What is Solar PV?
How does Solar PV work?
The production of electric power through solar cells is known as
solar photovoltaics or solar PV. Solar PV panels, or modules,
consist of many photovoltaic cells that are made up of thin layers
of semi-conducting material, normally crystalline silicon, which
produce electricity when exposed to light. Solar PV differs from
solar thermal in that PV enables property owners to generate
electricity while solar thermal provides hot water.
How important is the location?
During manufacture, the silicon material is chemically treated
to alter its electrical properties. This means that when light hits
the cell, an electric field is created across the layers and
produces a current flow. The greater the intensity of light, the
more electricity is produced. Solar PV panels are linked to each
other in series and then connected to the building's main consumer
unit or fuse board via a device called an inverter. This device
converts the panel output from direct current (DC) to the
alternating current (AC) compatible with mains electricity. Whilst
allowing household devices to use this solar power just like normal
mains electricity, excess electricity can be exported onto the grid
at times when the instantaneous demand from the building is less
than the power produced by the panels.
How much electricity can Solar PV produce?
The location of the solar PV is very important because of its
sensitivity to the intensity of light. Solar PV modules need to
receive the maximum possible amount of light and should therefore
be installed on a south-facing roof. Due south is
preferable as efficiency drops off in correlation to the angle of
deviation from a due south orientation.
The angle of tilt of the modules is also important with the
ideal range in the UK being between 35° and 40°, depending on
latitude. Please refer to this table.
It's not advisable to install solar PV modules where trees or
surrounding buildings will cast shadows on the array as any shadow
affects the performance of the entire array and not just the
modules in shadow.
How does this relate to the Feed-in Tariff?
The output of photovoltaic panels is generally specified in
kilowatts (kW) or kilowatts peak (kWp). The panel area required to
produce an output of 1 kWp varies with panel technology, but a
typical 1 kWp array would have an area of around 7m2 and
produce approximately 800 kWh annually.
Care and Maintenance
Based on a 2.4 kWp array with optimal due south orientation etc.
this can be expected to generate approximately 2,000 kWh/yr
(kilowatt hours per year). The feed-in tariff provides
- a generation payment for every kWh produced whether it is
consumed or exported to the national grid.
- a export payment for each unit exported to the grid (normally,
unless requested otherwise, in domestic scenarios this is assumed
to be 50% of the kWhrs generated.)
- additionally the saving on electricity bills, by using any or
all of the electricity produced you will save on purchased
electricity. If electricity prices rise, the savings increase and
the payback time on the original investment shortens.
Do I need an EPC?
PV panels produce no noise, have no moving parts and can be made
to blend unobtrusively into the surrounding structure. Panels have
an average lifespan of thirty years, have no direct impact on the
environment and require minimal maintenance (ideally an annual
clean and performance assessment).
How will my generated output vary throughout the year?
From 1st April 2012, customers in England, Wales and Scotland
wishing to get payments under the government's Feed-in Tariff (FIT)
for solar PV will need to be able to prove that their home has an
EPC rating of band D or
above to receive FITs at the standard rate. You will
therefore need to be able to produce your existing EPC (as long as
it is less than ten years old) or obtain a new one.
You can complete a survey on the Energy Saving Trust website
that will give you an indication of the likely band that your
property will receive. Visit http://hec.est.org.uk/
Do I need planning permission to install solar panels?
The amount of electricity generated in a given month can vary
greatly depending on daily sunshine hours, the angle of the sun
relative to the PV modules and local weather conditions. The
majority of the annual output will be generated during the summer
months. A rough indication of how the monthly generation will
typically vary can be seen here.
What savings will I make?
You don't need planning permission for most domestic solar panel
systems, but you should check with your local planning officer if
your home is a listed building or is in a conservation area.
What is the extent of Ecoliving’s Service?
A typical solar PV array will produce enough electricity
(approx. 2,000kWh/year) to meet 30 - 40% of the annual electricity
needs of a family of 4. This is equivalent to powering the washing
machine, dishwasher, oven and ironing for a year. This represents
almost 1 tonne of CO2 a year.
Do Solar PV panels come in different colours?
Ecoliving provides a single source service with one point of
contact supporting you right through from initial discussion and
design to installation and commissioning and then registering to
receive Feed-in Tariff payments.
Do you include for any structural approval/check of the existing trusses?
Most panels come with an aluminium frame but there are panels
available with a black frame which blends into dark slate or tiled
Do you include for the costs of any scaffolding/access requirements?
Generally speaking a visual inspection both internally and
externally is sufficient to proceed with the project. Where a roof
appears to be in poor repair, the site particularly exposed or the
roof fixing team uncover an issue (e.g. rot or nail sickness) it
may be pertinent to seek advice of a structural engineer. Any costs
would be agreed between the structural engineer and the customer
directly with the customer being liable for them.
Ecoliving Ltd. provides a 2 year workmanship warranty on all
Solar Photovoltaic installations and covers leaks or structural
issues proven to be as a direct result of the solar
What is the guarantee period for the system?
All access equipment is included with all standard quotes. Where
limitations dictate that specialist access equipment is required
then this would be highlighted at quotation stage.
What is the guarantee period for the inverter?
Different panels offer different guarantees. The majority of
panels come with a 10 or 12 year product warranty which relates to
the manufactured quality. The performance efficiency is a separate
guarantee based on 25 years and is typically a minimum 80%
efficiency of original performance after 25 years.
What is the anticipated timetable of these works?
Most inverters come with a standard 5 or 10 year warranty.
What preparatory work is likely to be required before your start on site?
Typically we are on site within 3 weeks of receiving
Very little, only to ensure the installation team can have
vehicular access for delivery, space for access equipment around
building, access into the loft area and cupboard where
generation meter is to be placed.