GLOSSARY
  NORTHPORT                          ENERGY
Almost every field has developed its own unique, and sometimes challenging, vocabulary.  This is certainly true for the field of renewable energy.  We offer the following list of commonly used terms and definitions to assist. For an even more exhaustive glossary, the Department of Energy provides an excellent one on their web site:   http://energy.gov/eere/energybasics/articles/glossary-energy-related-terms 


AIR
The mixture of gases that surrounds the earth and forms its atmosphere, composed of, by volume, 21 percent oxygen, 78 percent nitrogen and 1percent miscellaneous other gasses.

AIR INFILTRATION MEASUREMENT
A building energy auditing technique used to determine and/or locate air leaks in a building shell or envelope.

ALTERNATIVE FUELS
A popular term for "non-conventional" transportation fuels derived from natural gas (propane, compressed natural gas, methanol, etc.) or biomass materials (ethanol, methanol).

ARRAY (SOLAR)
Any number of solar photovoltaic modules or solar thermal collectors or reflectors connected together to provide electrical or thermal energy.

AVERAGE DEMAND
The demand on, or the power output of, an electrical system or any of its parts over an interval of time, as determined by the total number of kilowatt-hours divided by the units of time in the interval.

AVOIDED COST
Avoided cost is the cost the utility would have incurred had it supplied the power itself or obtained it from another source.

BALANCE-OF-SYSTEM
In a renewable energy system, refers to all components other than the mechanism used to harvest the resource (such as photovoltaic panels or a wind turbine). Balance-of-system costs can include design, land, site preparation, system installation, support structures, power conditioning, operation and maintenance, and storage.

BASELOAD CAPACITY
The power output of a power plant that can be continuously produced.

BASELOAD DEMAND
The minimum demand experienced by a power plant.

BENEFITS CHARGE
The addition of a per unit tax on sales of electricity, with the revenue generated used for or to encourage investments in energy efficiency measures and/or renewable energy projects.

BIOCHAR
Biochar is charcoal used as a soil amendment. Like most charcoal, biochar is made from biomass via pyrolysis. Biochar is under investigation as an approach to carbon sequestration to reduce carbon dioxide emissions.

BIOMASS
As defined by the Energy Security Act (PL 96-294) of 1980, "any organic matter which is available on a renewable basis, including agricultural crops and agricultural wastes and residues, wood and wood wastes and residues, animal wastes, municipal wastes, and aquatic plants.”

BUILDING OVERALL HEAT LOSS RATE
The overall rate of heat loss from a building by means of transmission plus infiltration, expressed in Btu per hour, per degree temperature difference between the inside and outside.

BUY-ALL / SELL-ALL
Some utility companies offer an alternative to the Net-Metering option by allowing a solar array to be installed on a separate meter. Under this type of connection you will sell all of the energy produced by the solar array rather than using it in your home. In return, the customer agrees to puchase all of their energy from the utility as well.

CARBON DIOXIDE
A colorless, odorless noncombustible gas with the formula CO2 that is present in the atmosphere. It is formed by the combustion of carbon and carbon compounds (such as fossil fuels and biomass), by respiration, which is a slow combustion in animals and plants, and by the gradual oxidation of organic matter in the soil.

CARBON MONOXIDE
A colorless, odorless but poisonous combustible gas with the formula CO. Carbon monoxide is produced in the incomplete combustion of carbon and carbon compounds such as fossil fuels (i.e. coal, petroleum) and their products (e.g. liquefied petroleum gas, gasoline), and biomass.

CLEAN POWER GENERATOR
A company or other organizational unit that produces electricity from sources that are thought to be environmentally cleaner than traditional sources. Clean, or green, power is usually defined as power from renewable energy that comes from wind, solar, biomass energy, etc. 

COGENERATION
The generation of electricity or shaft power by an energy conversion system and the concurrent use of rejected thermal energy from the conversion system as an auxiliary energy source.

