Stand-alone photovoltaic system: definition, operation and potential
In the mountains we see more and more often, in isolated mountain huts, check solar panels. PV systems are self-employed, similar to those used in mobile homes and boats. These solutions are more and more extended in the countries in the developing world, where the objective difficulties to connect to the national grid community located in inaccessible places are factors that are pushing the demand for stand-alone installations.
Such systems can be directed to power of individual residential units or structured for micro-grids: these are currently the most suitable answer from an economic point of view, social and technical needs of entire communities isolated "
But in countries such as Italy it is possible to create an independent system while having the ability to link up to the national grid?
System independent, viable, yes, but ...
"The technical feasibility is there and it is tested by time, but we must consider two problems, one of the other economic regulatory nature. In the first case it is possible to create a "island" in a context not connected to the national grid. " It must be said, however, that in Italy, as in many other countries of the European Community is not possible to fit a "dual" or autonomous, but with the ability to connect, and then to receive the supply of electricity from the national grid in the event of necessity.
That said, you need to specify what is meant by a stand-alone system: consists of a generation plant, one storage and one of transformation: the first generates precisely energy (eg solar panels), the second store (battery lead, similar to that of the car but definitely more powerful, or the option to request more and more lithium) and the third turns the current accumulated in the right voltage and frequency to those who use it (inverter).
Let's move on to the charges: "Compared to a photovoltaic system connected to the network, a stand alone has cost more as given by the system of accumulation: to give only a general idea, as are many variables in play, if the cost for a 'residential users is 2 € / Wp for one self you go about 5 euro. "
Other issues to consider, on a practical level, are represented by the fact that "the autonomous system has two limitations: one of power (a domestic standard is 3 kW) but also one of energy (kWh), which implies a limit on the period of time when you can use the 3 kW. This limit depends on how much energy is produced by solar panels, and then the area where the system is installed, and the ability to store energy of the batteries. "
So who decides to create an independent system must calibrate its energy according to the use he is to do, "for example, the user should know that the washing machine must activate preferably in a sunny day to charge batteries on average."
Rosy outlook thanks to the smart grid
If in Italy and, in general, in industrialized countries, is an independent system available today but still too expensive and inconvenient than the solution "solar networked" in developing countries has already established itself as an increasingly attractive, "there has been a steady increase of demands in these countries. Throughout the tropical and equatorial species with micronets. ».
Precisely the latter can become interesting even in contexts such as Europe, "in the future thanks to the smart grid could be envisaged energy contributions focused in small communities. Will have to change both the technology of distribution networks, still tied to optics are presented for single direction electricity, both the legislation - which in many countries is rigidly anchored to the logic of charging inadequate - and the mentality in projects we make, we make adequate training to end users. Changing habits of the users seem difficult, but more often than not occurs rapidly and with complete success. "
25/09/2012
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Translated via software
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Source:
Italian version of ReteArchitetti.it