Solar Power Glossary
AC coupling: AC coupling (Alternating coupling) allows AC singles to pass through a connection. Commonly referred to as DC-blocking, this electronic engineering arrangement rejects any DC components within a signal, passing only the AC elements.
AC isolator: An Alternating Current isolator switch safely isolates a section of an electrical circuit from the power source when required.
Activated stand life: More commonly referred to as shell life also known as Activated shell life is the period of time that a charged battery within a specified temperature can be stored before its capacity falls to an unusable level.
Alternating current (AC): Alternating current is the one that is produced indirectly by solar panels with the aid of an inverter because, traditionally, solar panels produce DC energy, which is then converted into AC power by the inverter.
Alternative energy: It refers to energy sources other than fossil fuels or nuclear power. This includes all renewable sources such as Solar, Wind and Hydroelectricity, which do not deplete and can be replenished.
Ambient temperature: The term ambient means “relating to the immediate surroundings.” So, Ambient temperature simply means the temperature of the surroundings. Since solar panels love light but hate heat, this affects how well panels work.
Ampere (A): “Amp” for short, is the flow of constant electrical current moving from one point to the other. In solar panel systems, amp currents will flow from a panel connected to an electrical circuit.
Ampere-hour (A·h or A h or Ah): Also abbreviated as amp hour, it describes the battery capacity that allows one ampere of current to flow through the conductor for one hour.
Ancillary services: Are specialised services or tasks that help grid operators maintain a dependable and reliable operation of the electricity system.
Angle of incidence: In the Solar world, the angle of incidence is the angle formed between the line from the surface passing through the centre of the solar disc and the normal to the plane as compared to the sun’s rays.
Annual solar energy yield: From a solar panel system, it is the amount of kilowatt-hours that solar panels will generate over a 12-month period.
Anode: Is the negative terminal of the solar cell. It attracts the chemical energy, stores it and turns it into electricity.
Anthropogenic: Refers to environmental change caused or influenced by people but can be curtailed by renewables such as solar power.
Anti-islanding: Solar anti-sliding is a safety feature built into the grid-connected solar power systems that monitor the voltage and current flow. During a power outage, it will automatically disconnect the system from the grid.
Arc fault: An arc fault in a solar system occurs when a tiny electrical arc jumps across an air gap, creating a short but intense burst of heat and light, which can cause fire. This can happen if there is damage to the PV connector or electrical wiring.
Array: A solar array is a collection of multiple solar panels wired together into a circuit that generates electricity.
Array over-sizing: Sometimes called inverter oversizing is the concept of installing more solar panels with a higher capacity than the rated size of your inverter to harvest energy when production is outside sun hours.
Australian Energy Market Operator (AEMO): Is an establishment that manages the electricity and gas systems and markets across Australia, targeting 100% renewable generation in the Australian National Electricity Market (NEM) by 2025.
Avoided Cost: Also known as net metering, it is the marginal or incremental cost required to pay an independent power producer for an electric utility, electric energy, capacity, or both.
Azimuth angle: Is the horizontal angle solar panels face in relation to the equator as measured clockwise from north. At solar noon in the southern hemisphere, the sun is always directly north. The tilt or elevation angle is the vertical “up” angle the panels face towards the sky.
Battery Backup: A solar battery backup system allows you to use the solar energy you capture that keeps your appliances running even when the power grid is down.
Balance of System (BOS): Encompasses all components of photovoltaic systems required to operate and integrate into grid-tied or off-grid systems except the solar panels themselves.
Baseload: The lowest amount of electricity used by a grid or electrical system, generally over 24 hours to meet fundamental demands.
Battery: A solar battery is a device that stores potential chemical energy generated by solar panels.
Battery Bypass Switch: A physical switch that instantaneously returns your essential circuits back onto the grid if your battery is flat or misbehaving.
Battery Capacity: Total amount of electricity stored by the battery and is expressed in ampere-hours.
Battery Case: The durable safety case that protects the battery cell or cells from the inside.
