Barrels
A unit of volume equal to 42 U.S. gallons. Source
Biogas
The gaseous product of the decomposition of organic matter. Source
Biomass
Organic non-fossil material of biological origin constituting a renewable energy source. Source
Capacitor/Supercapacitor
A capacitor stores energy by means of a static charge as opposed to an electrochemical reaction. Applying a voltage differential on the positive and negative plates charges the capacitor. The supercapacitor, also known as ultracapacitor or double-layer capacitor, differs from a regular capacitor in that it has very high capacitance. Source
Capacity
The maximum output, commonly expressed in megawatts (MW), that generating equipment can supply to system load, adjusted for ambient conditions. Source
Capacity Factor
The ratio of the electrical energy produced by a generating unit for the period of time considered to the electrical energy that could have been produced at continuous full power operation during the same period. Source • Learn More
Coal (hard)
Anthracite coal is a hard, brittle, and black lustrous coal. It is considered the highest rank of coal. It contains a high percentage of fixed carbon and a low percentage of volatile matter. Source
Coal (soft)
Bituminous coal is a middle rank coal between subbituminous and anthracite. Bituminous usually has a high heating (Btu) value and is the most common type of coal used in electricity generation in the United States. Bituminous coal appears shiny and smooth when you first see it, but look closer and you may see it has layers. Source
Coalbed Methane
Methane produced from coal seams. Coalbed methane is formed during coalification, which is the geologic process that transforms organic material into coal. Source
Conventional Crude
A mixture of hydrocarbons that exists in liquid phase in natural underground reservoirs and remains liquid at atmospheric pressure after passing through surface separating facilities. Depending upon the characteristics of the crude stream, it may also include 1. Small amounts of hydrocarbons that exist in gaseous phase in natural underground reservoirs but are liquid at atmospheric pressure after being recovered from oil well (casing head) gas in lease separators and are subsequently comingled with the crude stream without being separately measured. Lease condensate recovered as a liquid from natural gas wells in lease or field separation facilities and later mixed into the crude stream is also included; 2. Small amounts of nonhydrocarbons produced with the oil, such as sulfur and various metals; 3. Drip gases, and liquid hydrocarbons produced from tar sands, oil sands, gilsonite, and oil shale. Liquids produced at natural gas processing plants are excluded. crude oil is refined to produce a wide array of petroleum products, including heating oils; gasoline, diesel and jet fuels; lubricants; asphalt; ethane, propane, and butane; and many other products used for their energy or chemical content. Source
Conventional Gas
Natural gas that is produced by a well drilled into a geologic formation in which the reservoir and fluid characteristics permit the oil and natural gas to readily flow to the wellbore. Source
Economic Lifetime
The time period over which an asset's net present value is maximized. Economic life can be less than absolute physical life for reasons of technological obsolescence, physical deterioration, or product life cycle. Source
Energy Crops
Energy crops are grown specifically for use as fuel and offer high output per hectare with low inputs. Learn More
Energy/Power Density
Energy density is the amount of energy in a given mass (or volume) and power density is the amount of power in a given mass. The distinction between the two is similar to the difference between Energy and Power. Batteries have a higher energy density than capacitors, but a capacitor has a higher power density than a battery. This difference comes from batteries being able to store more energy, but capacitors can give off energy more quickly. Source
Fission
The process whereby an atomic nucleus of appropriate type, after capturing a neutron, splits into (generally) two nuclei of lighter elements, with the release of substantial amounts of energy and two or more neutrons. Source
Flywheel
Flywheel energy storage systems (FESS) use electric energy input which is stored in the form of kinetic energy. Source
Fusion
A reaction in which at least one heavier, more stable nucleus is produced from two lighter, less stable nuclei. Reactions of this type are responsible for enormous release of energy, such as the energy given off by stars. Source
Geothermal
Hot water or steam extracted from geothermal reservoirs in the earth's crust. Water or steam extracted from geothermal reservoirs can be used for geothermal heat pumps, water heating, or electricity generation. Source
High Altitude Wind Energy
Wind power generated between altitudes of 500 - 12,000m. Source
High Temperature Thermal
A collector that generally operates at temperatures above 180 degrees Fahrenheit. Source
Hybrid Flow Battery
The flow battery is a form of battery in which electrolyte containing one or more dissolved electroactive species flows through a power cell/reactor in which chemical energy is converted to electricity. Additional electrolyte is stored externally, generally in tanks, and is usually pumped through the cell (or cells) of the reactor. Hybrid flow batteries, such as zinc bromine batteries, contain metallic species deposited in one of the half cells. Source
Hydrogen Fuel Cell/Electrolyzer
