Standardize your energy knowledge with our glossary!

Experienced content writer with over 4 years of experience in the energy sector and many industry-related publications released.

Gabriela Stawiarska

As we’re now adding energy topics to our usual publications’ agenda, it might be a good moment to take a quick step back and break down some of the most recurring terms. Much like with the already well-known eMobility, the energy industry holds quite a word stock to itself. While some of them can be considered general knowledge, others not only cause some confusion, but are purely unknown to many people.


As the intricate industry befits, the nomenclature can seem impenetrable at first, but once the general grasp is held, there should be no more confusion.

This is a type of current that reverses its direction periodically. Generally, AC power is the most commonly used form of electricity based on the available voltage from the electrical grid. Being the fundamental form of electricity, AC current is what’s used to get devices like kitchen appliances, TVs, fans and lamps running in homes and businesses.

DC is a type of current that flows in one single direction. As its name suggests, it does not change direction like AC. DC can flow freely through various mediums like wires, conductors and semiconductors. It is mainly used by various electrical devices such as computers and batteries, but also for some of the railways or electrochemical processes.

DNOs are companies that own and operate networks for electricity transmission and distribution. They work as the link between generation sources, such as power plants or renewable energy sources, and consumers.

It refers to a level of electrical potential that exceeds the usual safety threshold and necessitates extra precautionary measures when using related equipment or conductors. Put simply, high voltage is power strong enough to cause injuries or damages like fire hazard.

This is the flow of electrons through a conductor. It expresses the rate at which electric energy is transferred, and it's measured in amperes (A).

Energy conversion is the process of converting one form of energy into another. For example, electricity is a type of energy that can be converted from other forms, such as coal or wind. This conversion process usually involves an energy source being transmitted through a generator and then transformed into usable electricity.

This is the minimum amount of energy required to be generated by a power plant at any given time. Generally, it corresponds to the constant demand for electricity and is usually provided by large plants such as coal or nuclear power plants.

This refers to the energy obtained from sources that are not depleted when used. Examples of renewable energy include solar, wind, hydroelectric and geothermal power.

This is a process that involves adjusting energy consumption to reduce peak electrical load. It includes techniques such as using more efficient appliances, scheduling the use of large appliances during off-peak hours, and curtailing nonessential uses of electricity during peak periods.

Micro-generation is a term used for small-scale electricity generation, typically in residential settings. It involves generating electricity using renewable energy sources such as solar photovoltaics, wind turbines or micro-hydro systems. This type of energy production can drastically reduce the demand on traditional power grids and help households become self-sufficient when it comes to their energy needs.

Peak demand refers to the time of day when electricity usage is at its highest. This usually occurs during weekday afternoons and evenings due to increased residential, commercial and industrial loads. Managing peak demand can be a challenge for grid operators as they need to balance supply and demand in order to keep the system stable. To cope with these periods of high demand, electricity companies often encourage people to shift their energy habits to lower peak times and use energy more efficiently.

An amp is a unit of electrical current that measures the amount of electricity flowing through an electric circuit. It’s abbreviated as ‘A’ and it can be used to measure the power supplied by a battery or generator

A watt is a unit of power that measures the rate at which electrical energy is used or generated. Watt is an equivalent to one joule per second.

An energy meter, also called a watt-hour meter or kilowatt-hour meter, is an instrument used to measure the amount of electrical energy consumed by a specific appliance or device. It measures the number of kilowatt-hours (kWh) that have been consumed and can be used to calculate electricity bills.

It is the rate at which electrical energy is transferred by an electric circuit. Many people mistakenly believe that electric power is exchanged in the market - however, it's actually energy which exchanges hands. This makes sense when you consider electricity as a product of its two components: power and time. When we buy electricity from suppliers, this comes to us measured according to kilowatt-hours

Automatic meter read (AMR) is an advanced technology that automatically reads and transmits electric meter readings without any manual intervention. It eliminates the need for a technician to physically visit each customer’s premises in order to collect data.

Net metering is a billing system used by utilities that allows customers with micro-generation systems to be compensated for any excess electricity they generate. The system works by measuring the difference between the energy that a customer generates and the energy they consume. The amount of electricity generated is credited to the customer’s account, allowing them to offset their electricity costs and possibly even make a profit from their micro-generation system.

A circuit is an electrical system that enables electricity to flow from one place to another. It consists of a number of components such as wires, resistors and capacitors. The purpose of using a circuit is to control the current by creating pathways for it to follow.

A circuit breaker is a device that is used to automatically shut off the flow of electricity when there is an overload or short circuit. It helps prevent damage to electrical systems by quickly disconnecting the current when an unusually high amount of electricity passes through it.

