Solar power generation: Photovoltaic system
Type of solution : Solar power generation
- Objectives: Conversion of sunlight into electrical and thermal energy.
- Description: Photovoltaic systems (PV) are composed of solar panels, which are devices designed to convert solar energy into electricity using photovoltaic cells. Unlike conventional methods of electricity generation that rely on electromagnetic induction to produce alternating current in the circuit, photovoltaic conversion occurs directly when sunlight interacts with the electrons and components of the plates, generating direct current.
In the case of a stand-alone (off-grid) PV system, such as the one used for agricultural irrigation, additional components are required, such as a charge controller, a battery or a battery pack, and a DC to AC inverter.
On the other hand, when connected to the grid (on-grid), a solar inverter is needed to transform the electrical energy generated by the solar panel from direct current (DC) to alternating current (AC). In addition, a bi-directional meter is incorporated which registers the electricity generated by the solar panel and allows surplus energy to be fed back into the grid.
The additional electricity fed into the grid is converted into “energy credits”, which can be used at times of low sunlight, such as at night or on cloudy days, or in the coming months. This results in reduced electricity costs, increased competitiveness of rural enterprises and strengthened income and sustainability of the projects.
Technological applications that make use of sunlight
- Aqualuz. Technology oriented to the treatment of cisterns, which only uses sunlight, without the need for chemical substances, sophisticated filters or interventions in the cistern. Its assembly only requires 10 minutes, with daily use for 20 years, and its maintenance only requires soap and water. The technology consists of a stainless steel box covered by glass and a simple pipe connected to the cistern.
- Solar distiller. This is a low-cost, easy-to-operate robotic prototype (DSR) with a solar tracking system, intended for residential, laboratory and industrial applications for water distillation. The equipment is composed of four fundamental parts: receiving trough; absorber tube; robotic antenna mobility system; and condenser cooling system.
- Solar Desalinator. This technology promotes solar distillation by completely removing all salts, heavy metals, bacteria and microbes present in the contaminated water, as well as various pesticides, due to the high temperatures and ultraviolet radiation. At the end of the process, a simple reconstitution of the salts is easily carried out for use as drinking water.
- Solar dryer: This consists of a part that simultaneously performs the function of collecting solar energy and serving as a drying chamber, where the solar radiation is directly incident on the product placed in the dryer. The air is heated and the circulation is by natural convection, resulting in a fast and low-cost drying process.
Cost and resources
- The cost of a residential solar PV system (including installation and materials) is approximately USD 3,600, considering the use of a 3.46 kWp generator installed in a residence with an average monthly consumption of 372.6 kWh.
- With an investment of about USD 35,000 in a solar PV system, it is possible to obtain a commercial system with an expected energy generation of 585,000 kWh per month. With a maintenance cost of USD 4,150 and depreciation of 1.5% in the first year and 0.7% of the acquisition cost in the remaining years (25 years lifetime).
Advantages
- Its main advantage is that it is a technology that harnesses the sun’s source, reducing CO2 emissions in food production and the home, particularly in places where the conventional electricity grid is unavailable.
- It significantly reduces energy costs over time. It even generates additional income for families by selling excess energy to the grid.
- They have a 25-year lifespan and require little maintenance. Generally, they only need cleaning and checking that they are working properly.
- Photovoltaic technology is continuously improving, making the technology increasingly efficient and affordable for rural households.
Complexity
- The adoption of PV panel technology is considered relatively affordable, due to its simplicity and environmental benefits. However, the initial investment in the purchase and installation of PV panels can be a barrier for most farmers with limited resources. Also, access to technical advice, availability of supplies needed for installation and maintenance, as well as the existence of supportive policies, represent a challenge for the adoption of this technology.
Sources:
- RENOVA-SEMIÁRIDO. Cartilla Energía Solar. https://renovasemiarido.insa.gov.br/