A translation-oriented analysis of a report issued by the European Photovoltaic Industry Association

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Chapter 1  
SOLAR PHOTOVOLTAICS - A BASIS FOR CHANGE 
Premise 
Electricity supply systems all over the world are facing the most rapid 
changes in their operating environments and technologies. These rapid changes 
require a more multi-faceted approach to confront with energy demand in a 
responsible manner.  
Policymakers, industries and business managers recognize the importance 
of investing in renewable sources to face climate changes, because these sources  
are essential to reduce greenhouse gases and guarantee the security of a safe and 
local energy supply. 
Solar  photovoltaics (PV) development in EU is the right solution to create 
a sustainable economy for the future, where technology innovations create jobs 
and social cohesion; so the right regulatory framework and market conditions can 
ensure that PV will fulfill its full potential as a clean and renewable energy 
source in our future energy mix. Switching to solar photovoltaic electricity is a 
realistic and competitive option for achieving our energy and environmental 
goals, in fact its costs are projected to fall farther over the next 10 years, on the 
contrary the costs for the construction of new nuclear plants, which have risen 
over the last decade, will continue to rise. PV technology has shown impressive 
price reductions over the last 20 years, with the price of  PV modules decreasing 
by over 20%, so there is an interesting opportunity for further generation cost 
decline: around 50% until 2020.
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1.1 How does solar photovoltaics work? 
 ―Photovoltaic‖ is a compound noun, derived from two words : ―photo‖ 
from Greek meaning light, and ―voltaic‖ from volt, the unite measure of electric 
potential at a given point. Photovoltaic (PV) is a renewable energy technology 
that converts solar radiation directly into electricity, notably solar energy is 
abundantly available for free to meet the world‘s energy needs. Photovoltaic 
systems use cells, consisting of one or two layers of a semi-conducting material, 
to convert solar radiation into electricity, so when a cell collects the sun‘s light it 
creates an electric field across the layers, causing electricity to flow. The 
performance of a solar cell is measured in terms of its efficiency at turning 
sunlight into electricity. Improving solar cell efficiencies while holding down the 
cost per cell is an important goal of the PV industry.  
A number of solar cells electrically connected to each other and mounted in a 
support structure or frame form the so called  module. Modules are designed to 
supply electricity at a certain voltage, such as a common 12 volts system, and the 
current produced is directly dependent on how much light strikes the module. 
Each module is configured with cells in increments of 12; therefore modules 
come in 12, 24, and 48 volts. Multiple modules can be wired together to form an 
array. In general, the larger the area of an array, the more electricity that will be 
produced. Photovoltaic modules produce direct-current (dc) electricity, they can 
be connected in both series and parallel electrical arrangements to produce any 
required voltage and current combination. 
PV cells are made from silicon, one of the most available raw material of 
the earth commonly found in sand; for solar cells, a thin semiconductor wafer is 
specially treated to form an electric field, positive on one side and negative on 
the other. When light energy strikes the solar cell, electrons are knocked loose 
from the atoms in the semiconductor material. If electrical conductors are
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attached to the positive and negative sides, forming an electrical circuit, the 
electrons can be captured in the form of an electric current, that is, electricity.  
There are two main types of photovoltaic technologies :  
crystalline silicon technology and thin film technology.  
Crystalline silicon cells are made from thin slices cut from a single crystal of 
silicon (monocrystalline) or from a block of silicon crystals (polycrystalline), 
their efficiency ranges between 12% and 17%.  
It is possible to distinguish among three main types of crystalline cells : 
• Monocrystalline (Mono c-Si) 
• Polycrystalline (or Multicrystalline) (multi c-Si) 
• Ribbon sheets (ribbon-sheet c-Si). 
Crystalline silicon technology is the most common technology representing about 
90% of the market today. 
Thin film modules are constructed by depositing extremely thin layers of 
photosensitive materials onto a low-cost backing such as glass, stainless steel or 
plastic.  
At the moment four types of thin film modules are available : 
• Amorphous silicon (a-Si) 
• Cadmium telluride (CdTe). 
• Copper Indium/gallium Diselenide/disulphide (CIS, CIGS) 
• Multi junction cells (a-Si/m-Si). 
Today other types of photovoltaic technologies begin to be 
commercialized or are  at the research level, among them the most important are 
concentrated photovoltaic and flexible cells. In the concentrated photovoltaic 
technology, some solar cells are designed to operate with concentrated sunlight, 
they are built into concentrating collectors that use a lens to focus the sunlight 
onto the cells. The main idea is to use very little of the expensive semiconducting
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PV material while collecting as much sunlight as possible. Efficiencies are in the 
range of 20 to 30%. Flexible cells are very similar in their production process to 
thin film cells, the cell can be flexible when the active material is deposited in a 
thin plastic. This technology opens the range of applications, especially for 
building integration (roofs-tiles) and end-consumer applications. 
