Electric Energy – What It Is, How It Is Produced, and How We Use It

What is electric energy?

The concept of electric energy can be understood in several ways. Leaving aside the strict scientific terminology of physics, electric energy can be described as the energy that an electric current delivers to a device performing work. Electric current itself is the ordered movement of electric charge carriers through a conductive material.

In nature, electric current appears in several forms, most notably:

• Atmospheric discharges (thunderstorms), where air serves as the conductive medium,
• Nervous system activity, where electrical conduction is enabled by biochemical processes, particularly the action of the sodium–potassium pump,
• The solar wind, a stream of particles flowing from the Sun.

Humans learned to harness electric current relatively recently—only at the beginning of the 19th century. This was a breakthrough achievement, allowing for the electrification of industry and freeing technological processes from the natural day–night cycle.

The history of electric energy – from discovery to modern technologies

The origins of global power engineering date back to 1800, when Italian scientist Alessandro Volta invented the electric cell—the first artificial source of current and the predecessor of today’s batteries. This led to inventions such as the arc lamp, first used in the Paris Opera. In 1881, the International Exposition of Electricity in Paris showcased light bulbs, which eventually replaced gas lamps.

Just a year later, the first power plant was built in London, supplying electricity to nearly a thousand homes. Soon after, plants were established in Germany and Paris. By 1890, the French capital boasted a combined power capacity of about 5,000 horsepower.

The young field of electrical engineering quickly accelerated. By the late 19th century, electricity was already in practical use, and the first urban power grids were established. This era also gave rise to inventions such as the telephone, electric motor, tram, and television.

Today, electricity powers virtually every industry. Of particular note is photovoltaics, which generates electric energy from solar radiation through the photovoltaic effect. Silicon photovoltaic micro-installations are now a common sight on residential and industrial rooftops, while large-scale solar farms continue to expand. The world’s largest solar farm is in Gonghe County, Qinghai Province, China, covering over 600 km²—roughly the land area of Singapore—with an output of 15,600 MW as of 2023.

Electricity also unlocks the potential of wind and tidal energy. The rapid development of onshore and offshore wind farms is considered an environmentally friendly alternative to traditional coal-fired power plants.

The production, transmission, and consumption of electric energy on a large scale are increasingly managed through smart grids. These integrate wireless communication, smart meters, and artificial intelligence algorithms to automate and optimize energy flow, creating flexible, scalable systems while reducing transmission losses.

Another rapidly growing technology is energy storage, which addresses the main limitation of electricity—its need to be used as it is produced. Storage systems differ in cell technology and capacity. A notable example is the Tesla Powerwall, an efficient and relatively affordable home energy storage solution.

How electric energy is produced today

Modern electricity is generated on a massive scale using various methods:

• Coal-fired power plants – the simplest but least environmentally friendly, relying on finite natural resources and producing significant emissions.
• Gas-fired power plants – more ecological than coal, but still nonrenewable.
• Nuclear power plants – although classified as nonrenewable, nuclear energy is far more efficient and emits far less carbon than coal.
• Renewable energy sources – including wind farms, hydropower plants, solar farms, biomass/biogas facilities, and geothermal systems.

Despite their differences, all these methods ultimately drive a generator that converts mechanical energy (from steam, wind, or water) into electricity.

The future of electric energy lies in sustainable development, advanced storage technologies, and the ongoing modernization of power grids to ensure more stable, low-loss transmission.

Units of electric energy – how we measure it

The basic unit of electric energy used to calculate consumption is the kilowatt-hour (kWh). This represents the amount of energy consumed by a device with a power rating of 1,000 watts operating continuously for one hour. Consumption is measured using an electric meter, which can be:

• Induction meters – the oldest type, with an aluminum disk that spins faster as more power is used,
• Electronic meters – digital displays provide more precise readings,
• Smart meters – transmit real-time data directly to the energy supplier, reducing billing errors and enabling rapid detection of outages.

Meters can also be one-way (measuring only energy drawn from the grid) or two-way, which also measure energy fed back into the grid—essential for photovoltaic installations.

Everyday uses of electric energy

Electricity powers nearly every aspect of modern life:

• Household appliances and electronics,

• Lighting in homes and cities,

• Industrial machinery,

• Transportation, including railways, trams, and the rapidly growing electric vehicle (EV) sector.

For example, India alone registered over 2 million electric vehicles in a single year.