Aquaculture sites are often located in zones which are totally deprived of electrical energy, either because of their distance from any inhabited zone (pond and marsh), or because they are at sea (floating cages).
However, it is often necessary to have a minimum of energy available, to operate the feed distributors, or to operate an alarm, a pump, or any other electric system.

 

In our temperate zones, and especially south of the Loire (France), the sun is sufficiently present to provide energy which is often enough to operate such systems.
The main solar energy captors exist in two forms:
The solar heaters, which consist of tubes where a heat transfer agent, water generally, circulates,  which is used to absorb infra-red radiation from the sun to heat a room or any other installation (greenhouses...).
Photovoltaic cells, made up of silicon sensors which convert the solar radiation into electric power.
It is these photovoltaic sensors which are the most relevant for the fish farmer.  They are able, from a restricted surface area (1 m2) to produce a power which can reach 80 W at 12V.
In general,  although solar energy is free, the photovoltaic panels, on the other hand, are rather expensive, but fortunately, they can easily last several decades if they are good quality.
The early solar cells consisted of monocrystalline silicon, characterized by a collection of blue-tinted discs.  They gave a very good output, but were extremely expensive to produce, especially as their circular shape made it impossible to optimize the surface used.
 

Since then, polycrystalline silicon has appeared, whose active cells are blue tinted rectangles and the large crystals on the surface can be easily distinguished.  They currently provide the best energy / price ratio, and have an excellent quality which makes it possible to use them for twenty years.  Moreover, their rectangular shape makes it possible to fabricate panels of a reduced size.

Lastly, on the market, there are panels of amorphous silicon which are characterized by a grey-blue speckled surface, where the crystals cannot be distinguished.  They offer a  reduced cost (they can be found in small gadgets for the car or gardening),  but they have poor output, and a weak lifespan.  They are not practicable in aquaculture, where the conditions of use are too severe.

 

The arrangement of the solar panels is also very important to recover the maximum luminous flux from the sun.  In our regions (France), the optimum is obtained by directing the panel to the south and by inclining it at 45° to the ground.  The ideal situation would be to be able to direct them towards the sun throughout the day (like sunlowers)...

To best evaluate the requirements, it is necessary to recall some basic rules of electricity:

 

 

P in Watts, U in Volts, and I in Amps.