The photovoltaic technology have a wide range of applications: 
 Grid-connected power plants 
 Grid-connected domestic systems 
 Off-grid systems for rural electrification 
 Off-grid industrial applications 
 Hybrid systems 
 Consumer goods. 
Grid-connected power plants produce a large quantity of photovoltaic electricity 
in a single point. The size of these plants range from several hundred kilowatts to 
several megawatts. Some of these applications are located on large industrial 
buildings such as airport terminals or railway stations.  
Grid-connected domestic systems represent the most popular type of solar PV 
system for homes and businesses in developed areas. Connection to the local 
electricity network allows any excess power produced to feed the electricity grid 
and to sell it to the utility. Electricity is then imported from the network when 
there is no sun. An inverter is used to convert the direct current (DC) power 
produced by the system to alternative current (AC) power for running normal 
electrical equipments. 
Off-grid systems for rural electrification are connected to a battery via a charge 
controller. An inverter can be used to provide AC power, enabling the use of 
normal electrical appliances. These applications are used in remote areas 
(mountain huts, developing countries), where electricity is not easily available.
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Rural electrification means either small solar home system covering basic 
electricity needs in a single household, or larger solar mini-grids, which provide 
enough power for several homes.  
Off-grid industrial applications are very frequent in the telecommunications field,  
especially to link remote rural areas to the rest of the country. 
Repeater stations for mobile telephones powered by PV or hybrid systems also 
have a large potential. Other applications include traffic signals, marine 
navigation aids, security phones, remote lighting, highway signs and waste water 
treatment plants. These applications are cost competitive today as they enable to 
bring power in areas far away from electric mains, avoiding the high cost of 
installing cabled networks. 
Hybrid systems can be grid-connected, stand-alone or grid-support. A solar 
system can be combined with another source of power - a biomass generator, a 
wind turbine or diesel generator - to ensure a consistent supply of electricity. 
Consumer goods such as watches, calculators, toys, battery chargers, professional 
sun roofs for automobiles use photovoltaic cells; other applications include 
power for services such as water sprinklers, road signs, lighting and phone boxes. 
1.2 PV and environmental protection 
Solar PV systems have a very light carbon footprint with no direct 
emissions of carbon dioxide - the gas which causes global climate change – into 
air during their functioning. Although there are no CO2 emissions during their 
operation, a small amount occur during the manufacturing  process of the PV 
module.  
Carbon dioxide is responsible for more than 50% of the man-made 
greenhouse effect, it is produced mainly by the burning of fossil fuels. Natural 
gas is the most environmentally sound of the fossil fuels, because it produces half
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as much carbon dioxide as coal, and less of other polluting gases. Nuclear power 
produces very little CO2, but has other major safety, security, proliferation and 
pollution problems associated with its operation and waste products.  
 In order to measure the environmental impact of a product, it is necessary 
to make a Life Cycle Analysis (LCA), an analysis which takes into account the 
direct and indirect impacts during the complete product life-cycle, from material 
sourcing, manufacturing, transportation, construction, operation, dismantling to 
product collection and recycling. A commonly known measurement of the 
impact of a PV system on the environment is its Carbon Footprint, expressed in 
terms of the amount of carbon dioxide (CO2) emitted during its lifetime per 
kilowatt-hour (kWh). PV only emits 21,65 grams CO2/kWh, depending on the 
PV technology, while the average emissions for thermal power in Europe are 
900g CO2/kWh. In the last 10 years the carbon footprint of PV has decreased by 
50% thanks to performance improvements, raw material savings and 
manufacturing process improvements and in the future  the carbon footprint of 
PV will continue to decrease through the recycling of materials, the increased 
lifetime of  PV systems, advanced systems for the conversion of solar energy, the 
improvement of logistics that optimize the transportation. The technical lifetime 
of PV modules is about 30 years during which they produce electricity with no 
direct CO2 emission, moreover no pollution is emitted in the form of exhaust 
fumes or noise.  
 It is common to think that PV systems cannot "pay back" their energy 
investment within the expected lifetime of a solar generator because the energy 
expended, especially during the production of solar cells, is seen to overshadow 
the energy generated. The energy payback time (EPBT) of photovoltaic systems 
is an important criterion to show the sustainability of PV, it refers to the amount 
of time spent for power generation in order to compensate for the energy used to
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fabricate the PV system. The EPBT is calculated through LCA methodology, the 
major contributors to it are energy inputs into a PV system, consisting of 
different elements such as the frame, module assembly, cell production, ingot 
and wafer production and the silicon feedstock, and the energy output, which 
depends on the characteristics of the PV technology used and the location of the 
installation. Data from recent studies shows that today PV systems already have 
an energy payback time (EPBT) of 1 to 3.5 years. For areas with high solar 
irradiance, such as Southern Europe, the EPBT for thin film systems is already 
less than a year, on the other hand, in areas with lower solar irradiance, such as 
Northern Europe, PV systems with monocrystalline modules will pay back their 
input energy within 3.5 years. The EPBT can continue to get better thanks to the 
reductions in the energy requirements to produce commodity materials such as 
glass, semiconductor materials and foils. 
