Accelerated aging is testing that uses aggravated conditions of heat, humidity, oxygen, sunlight, vibration, etc. to speed up the normal aging processes of items.

An AC generator converts mechanical energy into alternating current electricity.

AC power plugs and sockets connect electric equipment to the alternating current power supply.

An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure.

An absorption refrigerator is a refrigerator that uses a heat source (e.g., solar energy, a fossil-fueled flame, waste heat from factories, or district heating systems) to provide the energy needed to drive the cooling process.

In physics, absorption of electromagnetic radiation is how matter (typically electrons bound in atoms) takes up a photon's energy — and so transforms electromagnetic energy into internal energy of the absorber (for example, thermal energy).

AGM batteries differ from flooded lead–acid batteries in that the electrolyte is held in the glass mats, as opposed to freely flooding the plates.

Absorbed dose is a dose quantity which is the measure of the energy deposited in matter by ionizing radiation per unit mass.

Absolute zero is the lowest limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as zero kelvins.

Absolute pressure is zero-referenced against a perfect vacuum, using an absolute scale, so it is equal to gauge pressure plus atmospheric pressure.

An instrument used for very accurate measurements of solar irradiance.

Abiogenic petroleum origin is a body of hypotheses which propose that petroleum and natural gas deposits are mostly formed by inorganic means, rather than by the decomposition of organisms.

The 2000-watt society is an environmental vision, first introduced in 1998 by the Swiss Federal Institute of Technology in Zürich (ETH Zurich), which pictures the average First World citizen reducing their overall average primary energy usage rate to no more than 2,000 watts (i.e. 2 kWh per hour or 48 kWh per day) by the year 2050, without lowering their standard of living.

The goal of economic dispatch is to minimize total operating costs in an area by determining how the real power output of each generating unit will meet a given load.

In British waters, the cost of removing all platform rig structures entirely was estimated in 2013 at £30 billion.

Ecological design or ecodesign is an approach to designing products and services with special consideration for the environmental impacts of the product during its whole lifecycle.

An ecological crisis occurs when changes to the environment of a species or population destabilizes its continued survival.

Eco-sufficiency refers to the concept or strategy to reduce the environmental footprint of modern societies. As a goal, sufficiency is about ensuring that all humans can live a good life without overshooting the ecological limits of the Earth, while at the same time defining what that good life may consist of.

Applied to goods and services that satisfy our needs and bring quality of life and reduction in environmental impacts. It is based on the concept of producing more goods while reducing the resources required, especially those resources that harm the environment.

The Eastern Interconnection is one of the two major alternating current (AC) wide area synchronous power grids in the continental U.S. power transmission grid.