Photovoltaic (PV) Systems

• A Photovoltaic (PV) System, also known as a solar power system is a renewable energy technology that converts sunlight into electricity.
• Solar panels capture sunlight and convert it into direct current (DC) electricity.
• The electricity can power homes, businesses, and entire communities.
• With solar panels, inverters, mounting structures, and a monitoring system PV systems are becoming increasingly popular as a clean and sustainable energy source.
• Solar panels capture sunlight and convert it into electricity, making them the most important component.
• Inverters convert DC electricity to AC electricity to power appliances.
• Mounting structures secure the solar panels in place.
• The monitoring system monitors the performance of the system and notifies the user of issues.

Types of Solar Power Systems

• Grid-Connected (On-Grid) Systems: These are connected to the public electricity grid. They offset electricity usage by feeding excess power back into the grid. These systems are the most common and do not require batteries.
• Off-Grid (Stand-Alone) Systems: These systems operate independently from the grid. They are often used in remote locations and require batteries to store energy when sunlight isn’t available.
• Hybrid Systems: These systems combine on-grid and off-grid components for greater flexibility and reliability. They can switch between grid power and battery storage as needed.

Components of PV Systems

• Photovoltaic (PV) modules are essential components consisting of interconnected solar cells that convert sunlight into electricity.
• A single solar cell generates direct current (DC) power, typically between 1 and 2 watts.
• Crystalline silicon solar cells, generally produce around 1.5 Wp. They have an open-circuit voltage (Voc) of approximately 0.6 V and a short-circuit current (Isc) of about 3.5 A.
• Multiple cells are interconnected in series and parallel configurations to form a PV module for increased voltage and current output.
• The amount of current generated by a PV module depends on the solar irradiance received, enhanced by parallel cell connections.
• Solar cell voltage remains relatively unaffected by irradiance and is primarily influenced by temperature variations.
• PV modules range from 5 W to 240 W, and multiple modules are interconnected to form a solar array for large-scale electricity generation.
• They convert the DC electricity generated by solar panels into alternating current (AC) for homes, businesses, and the grid.
• Beyond simple conversion, inverters ensure shaped output of AC waveform and standards.
• Inverters regulate the effective voltage of the AC output to maintain stability and efficiency in power delivery.

Types of Inverters

• String Inverters: Designed to handle panels wired together in a “string,” in series, converting DC electricity from the panels into AC electricity to power homes or businesses.
• Microinverters: Installed on each solar panel, and allow them to operate independently. DC electricity is immediately converted to AC electricity and sent directly to the home or business.
• Hybrid Inverters: Connect a solar system to a battery storage system. They manage power from both solar panels, batteries, and even power from the grid when needed.
• Essential for securely installing panels on rooftops, building facades, and ground-based structures.
• Mounting systems, typically made from aluminum or stainless steel, for stability and sunlight.
• Proper mounting protects panels from environmental factors and follow the sun's movement throughout the day to increase energy yield.
• They prevent battery overcharging or excessive discharge by managing the flow of electricity.
• Charge controllers regulate the input and output currents, for safe and efficient battery operation.
• Pulse Width Modulation (PWM) controllers are cost-effective and suitable for smaller systems.
• Maximum Power Point Tracking (MPPT) controllers optimize energy conversion efficiency and are ideal for larger and more advanced PV systems.

Cables

• Cables enable the transmission of electricity between system elements and necessary for energy transfer.
• Cable selection factors: current-carrying capacity, voltage rating, insulation type, and resistance to environmental conditions.
• High-quality cables ensure minimal energy loss and long-term reliability.

Energy Storage

• Primarily in the form of batteries to supply power during periods of low solar generation.
• Battery capacity is measured in ampere-hours (Ah) represents the amount of charge it can store.
• Lead-acid batteries are the most commonly used in PV systems due to their affordability and reliability.
• Lithium-ion batteries have gained popularity in solar energy storage because of their higher efficiency, longer lifespan, and faster charging capabilities.

Electrical Meters

• Photovoltaic (PV) meters specifically measure the electricity generated by a solar power system.
• These meters are one-directional, recording only the electricity produced by the solar system.
• Monitoring energy production helps users assess system performance, detect issues, and optimise energy usage.
• Grounding is safety feature in PV systems, providing a reference point for electrical circuits and a common return path for electric currents.
• It protects the system from electrical faults, reducing the risk of electric shocks, fire hazards, and equipment damage.
• With Grounding excess electrical charges safely dissipate into the earth, safeguarding the PV system components.

How Photovoltaic Cells Convert Sunlight into Electricity

• PV cells convert sunlight directly into electricity and can convert artificial light into electricity.
• Sunlight is composed of photons that contain varying amounts of energy.
• A PV cell is made of semiconductor material.
• Only photons absorbed provide energy to generate electricity when striking the PV cell.
• When semiconductor material absorbs enough sunlight, electrons are dislodged from the material's atoms.
• PV cells, panels, and arrays description:
• The movement of electrons creates an imbalance of electrical charge between the cell's front and back surfaces.
• Electrical conductors on the PV cell absorb the electrons generating electricity.
• The PV cell is the basic building block of a PV system. An individual PV cell produce 1 or 2 Watts.
• PV panels vary in size and electricity generating capacity.
• PV panels are connected in groups to form a PV array.
• An array can be composed of as little as two and up to hundreds of PV panels to generate electricity.
• PV cells generate DC electricity.
• Inverters used on PV panels or in PV arrays convert the DC electricity to AC electricity.
• A fixed position towards the equator optimise angle physical and economic performance.

Solar PV Power Projects In The Philippines

• Raslag Solar PV Park: Located in Pampanga, Philippines that Produces 53 gigawatt hours of electricity
• Cadiz Solar PV Park: Located in Cadiz, Negros Occidental, Philippines with a capacity of 132.5 MW with large area.
• Alaminos Solar PV Park: Located in Laguna, Philippines with a capacity of 120 MW that avoids approximately 111,034.37 metric tons of CO2 emissions annually.
• Subic Bay Solar PV Park: Located in Central Luzon, Philippines with a capacity of 100 MW, offsetting approximately 44,300 tons of CO2 emissions annually.

Advantages of Solar Energy

• Solar power can be used again and again without harming the surrounding environment.
• Solar power does not require much maintenance.
• Solar power saves money as the resources needed for maintenance are all solar.
• Solar power helps the environment and prevents pollution.

Disadvantages of Solar Energy

• Solar power can involve higher upfront costs.
• The energy is intermittent as as the weather can be unpredictable.
• Geographical limitations prevent all places from benefitting.
• Supply chain constraints add a long process in which we need approval on a lot of matters just to build the project in order to have renewable energy.