A smoke tube boiler is one in which hot exhaust gas from the engine passes through tubes running within a sealed container of water.

A smart meter is an electronic device that records information such as consumption of electric energy, voltage levels, current, and power factor

Smart lighting is a lighting technology designed for energy efficiency, convenience and security.

A smart grid is an electrical grid which includes a variety of operation and energy measures including an advanced metering infrastructure, smart distribution boards, home control and demand response.

Small, sealed, transportable, autonomous reactor (SSTAR) is a proposed lead-cooled nuclear reactor being primarily researched and developed in the United States. It is designed as a fast breeder reactor that is passively safe.

Small-scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power.

Small wind turbines (wind turbine) also known as Micro Wind are used for microgeneration of electricity, as opposed to large commercial wind turbines, such as those found in wind farms, with greater individual power output.

Small hydro is the development of hydroelectric power on a scale suitable for local community and industry, or to contribute to distributed generation in a regional electricity grid.

A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure.

The slewing drive is a gearbox that can safely hold radial and axial loads, as well as transmit a torque for rotating.

Skin friction is a component of drag, the force resisting the motion of a fluid across the surface of a body.

Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor.

In single-wire earth return (SWER) AC electrical distribution systems, costs are saved by using just a single high voltage conductor for the power grid, while routing the AC return current through the earth.

A single point of failure (SPOF) is a part of a system that, if it fails, will stop the entire system from working.

An alternating current electric power in which all of the voltage supplies change in unison. Generally used in light loads such as heating and lighting.

The one-fluid design includes a large reactor vessel filled with fluoride salt containing thorium and uranium.

A single-circuit transmission line carries conductors for only one circuit.

Power plants that utilise clean burning natural gas through a combustion turbine which drives a generator.

The Sievert is a derived unit of ionizing radiation dose in the International System of Units and is a measure of the health effect of low levels of ionizing radiation on the human body.

Errors introduced by less than accurate weather forecasting which affects the load forecasting and accurate commitment especially in renewable power generation such as wind and solar power.