Battery Cell: Is a single unit used to store electricity. A solar battery is generally composed of hundreds of battery cells linked together.
Battery Cycle Life: Is the number of charge and discharge cycles that a battery can undergo before losing performance using solar energy.
Battery Enclosure: Is a box designed to protect batteries from inevitable weather and battery troubles.
Battery Inverter: Is a device that helps convert produced energy from DC to AC power from a solar panel.
Battery Management System (BMS): Is an electronic control unit that monitors and manages all of the battery’s performance.
Bayonet Fitting: A light fitting is usual in many older buildings where a light bulb has to be pushed in against a spring and then slightly rotated to seat it in place.
Bifacial Solar Panels: Unlike regular panels, they can produce solar power from both their front and rear sides. That means that instead of valuable light going to waste, an additional gain of radiation on both sides is provided.
Black Start: In the context of solar batteries, it refers to the ability of the battery system to restart and power up after being completely drained.
Blocking Diode: Is a diode that is connected in series with a string of solar panels to block the flow of current from the battery to the solar panel thus preventing the battery from draining. It also protects the panel from overvoltage or overcurrent during surges in the system.
Break-even Point: The payback period is the amount of time it takes for you to recoup the cost from the initial investment. It is also the moment when savings from your solar system equal its cost which is typically 3-7 years, depending on your energy usage.
Brightness: The brightness of a light is how bright it appears to the human eye. The brightness of a solar light depends directly on the actual light-up power set by the controller. So, from the source, the brightness of solar lights depends on the system configuration.
Brownout: Is an intentional drop of power against the main supply level. During brownouts, the grid tie inverter shuts down automatically, and the system will not be able to perform unless you have a solar battery system with a backup circuit.
Btu (British Thermal Unit): Is a unit used to measure the heat content of fuels and energy sources. It is equal to 1055 joules. It is also defined as the quantity of heat required to raise the temperature of one pound of liquid water by 1° Fahrenheit (F).
Busbar: A solar busbar is a thin piece of aluminium or copper you see going down the squares or cells in the solar panel. Adding more busbars means more electrons are able to pass through; thus power and efficiency increase.
Building-integrated Photovoltaics (BIPV): Is a system consists of integrating photovoltaic systems into a building envelope such as the roof or the facade. It is dual-purpose, serving as an integral part of the building skin and generating electricity for on-site use or export to the grid.
By-pass Diode: Also known as free-wheeling diodes, are wired within the PV module and provide an alternate current to continue supplying power at a reduced voltage rather than no power at all. Bypass diodes also reduce the power loss and mismatch effects. Ideally, there would be one bypass diode for each solar cell, but it would be expensive.
Calendar Fade: Is the gradual performance deterioration that many battery types undergo even if not in use. Because of this phenomenon, even a slightly used home energy storage system is not immune as its guarantee expires. However, some battery types, like zinc-bromide batteries, don’t experience this problem.
Calendar Life: Is the period of time from the date of production during which the battery can be stored unused to the end of its life. Since heat leads to faster degradation, the duration depends on ambient temperature. It also includes other aspects such as shelving, aging, cycling and working condition simulation.
Capacity Factor: Is the measure of how much energy is generated over one year. Depending on the location, the capacity factor varies quite a bit for photovoltaic systems. In Australia, because of clouds and the earth’s rotation, a north-facing rooftop solar system in Hobart may have a capacity factor of 14%. In comparison, one in Darwin could have a capacity factor of 20%.
Carbon Dioxide (CO2): A greenhouse gas released from burning fossil fuels. Currently, 87% of human CO2 emissions result from burning fossil fuels, 9% from land use changes, and 4% from industrial processes such as cement making. Solar power reduces CO2 emissions. Solar power can help reduce CO2 emissions mainly by a clean and renewable energy source because it is not dependent on burning fossil fuels and other products.