A power inverter is an electronic device that converts direct current (DC) electricity into alternating current (AC). This is done by changing the voltage and frequency of the DC signal so that it can be used in AC-powered devices such as lights, fans, and other equipment. Power inverters are often used to provide backup energy during power outages or to supply electricity in remote areas.

An electrical conductor is an object that allows electricity to flow through it. Conductors are usually made of metal and can be used to connect two points in a circuit so that the current can move from one point to the other. Common conductors include copper wires, aluminum foil, and certain types of plastics.

A fuse is a device that contains a piece of metal, called a fuse wire, which is designed to melt when too much current passes through it. This helps to protect the circuit from being overloaded and prevents damage due to high voltages. Fuses are commonly found in electrical appliances.

Crucial points on the distribution map that transform voltage from high to low (or vice versa) and enable the transfer of energy between transmission systems and the distribution networks which then can bring it into homes.

(the nomenclature may change depending on the region) overhead electrical line that delivers power from the pole to any building or residence. This is the final stretch before electricity ‘enters’ the building.

They bridge the gap between large energy networks and individual households. Acting as integral nodes in the electric power grid, these devices are vital for providing electricity to homes and businesses by taking high voltage input from distribution lines and transforming it into a lower output that is safe for everyday use.

A backbone for electricity distribution, linking power from sub-stations to end user locations

A power line is an electrical cable or wire used to transmit electric energy from one place to another. It typically consists of multiple cables bundled together and covered in an insulating material. Power lines are used for a variety of applications, including powering homes, business and industrial sites.

is a measure that reflects the output of an electricity generator, such as a power plant. It is expressed in kilowatts (kW) or megawatts (MW). DNC is determined by the amount of energy available from generation sources at any given time, taking into consideration constraints imposed by technology and economics. Factors such as fuel costs, maintenance schedules

It’s the daily fixed fee paid to an energy supplier, usually by large-scale businesses, for maintaining their electricity supply. The standing charge is applied regardless of the amount of electricity used in any given period and can be an important factor when customers are deciding which electricity tariff is best for them.

It is a unique reference code given to each customer by their energy supplier. It is used by suppliers to identify customers and track usage and billing information. Supply numbers are typically five or six digits long, and can be found on all bills and statements sent out by the supplier.

The rate of payment for a given supply of electricity and/or gas. Tariffs can vary between different suppliers, as well as different types of customers (e.g., domestic, business). The most common tariffs are fixed-term contracts, variable tariffs, and discounted tariffs.

These are power plants designed to produce electrical energy mainly during peak periods when there’s an increased demand for electricity. They are used to supplement the base load that is provided by large power plants.

Smart grids

Learn about the power distribution system. How is it different from the gird and what are the types?

Being an eMobility leader in various projects across multiple startups, Piotr was responsible for OCPI and OCPP integration as well as EMP and CPO platforms development. With extensive expertise in the open standards field and eMobility tech solutions, he is leading teams of experienced developers and contributing with invaluable knowledge and experience.

Piotr Majcher

how the grid’s capacity is being optimized by new technologies

, we’re now staying in the broad topic of energy systems. Now, it’s time to take a closer look at it from a slightly different angle and focus on a specific part of the whole grid undertaking.

In order to understand it, it’d be useful to take a step back and look at the energy system as a whole. The global energy system is a vast and complex network that supplies energy to homes and businesses across the entire planet. It includes everything from power plants and transmission lines to distribution systems and end-use customers. Thus, four main branches may be distinguished:

The distribution may be deemed as the final stage in electric power’s delivery. It is responsible for carrying the electricity to the end-customers i.e. households. For some this description may get confusing with the grid itself, but it’s not quite interchangeable. To answer the question how is that different from the grid, we must look at the power distribution network as a portion of the whole grid.

The power grid is the entire electrical system that transmits electricity from the generating plants to consumers. This includes high-voltage transmission lines and substations, as well as lower voltage distribution lines and transformers. Power distribution network is a part of the grid owned or operated by a utility that is dedicated to delivering electric energy to customers and it refers specifically to the distribution system that carries electricity to individual customers. The grid also makes use of a top-down approach, with bulk electricity flowing from the power plant to consumers via transmission lines. The power distribution network, on the other hand, takes a more distributed approach, where smaller amounts of electricity are distributed from multiple sources within a local region

The power distribution network is made up of a complex network of circuits, cables, transformers, poles, junction boxes and other equipment that carries electricity from substations to homes and businesses.

Electrical power is distributed to individuals, commercial business and industrial complexes through an intricate network of substations, transmission lines and transformers. The process starts with electricity being transferred from the high voltage level of a major grid or station to local distribution substations where it undergoes transformation into medium levels ranging between 2-35 kV via specialized equipment called transformers. From there primary distribution takes effect sending energy along designated routes until sectionalizing points are reached, reducing it further by transformer units for use in homes and businesses. The voltage fit for the domestic appliances is known as utilization voltages.

