Solar energy is one of the most widely available and sustainable sources of energy. If harnessed, it is ten times more energy than all energy sources combined. Solar energy can be collected and converted into electricity using a photovoltaic system. Photovoltaic systems convert solar energy directly into electricity by means of solar panels or photovoltaic panels. A single solar panel produces approximately 2 watts, but when this individual cell is connected to a solar panel and then to a solar array, the solar panel can provide a large amount of electricity.
How do photovoltaic systems work?
Solar radiation is converted directly into electricity by the solar panels (solar panels). Voltage is generated when light hits the junctions between metals and semiconductors in the solar panel, the most popular and abundant source of semiconductors being silicon. Blocks of crystalline silicon are cut into thin wafers to create solar cells. The wafer is processed to separate the electrical charge and form a diode on both sides. A diode is a device that allows current to flow in only one direction. It is placed between metal contacts so that the current flows easily out of the cell
What are the key considerations for setting up a PV solar farm?
Finding the right place to set up
A solar farm can be built anywhere, provided there is enough space for installation. However, in order to maximise the capacity of a solar farm, it is best to set it up in full sunlight and keep it out of the sun as much as possible. Another consideration is the availability of the grid in which the generated electricity can be connected.
Secure a power purchase agreement
Photovoltaic solar installations require a significant investment and the expected lifetime of a photovoltaic solar power panel system is approximately 25 years. Due to the high set-up costs, a power purchase agreement of at least 20 years is required to ensure that prices and demand fluctuate and that the purchaser guarantees the offtake price
Consider the legal framework
The legal framework is one of the key issues in setting up a solar farm. A thorough assessment of these legal frameworks is required in order to legally operate and establish a PV solar farm. Some of the points to consider are:
- The time frame for obtaining a licence.
- Concerns about the integration of solar PV into the existing grid.
- The political climate and position on renewable energy in the country where the farm is to be established.
- Local land use restrictions.
- Solar power policies and incentives.
- A clear roadmap covering the entire life cycle of the project – from pre-operation to end-of-life.
Deciding what solar panels to use and the structure
To complete a PV system, solar panels are installed, structures are mounted and inverters are used to generate electricity and convert direct current (DC) to alternating current (AC) for use in homes and businesses. Batteries are optional and are used for additional electricity storage and off-grid use.
The solar panels that are widely used today are monocrystalline silicon, polycrystalline silicon and thin film solar panels.
- Monocrystalline silicon consists of a crystalline structure that is more efficient as electrons move more freely to generate electricity. However, monocrystalline silicon is more expensive.
- Polycrystalline silicon wafers are made up of many different crystals. It is less efficient but cheaper compared to monocrystalline silicon wafers.
- Thin-film solar panels are made from amorphous silicon and other materials, including cadmium telluride (CdTe) and copper indium gallium selenide (CIGS).
b. Mounting structures.
The mounting structure is used to support the solar panel, which should be able to withstand outdoor conditions. A widely used method is rack mounting, as it is robust, versatile and easy to construct. Another method used is ground mounting, which has a tracking mechanism that automatically moves the panel with the movement of the sun. This mounting structure captures more solar energy, but requires higher investment and maintenance costs.
Inverters convert the direct current generated by the solar panels into alternating current, which most homes and businesses are built with. Inverters can be a single inverter for converting electricity from all solar panels, or micro-inverters connected to each panel. Recently developed inverters allow for two-way communication between the inverter and the electrical utility. These new inverters help to balance supply and demand, reduce costs, promote grid stability and limit power outages.
Batteries are optional technologies for storing excess electricity generated that can be used off-grid. As solar energy is an intermittent resource, using batteries as storage can help build electricity production, especially during peak seasons.