Guides to installation of a Photo Voltaic system - MIEMA

Introduction
Thanks to its geographic
position in the central
Mediterranean region, Malta is
the EU member state with the
highest intensity of solar
radiation. This makes solar
energy the most useful type of
renewable energy for our
islands, being both clean and
abundant.

The popularity of photovoltaic (PV) systems in the Maltese
Islands has increased a lot over the past few years owing to
a drop in capital cost of such systems, the increase in the
cost of electricity, government rebates and general
environmental awareness.

What are photovoltaic systems
A photovoltaic (PV) system uses solar cell to convert solar
energy directly into electrical energy. The installation of a
PV system enables a homeowner to produce all or part of
his/her daily electrical energy requirements, depending on
the size of the system. There are two kinds of PV systems:
• Grid-connected
• Stand-alone
The systems installed in our islands are usually gridconnected.

Grid-connected system

Stand-alone system

Grid-Connected PV System
If the solar unit generates only part of the electricity needed
by a particular household, the rest is simply drawn from the
utility, since the house will remain completely connected to
the electrical network at all times. In case of a power cut
the system cannot be used unless additional components
like a backup inverter and batteries are installed.
The main components of a grid-connected system are:
• Solar panels
• DC to AC Inverter
• 2-way meter

Types of Panels
Different technologies exist concerning PV installations.
• The polycrystalline silicon is the most used technology
worldwide. These are made with the silicon wastes from the
electronic industry. This technology can reach good
production efficiency but there is the issue of the long term
sustainability of the raw materials.
• The other solution using silicon properties is the
monocrystalline technology. The advantage is the
relatively high efficiency (around 18%) but the production
costs are higher.

• The amorphous silicon technology is the cheapest one
but the one has the lowest efficiency.
Polycrystalline and Monocrystalline modules

Steps to be taken when installing a PV System
• Make sure there is permission for the installation of the
system.
• Select a system size that matches the demands of the
owner.
• Check that the installation site (usually the roof area) is
able to handle the desired system site. It is important to
make sure that the roof can handle the increased weight of
the PV system.
• Specify that all the equipment to be placed outdoor is
weather resistant.
• Install the system according to the provider’
specifications..

• Correct orientation and placement of panels is
extremely important to achieve optimum efficiency. The
panels should be south facing and with an inclination of 30
degrees.
• Place the PV arrays in order to avoid shading from
foliage, vent pipes, antennas and other arrays.

• The panels are usually mounted on metal frames. It is
important to use supports to avoid accidents in case of very
strong winds.
• Ground the system’s parts in order to reduce the threat
of electric shock and induced surges.
• Check for proper PV system operation
• Install the system according to the provider’
specifications.
• Ensure that the installation meets the local utility
interconnection requirements.