Engineering Recommendation G99
Contents |
[edit] Introduction
Engineering Recommendation G99, or EREC G99, was issued by the Energy Networks Association (ENA) in July 2018 and came into effect on 27 April 2019. It applies to organisations involved in developing generation projects that are connected to the grid. It also affects how different types or configurations of equipment must comply with the requirements.
EREC G99 was published by the ENA to replace EREC G59. After 27 April 2019, organisations were longer legally permitted to connect certain types of power generation equipment that was solely compliant with G59.
[edit] Changes brought about by EREC 99
EREC 99 established more stringent operating parameters for all new generation equipment 1MW (or larger) that would be connected to public distribution networks of licensed Distribution Network Operators (DNOs). It also changed the application process for this type of equipment and put new compliance and commissioning requirements in place.
Under EREC G99, this type of equipment must provide frequency response in either Limited Frequency Sensitive Mode (LFSM) or Frequency Sensitive Mode (FSM) to control active power output in response to frequency changes on the grid.
Generators over 1MW must also include:
- Fault ride through to keep them connected when there are significant voltage depressions due to faults on the grid.
- Fast fault current injection to support the system during a fault by quickly injecting reactive current in order to keep the grid voltage from dropping too low.
- Voltage control systems that can inject or absorb reactive power into the grid to control voltage.
- Enhanced variable reactive power capabilities.
- Testing and protection capabilities previously handled by large grid code compliant power stations.
[edit] Related articles on Designing Buildings
- Microgeneration for buildings
- Power generation
- Power supply.
- Smoothing the path to net zero.
- The future of UK power generation.
[edit] External resources
Featured articles and news
Mixed reactions to apprenticeship and skills reform 2025
A 'welcome shift' for some and a 'backwards step' for others.
Licensing construction in the UK
As the latest report and proposal to licence builders reaches Parliament.
Building Safety Alliance golden thread guidance
Extensive excel checklist of information with guidance document freely accessible.
Fair Payment Code and other payment initiatives
For fair and late payments, need to work together to add value.
Pre-planning delivery programmes and delay penalties
Proposed for housebuilders in government reform: Speeding Up Build Out.
High street health: converting a building for healthcare uses
The benefits of health centres acting as new anchor sites in the high street.
The Remarkable Pinwill Sisters: from ‘lady woodcarvers’ to professionals. Book review.
Skills gap and investment returns on apprenticeships
ECA welcomes new reports from JTL Training and The Electrotechnical Skills Partnership.
Committee report criticises UK retrofit schemes
CIOB responds to UK’s Energy Security and Net Zero Committee report.
Design and construction industry podcasts
Professional development, practice, the pandemic, platforms and podcasts. Have we missed anything?
C20 Society; Buildings at Risk List 2025
10 more buildings published with updates on the past decade of buildings featured.
Boiler Upgrade Scheme and certifications consultation
Summary of government consultation, closing 11 June 2025.
Deputy editor of AT, Tim Fraser, discusses the newly formed society with its current chair, Chris Halligan MCIAT.
Barratt Lo-E passivhaus standard homes planned enmasse
With an initial 728 Lo-E homes across two sites and many more planned for the future.
Government urged to uphold Warm Homes commitment
ECA and industry bodies write to Government concerning its 13.2 billion Warm Homes manifesto commitment.
From project managers to rising stars, sustainability pioneers and more.
Places of Worship in Britain and Ireland, 1929-1990. Book review.