 To conclude, PV systems provide a large amount of environmental 
benefits compared to fossil-fuel or nuclear technologies, so if governments adopt 
a wider use of PV in their national energy generation, solar power can give a 
substantial response towards international commitments to reduce emissions of 
greenhouse gases and climate change. Therefore PV can be the main source of 
electricity for the development of a clean and sustainable future. 
1.3 The impact of PV in Europe and worldwide – between 
advantages and disadvantages 
 The solar energy is the most dynamic and competitive  renewable energy 
resource, which assures a sustainable economic growth, more jobs and 
environmental protection, hence PV presents manifold advantages. 
PV is a clear and free-fuel energy source because, in order to function, solar 
panels only need the power of the sun, which is always available, avoiding noises
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and dangers for human health and reducing the global warming, on the contrary 
the burning of fossil fuels causes smog, acid rains, polluted water, with also the 
production of carbon dioxide.  
PV systems are easy to install and operate reliably for long periods of time with 
an estimated lifetime of 30 years and virtually no maintenance, in addition high 
quality standard are set at the European level to guarantee to buyers the reliability 
of the products. 
PV modules can be recycled, so the materials such as silicon, glass, aluminium 
used in the production process can be reused, with reduced costs of fabrication 
for new systems. 
Photovoltaic systems are unobtrusive, they can be integrated in buildings to 
cover roofs and facades in aesthetic ways, with the aim of diminishing energy 
consume. A PV system can be of various dimensions according to energy 
requirements, moreover the owner of a PV system can enlarge or move it if his 
energy needs change. European building legislation is continually promoting the 
use of renewable energies in public and residential buildings, as a consequence 
there is a continuous development of ecobuildings, which guarantee a large 
incorporation of PV systems in the built environment.  
PV can provide access to energy in rural areas, and so it enhances healthcare, 
education and economic opportunities, granting simple daily needs as house 
lighting, refrigeration systems, water drainage and telecommunications. PV can 
be the way to face the expanding electricity demand of millions people in 
developing countries, where electricity is not available, contributing to the 
development of these countries, in terms of healthcare, economy and political 
stability. 
Solar energy is locally available so it is not imported from other regions of the 
country or across the world, this obviously reduces environmental impacts
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related with transportation and our dependence on imported oil. For this reason 
photovoltaics plays an important role in securing energy supply. 
The PV sector contributes to the creation of jobs and wealth in Europe and 
worldwide. This sector grows up constantly thanks to the investments in research 
and technological innovation, this is possible because several countries have 
execute successful market policies; in Europe these countries are Italy, Germany, 
France, Spain, Portugal, Greece and Belgium, in which there is a strong increase 
in the number of jobs, in fact it is expected that the photovoltaic industry can 
create more than 200.000 jobs in the European Union by 2020, ranging from 
technicians who install and maintain the PV system to expert specialists working 
in high-tech solar cell factories. Europe‘s photovoltaic industry have to compete 
with companies from USA, Japan, China, Korea. China is building up a solid and 
competitive PV industry and wants to cover the entire value chain from silicon 
feedstock to complete systems and this already happens with a greater production 
capacity. Consequently Europe has to react to China‘s expansion in this sector 
supporting the research and investments in European countries, in order to avoid 
the transfer of PV production to China. 
What is important to remember now is the nuclear tragedy of March 2011 in 
Japan, which provoked  Germany‘s decision to close its nuclear power stations 
and Italy‘s rejection of nuclear power through the referendum of June 2011. 
These reactions represent a clear sign of European people‘s will to abandon 
dangerous energy resources and switch to renewable ones, in order to avoid other 
tragedies and safe our environment.   
 People today are more conservative with energy sources and they are in 
favour of green living; therefore solar energy can be more cost efficient. In this 
sense, one of the disadvantages of photovoltaics is that solar energy is more 
expensive to produce than traditional sources of energy, because of the high costs
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of manufacturing PV systems and conversion efficiencies of the equipment; but 
today the manufacturing costs are decreasing and the conversion efficiencies are 
raising, so the savings over time can justify the investment. 
The other drawback of photovoltaics is that on cloudy days the amount of 
electrical energy converted from the light of the sun is diminished to about 10 
percent of that of sunny days. So a home, which makes use a photovoltaic 
system, needs a system that must include batteries to store the energy generated 
by the sun's light. Most batteries are direct current, which would not favour 
operating appliances in the home from wall outlets, so PV systems must come 
with DC/AC inverters to supply the home with alternating current, such as power 
coming from our power company. 
Nowadays people are aware of the positive impact of photovoltaic 
technology, which presents a large number of advantages compared to the  
disadvantages, and the success of this technology depends on an efficient public 
dialogue which takes into account the total costs, risks and benefits. So PV 
industries have to invest in market researches, public relations and to pay 
attention to the needs and points of view of consumers.