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Photovoltaic solar systems
Updated: 09-Jul-2009
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Colin Reid is the technical director at the Enova Group and is a chartered engineer specialising in renewable and sustainable energy systems. He has over 20 years experience in the industry and lives with his wife and three children near Almancil.
Photovoltaic (PV) Solar Systems are those which use the sun’s power to generate electricity as opposed to thermal solar systems which generate hot water.
Until recently it has not been financially viable to install PV systems as the equipment is very expensive. It has only been fitted in locations where mains power is not available. However, recent legislation in Portugal now provides incentives for PV systems which now makes the technology much more viable for the domestic market.
The incentive comes from the price which EDP is obliged to pay you for generating electricity with a PV system. The current price which EDP pays is approximately 62 cents per KW hour in comparison to the 12 cents per KW hour paid for electricity consumed at home. With this incentive, it is possible to pay back the initial investment for the equipment within a period of approximately six years.
The largest Grid connected system, as it is known (i.e. a solar system that connects to the Grid and sells electricity back to EDP) is 3.68 KW. This comprises approximately 20 solar panels, each 1.6 metres high by 0.8 metres wide. This will occupy an area of approximately 30-40 square metres. The panels can be located either on a large south facing roof or a plot of south facing land. The panels should be inclined towards the south and should not be shaded at any time. The connection to the Grid is very straightforward: a cable connects the solar panels to an inverter which converts the low voltage DC (Direct Current) to 230v AC (Alternating Current). The AC supply is then connected to an outgoing meter and in turn, this meter connects to the National Grid. With this meter it is therefore possible to read the electricity generated. The existing meter for the house remains unchanged and continues to read the electricity consumed in the normal way.
In order to qualify for the Grid connected system at the special rate, one only needs to have a standard EDP electricity supply (normally minimum about 8KVA). The other important criterion is that one must have a thermal solar system fitted for sanitary hot water. This can comprise either a Thermosiphon System (panels combined with a hot water tank) or a Pumped Forced Circulation System (one where the tank is located inside, the panels outside and a pumped circulating system in between). A thermal solar system is recommended anyway as it allows the generation of sanitary hot water with solar energy for the majority of the year. These systems are normally backed up either by an electric immersion heater or a conventional boiler.
The application process should be carried out using a certified PV installer such as The Enovagroup. The certified company will firstly register you on the Government website. They will then make the application on your behalf when the appropriate date arrives (there are normally application days once every one to two months). If the application is successful, a registration tax of 250 euros + IVA is then paid and the system must then be installed within 120 days.
A legally binding contract is then signed with EDP which obliges them to purchase electricity from you for 15 years. The rate of 62c per KW hour is guaranteed for the first five years and then starts to tail off until it eventually equals the rate paid for electricity consumed. The solar panels themselves are guaranteed for 20 years and the system is expected to last about 25 years. As the return on the investment is made within approximately six years, there is a guaranteed net income therefore for the next nine years (equating to the 15 year contract with EDP).
The majority of the banks in Portugal provide up to 100 per cent finance for Grid connected PV systems. This particular option is most interesting as it means that the equipment can be completely financed by the bank but still allowing a monthly income which should more than cover the monthly payments of the finance.
Once again, it is vital to use a certified company such as The Enovagroup which can carry out all the registration and licensing, as well as the installation, commissioning and final connection to the Grid.
For more information, please call 282 960 969 or email colin@enova-group.com
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