Solar Industry Glossary

Array

AC & DC

The two types of electrical current. DC can be converted to AC and vice versa. What makes the two kinds different from one another is the flow of the electrical charge. DC (one directional) used electronics i.e. smartphone and laptops, custom motors, components such as transistors and microchips. AC ( bi-directional) say powerlines for resi (Domestic), commercial and industrial over long distance transmission and machines of all scale.

AC (Alternating Current) and DC (Direct Current) are two types of electrical current with different characteristics and uses. In DC, electricity flows in a single direction, providing a stable, constant voltage, ideal for electronics and battery-powered devices, such as laptops and solar systems. AC, by contrast, alternates direction periodically (typically 50 or 60 times per second) and varies in voltage. Generated by power plants, AC is more efficient for long-distance transmission because it can be easily transformed to higher or lower voltages, making it suitable for household appliances and grid distribution. DC is stable but less efficient over distances, while AC’s alternating nature allows for efficient power distribution across large networks.

Amps

Amps, measure the number of electrons flowing – water pipe analogy the rate of flow in a pipe or river – through a certain point per second. In other words, it describes the current flow through an electrical circuit. Amperage is the strength of the electric current and is expressed in amperes. The larger the amperage, the more electricity can flow through the circuit. Amps = Watts / Volts

BMS

BESS

Battery – Lithium Ferrous Phosphate

Lithium Iron phosphate (LiFePO4) batteries are a type of lithium ion (Li-Ion) rechargeable battery. Their benefits over the more traditional cobalt-based Li-Ion batteries are increased power output, faster charging, reduced weight and longer lifetime. Better suited to PV solar, LiFePO4 batteries are less prone to thermal runway and do not have the toxity of Lithium Ion. With longer life than the latter, this battery type has better all round environmental credentials.

Battery – Lithium Ion

A Lithium-ion battery is defined as a rechargeable battery that utilizes lithium ions moving between electrodes during charging and discharging processes. These batteries are commonly used in consumer electronics due to their high energy density and long cycle life. Lithium-ion (Li-ion) batteries are used in many products such as electronics, toys, wireless headphones, handheld power tools, small and large appliances, electric vehicles and electrical energy storage systems.

Cycle

Capacity Retention

Consumption – Medium Large Commercial

Consumption – Small Commercial

Small businesses have an average electricity consumption of 20,000 kWh per year – ranging from 15,000 kWh to 25,000 kWh of yearly usage.

Small business average electricity consumption ranges between 15,000kWh and 25,000kWh per year. The average is taken as 20,000kWh

DoD

Degradation

DESS

DER

DG

DNO

EV

ESG v CSR

ESG

EPC

Energy Efficiency Directive (EED):

Obligations under the EED include conducting energy audits, implementing energy efficiency measures and reporting on energy consumption and savings. Compliance is not only subject to penalties but will be a key element in commercial contracts and a competition factor between data centres. It will also impact the financing of such assets as ESG criteria become a crucial factor in loan agreements.

From 2024 Germany requires – others will likely follow -DCs must source 50% of their energy from renewable sources and from 2027 this obligation will be 100% renewable energy sourcing! Data centre operators can demonstrate compliance by using a “certificate of origin (GoO)” for the energy used. Data centres will become major purchasers in the commercial Power Purchase Market and the trend will increase on a European and international level.

Energy Rating

Emissions – Scope 1-3

EMS

Feed In Tariff (FIT)

The Feed-in Tariff for solar panels closed in March 2019. The cost of manufacturing solar panels has plummeted by 82% in the last ten years, according to the International Renewable Energy Agency (IRENA). These cost reductions are passed onto businesses when purchasing their PV system, providing healthy financial returns and a reduced payback period.

The Feed-in Tariff (FiT) was a UK government program introduced in 2010 to encourage renewable energy generation, mainly for solar, wind, hydro, and anaerobic digestion systems. It offered payments to individuals, businesses, and organizations that generated their own renewable electricity. Under the FiT scheme, participants received payments for each kilowatt-hour (kWh) of electricity they generated, with additional payments for any excess energy exported back to the grid.

The FiT had two main financial benefits:
Generation Tariff: A fixed payment for every kWh of electricity produced, regardless of whether it was used on-site or exported. Export Tariff: A smaller, additional payment for any surplus electricity fed back into the grid.

The goal was to make renewable energy systems more financially attractive, supporting the growth of small-scale green energy and helping reduce carbon emissions.

