Fitting a solar PV system gives a building its very own roof top power station and will reduce energy consumption and carbon emissions.
How does it work?
Solar photovoltaic (PV) systems take energy from the sun and convert it to zero carbon electricity.
The majority of Ecofirst solar PV systems consist of two main components:
Solar PV Panels - also know as PV modules, these are the principle building blocks of a solar PV system. Panels contain a series of photovoltaic cells made from a semi-conductor material (usually silicon) and these convert light into electricity. To give a desired electrical power output (measured in Watts) a number of panels are connected together to form a PV array.
DC/AC Inverter - this converts the direct current (DC) electricity generated by the panels into alternating current (AC) electricity that matches the building's mains electrical grid supply. If the building is not grid connected the inverter is usually replaced with a battery bank to store the electricity generated.
What can it be used for?
The power producted by a solar PV system contributes directly to the electrical demand of the building and in most installations substitutes electricity that would otherwise have been drawn from the National Grid.
If at any point more electricity is being generated than the building is using, the excess will be exported to the grid and payment can usually be received for this. In instances where the building is not grid connected, surplus electricity is stored in batteries.
The size of a solar PV system is referred to in terms of power output in full sunlight, known as its kilowatt peak (kWp), and is usually goverened by the available roof area and budget. A typical 2 kWp system, occupying around 20m2 of roof space, would generate between 1500-1800 kWh of electricity per annum, which can be up to 50% of the consumption of an average household.
A solar PV system generating 1650 kWh of electricity reduces CO2 emissions by around 710kg per year.
A typical 2 kWp solar PV system will generate about 50% of the electricity consumed by an average household*
*National average household consumption for electricity estimated at 3300kWp per annum.Does it suit my requirements?
Deciding whether a solar PV system is appropriate for you requires consideration of a number of factors such as:
- Specific energy or carbon reduction goals
- Available roof space
- Orientation & shading
- Mains electrical connection
- Local planning issues
- Budget
Unlike many other renewable energy devices, solar PV systems have no moving parts and therefore require minimum maintenance
Don't worry, Ecofirst Technical Advicers are here to help!
Which solar PV System?
There are a wide variety of solar PV systems, with a variations in many system components. Drawing on our experience and using carefully selected products, Ecofirst will always specify a hight quality system taylored to meet your specific requirements.
PV Panel
Solar PV panels consist of a series of photovoltaic cells made from one of three different types of semi-conductor material. The majority of panels Ecofirst use contain cells made from polycrystalline or monocrystalline silicon as these are the most cost effective. However, where the available space for a PV array is limited, we can specify high effiency panels containing so called hybrid cells, a combinaton of a monocrystalline silicon cell with a photovoltaic film, to maximise power output.
Roof Mounting System
On pitched roofs, solar PV panels can either be mounted above the roof or integrated within the tiles. In above roof mounting systems, typically used when retro-fitting, rails are fixed over the roof tiles and achored to the structure beneath. In roof integrated mounting systems, typically on new build, the panels are fixed directly to the structure flush with the roof tiles. On flat roofs, panels are mounted on pitched frames that are either fixed to the roof structure or ballasted. In cases where there is not a suitable roof, panels can be fitted to ground mounted frames.
The selection of PV Panel Type and Roof Mounting Sysetm will be based on factors such as:
- Roof Type - dictates whether a flat or pitched roof mounting system will be used and how it can be fixed
- Desired aesthetics - roof integrated mounting system are generally considered to have better aethestics
- Local site conditions - limited roof space may dictate the use of hybrid panels to obtain a required output
- New build or retrofit - roof integrated panels are easier to fit on new build properties
- Integrated with solar thermal - some roof integrated panels can be integrated with solar thermal collectors
- Local planning issues - in certain areas only roof integrated systems will be allowed
- Budget - above roof mounting is usually cheaper than roof integrated
DC/AC Inverter & Electrical Circuit
Ecofirst has access to a wide range of inverters and we use state-of-the-art software to select the model that will extract the maximum possible energy from your PV array. All the other components in the electrical circuit are spcified in accordance with the array and the inverter. Of the building is not grid connected the electrical circuit will require batteries and a charge controller, which will be sized to meet our specific predicted electrical demand.