COMMUNITY SHARED SOLAR
A solar-electric system that provides power and/or financial benefit to multiple community members. Community solar is an option for the estimated 85% of energy consumers who either do not own their homes, have roofs that are shaded or not appropriately oriented, or simply do not want to invest in a solar system on their property. There are many models for operating a community solar project. Typically, participants may either receive elctricity directly, or a credit for energy produced, from the portion of the project they own. 
   
CONSUMPTION CHARGE
The part of a power provider's charge based on actual energy consumed by the customer; the product of the kilowatt-hour rate and the total kilowatt-hours consumed.

DEGREE DAY
A unit for measuring the extent that the outdoor daily average temperature (the mean of the maximum and minimum daily dry-bulb temperatures) falls below (in the case of heating, see Heating Degree Day), or falls above (in the case of cooling, see Cooling Degree Day) an assumed base temperature, normally taken as 65 degrees Fahrenheit, unless otherwise stated. One degree day is counted for each degree below (for heating) or above (in the case of cooling) the base, for each calendar day on which the temperature goes below or above the base.

DEMAND
The rate at which electricity is delivered to or by a system, part of a system, or piece of equipment expressed in kilowatts, kilovoltamperes, or other suitable unit, at a given instant or averaged over a specified period of time.

DEMAND RESPONSE
Demand response provides an opportunity for consumers to play a significant role in the operation of the electric grid by reducing or shifting their electricity usage during peak periods. Electric energy can not be easily stored, so utilities have traditionally matched demand and supply by throttling the production rate of their power plants, taking generating units on or off line, or importing power from other utilities. Demand response seeks to adjust the demand for power instead of adjusting the supply.

DISTRIBUTION
The process of distributing electricity; usually defines that portion of a power provider's power lines between a power provider's power pole and transformer and a customer's point of connection/meter.

DISTRIBUTED GENERATION 
Distributed generation (DG) refers to electricity that is produced at or near the point where it is used. Distributed solar energy can be located on rooftops or ground-mounted, and is typically connected to the local utility distribution grid. States, cities and towns are experimenting with policies to encourage distributed solar to offset peak electricity demand and stabilize the local grid.

ENERGY
The capability of doing work; different forms of energy can be converted to other forms, but the total amount of energy remains the same.

ENERGY AUDIT
A survey that shows how much energy you use in your house or apartment. It will help you find ways to use less energy.

ENERGY STORAGE
The process of storing, or converting energy from one form to another, for later use; storage devices and systems include batteries, conventional and pumped storage hydroelectric, flywheels, compressed gas, and thermal mass.

​FEDERAL ENERGY REGULATORY COMMISSION (FERC)
The Federal Energy Regulatory Commission is the United States federal agency with jurisdiction over interstate electricity sales, wholesale electric rates, hydroelectric licensing, natural gas and oil pipeline transportation rates. FERC also reviews and authorizes liquefied natural gas (LNG) terminals, interstate natural gas pipelines, and non-federal hydropower projects.

FEED-IN TARIFF
Feed-in tariff (FIT) is an energy supply policy that promotes the rapid deployment of renewable energy resources. A FIT offers a guarantee of payments to renewable energy developers for the electricity they produce. Payments can be composed of electricity alone or of electricity bundled with renewable energy certificates. These payments are generally awarded as long-term contracts set over a period of 15-20 years.

Feed-in tariff policies are successful around the world, notably in Europe. Currently there are six U.S. states (California, Hawaii, Maine, Oregon, Vermont, and Washington) that mandate FITs or similar programs. A few other states also have utilities with voluntary FITs. There is growing interest in FIT programs in the United States especially as evidence mounts about their effectiveness as framework for promoting renewable energy development and job creation.

GASIFICATION
The process in which a solid fuel is converted into a gas; also known as pyrolitic distillation or pyrolysis. Production of a clean fuel gas makes a wide variety of power options available.

GEOTHERMAL ENERGY
Energy produced by the internal heat of the earth; geothermal heat sources include: hydrothermal convective systems; pressurized water reservoirs; hot dry rocks; manual gradients; and magma. Geothermal energy can be used directly for heating or to produce electric power.

HEAT PUMP
An electricity powered device that extracts available heat from one area (the heat source) and transfers it to another (the heat sink) to either heat or cool an interior space or to extract heat energy from a fluid.