The FiT scheme officially closed to new applicants on March 31, 2019. Systems installed and registered before this date continue to receive payments according to their agreements, but no new applications have been accepted since then. The closure marked a shift in government policy towards other forms of renewable incentives, including the Smart Export Guarantee (SEG), which offers payments only for exported electricity.

FCE

Grid

G99

If you are connecting large scale generation, above 16A (3.86kW) per phase or energy storage, then you will need to complete a G99 form.

G99 is the regulation; testing and cert. surrounding the connection of any form of generator device to run ‘in parallel’ or ‘synchronised’ with the mains electrical utility grid (National Grid)

G98

If you are connecting single or multiple phase generators at multiple premises of up to 16A (3.86kW) per phase you need to complete a G98 application form prior to connecting. If you are connecting large scale generation, above 16A (3.86kW) per phase or energy storage, then you will need to complete a G99 form

The G98 Form is used when systems are installed under 16A per Phase. This is an install and notify document that must be completed once the solar installation has been fit. There is a 28 day period after installation that this is allowable to complete

G100

G98 & G99

Needed for all generation >16 amps per phase />50Kw In excess of 50Kw will require witnessed testing. Both this and 59 are regulation and certification that ensures safe operators of generators and the grid isolating renewable and local power generation from grid fluctuation. Protection settings are an important fail safe to protect producer and grid. Systems that run in parallel to the grid must have include a relay to decouple the generator (wind/solar/hydro) from the grid if a problem arises on either side.

The G98 and G99 forms are used in the UK to apply for approval when connecting small-scale and larger-scale electricity generation systems, such as solar or wind, to the National Grid.

G98: This form applies to smaller systems (under 16 amps per phase, typically up to 3.68 kW for single-phase systems). It ensures that these systems meet basic safety and technical standards for connecting to the grid, with a simplified approval process.

G99: This form is for larger systems (above 16 amps per phase). It’s a more detailed and comprehensive application process, ensuring that systems above this threshold meet stricter grid compliance, stability, and safety standards, especially for systems that could have a larger impact on the grid.

G59

Industry standard for generators >16amp single phase – say 4kw PV phase. For and regs required for any generation system to connect with DNO

The G59 form was an application required in the UK for connecting larger-scale electricity generation systems, like solar or wind, to the National Grid. Used for systems above 16 amps per phase (typically over 3.68 kW for single-phase supplies), it ensured that the installation met grid safety and technical standards. The form was part of the G59 engineering recommendation, which outlined how these systems needed to operate in harmony with the grid to prevent issues like power surges or instability. This form was necessary to obtain approval from the Distribution Network Operator (DNO) before connecting large-scale generators. The G59 process has since been replaced by G99 standards, reflecting updates in grid technology and requirements.

Hybrid Inverters

Hybrid inverters differ heavily from the previous two inverters. The hybrid doesn’t refer to string and micro being blended, but rather inverters and batteries. Basically, like any other inverter, they convert DC to AC, but then they store the energy. This essentially eliminates the need for a battery, making them comprehensive and useful for living off-the-grid, or in areas with power issues. That being said, these have a higher upfront cost, as they are not standard and are considered premium attachments.

A hybrid inverter is a type of inverter that can manage both solar power generation and energy storage (like batteries) in a single system. It converts the DC electricity from the solar panels into AC electricity for use in your home, just like a regular inverter.

What makes it “hybrid” is its ability to also manage and store excess solar energy in batteries for later use, such as at night or during cloudy days. Hybrid inverters can also control the flow of energy between the solar panels, the batteries, and the grid, depending on the system’s needs. This makes them ideal for homes or businesses that want to maximize their solar energy use and increase energy independence.

ISO

IP66

IP65

IP21

IP Rating

Inverter Stats

System Size – The size of the solar system makes a direct impact on how much the inverter you need will cost. Regardless of whether it’s a string, micro or hybrid inverters – each has its capacity they can deal with. Many can handle simple 4kW systems quite easily, but when it begins to rise closer to ten, that’s when efficiency falls off.

Efficiency – Inverters often boast a 95% conversion rate at the lowest, with anything else being considered sub-par. But some inverters go up to 98%, using advanced technology and, therefore, incurring a higher price. Whilst 3% might not seem like a lot in the short term, the long term tells a different story.