Customers can sometimes be supplied with electricity through a secondary distribution system, to which they are connected through service drops. For those who have larger demands for power - usually businesses or industrial operations - a direct connection can be made at higher voltage subtransmissions.

… or at least some of the most crucial appliances enabling the whole undertaking:

 - essential device that safeguards all electrical circuits from being overloaded or facing a potential fire hazard. They serve as important safety measures by automatically cutting the power flow in moments of increased current, protecting your equipment and wiring with every turn-off.

 - crucial points on the distribution map that transform voltage from high to low (or vice versa) and enable the transfer of energy between transmission systems and the distribution networks which then can bring it into homes.

- (the nomenclature may change depending on the region) overhead electrical line that delivers power from the pole to any building or residence. This is the final stretch before electricity ‘enters’ the building.

- they bridge the gap between large energy networks and individual households. Acting as integral nodes in the electric power grid, these devices are vital for providing electricity to homes and businesses by taking high voltage input from distribution lines and transforming it into a lower output that is safe for everyday use.

 - a backbone for electricity distribution, linking power from sub-stations to end user locations

The distribution network can be classified under a few categories. The most common way to classify a network is by its design. Sometimes it’s also called “the method of connection”.

There are three main types of network designs that we can differentiate:

With radial, a single feeder distributes electricity through one-way circuits directly onto distributers located across each designated area. The radial Distribution System is the most cost-effective option for supplying power in remotely located areas and fairly easy to implement. This type of system uses a single source to serve multiple customers, however one disrupted line can cause an entire outage until repairs are completed, which makes it prone to malfunctions.


Looped power networks usually come with a back-up source of energy. When power from one direction fails, switches automatically or manually divert energy to keep electricity flowing in the other direction. The loop guarantees higher standards of reliability than the radial type. In the case of line faults, utilities can quickly locate them and switch around to restore service - enabling fast repair with minimal customer disruption.


Network systems offer a unique solution for customers needing reliable power in heavily populated and congested areas. This system consists of interlocking loop networks, providing multiple sources to deliver energy efficiently - though it comes with the highest price tag among all alternative options.

Other than design, power distribution networks can also be classified by the supply type or by the construction.


There are two types of supply than we can differentiate:

In terms of the construction there are underground and overhead systems. The underground system is a much safer option than overhead cables. It does come with drawbacks though - primarily its hefty initial cost. The overhead system is the most popular one, and despite being slightly less safe, it does come with higher levels of flexibility.

Learn about the power distribution network - how is it different from the gird and what are the types?

Power Distribution Network  - what is it and what are the types?

Learn about the microgrids and extend the knowledge about the energy system!

, we’re now starting the new year following up and elaborating on the topic of energy networks. It’s time to narrow it down to slightly smaller units.

A microgrid is a small-scale energy system that remains self-sufficient even when it’s completely off-grid. At the heart of such a system there is a local source of power production such as solar, wind or diesel generators which distribute the energy across its receivers in a controlled manner. In newer microgrid systems it’s getting more popular to install some sort of energy storage facilities in order to ensure even greater efficiency.

The U.S. Department of Energy defines the microgrid as follows:

“A microgrid is a group of interconnected loads and distributed energy resources (DER) within clearly defined electrical boundaries that act as a single controllable entity with respect to the grid. A microgrid can connect and disconnect from the grid to enable it to operate in both connected or island-mode.”


In terms of the size required for an energy system to be labeled as a microgrid, there really aren’t any strict patterns. The classification is based more on the actual form and ways of operation rather than size. Thus, a microgrid can be anything from a college campus that runs on solar panels to an island with its own source of energy. With such an approach it also should be clear that while the primary principles remain the same, the microgrids may significantly differ from one another.

While there are a couple of types of microgrids, they all share some alike features.

A microgrid is a local undertaking, meaning that there are defined electrical boundaries and a clear set of energy recipients within the system. Importantly, all the end-users are located in the close proximity of the energy source, making the transmission very efficient. Unlike with the “general grid” (in microgrid contexts, the grid is also known as a 

), where the long-distance transmission itself can consume up to 15% of the carried electricity, in the microgrid setting, all energy produced is utilized to its full potential. Cleanliness would be the second usually shared trait amongst microgrids - they oftentimes run solely on green sources of energy such as wind or solar. Specially popular solar panels have gained popularity in the last few years especially due to becoming affordable and easily accessible. Finally, being independent from the constraints of the macrogrid, microgrids are less prone to malfunctions, overburdening or blackouts.

