Range Anxiety is the fear that a vehicle has insufficient range to reach its destination and would thus strand the vehicle's occupants. The term, which is primarily used in reference to battery electric vehicles (BEVs), is considered to be one of the major barriers to large-scale adoption of all-electric cars.

The rare-earth elements (REE), also called the rare-earth metals are a set of 17 nearly-indistinguishable lustrous silvery-white soft heavy metals. Despite their name, rare-earth elements are relatively plentiful in Earth's crust, with cerium being the 25th most abundant element at 68 parts per million, more abundant than copper. The largest market for rare earths are for magnets, mostly using the so-called “technology metals,” which are used in everything from electric motors to lasers to cancer treatment to nuclear reactors to commercial lighting.

This is crude oil direct from the wellbore, before it is treated in a gas separation plant.

A raw material, also known as a feedstock, unprocessed material, or primary commodity, is a basic material that is used to produce goods, finished products, energy, or intermediate materials that are feedstock for future finished products. As feedstock, the term connotes these materials are bottleneck assets and are required to produce other products.

This is gas that is produced from the well, unprocessed natural gas or the inlet natural gas to a plant. The raw gas still contains natural gas liquidswater and some other impurities. The raw gas must be processed in a gas processing plant to make it ready to be sold. 

A reinforcing steel bar used to strengthen and aid concrete under tension for construction applications.

A rebar, or reinforcing bar, is a common steel bar that is used in reinforced concrete and masonry in order to strengthen and hold the concrete in its structure. 

A rechargeable battery is a type of electrical battery which can be charged, discharged into a load, and recharged many times, as opposed to a disposable or primary battery, which is supplied fully charged and discarded after use. It is composed of one or more electrochemical cells.

Rechargeable batteries are produced in many different shapes and sizes, ranging from button cells to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of electrode materials and electrolytes are used, including lead–acid, zinc–air, nickel–cadmium (NiCd), nickel–metal hydride (NiMH), lithium-ion (Li-ion), lithium iron phosphate (LiFePO4), and lithium-ion polymer (Li-ion polymer).

That proportion of the oil and/gas in a reservoir that can be removed using currently available techniques.

The ratio of recoverable oil and/or gas reserves to the estimated oil and/or gas in place in the reservoir.

Residual gas that remains in the drilling fluid despite being circulated to the surface. At the surface, it remains in the mudstream, which is suctioned from the mud pit and recirculated into the wellbore.

Carbon or hydrogen used to remove oxygen from iron ore to produce iron and steel.

Reformate is the output of fuel reformer. Such as gas stream often contains hydrogen, carbon monoxide and carbon dioxide. This reformate gas can be fed to a fuel cell, generally after some degree of cleanup.

Regen (regenerative braking) is an energy recovery mechanism that slows down a moving vehicle or object by converting its kinetic energy into a form that can be either used immediately or stored until needed.

Reheat furnaces are used to ensure that partly worked steel, which has been allowed to cool, arrives at its next processing stage at the optimum temperature. The furnace heats metal ingots, billets and blooms in order to bring them to the temperature required for hot-working.