G59 to G99: Changes in mains protection
Currently most developments with a grid-connected electricity generating output (for example, combined heat and power and solar photovoltaics) are required to be G59 compliant.
Updates to the Embedded Generator Regulations (EGR), which come into force on the 27th of April 2019 will place this requirement under the new G99 regime. The changes to the regulations will have minimal impact on generation systems less than 1MW in capacity (e.g. a CHP engine serving less than 2,000 homes).
For systems with a capacity over 1MW, the requirements become more onerous. The focus is on enabling local network operators (DNOs) to actively manage their electricity networks. This will include:
- Additional power system studies to demonstrate compliance with the regime. This will take time, so early engagement with the DNO is essential to avoid delays;
- Manufacturer’s may need to improve their design and specification to achieve compliance. This should be addressed early by the design team through engagement with manufacturers.
- Controls interfaces will be required, allowing the DNO to reduce the power of the generating plant to 0% .
The Regulations are complex, and the take-away message for developers is that early consideration of the impact of electricity generating plant on energy strategies, procurement and programme is now more important than ever.