Photovoltaic plants

Fully integrated panel

Fully integrated photovoltaic systems consist of modules set that seamlessly integrate with the architectural structure. It's obvious that is easier to make this kind of system when you are still in the design phase of the building because we can better assess the type of impact and the best solutions.
Photovoltaic systems are fully integrated when: -modules are the materials of roofing, building facades and buildings, thus having the same inclination and architectural features;
- modules and their support system form the roof structure of canopies and pergolas
- modules replace the transparent or semi-transparent facades or skylights providing natural lighting facilities inside the building;
- modules substitute part of the acoustic insulation panels of the acustic barriers;
- the modules and their supporting systems act as sun shield;
- the modules replace or integrate the windows' glass;
- the modules form the structural elements of the shutters.

Partially integrated panel

Partially integrated photovoltaic system occur when the modules don't replace the materials forming the support surface and they are installed on flat roofs and terraces in coplanar way, such as on the roof covering.
Can be considered integrated as partially integrated even those panels installed for example on the terrace which is surrounded by a balustrade wich partially hides the photovoltaic panels. Generally the partially integrated photovoltaic systems are used on buildings or parts of these wich are already existing.

Not integrated panel

PV System not integrated are so called because they just not integrated harmoniously with the structures or surface where they are. They are implants generally made on the ground or on structural component of buildings such as terraces, strata, shelters and/or urban and pathways elements.
The panels are installed in a non-coplanar way respect the surface on which they are fixed. Generally, from the aesthetic point of view, they have a greater impact. For this kind of system the prices are lower than the integrated and partially integrated one.

Inverter

To make compatible the energy generated by the photovoltaic modules with equipments for domestic and industrial use, you must convert the current from DC to AC frequency and operating voltage of the utility grid. This is possible interposing an inverter between the modules and the network.

Amorphous panels

- made with silicon not in crystalline form
- module efficiency: 6 – 8 %
- FV surface needed for 1 kWp:16 – 20 mq
- can be integrated in buildings
- in situations of low isolation, the amorphous silicon moduls have a higher yield, because they are also able to use the component of the light spectrum between 400 and 500 ne. Situation of low insolation there are in cloudy sky, when the light captured is mainly diffused light and therefore more saturated of blue spectrum
- medium sizes: to 30 from 40 cm of width per lengths until to 6m for strips of 136 Wp.

Monocrystalline panels

- derived from the fusion of pure silicon
- module efficiency: 13 – 17 %
- FV surface needed for 1 kWp: 7 – 9 mq
- dimensions: 1600 x 800 x 50 for 170 Wp

The peak power of a photovoltaic system is expressed in kWp (kilowatt peak) which is the maximum theoretical power that it can produce in standard conditions of insolation and temperature modules (1000 W / m³ and 25 °C), The following map shows, for the Italy, the annual manufacturability electricity of a PV System of 1 KW, well oriented and tilted, installed on a fixed structure.

The photovoltaic module is a set of silicon cells connected in series to form a string. If there are several strings, they are connected in parallel to form the module

The correct exposure to solar radiation of photovoltaic modules is a key factor to the performance of the system. The
decision about the technical feasibility is the existence in the installation site of the following requirements, which must be verified by the designer / installer when there is an inspection:

- availability of space required to install modules (must clear a space of about 8 to 10 m³ per kW of power) if a modules are installed in a coplanar surface of appliances of buildings; need more space if the system is installed in more successive rows of inclined structures placed on a flat surface);

system is installed in more successive rows of inclined structures placed on a flat surface);

a. exposure SOUTH (also accepted SOUTH – EAST, SOUTH – WEST, with limited loss of production);
b. tilt 30 to 35 degrees;

- there are not obstacles that create shade.

The average annual electrical manufacturability of a PV System can be assessed by a calculation that considers:

- della radiazione solare annuale del sito (determinabile ricorrendo a banche dati: UNI 10349, Atlante Solare Europeo, ENEA);

- the annual solar radiation of the site (determined using databases: UNI 10349, The European Solar Atlas);

- a correction factor calculated on the basis of orientation, angle tilt of PV modules and any temporary shadows;

- technical performance of solar modules, of inverter and other components;

- the reference environmental conditions of the site in wich the photovoltaic module operate (for example with the
increase of the operating temperature decreases the energy produced by the implant).

photovoltaic effect. This phenomenon occurs in materials called 'semiconductors' also used in production of electronic components, the best know of which is silicon. The positive aspects of photovoltaic technology can be summarized as:
- There is not any polluting emissions during the implant work;
- saving of fossil fuels;
- extreme reliability because, in most cases, there are not moving parts (useful life, normally, greater than 20 years);
- low operating and maintenance costs;
- system modularity (to increase the size you must increase the modules number).

According to these advantages, we must consider other aspects represented by:
- variability and uncertainly of sources energy (solar radiation);
- high cost of implants.

The main applications of photovoltaic systems are:
1. Systems (with tank) for isolated users from the network;
2. Systems for consumers connected to the low voltage network;
3. central production of electrical energy, usually linked to a medium voltage network.