INSTALLED CAPACITY
The total capacity of electrical generation devices in a power station or system.

KILOWATT (KW)
A standard unit of electrical power equal to one thousand watts, or to the energy consumption at a rate of 1000 Joules per second.

KILOWATT-HOUR
A unit or measure of electricity supply or consumption of 1,000 Watts over the period of one hour; equivalent to 3,412 Btu.

LOAD
The power required to run a defined circuit or system, such as a refrigerator, building, or an entire electricity distribution system.

LOAD LEVELING
The deferment of certain loads to limit electrical power demand, or the production of energy during off-peak periods for storage and use during peak demand periods.

MEGAWATT
One thousand kilowatts, or 1 million watts; standard measure of electric power plant generating capacity.

METHANE
A colorless, odorless, tasteless and highly flammable gas composed of one molecule of carbon and four of hydrogen. It is the main constituent of "natural gas" that is formed naturally by methanogenic, anaerobic bacteria or can be manufactured, and which is used as a fuel and for manufacturing chemicals.

MIDCONTINENT INDEPENDENT SYSTEM OPERATOR (MISO)
The Midcontinent Independent System Operator, Inc. is an Independent System Operator (ISO) and the Regional Transmission Organization (RTO) that provides open-access transmission service and monitors the high voltage transmission system throughout the Midwest United States, and Manitoba, Canada and more recently integrated a southern region which includes much of Arkansas, Mississippi, and Louisiana. MISO operates one of the world’s largest real-time energy markets.

NET METERING
The practice of using a single meter to measure consumption and generation of electricity by a small generation facility (such as a house with a wind or solar photovoltaic system). The net energy produced or consumed is purchased from or sold to the power provider, respectively.

NET ZERO
A net zero building is a building with zero net energy consumption on an annual basis, meaning the total amount of energy used by the building over a year period is roughly equal to the amount of renewable energy created on the site. Other terms for the same concept are zero-energy building, zero net energy (ZNE) building, net-zero energy building (NZEB), or net zero building, 

OFF-PEAK DEMAND
The period of low energy demand, as opposed to maximum, or peak, demand.

PROPERTY ASSISTED CLEAN ENERGY PROGRAMS (PACE)
PACE is an innovative mechanism for financing energy efficiency and renewable energy improvements on private property. PACE programs allow local governments, state governments, or other inter-jurisdictional authorities, when authorized by state law, to fund the up-front cost of energy improvements on commercial and residential properties, which are paid back over time by the property owners.

PASSIVE SOLAR (BUILDING) DESIGN
A building design that uses structural elements of a building to heat and cool a building, without the use of mechanical equipment, which requires careful consideration of the local climate and solar energy resource, building orientation, and landscape features, to name a few. The principal elements include proper building orientation, proper window sizing and placement and design of window overhangs to reduce summer heat gain and ensure winter heat gain, and proper sizing of thermal energy storage mass (for example a Trombe wall or masonry tiles). The heat is distributed primarily by natural convection and radiation, though fans can also be used to circulate room air or ensure proper ventilation.

PEAK DEMAND
In terms of energy use, peak demand describes a period of simultaneous, strong consumer demand or a period of highest demand in a billing period

PEAK POWER
Power generated that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.

PHOTOVOLTAIC
Photovoltaic (PV) is the name of a method of converting solar energy into direct current electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon commonly studied in physics, photochemistry and electrochemistry.

PHOTOVOLTAIC (PV; SOLAR) ARRAY
A group of solar photovoltaic modules connected together.

POWER
Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.
      
POWER PURCHASE AGREEMENT (PPA)
A PPA is an agreement between a wholesale energy producer and a utility under which the utility agrees to purchase power. The PPA includes details such as the rates paid for electricity and the time period during which it will be purchased. This arrangement is not explicitly allowed in all states; in some states, it may subject the system owner to regulation as a utility. 

