rely heavily on fuels to generate electricity. Using a
solar-diesel hybrid lowers consumption and maintains generator availability.
The cost of the solar installation is therefore offset in just a few years.