Solar Photovolatic - FAQs
Contents
- What is PV?
- What are the components of a PV system?
- How does a PV system work?
- Doesn’t PV technology need bright sunshine to work properly?
- Is PV suitable for use in the UK?
- How much will I need to power my home?
- Do Solar PV systems need batteries?
- How long will my PV System last for?
- Why should I invest in a solar PV system now?
FAQs
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What is PV?
PV stands for Photovoltaic. The PV process converts sunlight, the most abundant energy source on the planet, directly into electricity. The equipment required for this process has no moving parts and as a result requires minimal maintenance. In addition, the electricity is generated with no emissions and no noise.
A PV cell consists of two or more thin layers of semiconducting material, most commonly silicon. When the cell is exposed to light, electrical charges are generated and this can be conducted away by metal contacts as direct current (DC).
The electrical output from a single cell is small, therefore multiple cells are connected together to provide a more useful output. Cells connected in this way are encapsulated (usually behind glass) to form a weatherproof module or panel. Multiple modules can likewise be connected together in order to provide sufficient power for common electrical appliances.
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What are the components of a PV system?
Each PV system is constructed from different components. These include PV modules (groups of PV cells, which are commonly called PV panels); a charge regulator or controller for a stand-alone system; an inverter for converting direct current (dc) into alternating current (ac), the cabling to connect components together, and mounting hardware for the PV panel itself. This panel must be fixed to a roof or sited to get maximum daylight.
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How does a PV system work?
Daylight hits the photovoltaic cells and is converted to clean electricity. This is fed into the inverter, which converts the electricity from direct to alternating current, for use in the home. When the solar energy system is producing more power than is needed it can often be exported to the national grid. In such a system, during the night, power is imported from the grid in the normal way.
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Doesn’t PV technology need bright sunshine to work properly?
The electrical output of a PV cell is dependent upon the intensity of the light to which it is exposed. So PV cells will tend to generate more electricity on bright days than when skies are overcast. However, PV panels do not need to be in direct sunlight to work, so even on overcast days the panel will be generating some electricity.
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Is PV suitable for use in the UK?
In the UK, we get about 60% of the sunlight received at the equator - so there is still a lot of potential energy available! PV has been used in the UK over the last 20 years or more for many applications, particularly in remote areas where grid connection is impractical, such as weather monitoring stations, marine navigation aids, etc. Over the last few years PV technology has become more common in urban areas, often seen incorporated into the roofs and facades of homes, offices and factories.
A modest sized domestic grid connect system will provide a substantial portion of a household’s electricity needs for over 6 months of the year. Installations on commercial buildings are particularly effective, meeting the daytime demands of an office.
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How much will I need to power my home?
A typical domestic system of 1.5 kW (1500 Watts) in the UK would produce around a third of the annual electricity needed for an average family household (taking the average demand to be around 10 kWh per day). However, calculating the required system size would need to consider other factors too, for example whether the system is grid connected, and what the energy demand of the household is, etc.
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Do Solar PV systems need batteries?
Not normally. Since the system produces AC power from daytime solar radiation, it can power domestic appliances independently as long as there is sufficient daylight. If the system is also connected to the national grid, at nightime when the cells are not generating energy, electricity is taken from the grid in the normal way. Any excess electricity generated during the day, for example when you are at work, is sold back to your electricity supplier.
Batteries are only required if you want a truly off-grid solution and independence from any power cuts that might occur. They are also required if you own a property which is not attached to the grid in order that power produced during the day can be stored for use in the evening. Batteries add significant costs to a solar system so are normally only offered on specific request.
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How long will my PV System last for?
A well designed system will operate well in excess of the manufacturers 20 year warranty. The PV module with no moving parts has a lifetime expectancy of at least 40 years.
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Why should I invest in a solar PV system now?
There are a number of compelling reasons to make this investment now:
- Reduce or eliminate your net electricity bill - combined with the feed in tariffs (FITs) from your electricity supplier, create very favorable financial incentives for installing a solar system NOW.
- Declare clean energy independence! By investing in a solar PV system you generate your own electricity from daylight, a clean, silent, renewable energy source with no emissions.
- Enjoy long-term, trouble-free performance - PV panels usually come with a 20+ year warranty and 40+ year life expectancy, so your system should last for years to come, sheltering you from ever rising electricity prices.
- Add value to any property - The value of your solar PV system is added to the appraised value of a property. It’s one of the few home improvements that can be justified in terms of return on invested pound.
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