PUBLIC UTILITY REGULATORY POLICIES ACT (PURPA)
The Public Utility Regulatory Policies Act is a United States Act passed in 1978 as part of the National Energy Act. It was meant to promote energy conservation (reduce demand) and promote greater use of domestic energy and renewable energy (increase supply). The law was created in response to the 1973 energy crisis, and one year in advance of a second energy crisis. Energy companies were classified as natural monopolies, and for this reason, most were established with vertically integrated structures (that is, they undertook all the functions of generating, transmitting, and distributing electricity to the customer). Utilities became protected as regulated monopolies because it was thought that a company could produce power more efficiently and economically as one company than as several. PURPA started the industry on the road to restructuring and is one of the first laws that began the deregulation of energy companies.

RENEWABLE ENERGY
Energy derived from resources that are regenerative or for all practical purposes can not be depleted. Types of renewable energy resources include moving water (hydro, tidal and wave power), thermal gradients in ocean water, biomass, geothermal energy, solar energy, and wind energy. Municipal solid waste (MSW) is also considered to be a renewable energy resource.
      
RENEWABLE ENERGY CERTIFICATES
Renewable energy certificates (RECs, carbon offsets, or green tags). A renewable energy facility produces two distinct products. The first is electricity. The second is the package of environmental benefits resulting from not generating the same electricity—and emissions—from a conventional gas or coal-fired power plant. These environmental benefits can be packaged into a REC and sold separately from the electrical power. A REC represents the collective environmental benefits, such as avoided mercury, carbon dioxide (CO2), and other environmentally harmful pollutants, as a result of generating one megawatt-hour (MWh) of renewable energy. REC's are somewhat controversial in that they essentially give a pass to facilities that do produce harmful emmissions, rather than requiring them to remediate their operations.

RENEWABLE PORTFOLIO STANDARD (RPS)
A Renewable Portfolio Standard is a regulation that requires the increased production of energy from renewable energy sources, such as wind, solar, biomass, and geothermal. The RPS mechanism generally places an obligation on electricity supply companies to produce a specified fraction of their electricity from renewable energy sources. Certified renewable energy generators earn certificates for every unit of electricity they produce and can sell these along with their electricity to supply companies.
   
R-VALUE
A measure of the capacity of a material to resist heat transfer. The R-Value is the reciprocal of the conductivity of a material (U-Value). The larger the R-Value of a material, the greater its insulating properties.

SOLAR ARRAY
A group of solar collectors or solar modules connected together.

SOLAR CELL
A solar photovoltaic device with a specified area.

SOLAR COLLECTOR
A device used to collect, absorb, and transfer solar energy to a working fluid. Flat plate collectors are the most common type of collectors used for solar water or pool heating systems. In the case of a photovoltaics system, the solar collector could be crystalline silicon panels or thin-film roof shingles, for example.

SOLAR ENERGY
Electromagnetic energy transmitted from the sun (solar radiation). The amount that reaches the earth is equal to one billionth of total solar energy generated, or the equivalent of about 420 trillion kilowatt-hours.

SOLAR PANEL
A term generally applied to individual solar collectors, and typically to solar photovoltaic collectors or modules.

STRANDED ASSETS
Stranded assets is a financial term that describes something that has become obsolete or nonperforming well ahead of its useful life, and must be recorded on a company's balance sheet as a loss of profit.

SUPPLY SIDE
Technologies that pertain to the generation of electricity.

THERMAL EFFICIENCY
A measure of the efficiency of converting a fuel to energy and useful work; useful work and energy output divided by higher heating value of input fuel times 100 (for percent).

TRACKING SOLAR ARRAY
A solar energy array that follows the path of the sun to maximize the solar radiation incident on the PV surface. The two most common orientations are (1) one axis where the array tracks the sun east to west and (2) two-axis tracking where the array points directly at the sun at all times. Tracking arrays use both the direct and diffuse sunlight. Two-axis tracking arrays capture the maximum possible daily energy.

UTILITY-SCALE SOLAR
A utility-scale solar power plant can be one of several solar technologies – concentrating solar power (CSP), photovoltaics (PV), or concentrating photovoltaics (CPV). What distinguishes utility-scale solar from distributed generation is project size and the fact that the electricity is sold to wholesale utility buyers, not end-use consumers.