The following list gives you an overview of the most important terms used in the PV industry.

Alternating current AC

Alternating current means electricity with an ongoing and often periodic change of the current direction. It can be transformed into different tensions by a transformer.


Assetmanagement is a service, which includes tasks like controlling, monitoring of contracts or the organisation of general meetings.

Auditing processing of producer

Audit (latin audire, hear; audit, he/she/it hears; also translated into hearing) is generally referred to as investigation procedures, which are intended to  evaluate processes according to the fulfilment of requirements and guidelines.

Back Surface Field

A Back Surface Field is a layer of silicon solar cells, which reflect electro


Conductivity describes the is the ability to transport energy in a space.


c-Si is the chemical abbreviation for crystalline silicon.


Degradation means a decrease in the degree of efficiency of modules, which is a decrease in performance over time.

Degree of efficiency

The degree of efficiency shows the ratio of useful power to potentially existing power.


Diffusion is the full mixing of substances due to the distribution of particles. The particles move from areas with a high concentration to areas with a low concentration.

Direct current DC

Direct current means electricity which does not change its direction. It is constant in time.

Direct radiation

Direct radiation means the share of solar radiation, that strikes the earth's surface or PV module unscattered and directly.

Electric field

The electric field is a omnipresent physical field, which is caused by the power, that electrically charged particles have on the space around them. Thereby, the transfer of electrical energy is explained.


An emission is an output, a transmission or an issue of e.g. noxious substances or bonds.

Emission factor

An Emission factor describes the relation of the masses of a emitted substance to the inserted masses of a raw material. 

Emission saving

Emission saving means the avoidance or reduction in CO2 output.

Energetic amortization / energy payback time

Energetic amortization states how long a PV-system needs to run until the power, which was needed to produce the modules is produced.


Engineering, Procurement and Construction means a usual form of project execution and contract management in the building industry. The contractor is the EPC. The EPC fulfils all necessary performances to deliver a turnkey plant to the client.

Feasibility Study

A Feasibility Study serves to control the feasibility of projects. Solutions are analysed, risks are identified and chances of success are estimated to determine by which resources and during which time der wanted projectresults can be reached.

Global radiation

Global radiation is the hole radiation that strikes a surface. It includes direct and indirect radiation.

Hot Spot

Hot Spot generally describes temperature fluctuations within a module. This means in specific that there is an overheating of certain sections of the module which can be caused by e.g. unequal incidence of light, shading or a manufacturing defect.

Inclination angle

The inclination angle is the angle between a PV system and the horizontal. The individually optimal inclination angle depends on the latitude on which the system is installed.

Integrated series circuitry

The integrated series circuitry is used during the manufacturing of large-area modules in the thin-film technology. Thereby, the solar cell is cut into strips and afterwards the front of a cell is connected with the back of the neighboring cell.


A converter transforms direct current to alternating current.

Isle system

An isle system is an independent energy supply system without grid connection. The produced electricity is consumed by the producers and not fed in.

Kilowatt Hour

Kilowatt Hour is a unit indicating the amount of electrical work that can be done with 1,000 watts in an hour.

kWp (Kilowatt-peak)

Kilowatt-peak is the highest possible electric power of a PV system measured under standard test conditions.

Large off-grid power

Large off-grid power means power sources anywhere the sun shines. It massively reduces the volatile fuel and logistic costs of electricity generation. This hybrid solution combines photovoltaic solar arrays with batteries and back-up generators to ensure a stable and reliable power supply on demand. Systems are highly scalable starting from 30 to 300 kWp.

Large on-grid power

Such a highly scalable system covers up to 30% of your daily peak demand power without impacting power quality and saves significantly on peak-time power costs. 


The maintenance of a solar power plant includes preventive maintenance, testing and corrective maintenance of plants.

Maximum power point

The word refers to the working point of a solar cell at which the maximum performance, which means the maximum product of electricity and voltage, is reached. This point is not a constant one and depends on certain factors.

Micro off-grid power

Micro off-grid power means to avoid costly grid connections and generate power where you need it not where the grid is. The fully integrated hybrid system includes a battery and a generator backup for up to 30 kWp.

Micro on-grid power

Micro on-grid power means to reduce overall power costs and to protect yourself from rising electricity bills with your own power supply. Power storage allows you to use as much solar power as available while connection to the grid will cover you when needed.


A module consist of several solar cells and transforms sunlight directly into electrical energy.