Carbon Price: Is considered as the most economically efficient method of reducing carbon dioxide emissions to encourage polluters to reduce the amount of greenhouse gases they emit into the atmosphere. Carbon prices come in two types, carbon taxes and emission trading schemes.
Cathode: Is a positive electrode because it gains electrons rather than loses them in a reduction reaction. Essentially, a cathode is there to receive electrons from the anode. Simply put, this is how a battery produces electricity.
Central Inverter: Also called (string inverters) is a type of inverter used in solar modules to convert DC power from solar panels into AC power that can be fed into the electrical grid. Central inverter functioning is designed to operate at a fixed voltage and frequency.
Charge: This usually refers to putting energy into a battery. It can also refer to the basic electrical property of matter. Batteries can be charged using solar panels in two ways: through a direct connection or an indirect connection connected to the battery and charging device respectively.
Charge controller: As the name suggests, it is fundamentally a voltage or current controller to charge the battery and keep electric cells from overcharging. Solar charge controllers ensure the batteries are charged at the proper rate and to the proper level.
Charging: Putting energy into a battery. The solar panel converts sunlight into DC electricity to charge the battery. There are four solar charging stages, namely, bulk charging voltage, absorption charging, float charging and equalisation charging.
Circuit: A circuit is a closed loop that electrons can travel in. When a photon of sunlight strikes the cell, it knocks electrons loose from their atoms, then electrons are then able to flow between the conductors and through the circuit to generate electricity. A circuit can have one or many electrical components on it.
Conductance: An expression of the ease with which electric current flows through materials like metals and nonmetals. It is the reciprocal of resistance. It is measured in Siemens (S), the unit of electrical conductance in the International System of Units (SI).
Conductor: A conductor or electrical conductor is a substance or material carrying electric current. Conductors are not used in solar cells because solar cells or photovoltaic (PV) cells work on the principle of the photoelectric effect. Instead, Solar or photovoltaic cells are made of materials known as electricity semiconductors. The most common semiconductor used in photovoltaics is silicon.
Cost-effective: If something is worth your spending on it, it is cost-effective. Homeowners who install solar power systems can receive numerous benefits, including lower electric bills and eliminating them altogether. Your solar panels’ lifespan ranges between 25 and 30 years, and you will be able to power your home while saving big on your utility bills for its entire lifespan.
C-rate: Is a metric used to define the speed at which a battery is fully charged or discharged. In other words, it represents how quickly a battery can provide or absorb energy. The capacity of the battery is generally rated and labelled at
1C Rate (1C current), this means a fully charged battery with a capacity of 10Ah should be able to provide 10 Amps for one hour.
Cut off voltage: When the charge controller disconnects the load from the battery, and the voltage is activated. The manufacturer determines the battery’s cut-off voltage so that consumers can achieve the maximum capacity of their batteries. The cut-off voltage depends on the type of battery under use and differs from one battery to the other.
Current: The rate of flow of electric charge (i.e. the flow of electrons). There are two types. Although it may sound a bit technical, the difference between the two is fairly basic: Direct current (DC), where electricity flows through a conductor in one direction. And alternating current (AC) where electricity rapidly flows back and forth in a conductor.
DC Converter: A converter is a device that can convert direct current (DC) from one voltage level to another. In the context of solar panels, a DC-DC converter is used to convert the DC voltage generated by the solar panels to a different level that is more appropriate for the load or the battery storage system. A battery DC converter can allow batteries to be connected to a rooftop solar system.
DC Coupling: A system that connects directly to your Solar Panels before your generation meter. In a DC-coupled solar system, DC power from the solar panels can be used to directly charge any solar batteries, with no intermediary conversion to AC. This means that any electricity generated by your solar panels will be only inverted once from DC to AC. Any electricity needed to power appliances or feed the grid is converted to AC by an inverter, as is any electricity discharged from the battery.
DC optimiser: A device used in photovoltaic (solar power) systems to enhance solar panels’ efficiency and overall performance. It uses maximum power point tracking to improve the output of each solar panel in a PV array. DC optimisers can also enhance the safety of solar power systems. They can automatically shut down the power output from a panel if a fault is detected, reducing the risk of electrical hazards.
