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Glossary

Solar energy glossary

The terms of solar energy, explained in plain language. Direct definitions so you can read any quote or guide without getting lost.

Quick answer

This glossary defines 38 solar energy terms in Colombia in plain language: from kWp, inverter and peak sun hours to net metering, RETIE and UPME certification. Each term opens with a self-contained definition — it makes sense on its own — and continues with the detail, the key facts, the frequently asked questions and the related terms.

Units and quantities

The quantities a system is sized and quoted in. Understanding them stops you comparing figures that do not mean the same thing.

kWh (kilowatt-hour)

The kilowatt-hour is the unit of energy that appears on your electricity bill: it measures how much electricity you consume or generate over time. A solar system is sized from your monthly consumption in kWh, and the saving is also measured in kWh.

kWp (kilowatt peak)

The kilowatt peak is the unit that measures the capacity of a solar system under standard test conditions. It is the main reference for sizing an installation and for comparing prices: cost is usually expressed in pesos per installed kWp.

Peak power

Peak power is the maximum power a panel or system delivers under standard test conditions, expressed in watts peak (Wp) or kilowatts peak (kWp). It is the figure equipment is named, compared and quoted by.

Standard test conditions (STC)

Standard test conditions (STC) are the laboratory scenario in which a solar panel's capacity is measured: 1,000 W/m² of irradiance, a 25 °C cell temperature and a reference solar spectrum. They exist so every manufacturer measures the same way.

Equipment and components

What each piece of the installation does, how long it lasts and which purchase decisions depend on it.

Battery (storage)

A battery stores the energy the panels produce so it can be used later, for example at night or during a blackout. It adds autonomy and backup, but also cost, and its service life is shorter than the panels'.

Bifacial panel

A bifacial panel captures light on both faces: the front directly from the sun and the rear from light reflected by the surface below. It can increase generation when installed over light-coloured surfaces or on elevated structures.

Inverter

The inverter converts the direct current the panels produce into the alternating current used by your home or business and by the grid. It is the most intelligent component of the system and is usually the first to need replacing during its service life.

Microinverter

A microinverter is a small inverter installed at each panel, converting its energy independently. It improves performance under partial shading and allows panel-by-panel monitoring, at a higher cost than a string inverter.

Monocrystalline panel

A monocrystalline panel is made with single-crystal silicon, which gives it higher efficiency and a uniform dark colour. It offers more capacity per square metre than polycrystalline, which is especially useful when roof space is limited.

Mounting structure

The mounting structure is the set of supports that fixes the panels to the roof or the ground safely and with the right orientation. It has to withstand wind and weight for the whole life of the system without compromising the roof's watertightness.

Photovoltaic cell

The photovoltaic cell is the basic unit that produces electricity from light. A solar panel is made up of many cells connected together. Most are silicon, monocrystalline or polycrystalline, and each generates a small voltage.

Photovoltaic panel

A photovoltaic panel is the module that converts sunlight into electricity by means of semiconductor cells. It is the visible component of a solar installation and several panels connected together form the system's generator.

Polycrystalline panel

A polycrystalline panel is made with silicon of several crystals, with a bluish, mottled appearance. Historically it was cheaper and somewhat less efficient than monocrystalline; today its use has declined as the latter's prices have fallen.

Power optimizer

A power optimizer is fitted to each panel to maximise its individual output and sends the energy to a central inverter. It is the middle alternative between a string inverter and microinverters, useful on roofs with partial shading.

String inverter

A string inverter connects several panels in series — a string — to a single central inverter. It is the most common and most economical configuration; its drawback is that shade or a fault on one panel can affect the performance of the whole string.

Design, installation and performance

What determines how much energy a system actually produces, beyond the capacity the catalogue declares.

Degradation

Degradation is the gradual loss of panel capacity over the years, typically around 0.5% a year. That is why performance warranties guarantee a minimum percentage of output at 25 years.

Grid-connected system (on-grid)

An on-grid system is connected to the electricity grid and uses it as backup: it draws energy when the panels are not producing and exports surplus when they produce more than needed. It is the most cost-effective configuration and needs no batteries to generate savings.

Hybrid system

A hybrid system combines a grid connection with batteries, so it can keep working during a power cut. It provides backup for priority loads, at a higher cost than an on-grid system without storage.

Irradiance

Irradiance is the power of solar radiation falling on a surface at a given instant, measured in watts per square metre (W/m²). Accumulated over time, it determines the energy available to generate electricity.

