Frequently Asked Questions sul mondo del fotovoltaico.
A photovoltaic system directly transforms solar energy into electric energy. It’s basically composed of;
- photovoltaic modules or panels;
- inverters, transforming the direct current produced by modules into alternating current;
- power panels and cables.
Modules are constitued by a semiconductor material, the most used one is crystalline silicon. They represent the active part of the system because they convert solar radiation into electric energy. Photovoltaic systems can be connected to the electricity network (grid-connected) or directly to isolated users ( stand-alone), usually to provide isolated areas with electricity.
To sum up, the advantages are;
- Absence of any kind of polluting emissions;
- Fossil fuels conservation;
- Reliability of the systems because there are no moving parts;
- Minimized operating and maintenance costs;
- Possibility to modulate the systems (it’s possible to increase the system power by increasing the number of modules).
Photovoltaic modules can be installed on any surface of a building ( roof, front, terrace, etc), otherwise on the ground. The decision must be taken on the basis of the existance of the following requirements on the installation site.
- Availability of the necessary space to install the modules;
- Proper exposure and inclination of the modules surface.
The best conditions in Italy are:
- Southerly exposure ( South-East and South-West can also be accepted, provided the loss of production is low);
- Modules inclination between 25° (southern latitudes) and 35° (northern latitudes);
- Absence of obstacles blocking light.
In regards to the systems size the first important issue to consider is the possible increase or decrease in uses. For example, if electricity is free, why not to think about substituting the heating system ( gas or diesel) with electric devices? If the consumer chooses a photovoltaic system which is oversized if compared to his real energy needs, he can take advantage of the ARG/ELT 186/09 resolution allowing him to have a yearly balance adjustment considering all the redundant energy fed back into the grid.
However, it is to be understood that the best size of a system is the one allowing an energy pruduction which matches the present and future needs of the consumer.
The approximate cost for a system is usually between 2.000,00/2.200,00 euros/KWp including VAT for the small systems and less than 1.600,00-2.000,00 euros /kWp for big systems. The yearly maintenance cost is rather modest; it’s usually valued at about 1% of the system cost.
The overall useful life of a system is generally assessed at 20-25 years by technical and economical analysis. In particular the modules, which are the most expensive component parts, have a general guaranteed ( by producers) life over 20 years.
The maintenance of a photovoltaic system represents a very small expense and bother for the responsible party. Since it hasn’t got any mobile parts ( besides those systems using solar trackers), what is recommended is just a periodic cleaning of the panels surfaces (especially after sand containing rains) and a yearly control of the electric parts, both with a visual inspection and a check. It’s advisable to equip oneself with a device able to keep the system energy production constanly under control, in order to detect immediately possible anomalies which could cause heavy economic conseguences.
While the “incentives in capital account” provide for a grant aimed at the necessery investment to realize a system, the “feed-in tariff” is a incentive device remunerating the energy produced by a system along a period of some years.
GSE has the role of checking the systems, also working in collaboration with qualified third parties, to verify the conformity of the works with the projects and the truthfulness of the data communicated by the responsible party.
It’s possibile and particularly useful for those photovoltaic systems not connected to the grid (mountain huts, etc.) whose production, it is to be remembered, hasn’t been incentivized yet.
On the contrary, for the incentivized systems connected to the grid, the redundant energy can:
- be fed into the grid and taken afterwards when the production is lower than the needs require (for up to 200kW systems choosing the net metering service);
- be sold to the grid administrator ( for systems choosing the sale to the grid).
It’s possibile, but it’s important to distinguish two cases:
- For systems whose power is no more than 200Kw and that exploit the net metering, the electric energy fed into the grid and not used in the year of reference constitutes a credit, in terms of energy, than can be either used during the three following years or adjusted once a year;
- For systems whose power is more than 200Kw, and for those up to 200Kw not exploiting the net metering, it’s possible to feed back and sell the extra energy to the grid.
Yes it is, provided the joint owners meeting gives its approval.
Incentives are provided after the agreement stipulation and are calculated from the very moment the system becomes operational.
As underlined in the agreement, payments are made considering as value date the last working day of the month following the date the responsible party or the grid administrator sends the measures.
The 6/08/2010 decree defines as ‘responsible parties’ those who have the right to request and obtain the incentive rates, respecting the Decree requirements.
Those who can exploit the incentive are:
- corporate bodies;
- public subjects;
- apartment buildings.
The 07/05/2012 decree has provided for the ‘5th Feed-in tariff’. Further information can be found at ‘The Photovoltaic’ section
For all the activities connected to the GSE granting of the rate, the responsible party must register into the the provided GSE portal.
The 06/08/2010 decree provides for higher incentive rates for systems realized on coverings rather than on ground.