Deep cycle battery: A deep cycle battery is a lead-acid battery designed to be repeatedly discharged and recharged. Unlike regular batteries used in cars which produce a shorter burst of electricity, deep cycle batteries can produce ongoing, lower yet consistent, levels of power. Deep cycle batteries are used in solar power systems because they can be completely discharged without being damaged as quickly as normal batteries.
Depth of discharge (DoD): The term ‘depth of discharge’ is fairly self-explanatory – is the percentage of the battery that has been discharged relative to the total battery capacity. If you have a battery bank with a nominal capacity of 10 kilowatt-hours (kWh), at 70% DoD, for example, that battery bank has 3kWh of charge remaining. DoD has a connection to the cycle life of batteries.
Dielectric: A material that is essentially an insulator, which means that no current will flow through the material when a voltage is applied. Though dielectric material is a poor conductor of electricity, it is an efficient supporter of electrostatic fields. Currently, the most favoured dielectric material in Si solar cell production is SiN:H, deposited by the plasma-enhanced chemical vapour deposition (PECVD) process.
Diode: A diode is a semiconductor device with two terminals that only allow current to flow in one direction. Diodes are essential for solar power systems because they prevent what’s called “reverse bias.” Reverse bias is when the voltage of the solar panel is higher than the voltage of the battery.
Direct current (DC): Direct current (DC) electricity is what solar panels produce and what batteries hold in storage. As the panels absorb the sunlight, the current of electricity flows to an inverter to be switched from DC energy to usable AC energy. The inverters can convert DC energy into AC energy so that it can be used in your home to run appliances. This means if you choose DC solar panels, you will need to make an additional investment in inverters so that it is compatible for your home appliances.
Discharge: Specifically, battery discharge happens when a battery outputs electrical energy it discharges and the energy stored inside decreases. Whenever a load is connected to the battery, it draws current from the battery, resulting in battery discharge. The greater the current drawn by the load, the faster the battery discharges.
Discharge rate: The rate usually expressed in amperes or time, at which current is taken from the battery. In other words, This is a measure of how quickly a battery is discharged, measured by a C rating.
Distributed solar: It actually means distributed generation of solar power. Solar electricity produced by households using rooftop systems is referred to as ‘distributed solar’. It is extremely cost-effective in Australia. The opposite of distributed solar is utility-scale solar which consists of large solar farms where the electricity generated is sent directly into the grid.
DNSP: Stands for Distributed Network Service Provider. DNSPs are sometimes called supply authorities, electricity distributors, energy networks, or utilities. DNSPs are responsible for ensuring that customers in their distribution region have reliable and safe access to the interconnected grid. In addition, the revenue of DNSPs is regulated, so the DNSPs need to ensure that electricity supply is planned in a cost-effective fashion.
Dopant: A chemical element (impurity) added in small amounts to an otherwise pure semiconductor material to modify the electrical properties of the material. Boron and phosphorus are the two dopants normally added to silicon solar cells.
Dry cell: A cell (battery) with a captive electrolyte. A primary battery that cannot be recharged. A dry cell is a type of battery that is commonly used in solar panel installations. Unlike a wet cell battery, which contains a liquid electrolyte, a dry cell has a paste-like electrolyte that is immobilised.
Duty cycle: The ratio of active time to total time that is used to describe the operating regime of appliances or loads in photovoltaic systems. If a backup generator is used for 48 hours a year its duty cycle is 0.55%.
Efficiency: Solar panel efficiency is a measurement of how much of the sun’s energy a certain panel can convert into usable electricity. For solar panels, the higher its efficiency, the more sunlight energy will be converted into electrical energy. High-efficiency panels are more expensive but take up less space, and so can be useful for people with limited room on their roofs.
