What is a Solar PV system?
Most electricity is generated by burning fossil fuels. This releases carbon dioxide and other gases
into the atmosphere, which contributes to climate change. A Solar Photovoltaic (PV) system is one
that converts light directly into electricity on your roof with no waste and no emissions. This
electricity is used throughout your home in the same way as the electricity you currently buy from
your energy supplier. Harnessing the sun's energy and converting it into electricity will reduce your
fuel bills and at the same time reduce your daily impact on the environment.
How does it work?
When light hits the silicon in a solar PV cell, electrical energy is created. The electricity flows
through a cable and is collected at a central point, often located in your roof space. At this central
point the electricity is converted from Direct Current (DC) to Alternating Current (AC) and carries on
into your household electricity system. The electricity generated by your system works hand in hand
with your own system for all your electrical needs. If not, your needs will be supplemented by your
electricity supplier. If during the day you generate more electricity than you need this excess will
flow out of your home and back into the main electricity grid.
What systems are available?
Some solar PV systems are available as roofing products that replace conventional roof tiles. They
can be integrated into your roof without changing its shape or style. Not all roofs will suit all types of
products. An integrated system is particularly suitable if you are building or re-roofing a property. If
your roof does not need replacing, a framed system can be installed. This type of system is made
up of a number of solar panels that fit into a frame that is then attached to your existing roof. These
systems can be also be fitted on flat roofs, façade mounted or mounted on the ground.
What am I getting?
The electricity you currently buy from your energy supplier is sold to you in electrical units. You may
pay less for units you consume during the night and more for units used during daylight hours. An
electrical unit as itemised on your electricity bill is known as a kilowatt hour (kWh). When you invest
in a Solar PV system you are buying a system that produces electrical units for use in your own
home. Every unit you produce reduces the amount of electricity bought from your energy supplier
and therefore the amount of carbon dioxide released into the atmosphere.
How much electricity can Solar PV panels produce?
A solar PV system is measured in size according to the number of electrical units it would produce
in an ideal environment. The smallest system size usually installed on a domestic property is 1
kilowatt peak. In the UK, a 1kWp system is expected to produce at least 750 kilowatt hours every
year. The average household in the UK uses approximately 3,300kWh per year. Therefore a 2kWp
system will produce nearly half of your yearly requirements and avoid around 650 kilograms of
carbon dioxide emissions. With a life span of at least 25 years, a 2kWp system will generate 37,500
kWh and avoid approximately 16 tonnes of carbon dioxide emissions in its lifetime.
What type of system is suitable?
The size and type of system suitable for your property depends on your available roof area and your
budget. You should be matching your system to your daily electrical requirements to make best use
of the electricity you generate. You should try and plan for any future electricity requirements, given
that your system will be operating for at least 25 years. With very low transmission losses, clean
electricity will continue to be generated efficiently and reliably.
What are the key considerations for installing Solar PV?
The ideal roof pitch is approximately 35-40 degrees or less. PV can be successfully installed on a
flat roof as there is much scope for the ideal orientation. You will need at least 10m2 un-shaded,
exposed roof area facing predominantly south. Chimneys, roof lights or nearby trees can all shade
your PV and need to be taken into consideration when deciding where best to position it.
When is a system completed?
A system is completed once commissioned, i.e. when it has been tested and shown to be operating
correctly. Once the system is generating electricity, the installer will issue you a commissioning
certificate. Your solar PV system is now fully functional and contributing to your property's electricity
usage.
|
Download PDF
