Pulsed power is the science and technology of accumulating energy over a relatively long period of time and releasing it instantly, thus increasing the instantaneous power. They can be used in some applications such as food processing, water treatment, weapons, and medical applications.

Energy is typically stored as electric potential energy within capacitors, or in the case of explosive pulsed power, as chemical energy. The stored energy is released over a very short time scale resulting in a large amount of power being delivered to a load which can be used to study high energy density physics phenomena such as inertial confinement fusion using a Z-pinch, and plasma physics or to create electromagnetic radiation.

Some electrically driven pulsed power accelerators make use of pulse-forming lines to compress the current pulse before reaching the load, as is often the case when Marx generators are used as the prime power source. Other circuit architectures such as linear transformer drivers or impedance-matched Marx generators typically do not require any pulse compression.

Single pulse energies as high as 100 MJ, power as high as a "few hundred terawatts" with voltages between 10 kV and 50 MV, and currents between 1 kA and 10 MA, have been achieved at least as of 2006.

Pulsed power systems are used in inertial confinement fusion research, most notably at the Z Pulsed Power Facility at Sandia National Laboratories, which uses Z-pinch implosions for nuclear stockpile stewardship science. The MagLIF (magnetized liner inertial fusion) program on Z has achieved the second-highest fusion triple product recorded.

Several private companies are also developing pulsed power systems for commercial fusion power, including Pacific Fusion, Fuse, and First Light Fusion.

Railguns utilise pulsed power to quickly accelerate an object.