Electrolyte: The electrolyte is a nonmetallic (liquid or solid) conductor that carries current by the movement of ions (instead of electrons). It allows for the charge to flow between the cathode and anode. And this external flow of electricity can be used to do something useful, such as power a flashlight or a home.
Electromagnetic radiation: Electromagnetic radiation, also known as radiant energy (or radiation), is spread in the form of electromagnetic waves. It is a type of energy produced by electric and magnetic fields, taking a variety of names depending on the wavelength. Electromagnetic solar radiation is a phenomenon by which energy escapes from the Sun at the speed of light in the form of a wave.
Electron: A tiny negatively charged particle that hangs around atoms. Electrons in solar panels move as a result of the photovoltaic effect. When sunlight hits the solar panel’s photovoltaic cells, it excites electrons in the material, causing them to become “free” and able to move. These excited electrons then move through the material in response to an electric field, creating a current flow. This flow of electrons is what generates the electricity in a solar panel.
Electricity: Energy resulting from the flow of charged particles, such as electrons or ions. Solar radiation may be converted directly into electricity by solar cells (photovoltaic cells). In such cells, a small electric voltage is generated when light strikes the junction between a metal and a semiconductor (such as silicon) or the junction between two different semiconductors.
Embodied energy: Is the sum of all energy consumed in the production of goods and services. Embodied energy is used for most energy sources, even renewables. For example, wind turbines and solar panels must be manufactured, their components mined or otherwise processed, then they must be installed using energy, etc. In Australia, the energy payback time for a solar panel can be much less than one year, and the period for a complete rooftop solar system can be under two years.
Emissions: This often refers to greenhouse gas emissions from burning fossil fuels, but can also refer to other pollutants. Solar power facilities reduce the environmental impacts of combustion used in fossil fuel power generation. Unlike fossil fuel power generating facilities, solar facilities have very low air emissions of air pollutants such as sulphur dioxide, nitrogen oxides, carbon monoxide, volatile organic compounds, and greenhouse gas carbon dioxide during operations.
Energy audit: An energy audit is a comprehensive analysis of your home’s energy consumption and identifies measures you can take to reduce the amount of energy your home consumes.
Energy density: Is the amount of energy that can be stored in a given system, substance, or region of space.In the context of a solar panel system, it indicates the amount of energy that a PV system per unit area can generate in a year. A more efficient solar panel or more panels squeezed into the same area will produce more kilowatt hours per square foot. It is typically presented in Watt-hours per kilogram (Wh/kg).
Energy efficient: The more energy efficient something is, the less energy is required to produce one unit of output. Solar technology has made leaps and bounds toward higher solar cell efficiency, power output, and quality. Today, most top solar panels have conversion efficiencies above 20%, compared to their previous average of less than 15%.
Energy management relays: Are witches that allow loads to be turned on when there is excess solar power and turned off when there isn’t.If the Energy Management Relay on the inverter is deactivated, the solar power generated is fed into the public grid. If the inverter produces more than the set power, the relay switches and the generated power is supplied to the specified electrical consumers.
Energy storage: A device that reserves energy for use when demand exceeds the supply from your solar system. The stored electricity is consumed after sundown, during energy demand peaks, or during a power outage. Most common on residential or commercial buildings.
Escutcheon: In the realm of Aussie switchboards, it is a hinged plate that covers the wiring behind your circuit breakers or fuses. It’s your switchboard’s own personal security guard, keeping prying fingers and curious eyes away from the live wires.
ESOI: Known as Energy Storage on Invested is the amount of energy that can be stored by a technology, divided by the amount of energy required to build that technology. In the context of a solar panel system, it is the ratio of electrical energy delivered by a solar panel or battery over its lifetime vs. the energy required to mine and manufacture it.
Feed-in-tariff: A feed-in tariff or FiT for short, is a policy that is created to promote the usage of renewable energy resources (Mostly solar). The solar FiT appears as a credit on your electricity bill and is paid to you from your electricity retailer, usually at a set rate per kilowatt hour. Generally, FIT payments are made over a period of 15 to 20 years.
