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
Check out some of the best features and news from Designing Buildings as well as key stories from around the web.
New and updated CLC building safety guidance.
New UK National Buildings Database.
Building Safety Wiki Interviews
Chief executive of the British Woodworking Federation.
Planning condition discharge in England and Wales
A brief explanation from a building compliance expert, with further links.
Overheating guidance and tools for building designers
Guidance for dealing with element of building fabric control that have increasing importance.
Shading for housing, a design guide
From the Good Homes Alliance and British Blind and Shutter Association.
UK Standard Skills Classification (SSC)
A shared framework for describing skills needs.
Social media ban consultation comes to close
CIOB urges UK Government to consider social media’s role in careers guidance in ban debate.
The latest of eight Skills England apprenticeship units
The addition of battery manufacturing welcomed by ECA with a warning about the risks of fast-tracked apprenticeship units.
Building Control Independent Panel final report
A precis of a key report led by Dame Hackitt with full recommendations and link to the government response.
Building Safety recap April, 2026
A short and longer run-through of the month, with links to further information and sources.