Handbook of best practices

ackbone cables between shore and nodes. The consensus is to end up with DC power
around 300V at junction box level.
1.3.5.2 Autonomous
The autonomous buoys are powered using power generator systems such as solar panels,
wind turbines and wave activated generators. Normally, photovoltaic panels power
rechargeable secondary batteries that directly drive the buoy systems. However,
photovoltaic panels may be damaged at sea or during buoy servicing, so a small number of
primary batteries normally are still used as a reserve supply until a service visit can be
carried out. Power requirement for the buoy depends largely on the number and types of
sensors used the sampling frequency and the consumption due to frequency of
transmission.
1.3.5.3 Energy storage
Battery purchase is a large investment and the proper size and type of battery is critical in
your decision-making. There are many things to consider between the different technologies,
load requirements and longevity. The capacity of the battery is selected based on the power
consumption estimating various sampling rates and frequencies and the duration and
intensity of the sunlight throughout the year if solar panels are our choice as power
generator. We can also consider the energy produced by power generators such as wind
and wave if they are included. There are a large number of batteries available such as AGM,
Supercapacitor and lithium-ion. The implementation of the batteries onboard buoys must
comply with safety rules in order to avoid explosion.
1.3.5.4 Power generation
Photovoltaic (solar) systems are a dependable power source, even at high latitudes. Solar
Panels work on a simple principle, when sunlight is exposed to the panel surface, electrical
power is produced. Most solar panels have a long life and are typically selected based on
the wattage (power) produced for the buoy power requirements. Among the Solar Panel
options, fixed frame and semi-flexible solar panels are the most used for buoys. The fixed
frame panels tend to be rigid and are constructed of materials like tempered glass and
aluminium to make them very durable. The fixed frame panels power output varies from
model to model but generally is anywhere from 10 watts to 225 watts.
1.3.5.5 Wind turbine
Wind is a form of solar energy and is a result of the uneven heating of the atmosphere by the
sun, the irregularities of the earth's surface, and the rotation of the earth. Wind flow patterns
and speeds vary greatly over the land, since they are modified by bodies of water,
vegetation, and differences in terrain. However, they are more constant over the sea,
especially in the open-sea. Humans use this wind flow, or motion energy, for many
purposes: sailing, flying a kite, and even generating electricity. Hence, it is also used to
provide power to oceanographic instruments deployed under the water.
Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical
power can be used for specific tasks (such as grinding grain or pumping water) or a
generator can convert this mechanical power into electricity
(ref.http://energy.gov/eere/wind/how-do-wind-turbines-work). The smallest turbines are used
for applications such as battery charging for auxiliary power on oceanographic buoys.
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