Frameless panels: Also known as ‘glass-on-glass’ modules, have solar cells arranged in a grid between two pieces of glass. Glass on both sides of the module improves light transmission and, thus, improves the efficiency of the solar panels. Since there is no frame to support them, the glass on the panel has to be a little thicker to provide structural integrity to the panel.
Gigawatt: A gigawatt is a unit of measurement of electrical power. For some context, a gigawatt is equal to one billion watts. In the context of solar energy, a gigawatt often represents the capacity of large-scale solar arrays or the cumulative installation capacity of solar projects in a region. It can also be used to measure the total energy capacity of a state or country.
Gross-metering: Gross metering is a mechanism in which all the energy generated by your solar system is exported to the grid at a certain rate. In this case, the energy generated from your system is not consumed by you in any capacity.
Gross metering is a mechanism in which all the energy generated by your solar system is exported to the grid at a certain rate. In this case, the energy generated from your system is not consumed by you in any capacity. To meet your energy load, you will draw the required electricity from the grid at the usual electricity rate (retail tariff).
Heterojunction Cell Technology (HJT): Is a solar panel production method that has been on the rise since last decade. The technology is currently the solar industry’s best option to increase efficiency and power output to their highest levels. Unlike TOPCon, which uses a single material for its solar cells, HJT cells are made from two different materials, crystalline silicon and amorphous thin-film silicon, combining the best of two worlds.
Hybrid inverter: A hybrid inverter is an electronic device that combines the functions of a microinverter and a battery charger in one unit. This allows the hybrid solar inverter to intelligently handle power coming from your solar panels, solar batteries, and the utility grid all at the same time. Hybrid inverters are commonly used in conjunction with solar PV systems to allow the use of both grid-tied and off-grid configurations.
IEC 61701: Is commonly known as the testing standard for salt mist resistance for solar panels. With this test, panels undergo a series of salt sprays in a controlled environment. After the sprays, testers inspect the modules for physical damage. Panels that successfully pass IEC 61701 tests are a suitable choice for beach-front solar panel systems or systems near roads experiencing high levels of salting in the winter.
Inverter: Also known as a photovoltaic (PV) inverter, it is one of the most important pieces of equipment in a solar energy system. It converts the electricity (direct current) your solar panels create into a form (alternating current) that can be used by the appliances, lighting, and other electronics in your home.
Junction box: A junction box (JB) is an interface of a solar module with the external world, it channels the power generated by the solar module to the external world. It allows the safe connection between the photovoltaic (PV) panels and the rest of the electrical system. The additional function is to protect the outgoing line from the hot spot effect.
Kilowatt (kW): Is a unit of power equaling 1,000 watts. In relation to solar, the kW quoted represents the system’s power capacity. When a solar system is producing power during the day, at any given moment, the inverter will output a certain number of kilowatts.
Kilowatt-hour (kWh, kW·h): Is how much power is used or produced within an hour. For example, if a solar system produced 1kW continually for an hour, it produced 1kWh. This term accounts for time and illustrates how much power is or isn’t used from one hour to the next.
Levelised Cost Of Energy (LCOE): Also known as the levelized cost of electricity or the levelized energy cost (LEC), LCOE is a figure used to measure the average cost of generating one-kilowatt hour (kWh) of electricity over the lifetime of a generating asset. The LCOE of an energy-generating asset can be thought of as the average total cost of building and operating the asset per unit of total electricity generated over an assumed lifetime.
Lithium Iron Phosphate (LiFePO4): Is a type of lithium-ion battery that uses lithium iron phosphate as the cathode material to store lithium ions. Lithium iron phosphate batteries have a lifecycle two to four times longer than lithium-ion. Additionally, lithium iron phosphate batteries can be stored for longer periods of time without degrading. They might not be the cheapest lithium-ion battery solution, but they are a smart investment.
