- What is a ON GRID Solar Orchard?

The on grid photovoltaic system is made up of two fundamental parts: one of a photovoltaic field in where the energy coming from the solar light takes shelter and transforms into electricity, and the other part of transformation of this electrical energy for its injection to the grid. The installation consists of a photovoltaic system that produces electrical energy in DC (CC) by means of interconnected photovoltaic modules, and that thanks to a ondulador system (Inverter) transforms the DC (CC) into alternating current (AC) with the frequency characteristics and intensity that the electrical company demands. In addition, it is necessary to consider the produced energy and the consumed energy being installed two independent accountants (or a bidirectional accountant) to be able to make the count of the Kwh. injected in the grid and the Kwh. consumed by the system. The installation is connected to the grid of the company of electrical distribution of the zone and the type of current that would be provided would be the same one that the company offers for the houses, that is to say, 220 V and 50 Hertz in alternating current. All the produced solar energy would be injected to the grid (not only one part or the excesses). The explanation is clear: RD 436/2004 establishes a premium (0.4404 € by Kwh injected to the network) very superior at the cost of the Kwh. conventional (0.0765 € + fixed Concepts, which would add about 0.10 € by consumed Kwh of the grid) so that the new electrical solar generator obtains an economic compensation in its initial investment. In case the solar generator electrical consums, would be losing the difference of price between the photovoltaic Kwh. and the conventional one, which would make the concept useless of economic aid that the RD tries to introduce. Therefore the solar generator never will be auto producer, simply is producing, whereas the effective premium established in levels superior to the cost of the conventional energy stays. The RD establishes that all the produced energy must be injected in the grid. The objective of this legislation is to obtain a selective power saving, taking advantage of the gratuitous and clean solar energy to the maximum, in damage of the conventional one, since the objective is to save energy and to increase our independence power and to fulfill the protocol of Kyoto. For the calculation of the premium, it is necessary to be sent to the new RD, RD 436/2004 establishes that a connected photovoltaic installation to grid of less than 100 KW of power in the investor, will receive a percentage of an electrical tariff average or of reference, defined in the articulate 2 of RD 1432/2002. For the year the 2006 value of this tariff of reference is 7.65 c€/KWh. Thus in the articulate 33,1 of RD 436/2004, settles down that the premium to receive by an installation FV of less than 100 KW is of:

- 575%, during the first 25 years --> 0.4404 €/KWh.

- 460% as of the 25 years --> 0.3523 €/KWh.

The necessary space for this type of installation varies according to the power, taking like reference that stops an installation of 1 KWp is necessary to install 8 - 9 m2 of photovoltaic modules that would be placed of the best possible way, causing that these were inclined in the angle that more yield gave the installation, that in the case of solar followers, would be always perpendicular to the incident solar radiation.

Next a comparative general study between fixes and trakers (one and two axis) installations.

Thanks to the monitorized control of the system, the operation will limit the pursuit of the production (which it will to this end have to be similar to the production estimation) that will be able to be visualized in display or existing accountant. The inverters of the installation allow the communication via RS-485 with any user through technology GSM or GPRS. Any incidence will be registered once go the data in the computer. (In case of the installation of the interface of capture of data). The control system so anticipates the connection to an external device (as one alarms) with warning in case of failure of the system or losses of energy. As minimum a pair of times to the year would have to inspect visual of the generating field and to make a cleaning if it is necessary. It is necessary to have present that the same inclination of the panels favors the auto cleaning.
The installation is guaranteed during 3 years, previous contract of annual preventive maintenance. The preventive maintenance of the installation will include at least one visit (annual for the case of installations smaller power of 5 kWp) in which will be made the following activities:

- Verification of the electrical protections.
- Verification of the state of the modules: verification of the situation original respect the proyect and verification to the state of the connections.
- Verification of the state of the investor: operation, signal lamps, alarms, etc.
- Verification of the mechanical cable state and terminals, transforming, ventilators/extractors, unions, cleaning.

General scheme of operation type:

One appears next, like reference, the power production of the installation and the income generated under the conditions of historical solar radiation pertaining to the province of La Coruna (North West-Spain).