The last decade has seen a general increase in the use of renewable energy sources, in particular solar energy. This increase may be due to foreseeable depletion of fossil energy resources and the environmental consequences of its exploitation. Since the start of the Sotavento Galicia Foundation, this project has been developed as a rigorous analysis of the different PV technologies in the market at the time of its implementation.
To do this, Sotavento has set up three equal photovoltaic power installations with identical components (panels and inverter) but with different solar tracking technologies. This technological diversity has allowed comparative studies to be made between the most common monitoring systems and fixed installation.
The main goal was to make a comparison of electricity generation from fixed and mobile photovoltaic systems, checking the impact of the solar tracker installation for photovoltaic panels in the geographical area where the Sotavento Wind Farm is located. The systems analyzed in this project were:
- Fixed installation
- Installation with a one-axis solar tracker using the astronomic calendar
- Installation with a two-axis solar tracker with solar prisms
Another objective was the distribution of the results in a simple and interactive way; for this, a computer application was created showing instantaneous and historical data of the three facilities: production, yields, CO2 emissions avoided, costs, etc.
The following photovoltaic systems have been used:
- Fixed installation without solar tracking, with a 35° above-ground south facing angle
- A one-axis tracker, with East-West orientation and permanent 35º above-ground inclination. Solar tracker with astronomical calendar. The orientation motor is powered by a battery that is charged with electricity generated by a solar panel on the installation
- A dual-axis tracker, with East-West and winter-summer orientations. Solar tracker with prisms that detect the position of the sun. The electricity that the orientation motor needs is supplied by the network
Each installation has 15 polycrystalline photovoltaic panels of 120 Wp. In total, the power capacity in each block of panels totals 1,800 Wp.
The measurement values of electric power, voltage, current, power generated, etc. were made by network analysers, stored in a database for investigation, and subsequently shown through an interactive program incorporating additional information for better distribution of the project.
Besides these facilities, and prior to this project, Sotavento has two installations of photovoltaic solar panels: monocrystalline and thin film technology (CIS).
The project was completed in 2008. Installations with solar tracker were withdrawn, keeping fixed installation.