08 · Glossary
Energy terms · A–Z
Last updated 2026-04-21
Draft published
First-pass content live. Engineering review and Opnor-team validation in progress — see the "author backlog" callouts at the bottom.
Acronyms and terms that appear throughout the rest of the docs. One-line definitions optimized for quick reference; deeper articles linked where they exist.
Energy units
kWh — kilowatt-hour
Energy unit. 1 kWh = 3.6 MJ. The standard unit for electricity billing.
MWh — megawatt-hour
1,000 kWh. Used for plant-scale electricity consumption.
GJ — gigajoule
10⁹ joules. The industrial standard for thermal energy. 1 GJ ≈ 278 kWh.
MJ — megajoule
10⁶ joules. Used for individual fuel consumption (e.g. natural-gas calorific value).
BTU — British Thermal Unit
1 BTU ≈ 1.055 kJ. Common in US documentation; rare in Quebec.
m³ — cubic metre (gas)
Volume of natural gas at standard conditions. Typical NG calorific value: ~37 MJ/m³.
L — litre
Volume unit. 1 L of diesel ≈ 36 MJ; 1 L of propane ≈ 25 MJ.
Power and load
kW — kilowatt
Rate of energy use. 1 kW used for 1 hour = 1 kWh.
HP — horsepower
1 HP ≈ 0.746 kW. Common in nameplate ratings of older equipment.
nameplate kW
The rated power of an asset, read off the equipment label. Doesn't necessarily reflect actual operating power.
LF — load factor
Ratio of actual power to nameplate power, expressed 0–1. A motor running at 65% load has LF = 0.65.
operating hours
Annual hours an asset is energized. Continuous-duty motors typically 8,000+; intermittent process equipment 1,000–4,000.
Audit + measurement terms
ECM — Energy Conservation Measure
A specific intervention that reduces energy consumption. VFD retrofit, motor upgrade, heat recovery, steam trap repair are all ECMs.
Audit
A structured analysis of an industrial site's energy use, identifying where savings can be captured. ISO-50002 defines three audit levels.
M&V — Measurement & Verification
Post-implementation verification that an ECM is delivering the savings it was modelled to deliver. IPMVP defines four M&V options.
Baseline
The pre-implementation reference for measuring savings. Typically 12 months of utility data + production normalization.
Realization factor
The ratio of measured savings to engineered (predicted) savings. Typically 0.75–0.95 for well-modelled ECMs.
Confidence score
Opnor's per-asset data-quality measure (0–100%). Combines source quality across kW, load factor, operating hours, and fuel fields. See the confidence article.
Reconciliation
Process of matching top-down utility-bill consumption against bottom-up asset-level estimates, identifying and resolving the gap. See the reconciliation article.
Standards and protocols
ISO-50002
Energy audit standard. Three depth levels (1=walkthrough, 2=detailed, 3=investment-grade). Opnor's 2-week deep-dive is Level-2 conformant.
ISO-50001
Energy management system standard. Different from 50002; not required for SEA eligibility.
ISO-50015
M&V standard, complementary to IPMVP. Used in EMIS compliance reporting.
IPMVP
International Performance Measurement and Verification Protocol. Defines four M&V options (A, B, C, D).
AACE
Association for the Advancement of Cost Engineering. Defines five cost-estimate classes (1=most accurate to 5=screening).
P.Eng.
Professional Engineer. The signatory whose seal/signature appears on Opnor audit reports. OEQ-regulated in Quebec.
OEQ
Ordre des ingénieurs du Québec. The Quebec professional engineering regulator.
AEE
Association of Energy Engineers. Issues the CEM (Certified Energy Manager) credential.
Hydro-Québec programs
SEA — Solutions efficaces d'affaires
HQ's primary industrial-energy program. Funds audit costs (typically up to ~75%) and partial ECM implementation.
ÉcoPerformance
HQ's project-funding program. Triggered for larger consumers or larger capex projects, often 10 GWh-equivalent threshold.
Énergir
Quebec gas-distribution utility (formerly Gaz Métro). Runs gas-side incentive programs that often stack with HQ electricity-side incentives.
Carriers and emissions
Carrier
An energy form delivered to the plant: electricity, natural gas, propane, diesel, biomass.
tCO₂ — tonnes of carbon dioxide equivalent
Standard unit for emissions. Quebec grid is mostly hydro, so electrical-side tCO₂ is unusually low (~6–10 g/kWh).
Scope 1 emissions
Direct emissions from on-site combustion. Boilers, kilns, fleet diesel.
Scope 2 emissions
Indirect emissions from purchased electricity. Calculated using the local grid emissions factor.
Scope 3 emissions
Indirect emissions in the supply chain. Out of scope for most energy audits.
Calorific value (CV)
Energy content per unit of fuel. Natural gas ~37 MJ/m³; diesel ~36 MJ/L; biomass ~9–18 MJ/kg depending on moisture.
Equipment + asset terms
VFD — Variable Frequency Drive
Electronic controller that adjusts motor speed. Saves energy on variable-load centrifugal applications via the affinity law (cube-of-speed). See VFD article.
IE class
Motor efficiency classification per IEC 60034-30-1. IE1 (basic) through IE5 (ultra-premium). See motor-upgrade article.
Centrifugal load
Pumps, fans, blowers — equipment where flow scales linearly with speed. Where VFD savings apply.
Constant-torque load
Conveyors, mills, mixers — equipment where torque doesn't scale with speed. VFDs help with control but not energy savings.
Steam trap
Plumbing component that releases condensate without releasing steam. Fails commonly; subject of survey programs. See steam-trap article.
Economizer
Heat exchanger in a boiler stack that pre-heats feedwater or combustion air using flue-gas heat. See heat-recovery article.
EMIS — Energy Management Information System
Continuous-monitoring system that tracks measured savings against engineered baseline post-implementation. Opnor sells this as a separate product line.
SCADA
Supervisory Control and Data Acquisition. Plant-floor control system. EMIS integrates with SCADA to ingest real-time data.
BMS — Building Management System
Building-level controls (HVAC, lighting). EMIS integrates with BMS for facilities-side data.
Cost engineering
AACE Class 4
Cost estimate accuracy class for screening / feasibility studies. -30%/+50%. Standard for audit-stage deliverables.
AACE Class 3
Budget-authorization class. -20%/+30%. Required for capital-committee approvals.
Direct costs
Equipment, material, and labour for the ECM itself.
Indirect costs
Commissioning, programming, surveillance, engineering, project management. Toggleable in Opnor's cost engine.
Contingency
Reserve for cost overruns. Three methods: blanket %, AACE class-based, BBA split.
Simple payback
Capex divided by annual savings. The simplest metric; doesn't account for time value of money.
NPV — Net Present Value
Time-discounted savings minus capex. Used for capital-allocation decisions where multiple ECMs compete.
🚧 Author backlog (Opnor team to fill)
- Cross-validate Quebec grid emissions factor against current HQ-published numbers (the 6–10 g/kWh range cited here)
- Add provincial-emissions reference for non-Quebec audits (Ontario, Alberta, BC have very different grid mixes)
- Flag jurisdictional terms that differ between Quebec, Ontario, and US (e.g. the 'P.Eng.' equivalent in each)