Off-grid system

An off-grid system is not connected to the grid and works on panels and batteries alone. It is the option for places with no access to the electricity grid, such as remote farms or non-interconnected areas, where it replaces fuel generators.

Orientation and tilt

Orientation (which way the panels face) and tilt (their angle) affect how much energy they capture. Near the equator, as in Colombia, panels are installed at a low tilt; the installer optimises both for your roof.

Peak sun hours (PSH)

Peak sun hours express a location's daily radiation as the number of equivalent hours of sun at maximum intensity. They are a key figure for sizing a system: the more PSH, the more energy each installed kWp generates.

Shading

Shading is the shadow cast by trees, buildings or other obstacles over the panels, and it reduces their output. A good design avoids shaded areas or uses microinverters or optimizers to minimise the impact.

Solar radiation

Solar radiation is the energy arriving from the sun at a surface. In Colombia, because of its equatorial location, it is relatively stable throughout the year. IDEAM's Solar Radiation Atlas is the official reference for this data.

System performance ratio

The performance ratio is the relationship between the energy a system actually produces and what it would produce under ideal conditions. It bundles the normal losses from temperature, wiring and the inverter; it usually sits close to 75-80%.

Regulation, paperwork and institutions

The Colombian framework: who regulates, what paperwork is needed and which category you fall into as a self-generator.

Bidirectional meter

A bidirectional meter records both the energy you draw from the grid and the energy you export to it. Your grid operator installs it when the system is legalized and it is the piece that makes net metering of your surplus possible.

CREG

CREG (Comisión de Regulación de Energía y Gas) is the body that regulates the Colombian electricity sector. Its Resolution 174 of 2021 (which replaced 030 of 2018) defines the conditions for small-scale self-generation and net metering of surplus.

Grid operator

The grid operator is the company responsible for the electricity distribution networks in your area. It is the one that receives a solar system's connection application, reviews the design, authorises the connection and installs the bidirectional meter.

Ley 1715 de 2014

Ley 1715 de 2014, amended by Ley 2099 de 2021, promotes renewable energy in Colombia with tax incentives: an income tax deduction, VAT exclusion, exemption from import duties and accelerated depreciation, subject to prior certification with UPME.

Net metering

Net metering is the scheme that lets you deduct from your bill the energy your system exports to the grid when it produces more than you consume. In Colombia it is regulated for small-scale self-generators by CREG Resolution 174 of 2021, which replaced CREG 030 of 2018.

RETIE

RETIE is Colombia's Technical Regulation for Electrical Installations. It sets the safety requirements electrical installations must meet, solar ones included, to protect people and property.

Self-generation

Self-generation is producing your own electricity for your own consumption, for example with solar panels. In Colombia, small-scale self-generation has a specific regulatory framework that allows connection to the grid and the export of surplus.

Small-scale self-generator

This is the regulatory category for someone generating energy mainly for their own consumption, with a capacity below the threshold the regulation defines. Simplified connection conditions and net metering of surplus apply to them.

Surplus energy

Surplus is the energy your solar system generates but you do not consume at the time, and which is exported to the grid. Through net metering, that surplus is offset on your bill under the regulation in force.

UPME

UPME (Unidad de Planeación Minero Energética) is the body that, among other functions, certifies renewable energy projects so they can access the tax incentives of Law 1715, following the procedure in Decreto 829 de 2020.

Money, contracts and financing

The ways of paying for a solar project and how to work out whether it is worth it.

PPA (power purchase agreement)

A PPA (Power Purchase Agreement) is a contract in which a third party installs and operates a solar system at your site and you pay only for the energy generated, with no up-front investment. It is common on business projects.

Return on investment (payback)

Return on investment, or payback, is the time it takes for the accumulated saving on the bill to match what the solar system cost. From that point on, the energy the installation produces is net benefit for the rest of its service life.

Solar leasing

Solar leasing is a finance lease in which an institution buys the system and leases it to you, with a purchase option at the end. It allows installation with no up-front outlay and has accounting advantages for companies.

Glossary reviewed on 2026-07-29.

Sources: Ley 1715 de 2014 (Renewable Energy Law) (opens in a new tab) · Ley 2099 de 2021 (Energy Transition Law) (opens in a new tab) · Decreto 829 de 2020 (tax incentives decree) (opens in a new tab) · Resolución CREG 174 de 2021 (net metering regulation) (opens in a new tab) · UPME (opens in a new tab) · Solar Radiation Atlas of Colombia (opens in a new tab) · RETIE — Technical Regulation for Electrical Installations (opens in a new tab)

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