Electromagnetic energy is the energy that comes from electromagnetic radiation. This radiation is composed of waves, such as radio waves and visible light, that move at the speed of light in a way that is suggestive of both waves and particles. Electromagnetic radiation causes both electric and magnetic fields. Only a small part of the electromagnetic field is visible; this part of the electromagnetic spectrum is known as the visible spectrum.

The field of electrodynamics, which is a subfield of electromagnetism, is the aspect of physics that focuses on the study of electromagnetic energy. It is an ongoing field, as electromagnetic energy is a significant part of the field of quantum physics, which is still a major area of study in modern physics. One major area of interest in the study of electromagnetic energy is the wave-particle duality of electromagnetic waves. When analyzed over long periods of time and long distances, electromagnetic waves are seen to behave as typical, oscillating waves. Over short distances, however, these waves behave as particles based on their movements and deflections.

People have started to utilize electromagnetic energy in the form of solar power, using solar panels to gather the radiant energy that comes from the sun and use it for electricity. This has many advantages, as the energy is clean and renewable. Many hope that, in the long run, it will provide a viable alternative to gaining energy from fossil fuels. Solar panels are dependent on weather, though, so they are not very useful in parts of the world that experience heavy cloud cover on a regular basis. The electromagnetic energy from the sun is also used to power various satellites and other devices in space that can not be readily or easily fueled with fossil fuels.

Plants also make extensive use of electromagnetic energy from the sun; that energy is an essential part of photosynthesis, the method by which plants produce food. The solar energy is converted to chemical energy that powers the processes allowing plants to produce the glucose they need to survive from carbon dioxide and water. The byproduct of this reaction is oxygen, which is necessary to human survival.

Electromagnetic energy is also used for communication purposes. Radio waves are electromagnetic waves that are used at a variety of frequencies for communication purposes. Nikola Tesla even postulated that electromagnetic waves could be used to power various devices remotely over large distances, though his theories on the subject were not put into practice.