Solar Parks

Basic information on the technology

Photovoltaic electricity is based on the photoelectric phenomenon and it is produced via transformation of solar light, without intermediary thermal processes. The photovoltaic systems were discovered in 1839 and were broadly used for the first time in the middle of the '50s for space applications (satellites). Initially their output, that is to say the percentage of solar energy that they convert in electric energy, was very small, roughly 1%. However, with the passage of years and extensive research, the output of photovoltaic systems ranges between 13% and 16% today, a value that is considerably higher than the past, but still remains low in comparison to the corresponding values of other renewable energy sources.

A complete photovoltaic system includes one or more photovoltaic elements electrically connected to each other and, consequently, a photovoltaic array is formed by many photovoltaic systems. These systems produce direct current (DC) that is suitable for small requirement applications (e.g.- lighthouses, lanterns etc) and, for that reason, a specific system of inverters is essential for its transformation into alternating current (AC) and its use in compatible applications, such as residences, industries, systems of telecommunications (aerials etc).

Generally, the photovoltaic systems are separated into three big categories: a) low power photovoltaic (1mW- 100W) that are used in appliances such as the microcomputers parking meters or removed lamps of lighting, b) medium power photovoltaic (100W- 200kW) that are used for autonomous or isolated residences or electric installations or even interconnected installations, and c) high power photovoltaic (>200kW) that usually function as electric energy production stations on the local level and are connected to the network.

The world market

The market of photovoltaic (PV) in the world has seen a significant increase in the past few years, mainly because of the gradual reduction of the initially high cost, as well as the incentives that are offered at a national level in the various countries. Indicatively, in 1988, PVs of total power of 33 MWp were being installed and today the total installed power has reached roughly a power of 2900 MWp. This value has been achieved mainly due to the high growth of PV in three countries, Germany, Japan and USA, which corresponds to 89% of world production. Here it should be noted that none of these countries has better solar potential (solar energy per square meter) than Greece.

Provided that the cost of PVs continues to decrease and considering the environmental effects of conventional methods of production of electricity, the market of PVs is expected to be developed at the same or even faster rate in the future. This is also included in the policy of international institutions and organizations, with the resulting significant support, incentives and investments in this technology. The capability of PVs to be installed in a wide array of sites (roofs, blocks of flats, plots, etc.), without particular restrictions and without notable optical disturbance, creates a potentially inexhaustible margin of development of this technology.

The incentives that are offered by governments and are applied via legislation are similar to the ones of wind power. Specifically, they are divided, again, into Fixed Price systems and Fixed Quantity systems. The difference from wind power is that usually for the electricity that is produced from PVs, the prices of sale and subsidies are higher, mainly because the increased capital cost of investment.

Photovoltaic in Greece

Examining the Greek market and the growth of PVs, one can anticipate it to become the prevalent element of the sector of Renewable Energy Sources in Greece. In a few words, their growth was almost zero (2.2 MWp in 2003) at least up to 2006, when the PV installations were limited to those of PPC in the islands (Kythnos, [Antikythira] etc) and in installations for private individuals in remote residences. Such growth is obviously disappointing, given the exceptional solar potential of our country. The main reasons for this small growth are the usual bureaucratic problems, the marginal incentives which constituted disadvantages for investment in PV and the monopolistic character of the energy sector up to 2001.

In 2006, with law 3468/2006, the legislative framework concerning the RES and, consequently, the PV was clarified to a large extent. Simultaneously, with the favorable pricing regulations and subsidies for the interested investors of small to medium-sized scale, a program of Growth of Photovoltaic Stations (GPS) was enacted, aiming at the growth in the number of photovoltaic stations, clearly for the production of electric energy. According to this program, the awarding of production permissions of PV stations of a total force 590 MWp for connection to the national network, 200 MWp for the non-interconnected islands and 50 MWp for the self-producers were anticipated. The investments in this category would be enforced by national and EU resources under the arrangement of the National Strategic Framework of Reference ESPA. It is obvious that, under these conditions, the growth of PVs should have increased radically. However, those measures increased the interest of many small-scale investors with the result that the number of applications for permission for production of electric energy to exceed by far (2489 MWp) the objective of the GPS program. This fact led, as result, the Ministry of Growth to have suspended the licensing process since 2007. It is clear that, despite the favorable regulations of law 3468/2006 and GPS, the problem of the lengthy licensing procedure still remains, having as a result, in the end of 2007, 5 MWp of PV to have been installed and the permissions for production to have been given for only 10 MWp. The investors that are active in the sector of RES, and particularly in the PV sector, wait patiently for the decongestion of the permissions for production and measures from the state in the direction of simplifying the licensing process.

Energoni Energy Group has scheduled the installation of low power photovoltaic units in various sites in Bulgaria and Greece, aiming to reach an installed power of 200 MW by the end of 2011.