Module efficiency

The module efficiency describes the relation between the output of electrical power of a module and the irradiated performance. The higher the module efficiency, the higher the output of the same surface area.

Monitoring of plant

Monitoring of plant means a detailed evaluation of the performance of the hole system and of components. By the monitoring of a plant you get current performance data which helps you to directly recognize drops in performance.

Monocrystalline Modules

Monocrystalline Modules have a homogenous orientated crystalline structure, by which higher efficiency than the one of polycrystalline modules can be reached. Because of the high production effort they are expansive.


MPP-Tracking forms the basis for operating a PV system at its maximum power point all of the time. For this purpose, the voltage is readjusted. The needed MPP-Tracker is part of a inverter or a regulator. 

O&M - Operations & Maintenance

Operations & Maintenance means the performance monitoring of solar cells to maximize plant performance to the highest possible level.


Operations includes the performance monitoring of a photovoltaic power plant as well as the bookkeeping.

Payback period

The payback period is the period of time during which the capital bound in an investment flows back.

Performance Ratio (PR)

The Performance Ratio specifies the share of electricity which is available in real terms.

Photovoltaic power plant (PV plant)

A PV plant consists of solarmodules, by which solar radiation is directly transformed into electrical energy.

Polycrystalline Modules

Polycrystalline Modules, which consist of inhomogeneously arranged crystals have a lower efficiency than monocrystalline modules, but, they are less expensive because of a simpler manufacturing process.

Producer auditing

Audit refers to investigation procedures, which are intended to  evaluate whether a company or its processes adhere to requirements and guidelines.

Pty. Ltd.

Proprietary Limited (Pty Ltd) is a company, which is limited by shares, where shareholders are afforded more protection when it comes to the level of liability that they face for company debts.

Quality assurence during the construction phase

Within the quality assurance during the construction phase regular quality controls and building controls take place to identify and to remedy deficiencies just in time.

Rated output

The rated output is the maximum output of a solar cell, determined under standard test conditions. It is expressed in Watt Peak.

Rating of plant

The rating of plant helps to determine the quality and the default risk of a PV system.

Reflection losses

Reflection losses means, that a part of the solar radiation is reflected by the surface of a solar cell und in that way cannot be used to produce electric energy.


Producers of renewable electrical energy get a remuneration payed by public utility companies for the feed-in into the electricity grid. The remuneration is regulated by the Erneuerbare-Energien-Gesetz.

renaturation, disposal

Dismantling generally describes the uninstalling of the PV system und the restoration of the original state of the roof top or green field. Usually, the removed defect and/or used modules are taken back by the installing company and then they are given to the manufacturer. The recycled modules can be used to generate new modules.

Revenue Enhancement

Revenue enhancement describes increasing the output of electrical power generated by a PV plant.

self- consumption

Self-consumption is the partial or complete usage of the generated electricity by the owner and will be remunerated separately in order to create a financial incentive.

Solar energy

Solar energy is the energy of solar radiation. It can be used in form of electric power, heat or chemical energy.


s.r.l. is a european legal form of society in Italy which means Società a Responsabilità Limitata.


SPOLEČNOST S RUČENÍM OMEZENÝM is in Czech Republic the same like Ltd.- private limited company.

Standard Test Conditions

Standard Test Conditions are an international standard to determine the rated output of modules in an objective way. Thereby, different modules can be evaluated and compared independently.

Sunshine hours

The number of hours per day during which direct sunlight exists are called sunshine hours.

Technical acceptance

By technical acceptance one means the inspection of the completed PV system according to the fulfilment of certain minimum requirements regarding special quality and test regulations.

Technical due diligance

Due Dilligence (DD) is a risk assessment, that is carried out with "due dilligence". It is normally made by a buyer when he or she buys shareholdings or real estate or in case of an initial public offering. Due-diligence-examinations analyse strengths and weaknesses of the object as well as corresponding risks. Therefore, they play a key role in the valuation of the object.

Thin- Film Module

Thin-film modules have a minimal thickness and are cheap in production. They are flexible and they have a low weight. Besides, their degree of efficiency is lower than the one of other modules.

Utility-scale power

Utility-scale power means the integration of solar power to diversify power sources, boost weak spots in the grid, cover transmission losses and boost production in summer peak time. 


Volt is the international unit of electric voltage.


A Wafer is a circular or squared thin disc. These discs are made out of mono- or polycristalline blanks and they are the base plate for electronic components.

Yield report

A yield report is a detailed report of the long-term rate of return, which a PV system can generate at its site. It supports the financing commitment of a bank.








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