RenewableNI – helping you to understand the renewable energy sector

There are many technicial terms and acronyms in the renewable electricity industry.  This glossary explains all those RNI has used in reports and consultations.

A-E renewable terms



  • BAU Demand: Business As Ususal Demand (normal)
  • BECCS: Bioenergy Carbon Capture and Storage
  • Blue hydrogen: Derived from natural gas,  the CO2 emissions are captured to either be used in industrial processes or stored underground using carbon capture, utilisation and storage (CCUS)


  • CAPEX: CAPital EXpenditure
  • CBA: Cost Benefit Analysis
  • CCC: Committee on Climate Change
  • CCS: Carbon Capture and Storage
  • CCUS: Carbon Capture, Utilisation and Storage
  • CID: Consents Issue Date
  • CRM: Capacity Remuneration Mechanism
  • CfD: The Contracts for Difference (CfD) scheme is the government’s main mechanism for supporting low-carbon electricity generation.
  • COP: heat pump (HP) measurement Coefficient of Performance
  • CPPA: Corporate Power-Purchase Agreements


  • DS3: Delivering a Secure Sustainable Electricity System
  • DG: Distributed Generation (defined by Ofgem as “electricity generation which is connected to the distribution network rather than the high voltage transmission network”.
  • Dunkelflaute: a period of time in which little to no electricity can be generated with the use of wind and solar power.


  • ECP: Enduring Connection Policy
  • EV: Electric Vechile
  • Energy Strategy: published in December 2021, Action Plan published in 2022, by the Department for the Economy.

K-O renewable terms



  • LCOE: The Levelised Cost of Electricit is the discounted lifetime cost of building and operating a generation asset, expressed as a cost per unit of electricity generated (£/MWh). It covers all relevant costs faced by the generator, including pre-development, capital, operating, fuel and financing costs.
  • LCTA: Least Cost Technically Acceptable.
  • LDS: Long-Duration Storage
  • LTE: Lifetime Extension


  • MEC: Maximum Export Capacity
  • MtCO2: Metric tons of carbon dioxide equivalent


  • NIRO: Northern Ireland Renewable Obligation scheme


  • OMS: Order Management Systems
  • OPEX: Operational Expenditure

F-J renewable terms


  • FAQ: Firm Access Quantities
    Firm Access means that if the output on to the grid by a particular generator is changed by the Transmission Operator due to a network limitation (known as ‘constraint’), then it may be eligible for financial compensation as set out in the Trading & Settlement Code (From SONI Ltd)
  • Feed-In Tariffs (FIT):Government scheme to promote the uptake of renewable and low-carbon electricity generation. It requires participating licensed electricity suppliers to make payments on electricity generated and exported by accredited installations.


  • GHG: Greenhouse gases
  • Grey Hydrogen: Greated from natural gas, or methane, using steam methane reformation but without capturing the CO2 made in the process.
  • Green Hydrogen: Produced by splitting water using electrolysis that has been powered by renewable energy sources such as wind or solar. This is the cleanest type of hydrogen as CO2 is not produced as a by-product.


  • HP: Heat Pump


  • IPCC: The Intergovernmental Panel on Climate Change (IPCC) is the United Nations body for assessing the science related to climate change.
  • I-SEM: Integrated Single Electricity Market
  • ISCC: Installed Sychronous Condenser Capacity
  • ISEA: Irish Solar Energy Association
  • IRENA: International Renewable Energy Agency


P-Z renewable terms


  • Pink Hydrogen: Generated through electrolysis powered by nuclear energy. Nuclear-produced hydrogen can also be referred to as purple hydrogen or red hydrogen.
  • POR: Primary Operating Reserve
  • PSO: Public Service Obligation
  • PV: solar panel/ Photovoltaics



  • RES: Renewable Energy Sources
  • RES-E: Renewable Energy Sources – electricity
  • REFIT: Renewable Energy Feed-in Tariff
  • RESS: Renewable Electricity Support Scheme
  • ROCs: Renewable Obligation Scheme
  • RTE: Round Trip Efficiency



  • TDPNI: Transmission Development Plan



  • WACC: Weighted Average Cost of Capital
  • WEGS: Wind Energy Development Guidelines


Do you have any other renewable acronyms and terms from the renewable industry that would be helpful? Email for inclusion in the RenewableNI glossary.

Useful links

Please note, these are external pages and not maintained by RenewableNI.

Northern Ireland’s Energy Strategy

Energy Strategy Action Plan, published January 2022.