Power Optimisers – These are not inverters, but directly impact their performance. Power optimisers are to be attached to a solar panel(s), and this optimises the output of each panel. It does this by automatically tweaking the voltage and current to maximise the power generation. The issue with this is, of course, that you must add one to each panel.

Grid-Tied Inverters – Grid-tied inverters are designed to interact with the original electricity grid. This allows for several things, but the most convenient is the ability to feed your electricity to the grid itself. This lowers your energy costs, but if you manage to generate more than you use, you can earn yourself credits. This is convenient because you don’t have to manage battery charging or complex power controls.

Inverter

IPP

kWp

kWh

kW

Load Shifting

Mini Grid

MPPT

Max Charge v Discharge

Microinverters

O&M

Panel Mismatch

Phase

PPA

Power Optimisers

Photovoltaic (PV) Panel

Peak Shaving

Peak Demand

Standing Charge

System Size

Solar Panels

SoH

SoC

Sleeving

Single Phase Power

A type of alternating current (AC) in which all voltages vary in unison. Single phase power is the most common household power circuit. It is often used to power lighting, heating, televisions, and other appliances.

Single-phase power is a type of electrical power distribution commonly used in homes and small businesses. In a single-phase system, electricity is delivered through two wires: one live (or “hot”) wire that carries the current, and one neutral wire that completes the circuit. The voltage alternates in a sinusoidal pattern, providing a continuous flow of power.

In simpler terms, single-phase power is the most basic form of electricity supply, providing a steady flow of power, but it is generally suitable for lower power applications. It’s typically used in residential settings because it’s sufficient to run most household appliances like lights, refrigerators, and televisions.

String Inverters

These are the most common inverters by far. They connect a series of solar panels via a long string and syphon the DC energy into it. The DC energy is raw solar power, unusable until it’s pulled into an inverter and changed to AC, which is the type of energy that most electronics use. String Inverters are very cost-effective, especially when used on larger system installations. However, if one panel underperforms due to shading, damage or another type of obstruction – you can expect the rest to similarly underperform.

A string inverter is a device used in solar power systems to convert the DC (direct current) electricity generated by solar panels into AC (alternating current) electricity, which can be used in homes or businesses. In a system with a string inverter, the solar panels are grouped together in “strings” (usually 10-20 panels per string), and the inverter processes the electricity from each string of panels at once.

It’s called a “string” inverter because the panels are wired together in series, forming a string. The inverter then converts the combined output from all the panels in the string. This type of inverter is commonly used in residential and commercial solar systems because it’s relatively simple and cost-effective.

Scope 3

Scope 2

Scope 1

Three Phase Power

A type of alternating current (AC) that ensures constant power supply. Unlike single phase power where electrons travel through one wire, here the electrons move through three wires at slightly different times. Three phase power is usually used by electrical grids to transfer electricity, or to power industrial machinery, large motors and other heavy loads. Essentially converting power over separate currents, out of phase with one another. Residential systems would utilize a single-phase solution.

Three-phase power uses three live wires, each carrying an alternating current (AC) that is offset by 120 degrees from the others. This means the power delivered through each wire is out of phase with the others, creating a more constant and balanced flow of electricity.

Throughput

Volts

Volt measures the force or pressure – water pipe pressure analogy – required for an electric current to flow past a wire. In other words, it also determines the speed at which individual electrons flow through the circuit. Large home appliances like washing machines, refrigerators, and air conditioners operate at 240V. On the contrary, smaller devices like computers, TVs, light bulbs, etc., operate at 120V. Volts = Watts / Amps

A volt (symbol: V) is the unit used to measure electric potential difference or electric pressure. It essentially indicates how much “push” or force is driving electric charges through a circuit.

In simple terms, voltage can be thought of as the “pressure” that pushes electrical charges through a wire, similar to how water pressure pushes water through a pipe. The higher the voltage, the more force there is to move the charges.

Technically, one volt represents the potential difference that will drive one ampere of current through a conductor with one ohm of resistance. For example, a 1.5-volt battery provides enough electric potential to push current through a small device like a flashlight, whereas a 240-volt wall outlet found in the UK provides a stronger push, suitable for powering larger household appliances.

Watts

Wattage, commonly known as watts, is the power an electric appliance consumes. In other words, it is defined as the “electricity at work” or power a device takes to run. The higher the wattage, the more the output and power of the appliance. Watts = Amps × Volts

Watts, amps and volts are the units. The equation is Power (P measured in Watts) = Current (I measured in Amps) x Voltage (V Measured in Volts)