The solar radiation that reaches the Earth in a year represents more than 10,000 times the world’s energy consumption of all forms and combined uses and our benefactor star has a predictable lifespan of 5 billion years.
Fossil (coal, oil and gas) and fissile energy deposits (uranium), even the most extreme, represent only a few dozen years at the rate of their current consumption (one little more than a century for coal), and since this consumption does not cease to increase, in particular with the thirst for “savings emerging ”from the most populous countries on the planet (China, India, Brazil) to imitate our own behaviours, the end of their exhaustion does not stop getting closer.
The photovoltaic effect, discovered in 1839 by the French Antoine-César Becquerel, designates the capacity that certain materials have, especially semiconductors, to directly convert the different components of sunlight (not heat) into electricity.
The photovoltaic effect thus represents the only existing alternative to
production of electricity from the mechanical force, since all other techniques without exception, renewable or not, make use of rotating generators (alternators or dynamos) which can be operated in various ways: steam, wind, the force of water, current sailors …
In addition to this specificity which clearly distinguishes it from others technical, photovoltaics has many qualities that have as many advantages:
Based on an imperceptible physical phenomenon
its functioning causes absolutely no nuisance or impact on the environment
no movement, no noise, no smell, no emission whatsoever.
The operation of a photovoltaic system does not require any moving part, the risk of breakdown or accident is therefore almost zero and the level of reliability very high.
The physical characteristics of photovoltaic materials do not deteriorate over time, and the performance of the panel’s decreases, that we can possibly observe and mainly due to minor manufacturing imperfections, is very slow and very limited, this which allows manufacturers to provide a guarantee of performance that can go up to 30 years old.
Apart from the investment cost, access to energy resources primary is completely free and free, since it is the light of the sun, and since the maintenance and servicing needs are very reduced (they mainly concern the electronic regulation and connection), the economic outcome is predictable with a high degree of certainty.
The amount of energy recoverable in a given location is directly proportional to the area exposed to sunlight, which gives photovoltaics an intrinsically modular and flexible character: the surface area of the sensors ranges from a few cm2 to supply a calculator to several hundred thousand m2 for ground-based plants and this size can be changed at any time by simple addition (or withdrawal) of “slices”, without even interrupting the operation of the existing installation.
Free, harmless, accessibility, security, reliability, modularity, flexibility: the combination of these qualities available to photovoltaics means that its fields of application are extremely diverse and can meet a wide variety of needs in all kinds of situations, especially more than the different manufacturing technologies of the modules which are available today and will be tomorrow thanks to the many axes industry research to adapt the photovoltaic system the characteristics of the place and the intended use of the energy produced.
Certain sites, dwellings or others, are not or cannot be connected to the public distribution network because it is technically too complex to extend the network to them (in mountainous areas by example) or because the cost of such an operation is not justified by compared to other existing solutions. These sites are called "sites isolated ”.
Solar Voltaic Energy
However, it is often essential to have access to electricity in order to provide some basic services such as lighting, production of cold, or the power of radio. These sites may then be supplied with electricity by solar photovoltaic energy.
Photovoltaic solar makes it possible to bring electricity to an isolated site, there where it is expensive to produce.
The components of a solar system
THE PHOTOVOLTAIC MODULE
The module includes several photovoltaic cells assembled together to each other thanks to an electrical circuit, the photovoltaic module is the central element of a photovoltaic Solar system. To avoid damage caused by the return of current to the module, a bypass diode is installed on each diode. The dimension of the modules photovoltaics varies from manufacturer to manufacturer.
The function of the inverter is to transform the direct current coming from AC panels. Using an inverter is not essential for isolated sites.
THE CONVERTERConverters make it possible to adapt the power generated in order to make it useful. We have two types of converters for a panel solar: DC / DC and DC / AC. The former provide a DC voltage different from the incoming one and the others make it possible to obtain a AC voltage.
THE SOLAR BATTERY
The role of the battery is to store energy for use when the panels don’t create energy at night. The
Solar batteries are essential on an isolated site. The batteries are charged during daylight periods in order to be able to supply the site night or days with very bad weather.
THE REGULATOR OR CHARGE CONTROLLER
The regulator allows regulating the energy coming from the panels until the battery stops charging the battery when it is fully charged in order to avoid overcharging the battery and discharge, by controlling the outgoing energy. The regulator prevents the battery from ageing prematurely and optimizes charging and discharging.
Most consumer electrical appliances operate on alternating currents. These devices will require an inverter that will transform the direct current, produced by panels, in alternating current.
Electricity produced in direct current by solar panels
(1) is stored in lead-acid batteries
(2) A solar regulator
(3) protects batteries from too deep discharges and overloads.
(4) Electricity is consumed in the receivers
as needed of the user:
direct current (12V, 24V) directly from the battery, for small systems
in alternating current 230V, via an inverter, for solar system fatter Autonomous solar system are very easy to use, they do not require almost any maintenance compared to a group generator. They are also completely silent and do not generate pollution (exhaust gas, used oil, CO2).
It costs less than an extension of the Sénélec electrical network (if there is more than one km to cover), and once purchased, there is no more bill to pay!
An autonomous solar system is sized according to the needs user's electrical system. In the case of solar photovoltaic, the battery undergoes most of the time one cycle per day, that is, it is recharged during the day and then discharged in the evening. The depth of battery discharge at each cycle directly influences its battery life.
The deeper the discharge, the shorter the battery life.
The price of panels has been falling steadily since 2008 and has reached very low levels today. Inverters and regulators, such as many electronic devices, see their prices drop little by little.
Only batteries remain expensive, and their price is not close to going down because of the lead speculation and the demand generated by electric automobiles.
This makes off-site solar systems more and more accessible, but not within the reach of all budgets because of the batteries.