A fuel cell is a device that converts chemical potential energy (energy stored in molecular bonds) into electrical energy. A PEM (Proton Exchange Membrane) cell uses hydrogen gas (H2) and oxygen gas (O2) as fuel. The products of the reaction in the cell are water, electricity, and heat. Source Electrolysis is the process of using electricity to split water into hydrogen and oxygen. This reaction takes place in a unit called an electrolyzer. Electrolyzers can range in size from small, appliance-size equipment that is well-suited for small-scale distributed hydrogen production to large-scale, central production facilities that could be tied directly to renewable or other non-greenhouse-gas-emitting forms of electricity production. Source
Hydropower
The use of flowing water to produce electrical energy. Source
LCOE
Levelized Cost Of Energy, Levelized cost (LCOE) in USD2010/MWhe LCOE = α · I + OM + F ____ E (Equation A.III.1) α = ____r 1 − (1 + r) −LT (Equation A.III.2) I = _ C LB · ∑ t = 1 LB (1 + i) t · ( 1 + __d (1 + r) LT ) (Equation A.III.3) OM = FOM + (VOM − REV + dυ) · E (Equation A.III.4) E = P · FLH (Equation A.III.5) F = FC · _E η (Equation A.III.6) Where: • LCOE is the levelized cost of electricity. • α is the capital recovery factor (CRF). • r is the weighted average cost of capital (WACC—taken as either 5% or 10%). • I is the investment costs, including finance cost for construction at interest i. • C is the capital costs, excluding finance cost for construction (‘overnight cost’). In order to calculate the cost for construction, the overnight costs are equally distributed over the construction period. • d represent the decommissioning cost. Depending on the data in the literature, this is incorporated as an extra capital cost at the end of the project duration which is discounted to t = 0 (using a decommissioning factor d, as in (Equation A.III.3)), or as a corresponding variable cost (dv in (Equation A.III.4)). d = 0.15 for nuclear energy, and zero for all other technologies (given the low impact on LCOE). • OM are the net annual operation and maintenance costs; summarizing fixed OM (FOM), variable OM (VOM), and variable byproduct revenues (REV). As a default and if not stated explicitly otherwise, carbon costs (e.g., due to carbon taxes or emission trading schemes) are not taken into account in calculating the LCOE values. • E is the energy (electricity) produced annually, which is calculated by multiplying the capacity (P) with the number of (equivalent) full load hours (FLH). • F are the annual fuel costs, • FC are the fuel costs per unit of energy input, and • η is the conversion efficiency (in lower heating value—LHV). • i is the interest rate over the construction loan (taken as 5%). • LT is the project duration (in operation), as defined in IEA (2010). • LB is the construction period. Source
Lead-acid Battery
A type of battery that uses plates made of pure lead or lead oxide for the electrodes and sulfuric acid for the electrolyte. Source
Levelized Cost
The present value of the total cost of building and operating a generating plant over its economic life, converted to equal annual payments. Costs are levelized in real dollars (i.e., adjusted to remove the impact of inflation) Source
Lithium-Ion Battery
A lithium-ion (Li-ion) battery is an advanced battery technology that uses lithium ions as a key component of its electrochemistry. During a discharge cycle, lithium atoms in the anode are ionized and separated from their electrons. The lithium ions move from the anode and pass through the electrolyte until they reach the cathode, where they recombine with their electrons and electrically neutralize. The lithium ions are small enough to be able to move through a micro-permeable separator between the anode and cathode. Source
Low Temperature Thermal
A collector that generally operates at temperatures below 180 degrees Fahrenheit. Source
Megawatthour (MWh)
One thousand kilowatt-hours or 1million watt-hours. Source
Methane Hydrates
Solid, crystalline, wax-like substances composed of water, methane, and usually a small amount of other gases, with the gases being trapped in the interstices of a water-ice lattice. They form beneath permafrost and on the ocean floor under conditions of moderately high pressure and at temperatures near the freezing point of water. Source
NaS (Sodium Sulfur) Battery
The sodium sulphur battery is a high-temperature battery. It operates at 300°C and utilises a solid electrolyte, making it unique among the common secondary cells. One electrode is molten sodium and the other molten sulphur, and it is the reaction between these two that is the basis for the cell reaction. Source
Ocean Wave Energy
Ocean waves contain tremendous energy potential. Wave power devices extract energy directly from the surface motion of ocean waves. In many areas of the world, the wind blows with enough consistency and force to provide continuous waves along the shoreline. Source
Offshore
That geographic area that lies seaward of the coastline. In general, the coastline is the line of ordinary low water along with that portion of the coast that is in direct contact with the open sea or the line marking the seaward limit of inland water. If a state agency uses a different basis for classifying onshore and offshore areas, the state classification should be used (e.g., Cook Inlet in Alaska is classified as offshore; for Louisiana, the coastline is defined as the Chapman Line, as modified by subsequent adjudication). Source • Learn More
Oil Shale
A sedimentary rock containing kerogen, a solid organic material. Source
Onshore
A direction landward from the sea. Source
Particulate Matter
A small, discrete mass of solid or liquid matter that remains individually dispersed in gas or liquid emissions. particulates take the form of aerosol, dust, fume, mist, smoke, or spray. Each of these forms has different properties. Source
