Terminology used in energy project development, delivery and operations — defined as practitioners use it.
Reference
Terms used across the project lifecycle.
60terms
Terms defined
Across seven disciplines
7disciplines
Categories
Development through operations
5stages
Lifecycle coverage
Develop, design, finance, build, maintain
6standards
Code families
NFPA, IEEE, ASCE, IBC, IEC, UL, OSHA
A working glossary of the terminology used in energy project development, delivery and operations.
TransGlobe Power
Glossary
Development and origination
Terms used from site identification through to the point a project is ready to build.
Greenfield / brownfield — a site with no prior development, versus one with existing industrial use or infrastructure.
Site control — the legal right to use a site, typically an option agreement during development converting to a lease or purchase at NTP.
NTP (notice to proceed (NTP)) — the owner’s instruction authorising the contractor to begin construction.
LNTP (limited notice to proceed (NTP)) — partial authorisation, usually to secure long-lead equipment before full NTP.
COD (commercial operation date (COD) date) — the date the facility is deemed capable of commercial operation date (COD) under its contracts.
Capacity factor — actual output over a period divided by theoretical output at nameplate for the same period.
LCOE (levelised cost of energy) — lifetime cost divided by lifetime generation, used to compare technologies on a common basis.
Stage gate — a defined decision point at which a project must satisfy criteria before further capital is committed.
Interconnection and grid
The vocabulary of connecting a generator to the network — usually the longest-lead item on a project.
POI (point of interconnection) — the physical point at which the facility connects to the transmission or distribution system.
LGIA / SGIA — large and small generator generator interconnection agreement (GIA)s, setting obligations, milestones and cost responsibility.
Cluster study — interconnection requests studied together as a group rather than serially.
Network upgrades — transmission system reinforcements required to accept a new generator; cost is allocated across the cluster.
Curtailment — instructed or economic reduction of output below what the resource could produce.
Basis risk — the difference between the price at the node where power is injected and the hub price a contract settles against.
Nodal / zonal — market designs that price energy at individual nodes or across broader zones.
Ride-through — a generator’s ability to remain connected through a voltage or frequency disturbance.
PPC (power plant controller) — the control system managing plant-level real and reactive power against grid instructions.
Commercial and offtake
How a project earns revenue and how that revenue is contracted.
PPA (power purchase agreement) — a contract to sell power at agreed terms, usually the basis for project financing.
Offtaker — the counterparty purchasing the output; its credit quality drives financeability.
VPPA (virtual PPA) — a financial contract for differences settled against a market price rather than physical delivery.
Merchant — selling into the market without a contracted offtake, accepting price risk.
Revenue stack — the combination of energy, capacity, ancillary services and incentive revenue a project earns.
Tenor — the term of a contract or debt facility.
DSCR (debt service coverage ratio) — cash available for debt service divided by debt service due; drives debt sizing.
Safe harbor — establishing a beginning-of-construction position to preserve incentive eligibility under prevailing rules.
ITC / PTC — investment and production tax credits, the two principal federal incentive mechanisms.
Engineering and design
Terms used in technical definition and design coordination.
BOP (balance of plant) — everything other than the primary generating equipment: civil, electrical collection, controls, roads.
IFC (issued for construction) — the drawing revision released for building, as distinct from IFR (review) or IFP (permit).
Basis of design — the documented assumptions, criteria and standards a design is built against.
Geotechnical investigation — subsurface testing establishing soil conditions for foundation design.
Pile refusal — a driven pile failing to reach design depth, usually indicating rock or dense material; a common cause of foundation redesign.
GCR (ground coverage ratio) — module area divided by land area; drives yield, shading and land take.
DC:AC ratio — installed DC capacity relative to inverter AC rating; higher ratios raise yield but increase clipping.
Clipping — energy lost when DC output exceeds inverter AC capacity.
Single-line diagram — the schematic showing electrical distribution from generation to the point of interconnection.
Construction and delivery
Terms used from mobilisation through turnover.
EPC — engineering, procurement and construction, typically delivered under a single wrapped contract.
Owner’s engineer — the technical adviser representing the owner’s interest during design and construction.
IE (independent engineer (IE)) — a third-party engineer appointed by lenders to review technical assumptions and progress.
Submittal — contractor documentation issued for review to demonstrate compliance with the specification.
RFI (request for information) — a formal query from contractor to designer where documents are unclear or conflicting.
Punch list — outstanding items identified at substantial completion that do not prevent operation.
Substantial completion — the point at which the facility can be used for its intended purpose.
Final completion — all work complete including punch list, with documentation delivered.
Turnover — the formal handover of systems, records and responsibility from construction to operations.
LDs (liquidated damages) — pre-agreed sums payable for delay or performance shortfall.
Operations and asset management
Terms used once the asset is generating.
O&M — operations and maintenance, covering preventive, corrective and predictive activity.
LTSA (long-term service agreement) — a multi-year maintenance contract, common on rotating equipment.
Availability — the proportion of time the plant is capable of operating, distinct from whether it actually generated.
PR (performance ratio) — actual output relative to modelled output under the same conditions; the primary measure of PV health.
Degradation — the gradual decline in module or cell output over time, typically warranted at a defined annual rate.
Soiling — output loss from dust, pollen or other deposition on module surfaces.
SCADA — supervisory control and data acquisition, the monitoring and control layer across the plant.
Augmentation — adding storage capacity over time to offset degradation and maintain contracted output.
Warranty claim — a formal notification against equipment or workmanship warranties, requiring contemporaneous records.
Permitting, safety and compliance
Terms used in approvals and regulatory work.
AHJ (authority having jurisdiction) — the body that interprets and enforces code locally; interpretations vary.
NEPA — the federal environmental review framework, triggered where there is a federal nexus.
CUP (conditional use permit) — local land-use approval subject to conditions carried into design and construction.
Setback — the minimum distance required between equipment and a boundary, dwelling, road or other feature.
Shadow flicker — intermittent shading from rotating turbine blades, assessed against local limits.
HSE — health, safety and environment.
LOTO (lockout / tagout) — the procedure isolating energy sources before work begins.
Arc flash study — analysis establishing incident energy and required PPE at each electrical location.
Commissioning — the structured process of proving systems perform as designed before handover.
FAQ
Common questions
Usage
How to read this.
Why publish a glossary?+
Because precision matters in this work. A shared vocabulary shortens the distance between an enquiry and a useful answer, and terms like availability, capacity factor and performance ratio are routinely used interchangeably when they mean different things.
Are these definitions standard?+
They reflect common industry usage. Where a term is defined contractually — availability and substantial completion in particular — the contract definition governs, and it frequently differs from general usage.
What is the difference between availability and capacity factor?+
Availability measures whether the plant could operate. Capacity factor measures what it actually produced against nameplate. A plant can show high availability and low capacity factor if the resource was poor or output was curtailed.