Megajoule (MJ): It denotes one million joules, the measure of the energy required to produce heat or perform work. Solar panel installations are often rated by the amount of energy they produce in Megawatts (MW) or Megawatt hours (MWh). Megajoules are important for solar panel installers and energy providers as they use them to estimate the amount of energy required to run electrical components.
Megawatt (MW): Is a unit of electrical power that is equal to one million watts, or one thousand kilowatts. Typically, domestic solar panel systems have a capacity of between 1 and 4 kilowatts. Residential solar energy systems produce around 250 and 400 watts each hour. However, it is estimated that, on average, solar panels that can produce 1 megawatt of power can generate enough electricity.
Megawatt-hour (MWh): Is a unit of measurement that describes the amount of energy produced by one Megawatt over the course of one hour. Solar panels will generate 24.5% of their potential output, assuming the sun shines perfectly brightly 24 hours a day. 1 megawatt (MW) of solar panels will generate 2,146 megawatt hours (MWh) of solar energy per year.
Microinverter: A small inverter attached to solar panels, converting DC (direct current) into AC (alternating current). Microinverters contrast conventional string/ central solar inverters, in which a single inverter is connected to multiple solar panels for maximum control and reliability.
Monocrystalline silicon: The material that monocrystalline solar cells are fabricated from. Each cell is a slice of a single crystal of silicon that is grown expressly for the purpose of creating solar panels. It is cylindrical in shape and made up of silicon ingots. Monocrystalline solar panels have the highest efficiency rates, typically in the 15-20% range.
Multimode inverter: Sometimes referred as a Hybrid inverter, it is an inverter which can simultaneously manage inputs from both solar panels and a battery bank. Multimode inverters function like a common grid-tie solar inverter but can generally operate in one of several different modes, depending on the application. This includes battery backup mode, which provides a limited level of backup power in the event of a blackout.
Maximum Power Point Tracking or MPPT: With its super smart algorithms, MPPT acts like a smart controller or optimizer for solar panels. To put it simply, they convert a higher voltage DC output from solar panels (and a few wind generators) down to the lower voltage needed to charge batteries. Its responsibility is to continuously monitor the operating conditions of the panels and guarantee that they are constantly running at peak efficiency, regardless of the weather or level of shade.
Net metering: This is a billing mechanism that credits solar energy system owners for the electricity they add to the grid. That means only solar energy that’s not used in your home is sent to the grid – and you receive a payment (or ‘feed-in tariff’) for that excess. In Australia, net metering is used to offer two-way reading. It has the ability to track your solar energy usage and report that data into the grid. Your net metre might compute your grid balance if you were able to benefit from solar feed-in tariffs.
Nominal capacity: Or rated capacity is the total amount of energy, which theoretically can be stored in and withdrawn from a battery. Some batteries are designed to be modular, so you can increase your storage by adding more units.
Nominal capacity: Refers to the amount of energy an EV battery can store and subsequently release under optimal conditions. It serves as a fundamental indicator of a battery’s performance, providing insights into the driving range, efficiency, and overall capabilities of an electric vehicle. Nominal capacity is denoted in ampere-hours (Ah) or kilowatt-hours (kWh).
Photovoltaic (PV): The term is derived from the Greek terms photo and phos, which means light, and volt, which means electricity. Solar photovoltaic is an elegant technology that produces electricity from sunlight using semiconducting materials such as silicon without moving parts.
Polysilicon (multicrystalline silicon): Is a high purity, polycrystalline form of silicon, used as a raw material by the solar photovoltaic and electronics industry.
Polysilicon solar cells typically have efficiencies ranging from 15% to 20%. This means that they can convert 15% to 20% of the sunlight they receive into usable electricity.
Power density: In relation to solar panels, it is the amount of energy or power, measured in watts, generated per meter squared. The higher the power density, or watts/m2, the more powerful your solar panel is. For example, the REC Alpha Pure-R has a power density of 223 watts/m2 and a total power output of 430 Wp per panel.