There are two main types of microgrids hidden under many names. We differentiate mostly: grid-connected and off-grid microgrids.

 microgrids are the ones that cannot be connected to the main electrical grid, meaning they all have an individual source of energy. They can be found particularly in remote areas that are too far and costly to operate from centralized energy sources. Amongst those, we can differentiate locations such as small islands or far-flung but habitable regions in Siberia. Off-grid microgrids can leverage various forms of distributed generation, such as renewable energy sources like solar or wind power, along with an efficient integrated storage system.

The off-grid microgrids used to rely mostly on diesel generators, of which shipping to remote areas was a fairly costly investment. Because of that, the transition to renewable energy is gaining momentum across many operators. On top of the green sources, many also found some energy storage facilities beyond useful and installed them, making the micro energy systems highly smart and self-sufficient. This switch to more modern ways, has led the off-grid microgrids to being one of the most efficient energy systems out there.

These are the microgrids that have the ability to connect/disconnect from the main grid. They operate both connected and autonomously when needed, allowing for emergency power supply or operation changes as conditions dictate. The dualistic possibilities in the operation ways ensure reliable electricity to locations even during macrogrid outages - all while keeping grid-connectivity possible. The disconnection is oftentimes called an island mode and the grid-connected microgrids are sometimes referred to as 


The most common question asked when talking about the islandable microgrids is: what’s the point of it when it can be connected to the main system?

. While macrogrid tends to get overburdened quite frequently, the microgrid users remain indifferent to whatever outages the main grid may have. This solution is especially useful in cases of hospital complexes, where there are few entities that require a constant flow of energy. Similar cases would be with the airports or college campuses.

The benefits also come the other way, as in cases when the macrogrid is reaching its peak capacity, the operators can advise the microgrid controllers that they should switch to an island mode in order to minimize the risk of a big-scale outage.

While these aren’t necessarily the types of microgrids, they can be classified as the topologies. Given that energy management architectures are paramount for a successful microgrid, it’s also worth noting them. They provide the structure to capture energy from different sources and incorporate it into the electrical grids efficiently.

Power sources with AC output are connected to AC bus through AC/AC converter, whilst DC output uses DC/AC converters. While they’re generally more versatile than DC microgrids, the conversion efficiency is lower.

Power sources with DC output are connected to DC bus directly or by DC/DC converters, whilst power sources with AC output are connected to the DC bus through AC/DC converter. With DC microgrids the conversion efficiency is higher which makes them a perfect fit for high-performance electrical demand. Unfortunately, they generally cost more to implement.

The hybrid microgrid allows energy to flow seamlessly between AC and DC power sources, via a bidirectional converter connecting both buses.


While the share of microgrids in the global energy market isn’t yet quite substantial, there’s no question that they make a great way of improving the global energy system’s reliability and efficiency. Amongst the benefits

 – microgrids can keep the lights on even if the power goes out, an especially important feature during extreme weather events.

 – microgrids are a great way to reduce carbon emissions, as they often employ renewable energy sources such as solar and wind, which have little to no environmental impact.

– microgrids can significantly reduce the cost of producing and distributing electricity, as they operate on a smaller scale and the energy is produced locally.

 – microgrids are more resilient to natural disasters or power outages than centralized systems, as their distributed nature offers greater protection from disruption.

 – microgrids can be modified easily to meet changing energy demands, allowing communities to respond quickly and efficiently to changing needs.

After publication about smart grids, we extend the knowledge on the topic. This time, learn about the microgrids!

Microgrids - where are they in the global energy system?

Download our PFD about smart grids and see how the energy industry changes!

Energy-related issues have made the news in the last couple of years probably more than ever before. From the massive shift in energy usage triggered by the onset of Covid to the recent blackouts all over the world, the electricity sector has known no peace recently.

It’s to no surprise, given how inordinate the scale of the entire energy industry is. Being at the core of the whole undertaking, the grid operators have a lot on their plates in terms of keeping everything stable and secure. Energy grids are the virtual spiderwebs that facilitate large-scale electricity delivery from production sites to nearly every home and business across the world. Unequaled in complexity, these incredible networks require intricate planning for cross-border or multi-state operations, delivering power generated by sources like coal plants, natural gas facilities and nuclear plants into electrical energy the humankind uses daily.

In response to the increased demand in electricity worldwide, numerous actions have been taken to ensure its smooth operation. This is how the concept of smart grids came to life.

While grid as such may be understood by many, the prefix “smart” may cause some confusion. In a nutshell, a smart grid is an electricity network based on digital technology, allowing for an interactive flow of energy and data. Generally, what makes the grid smart are the extensive digital features running in the background and optimizing the whole system. A smart grid has the ability to collect, monitor, analyze and manage data from a range of sources to optimize power distribution networks.

In our downloadable PDF, we shed light on all the important aspects of smart grids:

What are the characteristics of a smart grid?

The Energy Glossary - terms you need to know

16 FEBRUARY 2023 • 7 MIN READ