Peat
Peat consists of partially decomposed plant debris. It is considered an early stage in the development of coal. peat is distinguished from lignite by the presence of free cellulose and a high moisture content (exceeding 70 percent). The heat content of air-dried peat (about 50 percent moisture) is about 9 million Btu per ton. Most U.S. peat is used as a soil conditioner. The first U.S. electric power plant fueled by peat began operation in Maine in 1990. Source
Photovoltaic
Energy radiated by the sun as electromagnetic waves (electromagnetic radiation) that is converted at electric utilities into electricity by means of solar (photovoltaic) cells or concentrating (focusing) collectors. Source
Pumped Hydro
A plant that usually generates electric energy during peak load periods by using water previously pumped into an elevated storage reservoir during off-peak periods when excess generating capacity is available to do so. When additional generating capacity is needed, the water can be released from the reservoir through a conduit to turbine generators located in a power plant at a lower level. Source
Redox Flow Battery
Redox flow batteries (RFB) represent one class of electrochemical energy storage devices. The name “redox” refers to chemical reduction and oxidation reactions employed in the RFB to store energy in liquid electrolyte solutions which flow through a battery of electrochemical cells during charge and discharge. Source
Salinity Gradient Ocean Energy
At the mouth of rivers where fresh water mixes with salt water, energy associated with the salinity gradient can be harnessed using pressure-retarded reverse osmosis process and associated conversion technologies. Another system is based on using freshwater upwelling through a turbine immersed in seawater, and one involving electrochemical reactions is also in development. Source
Scalability
A characteristic of a system, model or function that describes its capability to cope and perform under an increased or expanding workload. A system that scales well will be able to maintain or even increase its level of performance or efficiency when tested by larger operational demands. Source
Sensible/Latent Heat Storage
Sensible heat storage is based on raising the temperature of a liquid or solid to store heat and releasing it with the decrease of temperature when it is required. Source
Shale Gas
Natural gas produced from wells that are open to shale formations. Shale is a fine-grained, sedimentary rock composed of mud from flakes of clay minerals and tiny fragments (silt-sized particles) of other materials. The shale acts as both the source and the reservoir for the natural gas. Source
Solar Fuels
Solar energy can be captured and stored directly in the chemical bonds of a material, or ‘fuel’, and then used when needed. These chemical fuels, in which energy from the sun has deliberately been stored, are called solar fuels. What is new here is not the fuels themselves, but the way that we can use energy from the sun to produce them. The word ‘fuel’ is used in a broad sense: it refers not only to fuel for transport and electricity generation, but also feedstocks used in industry. Source
Super Magnetic Energy Storage (SMES)
Superconducting magnetic energy storage (SMES) is a technologically advanced method of storing energy in a magnetic field, which is formed when a current flows around a coil. In order for this to operate efficiently as an energy storage system, the coil must be made of a superconductor that has no electrical resistance so that there are no resistive energy losses as the current circulates. Source
Tar Sands
Naturally occurring bitumen-impregnated sands that yield mixtures of liquid hydrocarbon and that require further processing other than mechanical blending before becoming finished petroleum products. Source
Terawatthour
(TWh) One trillion watthours. Source
Thermal Conversion
The process or technologies for producing energy by harnessing the temperature differences (thermal gradients) between ocean surface waters and that of ocean depths. Warm surface water is pumped through an evaporator containing a working fluid in a closed Rankine-cycle system. The vaporized fluid drives a turbine/generator. Source • Learn More
Tidal
A form of ocean energy in which tides coming into shore are trapped in reservoirs behind dams. Then when the tide drops, the water behind the dam can be let out just like in a regular hydroelectric power plant. Source • Learn More
Tight Oil
Oil produced from petroleum-bearing formations with low permeability such as the Eagle Ford, the Bakken, and other formations that must be hydraulically fractured to produce oil at commercial rates. Shale oil is a subset of tight oil. Source
Waste
Municipal solid waste (MSW) resources include mixed commercial and residential garbage, such as yard trimmings, paper and paperboard, plastics, rubber, leather, textiles, and food wastes. Also, wet waste feedstocks include commercial, institutional, and residential food wastes (particularly those currently disposed of in landfills); organic-rich biosolids (i.e., treated sewage sludge from municipal wastewater); manure slurries from concentrated livestock operations; and organic wastes from industrial operations. Source
Watthour (Wh)
The electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electric circuit steadily for one hour. Source
Wood and residues
Whole-tree biomass harvested explicitly for biomass, forest residues left after logging timber, and wood processing yields byproducts and waste streams. Source