Renewable Energy Target (RET): It is an Australian government scheme that encourages renewable electricity generation. It aims to reduce greenhouse gas emissions from the electricity sector. It functions by enabling the creation of large-scale generating certificates and small-scale technology certificates for each megawatt hour of electricity generated by large-scale power plants and small-scale system owners.
Round trip efficiency: It is a measure of the amount of energy put into a system compared to the amount dispatched and is expressed as a percentage. When selecting an energy storage system to go with your solar panels, round-trip efficiency is a crucial consideration in the context of solar panel installation. This is because more of the energy generated by your solar panels will be used if the round-trip efficiency is higher.
Self consumption: Self-consumption of photovoltaic (PV) renewable energy is the economic model in which the building uses PV electricity for its own electrical needs, thus acting as both producer and consumer, or prosumer. It means sending electricity right to your appliances from solar panels and storing electricity in a home battery for use later.
Single phase power: Refers to the distribution of AC current through a system that involves voltages in unison. Electricity from the grid (or your solar PV system) will only flow through the one active wire, while the neutral wire is connected to the earth at the switchboard. Single-phase power supply has less efficiency in comparison with three-phase supplies for an equivalent circuit.
STC (Small-scale Technology Certificate): Colloquially referred to as the Solar Rebate, it is like a discount coupon given to you against the cost of installing a solar power system at your home. You can claim an STC for any eligible renewable energy technology that generates electricity. The more STCs you have, the more your business qualifies for tax incentives and other rebates.
String: The cable on which solar panels are attached to a string inverter. The panels are attached in series, and the string delivers high voltage direct current to the string inverter.
String inverter: A device used with solar arrays to convert the energy that is generated (Direct Current) to usable electricity for a home (Alternating Current). A string inverter can usually handle many strings of panels that are connected to it. For example, a single string could include three strings of five panels each, totalling fifteen panels. String inverters connect strings of panels in one central location and are best for simple installations.
Temperature coefficient: A solar panel temperature coefficient is a metric representing the rate at which a solar panel’s efficiency decreases as its temperature rises. It’s an essential efficiency factor because solar panels operate most effectively when they’re under direct sunlight. However, there’s such a thing as too much direct sunlight — well, if the panels get hot enough.
Tier 1: Tier 1 solar panels are solar panels made by large, reliable solar panel manufacturers. Tier 1 manufacturers use the best grade materials to produce a solar panel, hence the solar panels are much more expensive. It’s not a system to judge the quality of solar panels – it’s a measure of ‘bankability’ based solely on financial criteria.
Three phase power: A 3-phase solar inverter sends the electricity evenly across the 3 wires, which minimises the voltage drop problem associated with a single-phase power supply. By using the three-phase connection, the power supplied to the grid is distributed evenly and leads to grid stability. It increases the local grid voltage, and your circuits will have less chance of short-circuiting due to high voltage issues.
Usable capacity: The portion of energy your battery can safely discharge for you to use under ideal operating conditions. Batteries have their own native load requirements. In other words, batteries require a certain amount of electricity to continue running. If you try to use beyond the usable energy of a battery, it may have detrimental impacts on the health and longevity of your battery.
Voltage Rise Calculations (VRC): Are commonly performed by solar contractors in Australia to find whether a specified home has a permission for exporting solar electricity into the power grid and if so, how much. According to the Australian Standards AS/NZS 4777, the voltage rise between a solar inverter and the street can be no more than 2 per cent (about 5 volts). In theory, you can use ohm’s law to calculate the voltage rise of a cable if you know the resistance and reactance of the cable.
Watt: Unit of measuring electrical power output or storage. In a solar panel, the watt is equal to amps multiplied by volts. It’s a simple power law to know what a solar panel’s rated output current is by knowing its rated output voltage and rated output power.
Author: Ben McInerney is a renewable energy enthusiast with the goal of helping more Australians understand solar systems to make the best choice before they purchase. Having an accredited solar installer in the family helps give Ben access to the correct information, which allows him to break it down and make it easily understandable to the average homeowner.