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Renewable energy field. Photovoltaic panels

Photovoltaic system is an installation for the production of electricity by the direct transformation of the solar radiation, through the photovoltaic effect. The basic device in a photovoltaic panel is composed by some photovoltaic cells made of monocrystalline, polycrystalline or amorphous silicon.

Silicon, as secmiconductor material, attracts the sunlight (also called photon rays) and releases electricity.

A photovoltaic plant is mainly composed by a set of photovoltaic panels, one or more groups of conversion of direct current in alternating current, an apposite counter for the measurement of energy produced, and other components.

The energy produced by the photovoltaic plant depends on the solar radiation; the more you go towards the Equator, the more the implant produces and fortunately, Italy has a good position of solar radiation.

The average working life of a photovoltaic plant mainly depends on the quality of the modules, the strenght of the inverter and

the climate conditions of the area in which it is installed. Since the tenth year, it is good practice making extraordinary maintenance consisting in the eventual replacement of some electrical components deteriorated by the time or the string inverters.

In order to have an idea of the lifelong of a technological and good quality photovoltaic implant, you should know that in the United States of America plants with modules Sanyo have been realized, and they keep on produce electricity (even if it is decreasing), for 50 years.

It is necessary an insurance cover for all the owners of a photovoltaic plant against eventual damage of the components for unfavorable weather conditions.

Require a technical visit and a free quotation


Require a technical visit and a free quotation


The so called “net metering” is a service which allows to put in the web the electricity produced by a photovoltaic system (or supplied by renewable sources) but not immediately auto consumed and then use it in another moment in order to satisfy clients ‘consumption.

The net metering is the most convenient contractual arrangement of course for who auto consumes most of electricity produced in his own photovoltaic plant or by renewable source.

The net metering is considered much more valuable than the network disposal, that is to say the self-consumption of the energy produced is much more valuable than its sale. If the self-consumption is at 100%, it makes approximately the double. However, it can be more productive, it only depends on the current price you pay for electricity.  Probably, if you are still with Enel and the captive market, you will not pay more than 0,18-0,24 €/kWh (the price always includes fees, given by the costs in the bill divided by kWh consumption). If you have another provider, or to the same EnelSi on the free market, you will probably pay a lot. Generally, who is on the free market attracts its customers by making them the promise of a locked price for 1 or 2 years, and then it increases the price after this period of time, so customers are the only victims.

In this case there is an indirect profit. It is given by the saving from the bill, which generally goes from 0,20€/kWh upwards (you can calculate the saving/profit in your specific case just by dividing the total expenditure of the bills in one year by the number of the same period of time).

In addition to the incentive tariffs foreseen by the “Fourth Energy Bill”, electricity produced by normal power photovoltaic plants which does not exceed 200 kW, will benefit of the service “Net metering”, which can be applied after 20 years of duration of the incentive tariffs. In the net metering the energy put in the net -which serves as a huge accumulator- is counted and withdrawn when it is needed, and at the end of the years there is an adjustment balancing between the energy produced and the used one: in the case in which the first exceeds the second, it will be used afterwards. The electricity produced by photovoltaic plants which do not benefit of the net metering, if it is included in the power supply (by using the regime called “network disposal”, can be: (a)withdrawn with conditions and methods set by the Italian Electricity and Gas Authority – this option is called “Dedicated Withdrawn” – or (b) placed on the free market.

For people who present a little or null percentage of self-consumption, can use the service called “network disposal” (or “dedicated withdrawn”), i.e. the sale of electricity produced to the operator, which is about 0.1 €/kWh.

Net metering is also recommended to people who consumes electricity during the night, when their implant does not produce. Indeed, power supply is used as a battery of unlimited dimensions. When our implant has produced energy which has been not used, we put it in the net, and when the exceeding energy is useful because the consumption is greater, or during the night, we can take the energy in the net, despite the accumulation of an “energy credit” which can be used even after years. It should be noted that, since the 1st January 2009, you can enter into a net metering contract with the Electrical Services Manager (GSE). Previously, it was made with the local distributor (Enel, Acea, etc.). Therefore, actors involved in this process are three: the user, the GSE and the local distributor.


If you are private, apartment block and a non-commercial entity, which use the service of net metering solely for their own utilities and their plants do not exceed of 20 kW of power, the contribution of exchange is not subject to VAT, and it is not relevant for Irpef.

If the plant is greater than 20 kW, for this category, energy put is considered a disposal for a commercial activity (sale of energy) and the contribution for the exchange will be a relevant amount for the VAT and for direct taxation, and an invoice will be issued to the GSE.

For business activities which have implants of all sizes with net metering regime, the contribution for the exchange is a relevant amount both for the direct taxation and for the VAT, and the user will issue an invoice to the GSE.

For the purchase or the realization of the implant the subsidized VAT rate of 10% is applied. The cost of the implant is depreciable according to the ordinary proceeding depreciation of capital goods, with a coefficient of 9% per year. If the implant is solely used for their own utilities/activities (indirect self-consumption) in a “net metering” regime, the contribution of the exchange represents a relevant amount both for the VAT and for the direct taxation, and the user will issue the invoice to the GSE. If instead the energy is given to the net and it is partially or completely sold (to the GSE or the free market), it entirely contributes to the determination of the entrepreneurial income, as well as the incentive tariff of the Energy Bill. This is independent on the destination of the photovoltaic energy produced. Therefore, the energy which is sold is subject to VAT and determines the tax base according to IRAP and IRES. Revenues from energy sale are subject to withholding tax of 4% by the GSE. The Fourth Energy Bill includes several bonuses, which are not cumulative, for specific kinds and application of photovoltaic plants. By simply considering the new things than the previous Energy Bill, the new Bill foresees a fixed premium of 0,05 € per kWh of produced energy in case of photovoltaic plants on buildings (excluded the ones with innovative features) which replace the relative coverings in eternit or materials containing asbestos (art. 14, paragraph 1-c). Besides, a bonus of 10% has been introduced (art. 14, paragraph 1-d) on the incentives for installations which present an investment cost -excluded the part of the work-related for at least 60% to a production made in the European Union (EU). Since the 2013, the tariff to which the increase is applied, is equal to the merely incentive. Anyway, the bonus is recognised on the whole electricity produced by the photovoltaic plant, regardless its use.