Molten-salt batteries are a class of battery that uses molten salts as an electrolyte and offers both a high energy density and a high power density.

A molten salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a molten salt mixture.

The mole (symbol: mol) is the unit of measurement for amount of substance in the International System of Units (SI).

Evacuated tube collectors make use of a glass tube to surround the absorber with high vacuum and effectively resist atmospheric pressure.

Evacuated flat plate collectors surround a large area metal sheet absorber with high vacuum inside a flat envelope made of glass and metal.

A eutectic system is a homogeneous mixture of substances that melts or solidifies at a single temperature that is lower than the melting point of any of the constituents.

EU Directive established an energy consumption labelling scheme.

ENTSO-E represents 42 electricity transmission system operators (TSOs) from 35 countries across Europe, thus extending beyond EU borders.

A set of policy initiatives by the European Commission with the overarching aim of making Europe climate neutral in 2050.

An energy exchange which develops, operates and connects secure, liquid and transparent markets for energy and commodity products around the globe which includes contracts for energy trading.

Ethanol fuel is ethyl alcohol, the same type of alcohol found in alcoholic beverages, used as fuel.

Used in the photovoltaics industry as an encapsulation material for crystalline silicon solar cells in the manufacture of photovoltaic modules.

Etendue is a property of light in an optical system, which characterizes how "spread out" the light is in area and angle.

An erg is the amount of work done by a force of one dyne exerted for a distance of one centimetre. In the CGS base units, it is equal to one gram centimetre-squared per second-squared (g⋅cm2/s2).

Loads served by the heating/cooling system that are not included in peak heating/ cooling block load calculations.

Equipment grounding is a component of electrical systems that protects against fault currents.

Epoxy refers to any of the basic components or cured end products of epoxy resins, as well as a colloquial name for the epoxide functional group. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups.

An epicyclic gear train (also known as a planetary gearset) consists of two gears mounted so that the center of one gear revolves around the center of the other.

Refers to contracts that include engineering, procurement and construction.

An enzymatic biofuel cell is a specific type of fuel cell that uses enzymes as a catalyst to oxidize its fuel, rather than precious metals.