The incentives in the Energy Bill is granted only for the types of applications 2 and 3, in particular for systems with
nominal power not exceeding 1 kW, connected to electrical network by placing the energy produced.
To make compatible the energy generated by the photovoltaic modules with equipment for domestic and industrial use, it is necessary to transform the direct current to alternating current frequency to the operating voltage of the utility grid. This is achieved by inserting an inverter between the modules and the network.
The panels are secured with efficiency of '80% to 20 th year and the inverter is expected to scheduled maintenance for
10 years.

Finally, a photovoltaic system consists of:
- Photovoltaic modules or panels;
- Support structure to install the modules on the ground, on a building or on any building structure;
- Inverter;
- Switchboards, cables and equipment rooms to store the equipment.

 

PLANT INSTALLATION

Potenza di nominale di un impianto fotovoltaico:
The photovoltaic plant must be realized according to the technical norms included in the attachment to the DM 19/02/07.
In particular it is necessary to certificate the conformity of the modules to the following norms, concerning the specific
technology used (crystalline silicium or thin foil).

The main stages for the realization of a photovoltaic plant are usually the following:

1. Those who want to realize a plant must address to a designer or to a specialized installation company for the study of a preparatory project and an economical quotation of the plant. This stage should include a careful survey of the
installation site made by the project designer or by the installation company. The production of energy from a
photovoltaic plant, in fact, is strongly influenced by its correct installation, that is by the ideal expositions to sun rays;

2. The responsible party has to take informations at the council office about the authorization procedure to follow and
has to demand the required authorizations and the building permission for the plant (see directions reported in the next paragraph 4);

3.the responsible party must pass the preparatory project of the plant to the operator of the local energy network (Enel,
A2A, Hera, etc.) and demand also the connection to the network, specifying if he wants to use the service of exchange
on place of the energy generated;

4. the operator of the local energy network informs the responsible party about the point of connection to the network,
together with the economic quotation and the times necessary for the realisation;

5. the responsible party ha sto accept the quotation and seal the contract with the operator of the local network;

6. after the realization of the plant, the responsible party send to the operator the communication of end of works;

7. per gli impianti maggiori di 20 kW il soggetto responsabile deve presentare all’Ufficio

Tecnico di Finanza (UTF) competente la denuncia dell’apertura dell’officina elettrica; non risulta invece necessario presentare all’UTF la denuncia dell’apertura dell’officina elettrica se l’impianto immette tutta l’energia prodotta nella rete (circolare 17/d del 28 maggio 2007 dell’Agenzia delle Dogane: disposizioni applicative del Dlgs 2 febbraio 2007, n. 26);

8. the operator of the local network provide the connection to the electrical energy.
When the plant is made and running, the risk to have no acknowledgement of the incentives depends only on the possibility that the plant is not in compliance with the requisites observed by the GSE during the evaluation stage. The main technical or procedural causes that can lead to the exclusion from the incentives after the start of the plant are:
- false declarations concerning the dispositions of DM 19/02/07;
- use of not-certificated photovoltaic modules;
- fail to observe the termo f 60 days from the date of the start of the plant, to submit GSE the demand of concession of the incentive tarif (except the opportunity to request the incentive from the beginning, according to DM 02/03/09);
- fail to observe the term of 90 days from the date of reception of the further request of integration from GSE, term necessary to submit further documents for evaluation's purposes;
- start of the plant after 14 months (24 months for the public subjects) from the date of the achievement of the limit of 1200 MW of installed photovoltaic plants.

Demand of incentive and of premium to GSE
The responsible party, within 60 days from the date of star of the photovoltaic plant, must present to GSE the demand of the incentive, including all the documents due according to the Resolution AEEG 90/07.
The day of start is the first usable date starting from which all the following conditions were operating:

- the plant is connected to the electrical network;
- all the meters necessary for the record of the energy produced are installed ;
- the contract for the exchange or the sale of the electric energy are operating;
- all the duties concerning the rules for the access to the nets are fulfilled.

CONNECTION TO THE NETWORK

Nominal power of a photovoltaic plant:
When the demand for the connection is submitted, the party has to pay an amount for the quotation. This amount is
defined in sections according to the power, as follows:
The connection service is distributed in low tension for required immission powers up to 100 kW, while it is supplied in medium tension for required immission powers up to 6.000 kW.
The tension level of the supply service does not state necessarily the value of the tension of the plant for the connection.
This means that, for instance, for the supply of the service in low tension the plant in net can be realized in medium
tension, but with the obligation to realize, by the distributing company, a medium/low tension transformation cab, so to
connect the user in low tension.

Amount
Value of the requested immission power
100 euro
Up to 50 kW
200 euro
Higher than 50 kW e fino a 100 kW
500 euro
Higher than 100 kW e fino a 500 kW
1.500 euro
Higher than 500 kW e fino a 1.000 kW
2.500 euro
Higher than 1.000 kW

 

it en ru ro